What size turbo for 427?
Thread Starter
Teching In
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What size turbo for 427? I have a c5r 427 with 8.5:1 compression. I am doing a custom single turbo kit on it this winter. I want to make around 700 rwhp. What turbo do you guys think is the best for this setup. PTE 76, 72??? Q-trim, ball bearing?
I am all confused?
Thanks
I am all confused?
Thanks
On The Tree
Joined: Jul 2002
Posts: 179
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From: Texas
I would talk to a sponsor that is experienced with turbos first if i were you. There are quite a few knowledgeable turbo guys in here ( me not being one, but am trying to be) and I am sure they can help. I am just saying you are talking about a custom turbo system with a stroker motor, a lot of money is involved, and I am sure you would want the right setup for your combination and goals the first time. IMO
You'll be much better off with an 80 or 88 than a 76.
The boost level and flow for a 427 and only 700 rwhp will be way outta the useful range of the 76. An 88 will be much happier at that operating point, and leave you some "room" to grow
Shouldn't have any problem spooling it either.
The boost level and flow for a 427 and only 700 rwhp will be way outta the useful range of the 76. An 88 will be much happier at that operating point, and leave you some "room" to grow
Shouldn't have any problem spooling it either.
Thread Starter
Teching In
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Originally Posted by ChrisB
Yeah, I say go for an 88 also.
It says on the Precision website that the gt76 ptq will support 975hp so I figured that was probably 800 in real world terms. I have seen some t88 on so supras and the don't spool until 6000
I want the car to be rediculous fast but I still want to be able to drive it on the street with minimal lag. I think the motor will probably only take 15 lbs of boost max because of the head bolt configuration or I will be lifting heads left and right.Thanks
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You will have no problems spooling an 88MM with 7 liters of engine. The GTQ 76 will make all the power you want, but it will probably spool TOO fast. the 88 will help to keep the power levels usable and will make the CFM you need for 700 HP at a lower inlet temp than a comparable 72 or 76...... more efficient.
Originally Posted by Whistler
You will have no problems spooling an 88MM with 7 liters of engine. The GTQ 76 will make all the power you want, but it will probably spool TOO fast. the 88 will help to keep the power levels usable and will make the CFM you need for 700 HP at a lower inlet temp than a comparable 72 or 76...... more efficient.
Stenod
Big!!!! 
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From: Texas, it's like your state, but better.
werd Stenod. go big or go home. the 101 gets my vote. 
i was thinkin the same thing just before i saw the post. just be sure and open up the AR on the turbine side pretty well, and it'll be pretty insane. i'd LOVE to do something like that.
i was thinkin the same thing just before i saw the post. just be sure and open up the AR on the turbine side pretty well, and it'll be pretty insane. i'd LOVE to do something like that.
that 975 is flywheel, which like you say may be 800rw and thats at max psi of 30 or so which you say you want to stay around 15.. i vote 88mm
also FWIW boost is not related to lifting the head, thats cylinder pressure. you can run 30# of boost on these engines and not lift the heads.. admittedly one or more things in the set up are inherently wrong at this point as 30psi SHOULD be at least 900rwhp.
also FWIW boost is not related to lifting the head, thats cylinder pressure. you can run 30# of boost on these engines and not lift the heads.. admittedly one or more things in the set up are inherently wrong at this point
as 30psi SHOULD be at least 900rwhp. 
Thread Starter
Teching In
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Originally Posted by CANNIBAL
What would ~10 lbs put down on a 427 with compression above, great heads and nice cam? Also, would this be a single turbo setup or dual?
Hopefully a PTE t76 gtq with a 427 at 10lbs boost it will make 700rwhp with good tuning.
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Lag with a small-frame T88 is going to be nonexistant. With a .96 tang housing on my friends 383 8:1 compression we were making 18 pounds of boost by around 3600 RPM's. A PT76-GTQ in reality will support more than 900-some-odd horsepower, pretty much all turbos on PTE's site are underrated. They used to rate the PT74 at like 850 horsepower but i've seen over 800 at the wheels with one.
The GTQ PT turbos support way more than the website suggests.... as well as having spool characteristics similar to a smaller turbo. With an engine that big in a street car, you will definately want SOME lag. A GTQ 76 MM on a 7 litre LS1 would probably put close to 1000 ft lbs to the wheels by 3500 RPM and be nearly undrivable at WOT. My vote is for the 88. It will make all the power you'll ever want at efficient operating speeds, and if you ever want to turn up the volume and go racing, it will put a 3300 lb car DEEP in the 8s.
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From: Bellingham, WA
Well if it was me personally I would look in the 88-91 mm range and shoot for bear. I think that is way way more turbo than your hp goals but will get you there very easily. The one thing I see is that with a 427 ci setup you will spool alot of turbos up very fast. I have a t-100 but would not put aspirations of a street car running this turbo.
A t-76 will achieve your hp goals though if that is what you want. mustang guys have gotten alot more hp out of a t-76 than some think. (Big daddy ran what 8.19 at 189 with a 77.8 mm max size????) I would say that it is very easily going to get your hp wants in your ballpark.
If your going to spend the money for a c5r block and all the goodies might as well get a big turbo (88-91)
You could just buy my 100 and be done though lol
Have fun with the build
Steven
A t-76 will achieve your hp goals though if that is what you want. mustang guys have gotten alot more hp out of a t-76 than some think. (Big daddy ran what 8.19 at 189 with a 77.8 mm max size????) I would say that it is very easily going to get your hp wants in your ballpark.
If your going to spend the money for a c5r block and all the goodies might as well get a big turbo (88-91)
You could just buy my 100 and be done though lol
Have fun with the build
Steven
