I've done some research about running a 70MM throttle body on an S2000 and have heard mixed results. Mainly I heard about some issues when going to 70mm, but could never find the info to back it up. I'd like to know some opinions on this if anyone has any!

It's going on an F20C. I got the throttle body for free so that's the only reason I considered this. I am wanting to run the 70MM throttle body and bore the IM to match it.

 

Which brand are you considering ?. I've always liked TB upgrades that I've done in the past on other vehicles, the added response is nice and you can always get a few hp gains though never quite as much as advertised IMO. I just bought a J's TB for the F20c, it is about 69 mmm at the leading edge but 64mm at the throttle plate, about 2mm larger than stock at the plate and on the exit. Our cars run a bit rich in stock form so there is some gains to be made by adding a bit more air flow. If it is a 70mm straight through TB, it sounds like a bit overkill.

 

My tuner said that when combined with a complete manifold bore and tune, I should still expect less than 10 HP, at a cost of nearly $1000 once it was all said and done. They look great at $250 for that basic part, but it doesn't sound like it ends up being worth it in the end.

 

I agree that bang for buck it is not the best mod most likely. Don't forget this is a free upgrade for me though. So basically my main concern is if it will hurt anything performance wise by installing it, since the F20 is already such a well tuned motor from the factory.

 

Also it is a straight 70MM.

 

I put a SOS one on my '05 model F22 motor. I can tell a little bit better flow, I got mine used so I wasn't out a lot of Money . I am Buying a AEM v2 intake tomorrow, I'll see if that will help it out. -Ken

 

not unless the intake manifold opening is matched.

 

I know my bdl 68mm has a bigger opening then stock(64-65?) And the stock tb is undersized for the im opening. But my bdl tapers down to the perfect bore of the OEM im and no tune car runs great.better pedal feel and throttle response and a hair louder.no before and after dyno tho.iirc the J's tb is 69mm and tapers down some and u should be able to bolt on no issues

 

I'm also interested in this subject.... I have a passwordjdm intake, toda header, spoon tp/exhaust, and a aem ems v2 I'm planning to tune soon, oh and some okada project coil packs (don't know if that really matters) but anyways I'm also thinking about picking up a 70mm throttle body but don't know if it's going to really make a difference or if it's just a gimmick considering the F20c1 is a well engineered motor If I do decide to get a 70mm throttle body, logically I would assume that boring/matching the intake manifold to the tb spec would be ideal and best way to extract the power and usage of the tb???? But is it really worth all that trouble considering tb cast around $220-$295 and boring/honing out the intake manifold is $$???

 

I was very similar to your thinking, a little worried about the fact that an F20 is a very well designed motor and I didn't want to throw it off.

I am going to go ahead and do it. Being a mechanic it's free for me to bore my intake to match the throttle body, and free to install haha. If it doesn't add any power, I'm still out 0 dollars so it seems worth a couple hours of work.