As an introduction, E85 is an alcoholic fuel that is 85% Ethanol and 15% Gasoline. E85 is a high octane fuel with an Octane rating of around 102 Octane points which, when compared to gasoline and it’s 92 Octane points rating, has an additional 10 points of Octane.

The advantage of using a higher octane fuel is that the in-cylinder flame front travel rate of a higher octane mixture is slower than that of a lower octane mixture. If you had watched my video series on tuning your timing and timing trends (here), then you may remember that the flame front travel speed is affected by many factors including mixture density and in cylinder pressure.

Having a higher octane mixture, slows down the burn rate. This means that we can increase our boost level, our compression ratio, or our timing advance and return the mixture to a normal burn rate similar to that of gasoline, having a similar level of ’safety’ in the cylinder, a similar mixture volatility, but albeit at a higher power level.

To put some exact figures to this phenomenon, switching from 92 Octane premium gasoline to 102 Octane E85 allows you ONE of the following options:

• Increasing your boost level by 6psi of boost above your gasoline maximum boost level.
• Increasing your static compression ratio by 2.5 compression points above your gasoline maximum safe compression level.
• Increasing your timing advance by 13 degrees of timing above what you would use for a gasoline tune.

(Or some combination of the three such as a 3psi boost increase with a 1 point compression hike, resulting in a similar overall increase in compression pressure and flame front travel speed).

Now the advantage of this high octane feature of E85 is that it allows you to build a more aggressive set-up, to reach a higher power goal, while having a similar margin of safety to that of gasoline. The real world benefit of this kind of set-up, is that you have two new possibilities opening up for you in your power build:

1. You can now reach higher power goals, on E85 at the same red-line, and with the same static compression ratio, by being able to run more boost on the same motor, safely.
2. You can now build high compression supercharged set-ups, because you will no longer need to take apart your engine to replace your pistons, to lower your compression ratio, or severely retard your timing to be able to boost a factory high compression motor.

The second interesting fact about E85 ethanol based fuels is that it reaches stoichiometry at an air:fuel ratio of 9.7:1 compared to an air:fuel ratio of 14.7:1 for gasoline.

By dividing those two figures into each-other it becomes apparent that an engine running on E85 needs 48% more fuel flow compared to the exact same engine running on Gasoline. For example, a 400hp 6 cylinder engine will require about 400cc/min injectors for a gasoline setup, but it would need almost 600cc/min injectors to be converted to Ethanol.

The advantage of this information, is that a car that is built to run on E85, has enough injector to also run on gasoline. The benefit of this kind of set-up is that having a dual-map ECU, with large injectors designed for E85, can be ‘detuned’ to reduce it’s injector duty cycle by 48% to run on gasoline. This is essentially how ‘flex fuel’ cars are mapped to run on either fuel, namely because their factory fuel system is oversized (for gasoline) allowing them to run either E85 or Gasoline.

The third interesting fact about E85 is that it has a LOWER energy output than gasoline.

E85 has can produce 25.2 Mega Joules of Energy per Liter of fuel, while Gasoline can produce a more potent 33.7 Mega Joules of Energy per Liter.

Your first thought, might be that gasoline is thus able to produce about 30% more horsepower on the same engine (because gasoline is a more potent fuel chemically speaking), however when you factor in that we are injecting 48% more fuel with E85 to reach a complete combustion and stoichiometery, then the net result of those two figures is that E85 has the potential to deliver 11% more horsepower on the same exact engine, when compared to Gaslone.

This 11% boost in power, is based on a straight gasoline to E85 conversion. More power can be found using E85 by taking advantage of the higher octane rating and tuning specifically for E85 or adding more boost and compression into the mix.

The advantage of this 11% power boost is that you can make more power with the same amount of airflow. The benefit here, is that if you have an engine that is maxed out at say 450hp because that is the maximum amount of air your supercharger can flow, you can add in another 11% (or 50hp!) by converting from gasoline to E85, without having to upgrade your airflow side of the equation (blower included).

So to illustrate how you can use the Power calculator to plan your E85 fuel conversion, I have prepared a short video showing the process. This video includes 3 main differences from using the calculator for a gasoline setup as follows:

1. The target power level you enter into the power calculator should be 11% lower than your actual power level. For example, if you are shooting for 450hp, then entering a target of 450/1.11 = 405hp will give you the right airflow side of the equation, including your intake, exhaust, and supercharger systems.
2. Once the calculator has given you the results of your airflow side of your build-up as described in step #1, you can add 2.5points of compression ratio to your maximum safe compression level. That is to say, that if the calculator recommends an 8:1 compression level as the maximum static compression ratio, then on E85, you can run up to 8+2.5 = 10.5:1 points of static compression and still have a safe set-up.This makes E85 an amazing option for supercharging cars that come from the factory with a higher compression ratio such as 10.5:1 or higher because E85 will allow you to boost this engine WITHOUT the need to take the engine apart and lower the compression ratio.
3. To calculate your fuel demands on E85, you need to inflate your power target by 48% as we explained earlier. So shooting for the same 450hp target, we should enter a target of 405*1.48 = 600hp to the calculator to give us the correct injector, fuel pump, and fuel line sizing for an E85 build-up.

