Back in the day, it was hard to really quantify the benefit of a your run-of-the-mill bolt-on modification. Sure, most mass-produced intakes and exhausts were shiny and and likely made some better noises compared to the stock components. However, local dynos were hard to come by and most people couldn’t afford fancy programmable ECU’s. So, we had to rely on manufacturer claims and the woefully divergent reviews on various web forums…most of which came down to the infamous “butt dyno.” One guy felt a huge power increase, another says the car is slower. Sigh.
Jon recently installed a newly revised Corksport Turbo Inlet Pipe on the Mazdaspeed 3. It’s design certainly looks much better than the stock piece. Thankfully, with a few simple datalogs (and some knowledge of Excel) it’s easy to see how it compares to the stock inlet. Over the course of a few logs pre-and-post installation over the same road, we can see that the Corksport inlet spools faster and holds a bit more boost from about 4500 rpm up on our setup. Target boost is 21 psi, so there is slight post-spool spike to tune-out.
While the butt dyno is happy as well, I’m glad there is some actual data to support the investment. The new inlet also fit nicely and the ricer in me loves the slightly louder spool compared to the Cobb silicone SRI alone (which has been installed for some time now).
Brand new from our friends at TXS is their front mount intercooler, pipe set and intake for the 2008 + Evo X.
Designed with a true power enthusiast goals in mind. We use 19×11.5×3 core with the proper fin density to ensure the best heat dissipation throughout the bar and plate core, while keeping pressure drop to a minimal. The use of a core this size is good for up to 800 hp! On each side of the core we use a 2.5 inch inlet and outlet allow this core to be used as a core only upgrade. Which bolts into the place of your stock intercooler seamlessly.
The piping kit comes with high quality silicone interconnects and T Bolt clamps.
The intake adds about 10 whp and 15 ft lbs of torque!
All in all it’s a combo that fits well, is affordable, and has obvious gains!
Yesterday Shaun and I were bs’ing online, as we usually do on Saturday afternoons, and the talk turns to Lotus. Admittedly, I don’t know much about them, except that they have always captured my imagination by being a performance oriented car, that is both attainable, and rare – two things I can always appreciate in a performance platform. One car in particular caught my eye on ebay – the color scheme just spoke to me!
So, I had the Exige bug going, and last night before eating some mediocre sushi with Jonathan, he built an badass version on Forza – down to the stripes. I’m not a huge video game person, but this thing was a blast….570 hp, around 2000 lbs. I might be east coast, but I know how to say yee-haw!
After watching Vettel win at Monza today (amazing BTW!) I started googling all things Exige, and found some cool stuff I figured I’d share.
Lotus has done a ton of development work on the car since it’s introduction. One neat version was the 270E was shown at Geneva this year and runs on your choice of three fuels – gasoline, alcohol, or methanol! (white car with green stripes in the gallery below)
And of course the grand daddy of ’em all – the car every Exige wants to grow up to be: Lotus’s own Sport Exige 05. This was developed in conjunction with RTN (of Bentley LeMans winning fame), and is a V6 NA monster – 400 hp + 1974 lbs = hold the hell on.
In the last segment we looked at the very basics of an Individual Throttle Body setup, and the very basics by which it works. This time around I wanted to go a bit more in depth and explore the different types of setups out there. I’m also going to attempt to give some insight into various technical features of each type as well.
Trumpet type – this is the image that most people have in their head when they thing of an Individual Throttle Body. Each airhorn, or trumpet is responsible for feeding an individual cylinder. However simple it may seem, the design of the trumpet itself has a tremendous amount to do with the performance that can be extracted from it. First, there is the length of the trumpet. Just like in a sealed intake manifold, the shorter the runner, the more top end power the engine will have, and the longer the runner, the more low and midrange power it will have. Altering the design of the bell also has alot to do with the overall powerband as well. These are the most simple type out there, as they use a simple butterfly valve to ingest air to the combustion chamber. There are several key elements in the design one chooses for their trumpet style. These will vary from engine to engine based on many factors, such as combustion chamber design, valve placement and diameter, cam lobe profile, etc. The proper taper of the trumpet will give you the best of all worlds – sufficient low speed volume so the car doesn’t become peaky, but providing significant velocity when the valve is fully opened, to mid and top end power. The trumpet design as mentioned, is highly interdependant on many other aspects of the engine. If anyone is interested in some helpful math formulas, let me know and I’d be happy to post them.
The above pictures shows a typical trumpet style ITB setup on a modern V6 engine. Note the taper of the trumpet that continues to the intake runner itself, providing a balance of low, mid and top end performance.
Slider ITB – Slider style throttle bodies were born out of logical belief that with the traditional butterfly valve style, you are giving up prescious air volume and velocity by having a shaft in the center of the bore. In a slider ITB, there is no throttle shaft. Instead, there is a door that slides open and closed to ingest air. As you can imagine, the packaging requirements tend to make these more space hungry and more expensive to produce. These are also said to give non linear throttle response, making them difficult to drive at lower speeds, and difficult to maintain a steady state speed.
