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Discussion Starter #1
Is a fair comparison for a turbo combination that works on a 6 l ls engine, vs a sbc with 9.5:1 compression, and brodix cylinder heads? Should the engines respond the same with the same turbos, or is it totally different. This is assuming decent turbo cams in both. Thanks
 

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Discussion Starter #3
Other people have run these turbos on 6 l ls, with good results, I am having no luck with them on a 383
 

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Discussion Starter #5
It’s the blocks fault?
I'm not saying that, but I'm trying to understand what is different, I happen to like the sbc. I've been told by several people that they flow differently, and it supposedly effects turbo choice
 

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Luck aside, with a properly spec'd combo (including turbo or turbos), sufficient supporting systems (fuel, ignition, and control sys) and good tune, the system should respond as expected. What are the details of the combo and what are you experiencing?
 

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Luck aside, with a properly spec'd combo (including turbo or turbos), sufficient supporting systems (fuel, ignition, and control sys) and good tune, the system should respond as expected. What are the details of the combo and what are you experiencing?
 

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Are you comparing a built 350 to a stock 6.0? The same turbo could
be used on both engines, same rules apply, back pressure, etc.
Honk has run the gen 1's with no problem-A stock 6.0 out of a truck
is strong, breaths well, makes power. Gone are the days of finding a 350
out of a junkyard that is as good. Once you start adding aftermarket stuff
then the 2 will get closer.
 

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Discussion Starter #9
It's a 383, I'm running a pair of vs 67/66. People seem to have good luck with them on the 6 l ls engines. I've so far pulled a leakdown and compression on it, 160-165 psi cranking (9.2:1 c/r), checked valve spring pressure, checked cam timing, pulled all the rockers and pressurized the exhaust sides and air sides to 10 psi(includes the wastegates and bov's), verified timing at 3k rpm, I even brought the timing up from 34 total to 37 total, and not pulling anything until it hits 4 psi. Ohmed out all the wires, checked all the plugs after shutting it down, all normal. Verified tdc on the balancer. I can't think of anything else to check. I put it on the transbrake last night, with no limiter engaged, 3.5 psi at 4400 rpm. My old combination ran a pair of t3 gt35's, and made 850 rwhp at 16 psi, and wasn't laggy at all, 61/62's,.63 a/r. New turbos have a .96 a/r. Here's a pic of the holley datalog from last night.
 

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Sorry, I didn't mentally connect this thread with the power down 200hp thread. Thanks Mufflerguy. If short block didn't change then I would not expect ring seal issues at upper rpms. Never hurts to monitor crankcase pressure to know what's going on though. Pop the old turbos on and see if power is restored. Sorry, not much help.
 

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Ever add significant fuel to see if there is any change?
when I was learning efi, I kept adding and adding fuel as advised by plugs, but nothing would change. Finially someone pointed me at the duty cycle data. Lol. Found the problem
 

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Discussion Starter #12
Ever add significant fuel to see if there is any change?
when I was learning efi, I kept adding and adding fuel as advised by plugs, but nothing would change. Finially someone pointed me at the duty cycle data. Lol. Found the problem
Just talked to him, he agreed they are too big as is for this combination, low compression ratio isn't helping either. He is going to make up a set of .68 a/r exhaust housings and hopefully that cures it
 
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