(If you are reading this on an external site such as facebook, please visit our site to see the complete article)

Example application:

A great example of an Ethanol conversion is the new Tri-Fuel Lotus Exige. The exige is a true Tri-Fuel care capable of running on Gasoline, Ethanol, or methanol.

The only modifications performed to the car as per the official lotus press release are:

• Sensors to detect alcohol content
• Slightly modified software for engine management controls/ECU’s over ethanol/gasoline and flex fuel
• Fuel lines compatible with alcohol
• Higher flow rate fuel pump and injectors
• Fuel tank material, compatible with alcohol

Making no changes to the airflow side of the engine, lotus is able to coax out an extra 51 hp or 19% more power from the same power plant simply by switching to an 11% more potent fuel mixture (as we mentioned earlier) coupled with another 8% coaxed through an alcohol specific tune with more aggressive mapping to take advantage of the higher octane and slower burn rate properties of alcoholic fuels.

Use the power calculator to design your E85 conversion

Technorati Tags: E85 Conversion, Power Calculator, supercharger performance

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2. Tuning your timing and timing trends

Is a question commonly asked on car forums, yahoo answers, and in the speed shops. Of course [this] stands for your specifically owned car, be it a work truck, a track dedicated racer, or a dual purpose vehicle that sees both daily use as well as occasional track time.

Any car can be supercharged …

… that is, if you know what you’re doing. Supercharging is by no means a new technology; it has been around since world-war II and is now a fairly straight forward process, so much so that you will find aftermarket companies supercharging the most ‘complex’ cars such as:

• The Gintani Supercharged BMW M3
• The Novitec Rosso Supercharged Maserati Gran Turismo S
• The PPI engineering Supercharged Audi R8

… All while maintaining, factory style warranties, drive-train longevity, and luxury car quality and refinement.

Truly, any car can be supercharged with the right ingredients and the right knowledgebase.

Today I’m going to give you the theory and an example of how to pull it off, using a Subaru Impreza 2.5 RS as an example from our friends over at r25.com.

There are three aspects involved in any custom supercharger application which are:

1. Supercharger Kit Design (or supercharger theory).
2. Supercharger Kit Fabrication (or the build).
3. Supercharger tuning (or the harmony).

The following can be considered your ‘to do’ list if you embark on this journey…

1-Supercharger Kit Design

Once you’ve decided to custom supercharge your vehicle and have set a certain target power goal in mind, the next step towards successfully modifying the car will be to design a complete and comprehensive upgrade path from naturally aspirated to supercharged.

This upgrade path will include (but is not limited to):

• The choice of supercharger head unit capable of producing the required flow and boost to reach your target power goal.
• The choice of the type supercharger (centrifugal, roots, or twin-screw) to match your desired driving characteristics.
• The effect the supercharger will have on intake air temps (depending on the supercharger adiabatic efficiency at the specific demand point on supercharger compressor map), and how that translates into the need for an intercooler system or water injection or an octane boost to reach the desired power goal.
• Designing the supercharger drive system with proper belt contact to the pulleys so they don’t slip and the right size pulley gearing to drive the supercharger.
• Modifying the fuel system with larger fuel injectors, elevated operating fuel rail pressure, and high capacity fuel supply including the pump, filter, lines and fuel rail.
• Modifying the oil delivery system to feed oil to the supercharger drive system as required.
• Last but not least, choosing the right auxiliary parts for air induction and exhaust systems t match your new power level.

I know this seems like an overwhelming amount of ‘research’ to do before you supercharge a car, and that is something I know first-hand from my first turbocharger build about 13 years ago.

However, once you go through the process once, you will realize that it’s really not that complex to perform and can even be calculated and automated using excel sheets, simple formulas or even software calculators.

2-Supercharger Kit Fabrication

So after crossing the first supercharger hurdle (which is indecision, paralysis of choice, and the overwhelming first-thought of doing the work required to ‘design’ the right kit); most people then get stuck in the fabrication of their intended kit.

The fabrication of a basic supercharger kit is going to require the following handy skills:

• Basic welding and brazing skills
• Mockup skills including making templates for supercharger and drive pulley mounting plates and support brackets.
• Knowledge of pulley system design including tensioning and idler pulleys as well as press fit pulley systems.
• Sizing and sourcing the required belt system to drive the supercharger.
• Basic hose and line skills for running fuel and oil lines safely, attaching leak proof fittings to the end of these lines, and tapping into the factory fuel and oil feeds and returns to plumb the supercharger into the car’s vital fluids
• Fittings knowledge such as Army Navy (A/N), National Pipe Thread (NPT), Metric …etc

3-Supercharger Tuning

If you have reached this stage, that means that you have picked the right parts and fit them to your car which is a great success. However, turning the sum of parts installed on the car from a collection of instruments into a symphonic harmony requires the right tune.