Typical Slider Type
Roller Style – the roller style throttle body is the third type of individual setup out there. In this type, you have two barrels, one that rotates inside another. These are essentially combining the linear throttle progression of a traditional butterfly setup, with the pure flow of the slider type. As you can imagine, these are the post costly to produce, and leave the least margin for error, as you no longer have the ability to alter runner length, taper, etc for a given application. Each component has to be machined on it’s own, meaning it’s got to be perfect out of the gate. The inner roller uses ball bearings for smooth and linear actuation.
Get your math right, your patience high, and a bunch of buddies to chip in on a CNC machine, and the roller is clearly the way to go from a packaging and performance standpoint. But there really is no margin for error.
Here is a very neat video showing a roller throttle body in action on an STi
So, now we’ve seen the different styles of ITB’s out there. In the next segment, we’ll get a bit more into design considerations of the most popular version, the butterfly style. This will include injector placement, trumpet location, and what all is needed to actually make one of these setups run a car.
While I’ve never been much of an American car guy, ya gotta give credit where credit is due. Lately, there is alot of very cool things that are happening in the American performance world, and most of it involves the legendary Corvette. Some of you might have seen this video by now, but it’s worth watching. This is the forthcoming ZR1 lapping the Nurburgring. While the GTR has received a ton of well deserved press, this really does step it up to another level.
Need more proof that these are legit supercars? How about the Pratt and Miller C6RS. This car defines cool. I mean come on…an 8.2 liter engine, full carbon body, fully sorted suspension. Your very own LeMans racer is just a phone call away! Take one Z06, add in a motorsports engineering company that just might know a thing or two about building a fast car, and the net result is a full fledged monster. This takes a Z06 to a whole other level, and I think represents the pinnacle of what properly engineered modifications can achieve.
COBB Tuning has been hard at work getting ready for the US debut of the R35 GTR and now that the time has finally come they are ready to release an onslaught of new products for this new beast from overseas.
COBB’s Accessport already has a great reputation from its success on other platforms and it surely has shown that nothing will change now that it is being tailored for use with the new R35.
Here are some whp results from both their Stage 1 and Stage 2 calibration maps.
Stage 1 is for a stock vehicle or a vehicle with just a cat-back exhaust. Stage 2 is for a vehicle with high flow cats or cat deletes and cat-back exhaust. Both stages require the use of the stock intake.
All too often on the web, you see guys talking about making big hp on cars through forced induction. Whether it’s a supercharger, turbo, twin charged, etc., there is always someone pushing the envelope here. But what about good old fashioned NA power? No boost, no having to inject various concoctions of combustible chemicals to be able to crank the timing – just plain ordinary air? I think it often gets left by the wayside.
I wanted to start a multipiece series on NA tuning, with particular emphasis on what to many people is the pinnacle of an NA setup – the Individual Throttle Body, or in web language, ITB. Let’s just get a basic understanding of what an ITB is and how it works.
As the name implies an Indivdual Throttle Body (ITB) means each cylinder has it’s own dedicated path for the air to reach the combustion chamber. The bodies are linked together so that they open and close together, thus allowing the engine to ingest the air required for the combustion process. There are several benefits that an ITB setup can have over a single throttle body. First and foremost is cylinder balance. With a single throttle body, you have little to no control over how much air is ingested into the the combustion chamber for each cylinder. As a result, you end up with air reaching the combustion chambers in varying amounts, at various speeds, which can leave you with cylinders producing different power levels. The amount this differs of course varies by the application. With ITB’s there is no sharing of air. Each cylinder is afforded unlimited air, and through tuning, the user can ensure that each cylinder is ingesting the exact same volume per air, at the exact same velocity. The second benefit is throttle response. With each cylinder now able to ingest it’s own dedicated stream of air, the combustion process starts quicker, and the engine responds faster to throttle inputs. Furthermore, because you now have individual paths of air vs a large single path, the volume of air and the velocity that can be ingested into the engine as the throttle plate opens is often more than a single throttle body setup allows. We’ll go into more detail on this last point in a future installment, as well as determining the right manifold design for a particular application, all with real world testing, graphs, videos and dynos!
As best I can tell, the first production car to use both ITB’s and fuel injection was the very rare BMW M1. This car was manufactured from 1978 to 1981, and used a combination of ITB’s and a mechanical fuel injection system developed by Kugelfischer and Bosch. BMW still uses ITB’s today on their M series engines.
In the next installment, we’ll look more in depth into various ITB setups as well as design differences, etc. In the meantime, take a look and listen at this clip from Option Video from Japan of a tuned Acura with ITB’s. If this doesn’t make you fall in love with an automobile, it’s pretty safe to assume you have no soul!
Kwame
Z1 Performance
Jonathan
Corner Balance 