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Discussion Starter #1
well where to start . i bought a hellion kit and installed it on my 331 foxbody notch . i have a t-trim charger on it b4 and made 510 rwhp at 10lbs of boost . i decided to take it off and put a turbo on it and unfortunately im barely touching 400 at 13lbs with a t76 with a 96ar . my car on the dyno after 4400 rpm is not making motor hp but the boost is up the can anyone help me ??? or have an explanation for that .im making low 400's at at 4400 rpm help me find the other 1700 rpm of power please i know i should at least be somewhere between 510 and 570 rwhp
 

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yo dude post the stats. there's too much to it to guess.

post compressor map. combination(heads, calculated airflow/pressure ratio), etc.

the turbine a/r will definitely have something to do with it, but my guess is you have plenty of turbine gas flow.



im gonna start with easy stuff.

are u sure about your inlet system restriction?
what about piping pressure drops
intercooler

the the pressure you listed at the discharge nozzle or manifold?

have you figured your pressure ratio and the compressor?

have you plotted the point on the compressor map?
are u sure where u are falling on the efficiency scale?
do all of the calcualtions.
 

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looking at a t76 map it flows enough for around 800hp. correct me if im wrong but 400hp is like 45 lb/min.

so no way the turbo itself is an issue.


assuming everything is good on ur system 13psi is about 1.88 PR. of course it isnt because things prohibit that.
 

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34-70 lb/min is about the map's range or about 640hp or so.

that assumes ur motor uses that volume well.

i guess what im sayin is TUNE. missin it somewhere is my guess. im not willing to calculate airflow for you at 4400rpms but it is probably near 55 considering drivetrain losses.

nowhere near a problem for that turbo.

tune man.
 

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What plugs and gap are you running? What ignition are you running? What is your complete combo?

Like others have said, post you're dyno readout with AFR's.
 

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Discussion Starter #7
ok my combo goes as this 331 stroker motor 8.5.1 comp. afr heads . andersonson cam . eldebrock intake . msd ignition msd 6a box i also run an anderson pms . my turbo kit consist of a hellion kit which came with a t76 turbo with a .96 ar housing . and evolution waste gate i am running an intercooler but dont know the size but it is the standard one from there website im running 60# injectors, 3.27 gears . the plugs i think are ngk 9's and the last i know they were gapped at .28 . im gonna run over to the shop today and try to get the dyno graph so i can post it up thank every one for the help
 

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whats your timing and fuel pressure set to?
 

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Discussion Starter #9
i know the timing is at 10 at the bottom and 20 to 22, 23 on top and the fuel pressure i ha e to get the info from the shop
 

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what is your AFR at WOT? i would say it should be 11.0-11.2 for saftey on pump gas
 

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A dyno grapgh would be nice to see and the air fuel ratio.

Which AFR heads and manifold do you have?

Who is tuning the car in Brooklyn and what kind of dyno is it?

I agree that your turbo is capable of around 700rwhp. It would have to in the tune or a mechanical issue.
 

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should have side to side play, NO IN AND OUT and should NOT touch the scroll at any point. i am going to say you might have an exhaust leak, your valve springs are shot, or you have a blown head gasket or leaking intake gasket. it doesnt plow oil out of the pcv does it ? at 13lbs off that 76mm on a 331 you should be making around 575 rwhp

does it break up at all or fall on its face ?
 

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Discussion Starter #15
A dyno grapgh would be nice to see and the air fuel ratio.

Which AFR heads and manifold do you have?

Who is tuning the car in Brooklyn and what kind of dyno is it?

I agree that your turbo is capable of around 700rwhp. It would have to in the tune or a mechanical issue.
-the car is being tuned on a dyno jet
-the heads are afr 185
 

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i'd say it's time to take it to someone who knows how to tune it, my stock shortblock 302 60mm turbo would kill your car right now lol. what are you using to tune it?
 

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i'd say it's time to take it to someone who knows how to tune it, my stock shortblock 302 60mm turbo would kill your car right now lol. what are you using to tune it?
Its not the tuner:shakehead my car is also being tuned in the same shop and is making power...
 

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at 13 pounds springs shouldnt even be close to an issue unless we're talking .650lift radical lift rates or something.

im using stock springs at 14. of course .420lift is why.

it could be exhaust related, but im only running 2.5" up pipe and no problem boosting to the moon. i know its not a 331 but ported 4v uses a tiny bit of airflow.


really more info is needed. i think if the a/f was too fat he'd notice the diesel like smoke, or if too lean to blowout hed burn a piston pretty quickly. dyno operators are pretty good about shutting it down.

plug blow-out, fat a/f, too much timing(counter-torquing), or actual boost at rpm is not really there. just dunno.
 

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cam grind? u using a blower grind on a turbo?
 
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