I was wondering if anyone has any experience or know about the power levels HP/PSI of a Precision model # 74HPSHP Part # 650-1825 with a .81 a/r on the back. No, it's not my turbo but was wondering what the HP level are going to be on a LS-Vtec build 84mm. My buddies purchased this turbo with the intention of reaching 750whp +.......Feedback Please...Thank You!!!!

 

Would that be the PT74?

 

PT74 yes, that turbo is rated for 1050hp , I would ASSUME it can make 750whp no problem

I'd prolly put the .96 A/R turbine on it though, it has a GTS turbine wheel


Modified by Boostfed.com at 10:40 PM 9/4/2007

 

Yes I believe it is a PT74 according to the part #......With a .81 ar wouldn't it hold it back at top end? Will it make 800whp?

 

i have seen a pt70gts make 820whp...

 

in a customers car on a built motor, stock bore, crane cams,81 a/r at 40 psi we made 803whp on a dynojet.

 

Wow, I like the numbers on that turbo...I have a question though, why is the majority of SPFWD using 4294r? Isn't that bigger than the pt74?

 

They are using the 42r with the 70mm inducer wheel.....a pt74 would not be legal..

 

OH, wow....Now I understand the concept of the whole thing better. So with the 70mm inducer wheel they run the 1.28 or so a/r housings in the back to get the power advantage...?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by FRernesto &raquo;</TD></TR><TR><TD CLASS="quote">OH, wow....Now I understand the concept of the whole thing better. So with the 70mm inducer wheel they run the 1.28 or so a/r housings in the back to get the power advantage...? </TD></TR></TABLE>

People are running 1.01, 1.15 and 1.28 A/R turbines on the GT4294R, the PT74 is bigger on the compressor side BUT the GT42R turbine wheel is larger then the GTS wheel

 

Ok, so to better understand this the PT74's compressor wheel is larger and the 42r is smaller but the turbine side of the 42r is larger...?correct so far? What are the pro/con's of the larger turbine side?

 

larger turbine side gets that power out efficiently instead of bottle knecking it but some people say that it hurts spool time and such but i dont agree with that, Theres people on here that are spooling these things like your sisters sc61, LOL.

 

LOL...Good one, yeah I agree I've seen these 42r's spooling like small frame turbos...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by FRernesto &raquo;</TD></TR><TR><TD CLASS="quote">Ok, so to better understand this the PT74's compressor wheel is larger and the 42r is smaller but the turbine side of the 42r is larger...?correct so far? What are the pro/con's of the larger turbine side?</TD></TR></TABLE>


Yes but keep in mind this is the GT4294R we are talking about, a GT4202 is 74.3mm inducer and 102mm exducer so..........

 

So......A GT4202 would not be legal correct? SPFWD that is....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by FRernesto &raquo;</TD></TR><TR><TD CLASS="quote">So......A GT4202 would not be legal correct? SPFWD that is....</TD></TR></TABLE>


NO. SFWD turbo limit is 72mm for the compressor inducer

 

Ok, so for someone looking to extract a large, large amount of HP the GT4202 would be great? Or a PT74? I'm just trying to gather some smarts cause I have some friends who are looking of insane HP.....Not me I love my little gt35r....lol

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Boostfed.com &raquo;</TD></TR><TR><TD CLASS="quote">NO. SFWD turbo limit is 72mm for the compressor inducer </TD></TR></TABLE>

I know FMFkid has a 4294 on his hatch but used a reducer to effectivly make the inducer smaller thus making is legal for power street and that is 67.7MM max . so in theory if you want a larger exhaust side you can just run a reducer on the bigger turbo

 

a 74mm turbo on a supra will be laggy.i can only imagine on a civic

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BoostR41 &raquo;</TD></TR><TR><TD CLASS="quote">

I know FMFkid has a 4294 on his hatch but used a reducer to effectivly make the inducer smaller thus making is legal for power street and that is 67.7MM max . so in theory if you want a larger exhaust side you can just run a reducer on the bigger turbo</TD></TR></TABLE>


I don't think that's legal for NHRA, the actual compressor wheel inducer can not be bigger than the rule.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tony1 &raquo;</TD></TR><TR><TD CLASS="quote">


I don't think that's legal for NHRA, the actual compressor wheel inducer can not be bigger than the rule. </TD></TR></TABLE>


I was gonna post the same thing, this was done last year in SPort FWD and then this year NHRA said that was a no go

 

Thats a big no go in NHRA, the wheel acually has to be 67.8
but its ok for the NDRA

 

Will a PT74 cause a lot of back pressure due to the small turbin ar housing?