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Discussion Starter · #1 ·
I'm looking at a single setup with plenty of mid-range power for messing around on the street and driving spiritedly through the mountains.

I've narrowed it down to needing about 84 lb/min of air and a pressure ratio of 2.2.

I've been looking through Garrett's guide for selecting the right turbo based on airflow and pressure ratios, but what dictates it being a low spooling turbo (about 3000-3500 rpm) versus a higher spooling (4500 rpm) when looking at compressor maps?

How much of the spool can be tuned buy selecting the right compressor and turbine housings?

Someone recommended a PT6870 CEA Gen2 for the above listed purpose, but $2400 is a bit steep IMHO. Willing to look at Borg Warner, Turbonetics, and Garrett as well.

--Matt
 

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Head of R&D at A1 Transmission
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You can't have it both ways. If you spec it out to run well on the street it will lose steam up top when you try to run 1/4, 1/2 or mile events. The turbo is only one part of the puzzle. Cams, converter, boost controller and especially tuning all make a complete package.

I would call Precision Turbo, Garrett, Comp, etc and see what they suggest given your intended powerplant combo but personally I wouldn't consider anything smaller than 76mm
 

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Discussion Starter · #4 ·
Look up forced inductions. They make custom borg turbos. Give them call. They can spec it
I'll check them out, thanks!

You can't have it both ways. If you spec it out to run well on the street it will lose steam up top when you try to run 1/4, 1/2 or mile events. The turbo is only one part of the puzzle. Cams, converter, boost controller and especially tuning all make a complete package.

I would call Precision Turbo, Garrett, Comp, etc and see what they suggest given your intended powerplant combo but personally I wouldn't consider anything smaller than 76mm
I'll have to call precision back since I decided to go single instead of twins. Already have heads/cams and existing converter is a 3000-3500 stall. I'm going to start perusing the GT500 guys to see what they're doing with single turbos.

I hope more people here will chime in with their single turbo setups and how their's build/hold boost.
 

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Try out an On3 turbo. You can get them fairly cheap and if you want something bigger or smaller it will only be minimal money's out of pocket.
 

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Its just a 2v :]
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647 Posts
Billet 7675 is a plenty enough turbo to play on the street an track Auto part Automotive super charger part Rim Muffler Metal


⚡⚡Turbo power for the win ??⚡⚡
 

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Discussion Starter · #8 ·
^^^ Yeah after speaking with Precision this week I've settled on the 7675 and talking with a few other people on the forum, seems like it will be the best all-around option.
 

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Discussion Starter · #10 ·
Ehh... don't really want to get involved in nitrous, plus I can't run much more than 20 psi with my current intake manifold of choice, so if it can maintain that all the way through the RPM range I should be good.
 

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Likes the corn brew
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Take a look at the BW S400s with a race cover and 80+mm FMW

You may want a t4 backside for better street manners, I have a t6 on mine and it can be a little laggy. I think that turbo with the largest t4 backside and turbine wheel will serve you well.
 

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I've got a T6 S475 w/ 87 turbine wheel.

It's a little sluggish but makes power (853rwhp @ 23psi and stock PI heads).

The T4 version will work well for what your doing
 

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Discussion Starter · #14 ·
I've got a T6 S475 w/ 87 turbine wheel.

It's a little sluggish but makes power (853rwhp @ 23psi and stock PI heads).

The T4 version will work well for what your doing
Good deal. From several people's advice I'm looking intently on the T4 S475 with 83mm turbine. Not sure on the race or standard cover yet.
 

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Slowly But Surely
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I run an old GT42/76 with a 1.10 housing it does really well, and I have a bigger hotside laying around I'd like to try out to see if I like it. Its laggy but it pulls great once its spinning.
 

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What does everyone think about the Precision PT8847?

About the same physically as the 76/75 but with a lot more compressor and turbine flow. Only comes in a .96 t4, but rather large wheels. They rate it to 1400hp, and I have seen some guys on Yellow Bullet make 1100-1200 wheel.

http://www.precisionturbo.net/Stree...ils/Street-and-Race-Turbocharger---PT8847/287

I wonder how a truck would run with this turbo on a CG Fab Hotside.
 

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Matt, forced performance super99 is a solid choice. Its moves 103lbs though but given that its not a T4 frame should still spool really quick for you. That Turbo alone should see full boost around 3500 rpm and pull all the way to the low 7k range. Granted I don't know your exact head flow setup but still a solid street turbo choice and they go on sale every now and again as well.

You would have to go much larger in a precision unit to find something comparable but then add in the lag
 

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I wouldn't run anything with a T3 frame as a single on a 5.4 DOHC. I'm using a T6 backside on mine.
Are you thinking because it will spool to quick and not have enough top end?
 

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El duderino
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if i were to do it again and build a street truck, i would go for a t4 housing with a 88mm compressor inducer. find a turbo with different turbine housings available so you can tune the spool and top end characteristics.

t6 housing here (holset hx60) with an ugly external variable vane setup 1.32 turbine a/r and an 82mm compressor inducer. 3500 stall and it spools pretty quickly for a big heavy diesel turbo. can build a few psi on the foot brake. it does run at roughly a 1:1 boost to back pressure ratio (ignoring gauge inaccuracies)
 
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