Ive been looking into fabbing up some itbs, but would it be worth it. Ive heard with an larger intake mani, and larger throttle body you can achieve similar results. true?

 

also my CR: is 10.5:1

 

i swapped from an AEBS IM + 70mm BBK TB to TWM 50mm ITB's and no other changes and picked up 19whp peak.

I'd never put DIY ITB's on a motor other than as an experiment. I sold my TWM's for $850. You can find them at a decent price.

 

i was thinking about doing the gsxr 1000 and fabbing them with some type of stock mani. I havent seen it done, but it looks solid, and only a few hundred bucks.

 

You can't compare a 1150cc+ plenum with 8" runners to ITBs that have 9-10" runners. It'll be harder to obtain the same intake velocity with the 8" runners compared to the 10" runners, at the same rpm.

A plenum properly sized for the rpm range you want to emphasize with 10" runners at X diameter is a "better" comparison. The AEBS manifold will always be a disappointment, as well as most aftermarket manifolds.

check this site out:
http://www.rossmachineracing.com/intakeparts.html
I.

 

[QUOTE=JerseySiPOS]You can't compare a 1150cc+ plenum with 8" runners to ITBs that have 9-10" runners. It'll be harder to obtain the same intake velocity with the 8" runners compared to the 10" runners, at the same rpm.

 

So is the gsxr 1000 throttle body swap useless?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by motormike40 &raquo;</TD></TR><TR><TD CLASS="quote">i was thinking about doing the gsxr 1000 and fabbing them with some type of stock mani. I havent seen it done, but it looks solid, and only a few hundred bucks.</TD></TR></TABLE>

well you didnt look very hard ......MANY MANY people on this board have done the gsxr itb's search for "diy itb" in the archives and you will find all the info you want

they are small though at only like 42mm opening so i dont think you would get very far with them