Re-Visited the Dyno yesterday...

BiG MiKE

BiG MiKE

Driver
So I took my car back to the dyno yesterday after changing a few things that gave me problems last time - BOV, couplers, fans, boost cont., actuator, etc..

Heres the thing which baffled the fawk outta me and everyone there - I am running a GT2871r .64a/r with Tomei 256/256, 740cc, etc.. all the nessessary mods for 350ish rwhp

@ 10psi (ATP's "Special" Actuator) I made 296rwhp/256rwtq

@15psi I made 328rwhp/283rwtq - everything seemed spot on - for those 2 runs

So we Tried for 18-19psi - Car would completely fall flat on its face @ 6500rpm and 330rwhp as if it had some sort of rev limitter (PowerFC was set to 7400rpm) AFR's were perfect, timing was good, hp and tq curve looked great.. it Just Stopped @ 6500 rpm even holding the pedal down - it sounded like someone had turned on the dyno brake (if that makes any sense)

Under no Load or lower psi the car would rev out perfect in/out of gear

The PowerFC was reading the MAFS max voltage? @ 4400mv
The TPS graph showed it was reading fine
AFR's were perfect
Timing was dead on

WTF?

Sidenote: The shop owner said the turbo may be failing @ higher psi or Locking up (which should/would restrict air flow causing the symptoms) He mentioned that he'd seen this before - idk guys wtf?! help

We also tried it a few times - it would happen everytime @ ~6300-6500 rpm
 
I had the same problem it's the turbo!!!
Except this: "Car would completely fall flat on its face @ 6500rpm and 330rwhp as if it had some sort of rev limitter (PowerFC was set to 7400rpm) AFR's were perfect, timing was good, hp and tq curve looked great.. it Just Stopped @ 6500 rpm even holding the pedal down - it sounded like someone had turned on the dyno brake (if that makes any sense)"

When we went from s15 T28 to a new GT2871r .64a/r we gain like 50whp.
Good luck!!
 
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SAS said:
how many miles are on the turbo? do you have any boost leaks?
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No boost leaks - we checked right before we headed out to the dyno
Turbo haz less than 2500 miles - bought it brand new for the build

z4k said:
Sounds like the cartridge on the turbo maybe failing.
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Thats what Steffan @ STP is thinking too.. shitty shitty shitty... brand new turbo FTL

BoostedKouki said:
Weak dyno..
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Dizzz guy... wheres ur dyno sheet?

E'sFactoryAE86 said:
Vids wouldve been sweet,,,
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Ive got one short clip from my fone - ill post it later

zolika said:
I had the same problem it's the turbo!!!
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Yeah.. its not the cheapest part to replace tho :( i guess ill beat on it @ 15psi for now :D I could live with 330rwhp for now
 
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Bringing this thread back - seems now that im looking @ my turbo the shit has more play than Abes backdoor which is why it was probably wasnt making power @ hi boost levels

Anyone know of anything I can do with a Garret GT2871r to fix or is it a total loss?
 
BiG MiKE said:
Bringing this thread back - seems now that im looking @ my turbo the shit has more play than Abes backdoor which is why it was probably wasnt making power @ hi boost levels

Anyone know of anything I can do with a Garret GT2871r to fix or is it a total loss?
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rebuilt it
 
gotcha. i was just checking, cuz i get tuners that call me occasionally that have the same issue and its cuz they forget to shut the damn top speed limiter off, lol
 
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