pt94 is it too big for the street?
01-29-2014, 09:30 AM
#1
pt94 is it too big for the street? Hey what's up ls fans. I have an 84 z28 with plans of having either a 404 build or 427 build for boost. I across a pt94 on a good deal (not bought It yet). I dont know much about turbos but the guy told me its on a t5 frame but has a small housing on it so it can spool quicker. He had it on a 370cid in a 92 camaro no ic but he has been told it can be driven on the street. I plan on running a 400 tranny with either 3.50 or 3.70 gears. Also I went to precision website and its listed under their street/race turbos. Is anyone running a 94mm turbo or the exact pt94 itself on the street? Thanks.
01-29-2014, 07:38 PM
#3
I'll throw out the cookie cutter "what are your goals" question since everyone seems to want to know what turbo to use, but doesn't give any info on what they want out of it in the first place.
01-30-2014, 10:14 AM
#6
It is going to be lazy regardless of housing. It is either an f or g trim turbine. Very large
~127/111 G or ~127/106 F
Compare that to
Gt55 turbine is 112/102
The large s400 turbine many run at 96/88
~127/111 G or ~127/106 F
Compare that to
Gt55 turbine is 112/102
The large s400 turbine many run at 96/88
01-31-2014, 02:48 AM
#7
See that's confusing the g and f trim. I dont know what to make of it. And the a/r as well. Which turbo will be best efficient and reliable for either 404 (stock block) or 434 build
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01-31-2014, 04:50 AM
#8
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Trim is just the ratio between the inducer and exducer of the compressor or turbine wheels in the turbo. Saying something is a G trim or an F trim or whatever trim is just the manufacturer's short hand for those ratios. The formula is:
((Minor Diameter/Major Diameter)^2) *100
The G trim is 76 and the F trim is 69.
Keep in mind that on the compressor wheel the inducer is the smaller diameter and the exducer is the larger diameter but on the turbine wheel it's reversed.
The trim affects the shape and weight of the wheels. On a compressor wheel a higher trim means the wheel is able to scoop up more air to force into the engine which makes for a faster spool time but can also lead to surging where the compressor is moving too much air low speed. On the turbine wheel higher trim will also help with faster spool but will limit the amount of exhaust gases which can pass through the turbine housing. You also have to take into account that increasing the trim of a wheel also increases the weight since you're effectively adding material to it. This will also have an effect on spool times since more weight takes more energy to move (yeah physics!).
The AR is another ratio that is harder to explain but for all intents and purposes it's the size of the actual housing. Bigger housing = more flow but less gas velocity to drive the turbine and visa versa.
((Minor Diameter/Major Diameter)^2) *100
The G trim is 76 and the F trim is 69.
Keep in mind that on the compressor wheel the inducer is the smaller diameter and the exducer is the larger diameter but on the turbine wheel it's reversed.
The trim affects the shape and weight of the wheels. On a compressor wheel a higher trim means the wheel is able to scoop up more air to force into the engine which makes for a faster spool time but can also lead to surging where the compressor is moving too much air low speed. On the turbine wheel higher trim will also help with faster spool but will limit the amount of exhaust gases which can pass through the turbine housing. You also have to take into account that increasing the trim of a wheel also increases the weight since you're effectively adding material to it. This will also have an effect on spool times since more weight takes more energy to move (yeah physics!).
The AR is another ratio that is harder to explain but for all intents and purposes it's the size of the actual housing. Bigger housing = more flow but less gas velocity to drive the turbine and visa versa.
