Got the main body pretty much into shape - need to finish one more side and then I can start adding features. Hopefully will be done by next Wednesday at the very latest........

 

Excuse me for ignorance, but what's the difference other than cleanliness?

 

Stock is 55mm, mine is 67mm.

Basically a big-@ss hole!

 

thats it... i'm jealous of your job...

 

You are going to kill my bank account. When is the dyno session taking place?

 

^ ^ ^ ^ ^
Like mavfan said...

Amazing this stuff you do.....
Is this a one -off or going to be in your store inventory?
Are you planning to do similar for S2, if its applicable....

 

Well, jgporsche is going to dyno his car this weekend with just the MAF upgrade. Then the following weekend he should have this throttle body and will dyno again. Hopefully he will see enough of a gain to make this project worth the 7.5 hours I have already spent on it.

 

I've heard extrude honeing our intake manifolds will actually hurt HP output. This is essensially the same method of feeding air. Perhaps this will be beneficial depending on how many ponies your pushing out.

 

Yep - that is where the dyno comes in, if it doesn't work there is no reason to proceed.

 

if there are hp gains worth the price, i will deffinently be in the market for one!

 

Hell... Even if I didn't make any HP with it... I'd still buy it!

 

Dan..... what a great thing to wake up to in the morning!!!! I can't wait until it's finished!

 

Every car is different, my experience with installing larger throttle bodies on several other cars is basically this... you end up losing some low-end torque / power. However, in most cases, it drastically improved the performance in the mid to upper rpm power.

I've had totally different results with all of my cars.

1 - 1987 Pontiac Fiero: Noticed an improvement in the lower rpms, but not the upper rpms (this is because the intake plenum becomes the next restriction and would not support any more air flow than the stock TB unit provided) 50mm to 57mm

2 - 2006 Pontiac Solstice: Noticed an improvement across the board. Eliminated any hesitation I had at certain warmer temperatures, much more power in the top end. (don't know the size)

3 - 2002 Ford Crown Victoria LX: A fairly noticable drop in torque off the line. The car is much slower to 25 now. In the mid to upper rpms though, I noticed a decent improvement in the mid to upper rpms, and my fuel economy improved. I need better gears to make up for the loss in the lower rpms. 65mm to 70mm.


So, it's really a crap shoot when you go with a larger throttle body. Sometimes car companies don't put a larger one in for emissions reasons, or for sound, or because the rest of the intake can't supply more power. I didn't follow the earlier threads, but... I'm under the impression you know significantly more than I do about all of this stuff, but I'm asking these questions for the rest of the people here who maybe don't know. Have you measured the interior diameter of the factory intake manifold? How does it compare to the smallest ID of the stock throttle body?

I'm REALLY interested to see what the performance increase is from the MAF. I can guarantee to you that you'll see a drastic improvement. I would love to see a before and after dyno tune with the larger TB and without!!!

I'm psyched... let us know!

 

The inlet to a stock 944S intake manifold is 62-63mm. The throttle body flange that bolts to the intake inlet is 58-59mm. I have a spare intake, that I had the inlet enlarged to 67mm

I'm excited about the MAF. This has been a project 18 months in the making. It has finally been realized. I will dyno it tomorrow. I will be doing lots of dyno testing on air flow on the 944S motor. Between MAF, throttle body, intake manifold, and air intake mods... I am looking forward to seeing what can be accomplished when the 16V cars are allowed to breathe. Those mods along with my free-flowing exhaust, and 4 into 1 header will REALLY make things interesting.

 

You guys continue to conduct some great experiments on these cars. One question, though. If the manifold opening is 63 mm, why go larger than 63 mm on the throttle body? Isn't the optimal course to create the smoothest possible path to reduce turbulence?

Keep up the good work.