I want you guys opinion on what setup i should use.
I have bought a LSX 427 with TFS 235 CNC heads. I already have a PT91 G-trim turbo, but itīs going to be too small.
1: Upgrade to a 98mm G-trim
2: Twin PT67 or PT71 billet turbos
I want to make 1600-1700 hp with as fast spool as possible.
Twin would be better so i can fit my water intercooler and tanks in the front of the car.
i would def go with the twins-the 67's would be a little on the small side.The 71's would be a much better match.your camshaft will determine the spool up speed more than anything else.
__________________ www.virginiaspeed.comcustom engines for street or race,tuning,installs,fabrication. check our our online store-i'm adding new products every day http://shop.virginiaspeed.com/main.sc757-468-5101 1979 Z28 Outlaw 10.5-670bbc twin promod 94's Crew Chief,engine builder,tuner of Phil Thomas's
LSX powered Mustang"The Renegade" 7.29, 198mph-best 1/8 et.4.70 @ 164mph 315 radials at 3275lbs
PT67 billet works perfect on euro engines and have made 750 whp. With the T4 0.96 housing i think they would work nice on my new engine.
My cam is a 248/252 with 0.650" lift and 115 lobe.
just because it made 750rwhp on one engine,doen't mean it will on every engine.You really need to calculate your lbs per min vs pressure ratio and look at the turbo map-the large engine will run at a much lower PR and require a larger turbo.you also need to consider exhaust backpressure into this equation.
__________________ www.virginiaspeed.comcustom engines for street or race,tuning,installs,fabrication. check our our online store-i'm adding new products every day http://shop.virginiaspeed.com/main.sc757-468-5101 1979 Z28 Outlaw 10.5-670bbc twin promod 94's Crew Chief,engine builder,tuner of Phil Thomas's
LSX powered Mustang"The Renegade" 7.29, 198mph-best 1/8 et.4.70 @ 164mph 315 radials at 3275lbs
I know. I work with this all day But not with V8:s ...
A 67 billet on a supra 3 lit makes 750 whp easy without backpressure. And a 427 cui is 7 lit. So i think it would make 1600 flywheel hp with T4 0.96 housing at 22-28 psi because i know they flow so much at that boost level.
But it would be easier with larger turbos, but i really want the spool.
Looks like you already made up your mind which way to go way before you posted this, so just go with what you have in mind and start putting them together, I'm sure it would be a monster. Good luck and keep us posted!
well why ask, if you are only going to argue? when you get a response from a noted sponsor,and someone who does know about it on a V8,take his advice,no point in saying well "i know this and this" you did ask after all
__________________ Eric
2002 Firehawk M6 #0490. LS1tech Stock. Tuned @ CMS
LS1Tech Reverse split Crew member #01
just because it made 750rwhp on one engine,doen't mean it will on every engine.You really need to calculate your lbs per min vs pressure ratio and look at the turbo map-the large engine will run at a much lower PR and require a larger turbo.you also need to consider exhaust backpressure into this equation.
You got an inside line on Precision Turbo compressor maps?
I sure would like to see one for a PT88.
__________________ 98Z28CobraKiller 370ci LQ9 + AFR225's + PT88 9.57 @ 142 so far
Iīm a world distributor for Precision turbo here in sweden. So i have been able to test a lot of cars in my dyno. But iīm quit new in V8:s so thatīs why iīm asking here.
IMO the 71's will work much better with your setup-like i stated before the camshaft will dictate the spool more than turbo size-i can tell you that the camshaft specs you posted will not give you the results you want.
you really can't compare a 3.0 inline 6 to a 7.0 v8,the long stroke of the v8 will make a ton more tq which greatly helps with spool.
__________________ www.virginiaspeed.comcustom engines for street or race,tuning,installs,fabrication. check our our online store-i'm adding new products every day http://shop.virginiaspeed.com/main.sc757-468-5101 1979 Z28 Outlaw 10.5-670bbc twin promod 94's Crew Chief,engine builder,tuner of Phil Thomas's
LSX powered Mustang"The Renegade" 7.29, 198mph-best 1/8 et.4.70 @ 164mph 315 radials at 3275lbs
I had this camshaft in my old 6.0 lit LQ9 with stock heads. I dynoed 1360 hp and ran 8.03 as best. I had power peak at 7200 rpm with that setup and it spooled very nice with my 91mm G-trim. But maybe i should listen to you and order a new camshaft from you. I will send you a pm about that with my new engine spec.
1360 on stock 317 heads WTF????? Oh and u dont really have to order a cam from him. No knock to va speed, but keep up your reasearch you will find what u allready was looking for. What ci was the lq9 and how much boost?
__________________ 760 HP 689 TQ !!! THANKS LETHAL PERFORMANCE!!!
14psi
Like I said, for that much power the 71mm will work better. The 6765 is great on Supras, I know a couple guys making 850whp, but those are very efficient motors and with very high boost you increase the efficiency greatly. A 427 wont be as efficient and you wont squeeze as much power from it. You may be able to make 1500 with the 67's, but you will be running them near the limit all the time.
do a couple of TC 76's Ask Tiago about his build. He has a lsx 427 build with twin 76's. Makes good power as well.
__________________ Winter build: TT w/ a/c setup built by Josh @ KYTP w/ tc72's LME built 408 LSX w/tfs 235 6 bolt heads, moroso oil pan, comp cam by Vengeance, the ole howling dana 60, bmr turbo k, full suspension by umi and spohn torque arm
Help me choose turbo setup! 
But not with V8:s ...
