40 mm Throttle Body

[overdrive535]

I've seen posts in the past asking about this, but where are teams sourcing their throttle bodies from? At SDSU we have a throttle body already, but it is less than ideal. I've found some manufacturers, but as of now no one has gotten back to us. Ideally I'm looking for one with a four bolt flange on it. Any help would be greatly appreciated. Thank You

[overdrive535]

I've seen posts in the past asking about this, but where are teams sourcing their throttle bodies from? At SDSU we have a throttle body already, but it is less than ideal. I've found some manufacturers, but as of now no one has gotten back to us. Ideally I'm looking for one with a four bolt flange on it. Any help would be greatly appreciated. Thank You

[JR @ CFS]

Don't jenvey dynamics do a 35mm? I seem to remember we switched from a 50mm down to a 35mm TB last year.

[Biggy72]

Jenvey makes a 40mm thin throttle body. We bought one last year, but as of right now I'm going to try to gut a stock cbr throttle body and make a new housing for the plate and tps to go onto. We'll see how it turns out.

[civicsit]

40mm for a 20mm restrictor? Man, I just don't get it sometimes...

[flavorPacket]

um, why don't you make your own?

[PedalOnTheRight]

Making your own slider or conical type is advantageous. Jenvey Dynamics makes some great products, we have bought from them multiple times in the past with excellent results (you'll have to fax them the order or buy a calling card, because they live in England).

Can you imagine we once ran a 48mm TB from Jenvey with our restriction? Stupid....

[Biggy72]

We once ran a 50mm throttle body from a Huyandia Accent. Definitely not ideal, but the car was very driveable and by far the fastest car in our group during the endurance. And the same car placed 5th in the skidpad weighing in at 625lbs.

[Hot Rod JayRad]

Jenvey stuff is nice and well discounted, but get your order in soon... they took 2 months to get us our tb

by the way, im not sure i see why a 40mm tb is bad news. as long as you have enough throttle resolution, you should run as big as you can.

[PedalOnTheRight]

40mm isn't necessarily wrong, one school of thought is to consider how much inlet flow you'll be letting in per degree of valve opening. When we downsized significantly, we found it much easer to control mid-throttle inputs.

[civicsit]

Yea, just think about it. At what throttle position are you actually reaching full throttle? 75%? 50%? So how much throttle travel are you loosing that your driver could be using to better control the car?

[drivetrainUW-Platt]

Jenvy makes good stuff but dont forget the crazy expensive shipping cost and stupid long lead time on the order...didnt make us to happy.

[overdrive535]

We have thought long and hard about building our own, as it is well within our capabilities.
If we cannot find a model on a shelf somewhere for a reasonable amount ASAP, this is the road we'll be taking.

[Hot Rod JayRad]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by PedalOnTheRight:
...When we downsized significantly, we found it much easer to control mid-throttle inputs. </div></BLOCKQUOTE>

Did you stick the motor back on the dyno after downsizing your tb? How did the power curve look?

[PedalOnTheRight]

We did not use the smaller TB with the same intake manifold as the larger one (it was on a different car). Bearing that in mind, the car developed peak torque in the same rpm range and made more power (but not due to the new tb). You shouldn't loose power from a downgrade from something like 50mm to 40mm, because you're still only flowing around 72g/s through the restrictor.

The main difference was in throttle modulation, aka driver feel. When you can control the severity of air flow at small throttle inputs, it's much easier to roll on the throttle sooner and more fluidly at corner exit.

I'll take the old throttle body to the flow bench when we go in a few weeks and let you know of any major differences.

[overdrive535]

Sorry to bump this, but thank you to everyone who replied to me. Working with Jenvey was really easy with the exception of the language barrier. Having a room mate from Manchester helped. The throttle body got here literally two weeks after I ordered it. Must be a slack time over in England.

[Baz]

Is there a certain throttle position sensor that works well with Jenvey throttle bodies and a PE ecu? I see they have some tpss on their website, but I would prefer to order from the US to cut down on shipping time. Is there a standard tps that most teams use?

[Wesley]

Holy resurrected thread!

I can tell you we JB welded a TPS from a Chevy S-10 on ours for 4 years in a row. I can also tell you that's a shitty way to do it.

They make a sensor that fits, but it isn't linear and the PE won't take a calibration curve. I think it's for a Lexus or something.

[BuckeyeEngines]

make a slide throttle right at your restrictor and use any linear 0-5v potentiometer. I never understand why anyone uses a butterfly type. We saw significantly less flow through them on the flow bench.

[B Lewis @ PE Engine Management]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Wesley:
They make a sensor that fits, but it isn't linear and the PE won't take a calibration curve. I think it's for a Lexus or something. </div></BLOCKQUOTE>

Hi Wesley, the calibration in the PE for the TPS is linear (2-point cal) as you mentioned. For an alpha-N setup this won't matter provided your calibration curve is not something with an extreme amount of curvature. Regardless of the measured TPS % determined by the ECU, the calibration will result in only one value being calculated in the main tables. For example, a throttle opening of 50% may actually be 35%, but the values in the table will be correct provided you tuned the engine with the same calibration.

Hope this helps.