Dyno 402 T76GTQ ### in
10-25-2006, 09:39 PM
#63
Originally Posted by 02SSLE
is there some kind of equation to figure out how much is all right?
You talk directly with Jose, he's probably the only one that can figure them out on paper. Him and Corky Bell.......the rest are just guessing...lol. I know its not easy, since you will require headflow, VE, compressor maps and turbine maps which are very hard to find.
10-25-2006, 10:24 PM
#64
Originally Posted by 02SSLE
is there some kind of equation to figure out how much is all right?
Mike
10-25-2006, 11:27 PM
#66
Originally Posted by Dbluegoat
only and 1000rwhp should never be used together
10-25-2006, 11:35 PM
#67
By the way, the following are the sizes for the S versus Q exhaust wheels:
Q
Inducer: 3.110"
Exducer: 2.695"
Exducer flow area: 5.70 in^2
S
Inducer: 3.200"
Exducer: 2.960"
Exducer flow area: 6.88 in^2
The S trim wheel has almost 21% more flow area than the Q trim wheel. I believe that will be significant when pushing these turbo's to the limit.
Mike
Q
Inducer: 3.110"
Exducer: 2.695"
Exducer flow area: 5.70 in^2
S
Inducer: 3.200"
Exducer: 2.960"
Exducer flow area: 6.88 in^2
The S trim wheel has almost 21% more flow area than the Q trim wheel. I believe that will be significant when pushing these turbo's to the limit.
Mike
10-26-2006, 10:49 AM
#68
Flow area is part of the equation, but where is blade height used? Just the difference between Garrett's old Q and GTQ is night and day and they both measure the same. Blade height and pitch are the only things that changed and it made a load of difference in power.
10-26-2006, 12:11 PM
#69
Originally Posted by DrTurbo
Flow area is part of the equation, but where is blade height used? Just the difference between Garrett's old Q and GTQ is night and day and they both measure the same. Blade height and pitch are the only things that changed and it made a load of difference in power.
The exducer dimension only describes the pressure drop aspect.
The GTS wheel will not only flow more than the Q-trim, but also will produce more power to spin the 76 mm compressor wheel. I really believe that alot of people who think they are choking the compressor are actually just not able to spin it fast enough.
10-26-2006, 12:39 PM
#70
Could be, but the only way to tell that would be by the intake temps. If they stay steady and won't produce more boost, then the turbine is done and the compressor still has room. If the temps climb hard, then they are ruunning the compressor wheel well above efficient output.
10-26-2006, 09:13 PM
#72
Originally Posted by 02SSLE
So what Kinda back preasure numbers should I see?
Mikr
10-29-2006, 11:04 AM
#74
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Well guys I tested the back preasure yesterday and found it to be 65 pounds in the passenger side manifold. I took off the block off plate on the manifold drilled and taped it. I put a preasure gauge on it under boost the guage read 65 pounds at 12 to 14 pounds of boost. Seems to be high. With cut out open it only drop 5 pounds of back preasure. Is this all you guys need?
10-29-2006, 11:11 AM
#75
Holy ****! That is WAY too high. 
Get that number down to about 25 psi at 15 psi boost and your power numbers are going to skyrocket!
65/14 = 4.6 backpressure/boost ratio. That's the highest I've ever heard of!
Mike
Get that number down to about 25 psi at 15 psi boost and your power numbers are going to skyrocket!
65/14 = 4.6 backpressure/boost ratio. That's the highest I've ever heard of!
Mike
10-29-2006, 11:11 AM
#76
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Also I think the waste gate spring is trying to bleed off some of the back preasure becasue it starts surging. It did this on the dyno. We took it off the dyno and pulled the spring. It's red 10 pound spring we made some shims and put under the spring in the wastegate and it made it better but didn't take it all the way out. I really notice it on the freeway. When I really lay into it. Any advice is much needed.
10-29-2006, 11:14 AM
#77
Describe your system in detail. Is it log, or tubular? What size primaries? What size crossover? What size log? What are the spec's on the turbo? What size downpipe? What size exhaust? What type/size muffler? Where is the cutout? Have you tested the BOV for leaks? Have you tested the cold side for leaks? What size intercooler? What size cold side piping?
High backpressure can be caused by a restriction on the cold side also. You may consider checking boost at the discharge of the compressor and comparing to the plenum. Anything more than 10% boost drop and you should do some improvements.
Mike
High backpressure can be caused by a restriction on the cold side also. You may consider checking boost at the discharge of the compressor and comparing to the plenum. Anything more than 10% boost drop and you should do some improvements.
Mike
10-29-2006, 11:36 AM
#78
4.6:1 backpressure is VERY high. I see 45psi back pressure @ 15psi of boost anytime I take the motor over 5500 rpms. This is with a Innovative T76 and R trim exhaust wheel. I am on a small housing .81 a/r though. On 10psi the car makes power out to 6500 rpms, but on 15psi I have to shift it around 5800-6000 because it dies off very quickly.
Instead of spending the money on playing with exhaust housings i've decided to just try a pt88 out on my setup. I'm just hoping I can spool it decently.
Instead of spending the money on playing with exhaust housings i've decided to just try a pt88 out on my setup. I'm just hoping I can spool it decently.
10-29-2006, 12:55 PM
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I don't have all the info but have some for you. It is log setup, T76GTQ from Precision, 3 inch down pipe and 3 inch CME SLP, the cutout is right at the 90 that crossover too the other side of car, I haven't checked cold side preasure. Please be patient with me. I am going to tap the turbo outlet side and check the boost preasure right out of turbo and at the manifold (boost guage).