Recommended Length Itb's

[480bhp.com]

iirc there's a few people on here with the AT direct to head bodies fitted, does anyone know the optimum length for the F4r engine within the constraints of the engine bay?

Horn choices are 40 or 60mm

Extension lengths are 70, 100 or 130mm

Cheers
Chris

 

[K-Tec Racing]

you want to be carfull here, length is critical to mid range torque on this engine (we have done ALOT of testing)

you can run shorter than the current Jenvey kit, but will loose mid range torque, but it wont effect the top end numbers.

you really need to pop it on a dyno and see what lengths work with the setup you have to get the best result.

Andy

 

[480bhp.com]

cheers for the input Andy, what length do the Jenvey's have?
(butterfly to trumpet tip)

Chris

 

[Daz Clio Cup]

i can measure mine tonight if you want chris, jenvey's with 90 trumpets

 

[480bhp.com]

Hi Daz,

If you could measure your Length tonight it would be good

Chris

 

[Daz Clio Cup]

Hi Daz,

If you could measure your Length tonight it would be good

Chris

:lolup: 6 1/2 inches!?!

235mm from head to trumpet, which is broken down to 105 from head to throttle butterfly and 130mm from butterfly to trumpet tip

 

[480bhp.com]

Cheers Daz, i just need to confirm a few things, then i can get them ordered

I'm surprised no one else joined in when they saw the length comment

Chris

 

[Daz Clio Cup]

let me know if you do any back to back comparisons, cos i've always been torn if to stick with the 90mm trumpets or go for 120mm ones