[blight]

Anyone build an intake with gsx itbs? I am thinking about fabing a manifold with itbs for my road race engine seeing everyone and their brother says to go fuel injection. If i am am going to go efi then i am going to do it right. and efi setup with proper velocity stacks and itbs is the way to go in my opinion.

each runner tapers down to the back throttle bodies which are 42mm

[blight]

for the point of each picture run your mouse over each attachment and the name of the file is what each of the picture is.

The throttle shaft also looks like it would be a really nice place to put a dry nitrous spray bar through. They have a bolt at the top and bottom that hold them together. Once removed you end up with two sets of two throttle bodies.

[Project89]

depending on the spacing of the tb's and this intake u might be able to adapt those tbs to this intake manifold

http://www.ebay.com/itm/SBC-CHEVY-CR...item45ff5ae138

[blight]

That is actually the manifold i was thinking of.

Would this be worth it compared to a good single plane carb?

[ap72]

The gsx tb's are WAY too small. They work well on small displacement 4 bangers but become a choke on anything with more than .5l per cylinder. So what is it worth- a 50hp loss at peak. With correctly sized lengths though they can pick up low end torque.

[KA67_72]

Blight,
I've always loved IR setups. You probably will have to experiment with how you read(average) manifold pressure. I'm developing a 4 barrel throttle body and was very surprised about how little air it takes to idle a motor. Throttle response is going to be lightning quick at the price of tip in being hard to control. If you have a manual you may find yourself riding the clutch a lot trying to keep it from bucking. This looks like a cool project. Keep us posted.

That's a great price on that intake, but there are some things Procomp should leave sacred. Is there nothing they won't make cheap Chinese knockoffs of?

Kevin

[4 Jaw Chuck]

Originally Posted by ap72

The gsx tb's are WAY too small. They work well on small displacement 4 bangers but become a choke on anything with more than .5l per cylinder. So what is it worth- a 50hp loss at peak. With correctly sized lengths though they can pick up low end torque.

Ap72 is right, I looked into this back in the 80's and there is a huge lack of flow capacity with motorcycle setups.

Would look cool though.

[blight]

I was looking for 48 mm from a boosa today no luck yet 42 is too small. 48 would about perfect.

tip in?

I am running an automatic with a 2400 stall

[KA67_72]

Tip in is when you start to open the throttle off idle. It looks like the Hilborn SBC stuff starts around 2-3/16. I have an old one here that is 2-1/16.

Kevin

[Project89]

Originally Posted by ap72

The gsx tb's are WAY too small. They work well on small displacement 4 bangers but become a choke on anything with more than .5l per cylinder. So what is it worth- a 50hp loss at peak. With correctly sized lengths though they can pick up low end torque.

not meaning to argue with u but how is that possible, the tpi engines of the 80's used a single tb with twin 50mm blades,and most stock tbs have a single 70-75mm tb.

u would think that eight 42mm blades would flow a helluva lot more, whats the throttle blades on a typical 750 or 850 carb measure???

[blight]

Originally Posted by KA67_72

Tip in is when you start to open the throttle off idle. It looks like the Hilborn SBC stuff starts around 2-3/16. I have an old one here that is 2-1/16.

Kevin

how is tip in "hard to control" then?

[blight]

Originally Posted by Project89

not meaning to argue with u but how is that possible, the tpi engines of the 80's used a single tb with twin 50mm blades,and most stock tbs have a single 70-75mm tb.

u would think that eight 42mm blades would flow a helluva lot more, whats the throttle blades on a typical 750 or 850 carb measure???

the throttle body has to flow what cfm the head is at,at max lift. i can't remember the exact flow rate of each throttle body size but it also has to do with the shape of them also.

[KA67_72]

With your converter you may not have issues with tip in. Even if you have problems with it at first, there are things you can do to sort it out like progressive linkages.

Kevin

[Project89]

Originally Posted by blight

the throttle body has to flow what cfm the head is at,at max lift. i can't remember the exact flow rate of each throttle body size but it also has to do with the shape of them also.

how about a common plenum per 2 cyls, sinc eno 2 cyls on the same side will be pulling air at the same time if u built a common plenum feeding 2 runners using 2 tbs to feed each plenum, should solve the issue of them being to small.

though this woudlnt be a true itb setup, i would assume it would still act the same as if it were

[blight]

I do not know enough to answer that question maybe someone else does. I just know what I am doing from what I have read/been told. That far in the tech on this subject I am in lack of information.