@v8jet posted:Agree, the short individual intake runners make the problem much more pronounced than. Interestingly although we don't have a reversion / stand off issue when we switched to the Holley we still have a breathing issue which points to headers. Over winter our plan was/is to switch to a cam which has a bit less duration , which we see causes the problem, and a bigger lobe separation angle which should also alleviate it. If we swap our cam and the issue is alleviated we'll report back. May also put engine one dyno and swap out the existing headers for the 1 5/8ths we use on Mustang and see what that produces before embarking on having any made.
GT40's run "turkey trays" so at least you stop the drips getting onto exhausts - that's then theory anyway and I was told if you see flames hit the throttle and it'll suck them into the engine.... okay...
Hopefully not hijacking the thread but we got confirmation today that our car has been given an FIA Historic Passport (with the Webers on) but not as a GT. Basically it means (unless the race organisers are "flexible" which in current climate they may be!) we have to race against Lola's, Chevrons, GT40's and 917's which is, (to put it mildly) complete BS and a kick in the teeth. We'd hoped it would open the door to lots of races and planned on going up against E Types, Griffiths Cobra etc but no, not according to the FIA we won't. According to them it's not a GT but a Two Seat Race Car. Utter nonsense.
So another reason we may not race the Mangusta but having come this far with the IDA's we are stubborn enough to try and get engine to work properly on Webers whether they are IDA's IDF's or DCNF's!!
The Holley runs with a common plenum intake manifold so the reversion pulses are intended to push the mixture into the next opening intake valve.
IF you want to see a light show, start the engine (with the 48ida's and just velocity stacks) at night. It's very impressive and the kids will like it better then a fireworks display!
I recently went to a 2x4 Holley set up on a C60A trans am intake manifold. So I repainted the underside of the hood.
The flame marks from the Weber velocity stacks were still on the underside of the hood.
Yep. The GT40 "cookie trays" are there MOSTLY to direct the fuel plumes into a safe collection area.
Detomaso actually figured out that all you had to do was go to a 5" tall velocity stack and the plume would stay in the stack. Interesting that NO other teams ever noticed that before?
There were a few sets of 58ida's made for Ford and Shelby to run on the 427's. NO ONE could get them to "work" (at least to their sanctification or expectations) so the Mark II's ran a single Holley carb. That isn't a disgrace and in human terms is the simplest to make work.
Why fight it? Run the Holley and put yourself in a more competitive class. You can't compete against Lola's. The thing weighs like 1,600 pounds. Otherwise you are just being an alchemist and turning lead into gold never really worked out?