When the car is supercharged, a few things will change about the car requiring a new tune as follows:

1-Based on our new peak airflow and our target air to fuel ratio, and based on what modifications we have done to our fuel supply system, then we need to optimize our injector pulse width (or injector duty cycle IDC) to achieve our target air fuel ratio which is both safe and power efficient for the new setup.

2-Now that the mixture is more dense with more boost, more air mass, and more fuel mass and higher intake air temps, we know that the combustion even will create a much faster moving flame front, which means we need to create a custom ignition timing curve to match the characteristics of our new engine combination.

3-Finally, the changes we make to the car’s tune have to be done in a way that the tune stays the same no matter how ambient air temps, humidity, and elevation change. You don’t want to tune a car in the summer only to have it run lean and burn a piston in the winter, and you don’t want to tune a car in the winter only to have it run rich and lose power in the summer.

The tune has to be flexible enough in that it can automatically compensate for slight variations in temperature (using your intake air temp sensor), slight variations in flow or boost levels from summer to winter (using your MAF/MAS or MAP sensors), and slight variations in the air quality or air density such as changes of altitude or humidity (most likely compensated for using feedback from your on board oxygen sensors and your short and long term fuel trims).

1.You also want to check and make sure that your tune isn’t load dependant and that your EGT’s are stable weather you are doing a fast pull in a short gear like 1st gear, or you are doing a slow pull in a long gear (like 4th gear) with a fully loaded truck cab.

If you are reading this far… CONGRATULATIONS…

Because you now know pretty much every base you have to cover to supercharge your own car. What is now left to do is to actually go out and implement this knowledgebase.

I know this seems like too much to work on; however, it IS systematic which is great for two reasons:

It can be applied to any car systematically. The challenges will be different on each platform, but the goal and the methodology is the same.
Once you’ve done it once, it can only get easier on your second try.
It really isn’t that hard to do; in fact, it is more lengthy a process than a hard one and the reason most people don’t make it all the way through is not because any one part of it was impossible, but rather because they just got tired before reaching the end of it.

The proof is in the pudding!

To prove to you that this isn’t a process reserved for people that work in world class speed shops such as Brabus or HKS or Magnuson … I bring to you today a true ‘shade tree mechanic” example of a guy named Shane.

Shane is a passionate Subaru owner that uses his 2000 Subaru Impreza RS both as a daily driver and as a weekend autocross car.

The car comes stock with a 2.5 liter SOHC boxer 4 cylinder engine delivering 165hp @5600 rpms through Subaru’s world class all wheel drive system.

The combination of the low weight of the RS, with the stout Impreza chassis, the traction of the intelligent all-wheel-drive system, and the grunt of the SOHC B4 make the car a great platform for the demands and complexities of the autox circuit.

1-Supercharger Kit Design

Supercharger head unit and type of supercharger:

With a target power goal of 220 horsepower, and the known desire for added low end torque, Shane chose to use an eaton M62 supercharger for this build up. The M62 is capable of 300hp @ 10psi depending on the generation of the supercharger, and so meeting our targets of 220hp @ 5psi is within its operating parameters.

Another advantage of using an Eaton supercharger is that the eaton head unit is a ’sealed’ unit using its own oil reserve separate from the engine’s oil. This means that there is no need to tap into the the engine’s oil feed and return systems simplifying the installation process and preventing any future headache with leaks.

Affect on inlet air temps

Having an efficiency between 55 and 60% for the Eaton MP45, the outlet temperatures for the air exiting the supercharger will be about 84 degrees higher than ambient.

Due to this temperature increase, and in order to produce repeatable power figures run after run without heat soaking the engine, an air to air intercooler was chosen to chill the inlet air charge back down to normal temps. Rather than using a typical WRX intercooler, Shane chose to use a Subar Forester XT intercooler which has a smaller profile and provides more clearance between the throttle body and the firewall. This choice of intercooler is beneficial for two reasons:

1- The top mount intercooler provides a very short air path between the supercharger and the throttle body compared to a front mounted intercooler in the bumper. This short air path should result in better throttle response and torque delivery which is important for a daily drive car and an autox setup.

2- The narrow profile intercooler is a ‘drop in’ solution which doesn’t require trimming and fitting of the larger WRX unit and simplifies the install.

Supercharger Drive System

The supercharger drive system is a simple take off of the original accessory belt on the engine. The factory belt is a 5-rib unit which is good enough for the target boost of 5psi (pressure ratio of 1.33). By looking at the M62 compressor map, we find that to supercharger requires 10,300 rpms to produce 220hp worth of air @ 5psi of boost.

