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SignUp Now!What did you run for mph and race weight when you came to this conclusion? Do you have some data logs of this or dyno sheets? Id think it would take a lot more rpm and boost to show a gain over the 65 if the comparison was on a 3.8. The big wheel version would be at about 600whp @21psi on a 3.8 if the parts were selected properly. Fwiw wouldnt buy an s trim and target boost that low on a 3.8 if i was spending the $ looking for more power.bison, the s-trim gains over the 65trim 5000+rpm with boost in excess of 21psi.motor has champion heads and intake,212/212 cam.
You can not create cfm without revving the engine higher or adding ci. The problem that most dont understand is that you can not get a higher mass flow with a larger turbo if the one you had was enough for the engine. More boost would make power faster than switching heads believe it or not. Charge air temps were plenty acceptable in the mid 80's through the pulls even at the highest boost pressures i saw with the 61.the restriction is going to be in the heads,,,you can create as much CFM as you want but if valves cannot displace it...you have a restriction.. you craeate a bottle neck
I have a brand new .96 4-bolt housing for my old GTK-850, it has a 4" v-band outlet. I will ship it to you for testing if your interested.
Datar
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No problem Brian, let me know when your ready for testing. The reason I am holding onto the 4-bolt .96 housing for the s-trim wheel Is to do a test with the 71hpq 3-bolt .85 vs the 4-bolt housing with the billet wheel. The GTK-850 ran out of steam on my combo at 25-26#. Cal was working the tune and said I was pretty much done. Maybe the exhaust was holding me back? I am running a dual 3" magnaflow cottons wish I could have uncapped the dump for a pull. Cal did say that my setup was one of the best he had tuned for drivability with a TSM setup. Thanks for taking the time to do the testing, bigger is definitely not always better...
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You would have to know the mph where the g force occured to compare. Ive hit over 1g with a stock turbo. Ive hit .8 @90+mph with my black car anmd the 66S/GTQ when i sprayed it on top of 26psi. It actually went to 28psi. 88% duty cycle on six 83 lb/hr injectors and 30gph alky flowing at the same time.What did you run for mph and race weight when you came to this conclusion? Do you have some data logs of this or dyno sheets? Id think it would take a lot more rpm and boost to show a gain over the 65 if the comparison was on a 3.8. The big wheel version would be at about 600whp @21psi on a 3.8 if the parts were selected properly. Fwiw wouldnt buy an s trim and target boost that low on a 3.8 if i was spending the $ looking for more power.
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nothing high teck im afraid.basically the strim required more fuel to run 24lbs and recored higher g forces.motor has 9to1 compression.on a 30inch drag radial the 62/65 with a very tight t.63 on it recorded .97 on a launch .87 up top at 25psi of boost once the larger exhaust .82 was on gforces dropped.i have seen over a g with the strim at 24psi.
Those are some good numbers for just a bowl clean up with stock valves. Did you grind the short side at all? Mine are as cast in those areas and this engine would need at least 35psi to make 590whp.Cool test- similar combo to mine back in the day. I think the stock heads with only a good bowl port can make plenty of power.
For years I ran a .033 over bore, 210/210 roller with stock 8445's with only bowl porting and stock size valves. Unported lower intake, stock throttle body, stock headers etc, but it put down 595rwhp with a V4 and TE45a P trim and a JayC race chip (guessing 22+ degrees or more) on 116 race gas with probably 27 psi boost (old gauge only went to 25 psi). I took it to 6400 rpm on a 17psi dyno run on 100 octane (403 hp 545 tq) and the hp curve was pretty flat from 3000-6400, but the tq would still fall linearly from a peak at 3000 rpm.
And these heads are sitting in the garage if you want me to clean them up and ship them to you for testing, they've been milled some too, so there may be a little more compression there too over a stock head.
Those are some good numbers for just a bowl clean up with stock valves. Did you grind the short side at all? Mine are as cast in those areas and this engine would need at least 35psi to make 590whp.
Here's an interesting side note: Last year my buddy's car had a stock block, stock stroke, 212-212 hyd roller, stock ported intake, precision plenum, accufab 70mm tb, ported irons, good fuel system, t-66 single bb. etc.. pulled 515hp at the wheels @ 26lbs. fast forward to two weeks ago, shortblock is now a stroker with a 224-224 cam, and a gtk 850. made 618hp with 645tq. @ 24lbs. oddly enough, when we took the car to the track, it ran only a tenth faster, and almost the same MPH as last year. :redface: