Finally finished my 56mm TB project for my motor. These are a pair of badass TBs for CFI I have been working on for a while. They also have needle roller bearings vs bronze bushings on the throttle shafts...oh soo smooth. Hopefully I will install these soon and maybe get to blast the car down the track and see how the motor likes them. I even cut balancing ports into these for easy balancing to make easier for me. A tune tweak will have to happen I'm sure and I need to find time for all this along with other projects that I'm working on. I'm also going to raise my fuel pressure up to 33psi, which should make things a little interesting. The way I see it, this is nothing but, CFI ZOOOOM!

 

Are they going on a Renegade intake on a decently powerful engine? A twin 50mm GM throttle body 454 large IAC footprint style marine TBI with 61# high pressure injectors that flow ~104 lb/hr @ 30 psi was not a limitation on a Victor Jr 2bbl manifold at the 450 hp level for me. Even at ~6,500 rpm the TB had more than adequate flow. I will say the 454 TBI on that Victor Jr 2bbl liked the Holley Projection heated TBI to 2bbl adapter though with divided bores. Might be worth fabing up a couple of TBI spacers at some point and testing them. 1" tall spacers might see some torque gains, if you have room under the hood for them. I have never had a TBI engine that did not run better with a TBI spacer.

 

Yes on both accounts. My goal is to run 11.99. I saw a restriction from the TBs when on the dyno, not a lot, but a restriction none the less. I do not think that I should have a restriction now. At that FP, I should have enough to support 480+ which should be enough to get me into the 11s. I have to stick the launch though. A 1.6, 60' should be good and I'm not far from that now. I just hope I don't break anything in the rear when I do that. The DRs I run bite pretty good and that's what I'm afraid of that a new diff will be in my future.

 

I broke 2 7.5 in 10 bolts. One on a car running 13.4s and one running 13.7s. Replaced with a 9bolt and if iirc got down to 13.2s and never broke that one.

 

IIRC he has a 1982 C3 Vette. Those half shafts get a bit weak. I had a set that were allegidly good for 500 hp in my 1980. Guess is it has a Dana 44 center section in 1982. Not really an expert on that year. I pulled the composite leaf out of my 80 and replaced it with a conventional leaf, seemed to help the car 60' better.

 

Hey Tom, Can you radius that transition from the bore to the mouth a little? I'd think that abrupt angle there might negate some of the benefit your looking for, with those beautifully done TB's. Gorgeous work.

Rooting for your 11.99.

 

Yeah, I've been thinking about that for a little. I was wondering if that would really hurt the flow that bad. These were a PITA to do and get right for sure. I LOVE the needle roller bearings, they work so nice now. I'm going to take another look at this and see if there is an easy way to round/taper that edge a little.

 

This may seem "hack", but could you use a 3-stone brake cyl hone to just put a little radius there? That would not cut too fast, and it would look nice/finished when you're done, I think

I BET the bearings are sweet! Those'll be the nicest CFI TB's ever made! I dig 'em.

 

Well, I decided to get another chamfer bit and redo that edge more and see how that works out. I have too many projects going on and may take me longer than I want to do this. The manifold project is taking more of a priority right now.