So I've read most of Bulletride's thread on DIY ITBs and talked to him about it a bit. With the budget I have for my build, the RHD ITB kit seems just a touch out of reach, so instead I'm thinking custom stuff.
I aim to build a 3.0L high compression stroker M20, running MS, ported head, and a 290 degree Dblias cam (yes I will be shipping that from overseas if I stay committed to using that cam).
After reading some of the information on the RHD site regarding throttle size selection, I'm not sure the 44mm ID of the Triumph bodies that Bulletride used are my preferred option. I have been doing some research into the GSXR 1000 throttle bodies used often by the Toyota guys on their 4 cylinders. The early (01-02) throttles are separable (the 03-04 are as well, but the come apart in pairs rather than individuals. They do tend to be more expensive than the Triumph throttles, have injector slots id have to plug, and I would have to buy two sets which would leave me with two spare throttles. However, the dimensions peaked my interest.
The throttles I'm interested in have a 50mm inlet. Yes, much bigger than the 44mm I'm already worried are too big. HOWEVER, the outlet is 42mm, which is a pretty serious velocity stack, and matches what RHD recommends for strokers on their site.
So my question is will that internal velocity stack win back the intake velocity I would lose otherwise? Manifold-wise, the ID of the stock intake runners I'd have the new runners welded to may be less than 42mm, but that gives me another opening for another velocity stack or smooth taper.
What do you guys think?
I aim to build a 3.0L high compression stroker M20, running MS, ported head, and a 290 degree Dblias cam (yes I will be shipping that from overseas if I stay committed to using that cam).
After reading some of the information on the RHD site regarding throttle size selection, I'm not sure the 44mm ID of the Triumph bodies that Bulletride used are my preferred option. I have been doing some research into the GSXR 1000 throttle bodies used often by the Toyota guys on their 4 cylinders. The early (01-02) throttles are separable (the 03-04 are as well, but the come apart in pairs rather than individuals. They do tend to be more expensive than the Triumph throttles, have injector slots id have to plug, and I would have to buy two sets which would leave me with two spare throttles. However, the dimensions peaked my interest.
The throttles I'm interested in have a 50mm inlet. Yes, much bigger than the 44mm I'm already worried are too big. HOWEVER, the outlet is 42mm, which is a pretty serious velocity stack, and matches what RHD recommends for strokers on their site.
So my question is will that internal velocity stack win back the intake velocity I would lose otherwise? Manifold-wise, the ID of the stock intake runners I'd have the new runners welded to may be less than 42mm, but that gives me another opening for another velocity stack or smooth taper.
What do you guys think?
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