L92 cam choice with turbo
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From: Newberg Oregon
L92 cam choice with turbo I am going to be rebuilding my 408 soon I was thinking of going with a sc but I have changed my mind and I would like to go turbo. My goal is about 750 whp that I can run on pump gas. I will be using unmilled l92's with -20cc piston's. I have read this will put me about 9.3:1 CR. What would be a good cam for my build? Waht are you L92 headed guys running for a cam? I am not going to turbo it for about a year but I figure if I put the cam in now I will not have anything to do to the engine.
Thanks Brandon
Thanks Brandon
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From: Colorado Springs, Co/ Central, Ca
It will be hard pressed with the 68mm exh wheel on 400+''. Your power will likely PK before 5K RPM. You would be better off with a S480 with the 87~92mm exh wheel, or a Garrett GT76, with the 94mm exh wheel, and 1.08 T6, or precision T4 .96 housing. If you want to run a T76 I would back the CI down to 370. My cam pick would be the ISKY 230/233@.050'', .592''/.595'', 114 lsa for a 408/turbo/NA compromise, and 230/230, .592/.592, 112 or 114 lsa for a good flowing 76~80mm turbo specific.
I would definitely go with a larger turbo. Im running a T76 on my 346 and Im expecting the power to peak near redline(6200rpm).
As for the cam, I would call up Pat G and have him spec you out a custom cam.
As for the cam, I would call up Pat G and have him spec you out a custom cam.
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T76 will choke that 408, my build is a 402 9.3cr with l92s ill be running a t6 88 mm and it should make 800 ish rwhp at 15psi or less. The Cam I chose was a custom one from comp. 230 238 575 585 on 114. This is going in a street car with a manual trans. I too am thinking about putting the engine in NA for now because my fabricator is swamped.
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From: Newberg Oregon
T76 will choke that 408, my build is a 402 9.3cr with l92s ill be running a t6 88 mm and it should make 800 ish rwhp at 15psi or less. The Cam I chose was a custom one from comp. 230 238 575 585 on 114. This is going in a street car with a manual trans. I too am thinking about putting the engine in NA for now because my fabricator is swamped.
Thanks Brandon
They're wiseco pistons with a -20 CC if memory serves. T4 refers to the inlet flange on the exhaust side of the Turbo. T6 is bigger. 88 mm turbos can be had with a t4 flange but for a 400+ CI motor I chose a t6 based unit to help keep back pressure down. Back pressure is the enemy of a Turbo system. As a general rule 2:1 back pressure is high. I.e if you have 10 Psi of boost you shouldn't have more than 20 Psi of exhaust pressure before the turbine. Not saying that it wouldn't work but just not optimal. Worst case scenario is high exhaust temps, cracking of the preturbine exhaust system, burned valves, blown header gaskets, etc, etc.
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From: Newberg Oregon
The cam is an off the shelf cam from texas speed, should I go with it or something else? When I bought my MS4 from them my engine builder said it had a lot of timing built into it or something and I needed an adjustable timing gear.
There seems to be no real magic cam that is best for boost. I know I have seen the theories behind reverse split or the the ideas of the perfect duration and lift. I am running a ridiculasly big cam on my 408. 654/660 248 252 112+2. I am at 800 rwhp on 14#. I have ported L92's and a FAST 102/102 setup. My turbo is a T6 96mm dbb. Just go with a cam that will make you happy over the next year and then boost the **** out of it.
