T4 PT88 owners! TIP ratio data?
10-04-2009, 03:34 PM
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T4 PT88 owners! TIP ratio data? So everyone tells me the PT88 will perform wonderfully on a 402, and that you can even run into the 8s with a PT88, While those all are true statements, who has a T4 PT88 on a 402 and runs fast with it? and What do your Turbine Inlet pressure ratios look like? (Backpressure vs Boost) I would like to know what the lowest possible backpressure ratio with the PT88 on a 402 could possibly be. And how many LBS/Min is the 88 most efficient at when dealing with high boost pressure ratios (2-2.5) CFM works also. My math works out to be that I require 1700CFM at 6500 at 22PSI or... at 85 degree compressor inlet temp, and no filter (14.7psi absolute) roughly 120LBS/Min. Really want to know that the IDEAL 402 with a T4 PT88 can make for power. I don't see it making enough to push me any faster than 9.50s since Im M6 and 3,800 lbs
10-04-2009, 08:07 PM
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I have seen a Pt88 go 8.30's at 160ish in a fox body..... It ran one for years also..it's a good turbo. Even with a stick its possible to go 8's... You do need to lighten up though.
10-05-2009, 09:31 AM
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Well yeah, but I bet the car was 3200 lbs or less, and had a Much smaller cube motor, which would produce less backpressure, and also run at higher boost pressures with the same efficiency. What about on a 402?
10-05-2009, 09:43 AM
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I think your right on target. I would be shocked if a 3800lb m6 ran better then 9.50's. th400 though.....and good Houston air.....game on for high 8's.
Although going 8's with anything and an t56 at 3800lbs is dam near impossible.
Although going 8's with anything and an t56 at 3800lbs is dam near impossible.
10-05-2009, 03:10 PM
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Ya Im thinking the same thing as well, throw my best effort at this PT88 and with my big 402 and 3800 lb raceweight, and M6, the Best scenario could be a 9.50 Many people will argue with that but everyone always knows more about your car than you do. It's a funny thing. I bet however a PT88-47 would rock and kick right down into the 8 with the M6 though.
10-05-2009, 04:04 PM
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sorry meat I wasn't targeting you with the people know more than you about your own car comment, talking about the people that tell me everything I have is fine the way it is, car should run 8s end of story something's wrong. Not in this post but others. If I could learn anything, it would have to be about where I am going to pull weight out of this overburdened tank of a car! not too easy!!!
Im keep going back and fourth in my mind over the path of the car, think Im just going to keep the turbo I got and make as much power with it as I can for educational purposes only. And then build a whole new kit myself for the 101.
Im keep going back and fourth in my mind over the path of the car, think Im just going to keep the turbo I got and make as much power with it as I can for educational purposes only. And then build a whole new kit myself for the 101.
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10-05-2009, 06:02 PM
#9
I know the feeling... IF you want to stay in the boost just hook up a clutch switch to cut spark for an instant while you shift....you'll barely lose any boost and keep up with any auto car on the street....This little trick made power shifting my 1100rwhp+ car possible...this was the only way it could happen... at least with a syncro tranny.... In fact I see no need for an auto on the street anymore with this little trick....
10-06-2009, 12:17 AM
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so not popping that BOV downtrack is that important ? I didn't think I lost any time at all re-spooling once I got a big enough BOV on, Once I have the trans gone through by liberty, I'll give speed shifting a try to see if I run any quicker. I still lift the throttle throught the gears as of now. What kind of ET difference was speed shifting your M6?
10-06-2009, 01:49 AM
#11
I know the feeling... IF you want to stay in the boost just hook up a clutch switch to cut spark for an instant while you shift....you'll barely lose any boost and keep up with any auto car on the street....This little trick made power shifting my 1100rwhp+ car possible...this was the only way it could happen... at least with a syncro tranny.... In fact I see no need for an auto on the street anymore with this little trick....
simple hold the throttle fully open and operate the clutch/gearbox as normal.
otherwhitemeat what kit did you use? not seen anyone else in the LS world doing it......
Chris.
10-06-2009, 08:17 AM
#13
awwww the good old flat shift kit! work an absolute treat at keeping turbos spooled up on Manual cars. i dont see why more people dont use them in drag racing. they are very popular, and not just with turbo cars but NA motors to, in other disaplines.
simple hold the throttle fully open and operate the clutch/gearbox as normal.
otherwhitemeat what kit did you use? not seen anyone else in the LS world doing it......
Chris.
simple hold the throttle fully open and operate the clutch/gearbox as normal.
otherwhitemeat what kit did you use? not seen anyone else in the LS world doing it......
Chris.