With a stock crank pulley having a diameter of 5.25” and a motor with a 6500rpm redline thanks to the iSpeed reflash, then Shane required a supercharger pulley sized to overdrive the supercharger inlet shaft to 10,300 rpms when the motor is at 6500 rpms.

Plugging all these numbers in we get a 3.3” diameter supercharger pulley which is very close to Shane’s original attempt of 3.25”. However these are idealized calculations assuming no pressure loss due to the intercooler system, and with a thin profile top mount intercooler having a significant pressure loss of 2 to 3psi to the incoming air, the actual supercharger snout pulley had to be downsized down to 2.75” to achieve the desired boost level.

For optimum belt to pulley contact, a custom idler pulley and mounting bracket were fabricated forcing the belt to wrap almost entirely around the supercharger snout pulley giving a healthy 200 degrees of belt contact on the pulley.

The belt for this system is a custom length 6-rib belt with 1-rib shaved down using an exacto knife which is a common ‘hot rodder’ trick for making custom belts.

Fuel Delivery

Since the horsepower increase on this setup is a modest 35% increase, the stock fuel injectors are capable of delivering the required increase in fuel supply , albeit at an elevated fuel rail pressure.

Fuel flow is related to the square root of fuel pressure and so a 35% increase in fuel flow requires a 82% increase in fuel rail pressure bringing the target rail pressure up to around 72psi.

In this specific buildup Shane employed a SX adjustable fuel pressure regulator set to 80psi (and resulting in a rich 10:1 AFR at WOT) with an upgraded STI fuel pump delivering 145lph at the newly elevated rail pressure. Shane also performed a parallel fuel rail modification to ensure equal flow and reduced pressure drop at the two cylinder banks. This is a common modification of V and Boxter configured engines to reduce the overall length of the fuel rail (creating two shorter parallel rails rather than 1 longer series rail) to reduce the pressure drop (and flow variation) between the first and last cylinder in the fuel path.

Auxiliary Buildup

To improve the overall volumetric efficiency of the engine, to produce more horsepower at a lower boost level, and too keep up with the intake and exhaust demands of the power increase, Shane has included into the build a custom 3” cold side intake with a fender mounted K&N filter, feeding into the M62 and out into 2” hot side piping feeding into the Subaru Forster XT top mount intercooler.

The air fuel mixture spins the engine to a new peak redline of 6500 rpms thanks to the iSpeed SR10 reflash and Delta 2000 cams with 226* duration and 8.5mm lift @.050”.

Then the exhaust gas exits through OBX equal length headers with fat 1.65” primaries feeding into a 2.25” collector and out a 2.5” OBX catback exhaust system.

The setup is tuned using an e-manage ultimate which can control both ignition timing as well as fuel injection duty cycle and the tune is monitored using a Dakota Digital EGT gauage, a Stewart Warner -30inHg-15psi Vac/Boost gauge and an Innovate LC-1 Wideband AF Controller displaying data through a ProSport Digital Wideband Gauge.

With a conservative 10:1 AFR and a modest 5psi of boost the car is still a blast to drive and a formidable contender at the autox circuit.

Since this is probably one of the lengthiest blog posts I’ve written in a while, I will cover the fabrication portion of this build through the following gallery (a picture is worth 1000 words).

Related posts:

1. Supercharged Performance for OEM Hot Rods
2. Engine Performance Parts for supercharged performance
3. Nitrous to boost your supercharged car

I’m currently working on a fantastic new article on custom supercharging ANY car. While writing that article, it occurred to me that I myself hadn’t done a complete build-up for quite some time now.

So it followed that I thought I could use this opportunity to kill two birds with one stone…

• Firstly: I could satisfy my ‘performance itch’ and build myself a new project and weekend car. The Benz is a great daily driver and a great cruiser, but quite frankly it is not enough muscle to keep up with the exotics littering the streets of Riyadh, Saudi Arabia… nor is it old enough or decomissioned enough for me to tear into into and do a severe build-up while it is still my daily driver.This makes building a second ‘project’ highly attractive (notice I said project and not car as I’m keeping this poll quite open).
• Secondly: I could use this as an opportunity to showcase everything that I’ve been blogging about for the past year or so including different themes such as the ‘top ender’ and the latest theme I’m working on which is ‘anything can be supercharged if you follow this path’.

So to maximize the appropriation of the information that will created, logged, blogged, and video-logged during the buildup; it makes the most sense to ask YOU (my readers and fans) what you’d like to see me build or do.

Now before I present you with the poll and the optional builds that I have in mind, I’d like to first say that this like any project is not going to be cheap.

You may notice that on my blog, I rarely talk about how much parts or kits cost and there are a few reasons for that:

• If you build up a great car and you win one race with it that you couldn’t have won before, then the ‘high’ that you get and the satisfaction you get from winning that race makes whatever you spent on the build up TOTALLY worth it. So talking about money and superchargers is somewhat a subjective topic. We do these builds because we love cars, not necessarily because we are looking for some ROI (return on investment).

