batikan

Here is the mod list of the car.
What is the largest size TB we can use on this car? Everything is done except the custom filter which will be made after we finalize the TB. I see BlueprintRacing has a 70mm - 72mm - 74mm one. Would 74mm one be too big?

Hytech Head Package (Cams, Valve Springs)
Spoon Headgasket
Toda Cam Gears
Hytech Header
T1R 70mm Single Exhaust
Inlinepro Intake Manifold
Full port polished head
AEM EMS Gen2

kent876

quite honestly sir with that setup i dont think you can go too big....ITB's arent to much for ur setup lol lol
this seems to be a great build... i love some more details on this with even a dyno sheet....
what compression pistons are you running?
id suggest datalog ur manifold pressure before and after the mod to see if you benefited from the bigger TB

suzuka-blue-s2k

What happened with your OBX ITB's?

H22toF20

This appears to be a different car. Nothing in his list matches his sign. Supposedly the throttle body size is determined by your plenum volume. At least that's what I got out of a thread on HT a couple years ago.

How's the Inlinepro manifold?

wadzii

the stock manifold needs about the biggest tb you can fit.

on a 00-05 manifold thats about 69mm, on a dbw manifold thats about 74mm

H22toF20

I would agree.

Testing on the Euro R manifold for the H22, showed that it liked a big throttle body. The Euro R has a small plenum like the s2k's manifolds. Power held out longer in the high RPM's with no power lost in other places.

With that being said, Gernby noticed no gains with a bigger throttle body on his DBW.

bpaspi

^ that must be influenced by the different Manifold design for the DBW engines.
I noticed a big difference in driveability when I switched from 62mm TB to 70mm in my '99 F20C.

wadzii

My car felt much stronger when i went from stock to 70mm on the dbw intake manifold, but my motor was in the process of falling apart so who knows.

I'll be re-testing everything soon. Going this weekend to pick up a new block, then the main thing i'm waiting on is rings from honda.

batikan

This is for a friend's car. I am happy with my ITBs
I didn't get the response I needed though
What size do you guys recommend for this setup?

Would a 74mm TB be too big? We have an Inlinepro Intake Manifold and a port polished head, so we need more ait going into the engine. We don't want the TB to be the bottle neck.

bpaspi

Depends on the intake diameter of your Inline Pro IM. You should have a constant diameter from TB intake up to where the plenum chamber starts.
For my old F20C manifold a 70mm TB was the biggest one that fits on it. I had to port match the intake diameter of the OEM IM to get a smooth transition from the TB. There is not much flat area for the gasket anymore. I wouldn't recommend a bigger one. But that's only valid for the F20C manifolds without DBW.