I have also done this with just retarding time timing to 0 or less...I can do that be using the nitrous table, and activate that through a wire with the same set up.... Both work... not sure which is better....I think I like the first way...less of a bang!
BTW This was an LT1 ...now it's a Dart sbc....
10-06-2009, 09:13 AM
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What kind of ET and or mph but I doubt the MPH part... was this trick worth for you? The resulting backfire doesn't hurt the turbo?
Is it possible with a trick like this, and a good clutch/tire setup, and leaving of a 2 step at boost that you could be as fast as an automatic?
Is it possible with a trick like this, and a good clutch/tire setup, and leaving of a 2 step at boost that you could be as fast as an automatic?
10-06-2009, 09:40 AM
#15
What kind of ET and or mph but I doubt the MPH part... was this trick worth for you? The resulting backfire doesn't hurt the turbo?
Is it possible with a trick like this, and a good clutch/tire setup, and leaving of a 2 step at boost that you could be as fast as an automatic?
Is it possible with a trick like this, and a good clutch/tire setup, and leaving of a 2 step at boost that you could be as fast as an automatic?
I also have a BOV and it does not compare to this at all...This is for anyone who has issues with boost falling off or just shifting in general..
If your boost does fall off even a little...you are going slower, there is no way around it...it will always be fast if it doesn't fall off.
As for if it could be as fast as an auto...I don't think so..only cause how an auto leaves the line, going down the track/road, yes, I believe it can stay with them....
With a 2 step and timing retard I can make 20+ psi, at a stand still, if I want but that is way too much to try and leave with. The way power hits the tires with an auto from a stand still/ at the line is way softer. That's why there is slipper clutches....
Like I said this is a street racing car.... and because it's the street even an auto can only leave so hard. Because of this..I believe a m6 can keep up with an auto from a stand still even on the street, and for sure rolling...
Does it hurt the turbo..I don't think its any diff then putting it on the 2step, so....
I think this all works well with m6 cars making lots of power..maybe 850whp or more, when I was making less then that, shifting and boost loss was less of an issue.....
Last edited by otherwhitemeat; 10-06-2009 at 09:45 AM.
10-06-2009, 12:52 PM
#16
My personal experience with the t4 88 is I hurt several of them at 20-24 psi on a 408. I know with the stick you are trying to stay with something that will spool good and go very fast for a m6 f-body. I would try a quick spool valve on a larger t6 turbo. It will spool as good as the t4 88, not have a bunch of backpressure, and make even more power(if needed).
10-06-2009, 03:07 PM
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Well the car is strictly drag race only now, a decision I made on r&r from Iraq when I blew a driveshaft, a 9" centersection, and a transmission on my 7th test and tune pass with the new setup, still leaving soft and running low boost pressures. Only got down to match my old N20 Stock motor times nearly exactly.
So all things considered, if its a Drag car only, it doesn't need to spool fast, it's spooled on the launch, and doesn't really lose much during a shift anyway I would however like to see if that flat shift trick will pick me up a tenth or so.. Believe I can easily drop into the 9s with what I got and just alot more tuning, and fix a few crappy parts of the kit like the downpipe and the whole charge side. there is power to gain everywhere in my crappy setup, think I can gain another 250 RWHP... Put me at 830 RWHP..
What numbers do other 408/88 owners run? what kind of problems? what kind of backpressure (the point of this thread! lol)
So all things considered, if its a Drag car only, it doesn't need to spool fast, it's spooled on the launch, and doesn't really lose much during a shift anyway I would however like to see if that flat shift trick will pick me up a tenth or so.. Believe I can easily drop into the 9s with what I got and just alot more tuning, and fix a few crappy parts of the kit like the downpipe and the whole charge side. there is power to gain everywhere in my crappy setup, think I can gain another 250 RWHP... Put me at 830 RWHP..
What numbers do other 408/88 owners run? what kind of problems? what kind of backpressure (the point of this thread! lol)
10-06-2009, 03:48 PM
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Actually, yes....
I want to be the world's fastest 6 speed one day and I believe it to be entirely possible with the 101 once I get that setup running but taking baby steps with the 88 until I know what Im doing, how to make the car use the HP its got with the M6, learn whatever tricks to drop the ET down etc. Then apply what I learn to the 101 and try and run 8.50s and make 1500 RWHP
I want to be the world's fastest 6 speed one day and I believe it to be entirely possible with the 101 once I get that setup running but taking baby steps with the 88 until I know what Im doing, how to make the car use the HP its got with the M6, learn whatever tricks to drop the ET down etc. Then apply what I learn to the 101 and try and run 8.50s and make 1500 RWHP