• There are many ways to reduce the cost of the build-up while still using quality parts like shopping for group buys, barely used parts, shopping the forums, and checking out local swaps and meets (one man’s beef is another man’s poison).

• If you are interested in exotic cars and ultra high performance vehicles (I plan to buy a lamborghinni when I retire, and I will probably supercharge that too), then a good forced induction build-up on an engine with a generous amount of displacement is going to be MUCH cheaper than buying even an entry level exotic. So again depending on what youér comparing your car to, a $10,000 supercharger kit may be ‘very cheap’ considering the alternative is a $150,000 used exotic with a $4,000 clutch kit that will go out on the fourth hard launch.

Either way, the build-up will not be free. To hedge the cost of the build I have a few things in mind:

1. I will use the power calculator to design the complete build before buying a single part, and so I will only buy each component once and save money on the parts list.
2. I will use ne-used (used parts that are like new) parts wherever possible to reduce costs without compromising the build. This makes sense on big ticket items such as buying al ow mileage supercharger head unit from a reliable source to save 2000 dollars off the build. Don’t worry, I will not compromise the reliability of the end product.
3. You will be able to have access to log of the build up for free through the blog. However, some of the more detailed design, fabrication, tuning, and testing work will be compiled in a Supercharger Performance produced Video that will be available for sale either in downloadable or digital media (DVD, Blueray..etc) format for a reasonable price.
4. After using and enjoying the vehicle and after the project completion, I will consider selling the vehicle and moving to a new build up. Usually project vehicles are a horrible investment (you never get back what you put into them). If a serious buyer and a decent offer comes up for the completed build up offering break even or better money for the car, then I will sell the car. Furthermore, if we make any profits from the sale, then a portion of those profits will be donated to a charity that I will choose later on when the time comes!

So this is your opportunity to shape the future of what you see and read on this blog.

Please vote for the build up that you would pay to watch below:

• Custom Supercharged DIY application from the ground up (for a car that has no available off the shelf kit). article coming soon
• Custom Supercharged Motorcycle. See example
• The top ender (A high rpm, cammed, and centrifugally supercharged vehicle with insane top end pull). See example
• The twin-charger (A combined turbocharged and supercharged vehicle, possibly using modified off the market kits). See example
• Supercharger head units rebuilt, ported and modified. See example
• Project low buck (in these bad economic times, do more with less). See example

The Poll

(if you are reading this on an external site such as Facebook, please go to our main site to participate in this poll)

Let us know what you’d like to see us build … and share this poll with your friends!

Technorati Tags: Custom Buildup, Poll, Supercharger Calculator, Supercharger Perfomrance

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How do you go about modifying a car that is truly a benchmark in its own class ?

The M3 has always been the top of the line street performer. With cheetah like reflexes, jaguar like top speed, and the growl of a lion, the M3 leaves nothing to be desired in the world of daily driven sports cars.

So how does one go about improving something that is truly best in class (5 seconds faster per lap in this video!), and something that is without a doubt the best that the OEM *and BMW is not any plain old OEM* had delivered?

Most enthusiasts would quiver at the idea of modifying a German car, let alone the M3. However, Sammy, the owner of the car in question here went ahead with a surgical strike buildup.

In trying to improve an already stout performer, the approach always has to be two fold:

The plan to upgrade this M3 was to play up it’s strongest inherent qualities : it’s balance, it’s poise, and it’s engagement.

To make the care more exciting and engaging, Sammy has chosen to upgrade the engine with the utilization of Akrapovic Titanium Exhaust and a Gintani Supercharger kit.

The exhaust is a beautiful titanium piece that is a direct bolt on to the old cat-back exhaust system and features a built pre-catalyst balance tube (H-pipe) as well as a post-catalyst X-pipe for better engine scavenging and cylinder bank balance. The titanium construction not only reduces the car’s running weight, but moreover titanium exhausts have a nice ‘resonance’ to them where they help amplify and meld the timbre of the exhaust sound into a more exotic and sinister sound.

Free Laptops College

The Gintani Supercharger boost the power output of the M3’s V8 using a vortech V2 supercharger, a custom Gintani intake manifold complete with a built in air to water intercooler, and a matching software tune. The use of a centrifugal supercharger enhances the linear and controllable performance of the M3 , while the choice of a short air path air to water intercooler (rather than a long path front mounted air to air) maintains the quick response of the naturally aspirated V8 engine that is typical of M3 performance. After all is said and tuned, the prototype Gintani Kit delivers over 480 rear wheel horsepower at 8.0 psi of boost.

What is great to see on this specific application is how a well designed exhaust system can dramatically improve the performance of a supercharged car. Sammy’s car is only running 7.5psi of boost meaning that the exhaust system has relieved the engine of 0.5 psi of exhaust back pressure. With this freer flowing exhaust and freer breathing engine combination the supercharger package when all is said and tuned delivered 512 rear wheel horsepower at a lower 7.5psi of boost!

In other words, the exhaust system (and a matching tune) on this application is worth 32 rear wheel horsepower. Considering the stock M3 delivered a respectable 315 rwhp on the same dyno, the combination here is worth 197hp which is surely going to enhance both the excitement and the engagement of this car.

With close to 600 crank hp on tap, Sammy then turned his attention to making the most of this power. A set of KW Variant 3 with adjustable rebound, compression, and compression rates allows the car to put down the power through the rear wheels and maintain its poise on high speed canyon runs. Sammy says they “feel amazing, smooth as hell, soak up bumps very well, especially thru the canyon, keeps wheels planted. Daily driving is fine, feel like its on the middle setting of the stock 3 settings.” which is a testament to the performance and the quality of the KW V3s.

Keeping the car’s stability at triple digit speeds is a new body kit from 3F engineering (not a body kit manufacturer but rather an engineering firm). The kit comprises three important components to help reduce the car’s drag and increase it’s down force at high speeds. A front and rear carbon fiber diffuser accelerate the air’s motion under the car creating a low pressure front under it for better road hugging and more controlled high speed cornering, while a carbon fiber low drag low profile rear spoiler adds down force to the rear end.

The front splitter / diffuser also guides generous amounts of air to the front mounted air to water heat exchanger for the intercooler system as well as to the massive brake ducts feeding now upgraded 380mm / 6 piston front and 345mm / 4 piston rear Brembo rotors. These massive units are the only thing that would qualify as an ‘upgrade’ on a car as stout as the M3 and they just “STOP -- thats what happens when [you] hit the pedal now, but consistantly and [don't] feel any fade.”

Last but not least in this exotic transformation are supercar sized 20X9 front and 20X10 Rear Agio sport wheels. The wheels are wrapped in Falken FK-452: 245/30/20 and 285/25/20 tires which are hard pressed to keep the power down in the first two gears.

With a buildup like this, other M3 (and in general German car owners) are always worried that the amount of power increase will negatively affect the rest of the car and especially the expensive high-tech manu-matic transmissions. In this situation there is nothing to worry about as “the DCT is running great… DCT still performs as it came, downshifts are perfect and fast as ever, and I love to hear the pssssshhhhh as i go to higher rpms and let off. From the outside you can obviously tell that the car is not stock , unless maybe I keep it at 2k rpm, otherwise you hear the air goin pshhhh! lol…it kinda makes me blush and feel like a giddy little kid everytime im in my car now.”

Technorati Tags: BMW, Centrifugal Superchargers, Intercooler, supercharger performance

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I received a question in email last week about using the power calculator to design a tri-y or 4-2-1 header for a 4 cylinder application.

The car in question is going to be used during a hill climb competition, and in this type of racing a consistent average power figure is more important than a single peak number as the car manages complex terrain, a wide rpm range, and the difficulty of losing power as air density gets lighter during the hill climb.

Although the power calculator defaults to giving you a 4-1 recommendation optimized for peak power, it is possible to use the power calculator to design more complex headers such as 4-2-1 systems using the following procedure.

Watch the videos here:

Part 1 -- Theory

Part 2 -- calculations

The procedure:

Steps for doing a 4-2-1 (using my 1.8 liter , 160 hp @ 5800, 6200 rpm redline, Mercedes) …

So i setup my target power and everything normally (230hp) and I run a normal calculation and I get:

13psi of boost
1.52″ primary diameter
15.03″ primary length
Collector 2.36″

(I happen to know that these are almost exactly the dimensions of the kleemann shorty header for my car which dynos +13whp untuned on the car)

Now I want to redo this calculation for a the 2-1 section

I go back to my inputs and i select ‘true dual’ exhaust and re-run the calculations

This gives me a cutout and midpipe diameter of 2X 1.67″

So that will be the diameter of my 2-1 section

So we go 1.52″ to 1.67″ to 2.36″ 4-2-1 … that’s the diameters.

To find the length of the secondaries … we have to redo the calculation for our second rpm peak… for example my car could really use a boost at 2500 rpms… as the automatic (when not in manual mode) keeps the rpms below 3000 for fuel economy and the car is a but sluggish unless you keep the rpms above 3200.

So with my target as 2500 rpms I go back and change my redline to 2500 rpms

I click calculate and get a huge figure 54psi of boost, but i know i’m really going to run 13psi (from the first calculation) so i need to reduce my target hp number till i get 13psi again

So i go back and reduce my target horsepower and calculate (it takes a couple of trials) till i get 13psi again… the target hp is around 95hp (with the redline set at 2500 rpms).

This gives me the following header numbers:

Header primary diameter = 0.84 inches << ignore this
Header primary length = 29.51 inches << This is what we’re looking for
Cutout & midpipe & collector diameter = 2 x 1.07 inches << ignore this
Cat-Back diameter = 2 x 1.0 inches << ignore this

So now we know the total length for a header tuned for 2500 rpms is 29.5″ and the total length for 6200 rpms is 15.03″ That means your 4-2-1 is 4X 1.52″ to 2X 1.67″ to 1X 2.36″ --> 2.25″ catback
primary=15″ long
secondary= total length -- primary = 29.5″-15″ = 14.5″

And that’s your 4-2-1

So you see if you already know your target power and your 2 target rpm peaks you can design your own header like this.
If you already have a header, you can work it backwards… it will just take some trial and error with the numbers till you figure out originally what the header was designed for.

Results

Technorati Tags: 4-2-1, header design, Power Calculator, supercharger performance, tri-y

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The Pettit racing supercharger kit is a complete solution for supercharging the RX8 including:

Results:

Technorati Tags: exhaust, header, Lysholm, Mazda, Renesis, RX8

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Transcript:

Hi , it’s Haitham again and this is another one of our.. how-to videos around the Power calculator on Supercharger Performance .com

What I’m going to talk about today…
is timing advance and tuning your ignition curve.

First we’re going to talk about some of the underlying concepts of ignition timing and timing advance

Then we’re going to look at some simulated timing curves

Then we’re going to summarize with some insights on how you can use this information to increase your horsepower by advancing or retarding timing, in the right places to gain more power.

First of all, let’s look at a 4 stroke engine animation …

This is top dead center… when the piston is all the way up the bore
This is bottom dead center … when the piston is all way down the bore.

Usually when when we talk about timing advance, we talk about ‘B.. T.. D.. C.. ‘ or before top dead center.

Usually the spark plug ignites the mixture before the piston reaches top dead center in the compression stroke.

Now the reason why we fire the plug ‘early’…
is that the mixture of air and fuel (and possibly water, methanol, or nitrous) takes some time burn…
and so the flame front takes some time to travel outwards and consume all of the air inside this top volume (comprised of the cylinder head volume, and the piston surface volume if the piston is dished)…

once the flame has consumed a large portion of the air fuel mixture… this flame, trapped between the piston and the cylinder head, creates ‘peak cylinder pressure’ and it is this cylinder pressure and expanding flame that pushes down on the piston making it rotate.

Now the trick here is that you have to synchronize the piston rotation, with the flame front burn rate so that you can hit the piston with peak cylinder pressure just after it cross top dead center and thus deliver ALL the force of the combustion into the rotation of the engine.

If you advance timing too much, you catch the piston on it’s way up and slow down it’s movement losing power
If you retard the timing too much, the piston outruns the flame front and very little power is transfered from the combustion into rotation

So there is a ‘perfect’ timing setting based on these two things:

piston speed: which is affected by rpm, and by Rod/Stroke ratio
flame front travel speed: which is affected by factors like mixture density, fuel to alcohol ratio, compression ratio…etc

Now let’s talk a little bit about the two main factors affecting timing advance:

The first is RPM. As RPM increases, the piston speed increases.

The thing is that the piston speed increases linearly with RPM … but the flame front travel speed only increases slightly with RPM due to more turbulance in the cylinder and a better mixture of air and fuel which allows the ‘fractal’ moving flame front to travel faster.

So going from 700 rpms to 7000 rpms, the piston increases it’s speed by a factor of 10, but the flame front only increases it’s speed by about a factor of 3.

So in a sense the piston is OUTrunning the flame front, and to re-synchronize the mixture so that we can catch the piston at top dead center we need to further advance the ignition timing.

To make up for this effect, the timing advance at 7000 rpms needs to be about 3 times the timing advance at idle and that’s how ‘mechanical timing’ came to be starting with a base timing of something like 10 degrees BTDC and growing out to 32 BTDC near redline if we’re talking for example about a large bore engine).

The second factor is mixture density. Which is typically measured by the car’s ECU with RPM, Flow and temperature sensors… But for this example we’re going to measure it in terms of volumetric efficiency since we can calculate that figure.

As the mixture increases in density, then so does the number of air and fuel molecules available for the flame front to expand outwards. This denser mixture allows the flame front to travel faster, as is typically the case with forced induction engines such as turbocharged and supercharged vehicles that cram more air and fuel into the cylinder.

If we leave this mixture alone at stock timing, then the air fuel mixture will out-accelerate the piston and catch it BEFORE top dead center which slows the engine rotation and exerts power rather than making it.

So as mixture density increases we retard timing to catch the piston once again just as it crosses top dead center. As the mixture density decreases, we advance timing to prevent the piston from outrunning the now slower moving… & less-dense mixture.

Of course there are other things that affect flame front travel speed besides mixture density…

such as:
octane rating (higher octane fuels burn slower)
the presence of burn accelerators such as nitrous oxide and oxygenated alcoholic fuels like ethanol and methanol,
or the presence of flame retardants such as water injection and high humidity.

Now that we have a basic understanding of timing curves, let me show you some simulated timing curves based on the 5.7 liter LS1 engine.

Now let’s talk about the advantages of knowing this information…

Dyno time
Different VE curves for modified cars
Not leaving any power on the table (nitrous or superchargers)

____________________________________________

The Apexi S-ITC is an older generation piggy back controller. The S-ITC stands for Super Ignition Timing Controller, and had a +/-15 degree advance/retard setting adjustable at 5 RPM points between idle and 7000 rpms.

At the time when this box was released, most timing controllers were either basic boost based retards such as the MSD BTM (boost timing master) or a fixed single externally triggered retard box for nitrous activation…etc

So, at the time, this product was much more advanced than the cruder forms of ignition tuning available by competitors. However, this product sold very poorly and was quickly discontinued.

The primary reason for the product’s failure was not the product itself, but rather lack of information in the general community about proper ignition tuning and the power potential that was being left on the table with un-tuned cars.

I hope that this how-to video here gives you a better idea about ignition tuning (since very few people actually discuss this aspect of supercharger performance and engine tuning in general). Even though the tools have changed over the years (and now we have full 16 X 16 timing maps that are 100% tunable to your desired timing), the basic theory remains the same, and the thirst in this community for this information is still there.

Technorati Tags: Power Calculator, supercharger performance, Tuning Timing

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Mod list:

• Kenne Bell intake system
• 90mm MAS
• Accufab single blade throttle body
• Kenne Bell 424 supercharger with a 9.25:3.0 drive ratio (peaking at 30psi)
• 60 lbs/hr injectors and a 1/2″ fuel feed line
• Crower Stage 2 Supercharger cams (222* @ 0.050 and a 0.475″ of lift)
• Kooks header
• High flow cats
• Bassani Cat-Back Exhaust
• Tuned to:
  • 11.7:1 air fuel ratio (pretty aggressive for these boost levels)
  • 23* Of timing advance at peak

The results of this assault on the STOCK short-block are:

700 wheel horsepower

749 ft-lbs of torque at 4100 rpms

10.19 second quarter mile pass with a 142mph trap speed!

Find the complete article here:

MMFF Magazine

No related posts.

The kit is based on the eaton TVS (twin vortex system) with the new 4 lobe rotors and 160* lobe twist.

AAT hasn’t released much detailed info on what’s included in the kit… but we do know is that it does include the following:

• Eaton TVS 2300 supercharger top
• AAT custom short-ram style air intake with high flow cone air filter and heat shield
• Optional Borla Cat-Back Exhaust system

The combination boost engine performance by increase horsepower from 426 horsepower @ 5,900 rpm and 420 lb.-ft. @ 4,600 rpm up to 501 rear wheel horsepower and 455 wheel ft.lbs of torque.

Assuming a 17% drive train loss this gives us an estimated 600 crank hp and a calculated approximate 6psi of boost which is a very modest boost level for the Eaton TVS and does not warrant an intercooler for this application.

For people interested in even more power increases… Borla offers a complete exhaust solution including after-market high flow headers, an x-piped midsection as well as the cat-back exhaust.

All of these parts are available as an ‘installed’ turn-key 500whp package through AAT or as standalone parts for a ‘DIY’ install.

Find out more info here:

Alternative Auto Tech

Borla

Technorati Tags: Camaro, Eaton TVS, exhaust, v8

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The only way to see these cars truly live up to their potential is on the track… with no further adue:

Ford Mustang Shelby GT-500

Cadillac CTS-V

chevrolet Corvette ZR-1

The Data

Car	Engine	Supercharger	Power	Power Band	Weight	Lap time
Shelby GT-500	5.4 V8	Twin-Screw ~13.5psi	540hp @  6200 rpms	2200 rpms	3920 lbs	104.3 seconds
Cadillac CTS-V	6.2 V8	eaton TVS , 2.3 Liter , 10.5 psi	556hp @ 6100 rpms	2300 rpms	4200 lbs	103.9 seconds
Corvette ZR-1	6.2 V8	Eaton TVS , 1.9 Liter ,  9 psi	638hp @ 6500 rpms	2600 rpms	3350 lbs	95.8 seconds

Obviously the car with the highest power to weight ratio and the widest powerband will be the most usable on the track, and the corvette shows this with mastery. What is really interesting here is the CTS-V. Having a lower power to weight ratio than the GT500 and a very similar powerband, this car is able to throw it’s heft around the track faster than a coupe. The secret here is that GM spent quite some time fine tuning the CTS-V suspension specifically for it’s challenging weight on the Nurburg ring in Germany bringing it in a ’stock’ configuration of 7:59.32 …

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