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Discussion Starter #1
I'm planning to turbo my 408w. Looking at the PT88 kit from B&G...

I'm told I should be able to make around 700rwhp with 15lbs boost...what kind of rwtq will I make at the lower RPM's? I'm a little concerned about turbo lag. This is a street / strip car.

What rear gear do you recommend?

Thanks,
Jim
 

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Turbo lag on a 408 with a PT88?? lol lag wont be your problem, choking your motor will be the problem. 408 cubes is a lot, you are going to need to step up to a T6 turbo, like a S480. Brian will set you up with the proper set up.
 

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I'm about to put a Precision gt4708 (80mm) with a T4 .96 AR. It's actually a T5 hotside they call it. Same size as a T6 but with a T4 size where it bolts up to the manifold. I'm putting this on a brand new 408 I have with AFR 205's, Victor 5.8 efi. I'll let you know how it works out, my buddy who builds 3000+ hp turbo cars said I shouldn't have any issues with this turbo on my 408 so we will see.
 

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Discussion Starter #4
low end power?

So...what kind of rwtq will I make at 2k rpms? 2500 rpms?

Brian at B & G advised that I'll need run 3.55 or even 3.27 rear gears...I want to make sure that the turbo makes up for this gear change & then some!

My hope is this set up will spring to life just off idle & pull like a freight train to 6k or 6500 rpms!

Will the pt88 & a well built 408 stroker do this for me?

Thanks,
Jim
 

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Wow your in for a surprise. Traction is going to be the issue not turbo lag. Have fun.
 

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I'm planning to turbo my 408w. Looking at the PT88 kit from B&G...

I'm told I should be able to make around 700rwhp with 15lbs boost...what kind of rwtq will I make at the lower RPM's? I'm a little concerned about turbo lag. This is a street / strip car.

What rear gear do you recommend?

Thanks,
Jim


Am I the only knw who thinks 700 is a little low for 15lbs through a 408? Seems it would make more. Definitely a bit much for the street.
 

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At least your hp goal is low, as If it only made 700rwhp with a 408, they are something very wrong. You should easily be over 800 to the wheels. saying is 15lbs will double your n/a hp. I'm running a bone stock 351 and looking to make 450rwhp or more If i decide to live on the edge. good luck
 

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Discussion Starter #12
turbo questions

This project is in the planning/saving $/data gatherimg stage at this point...

Clutch: I have a newly installed Ram clutch...I think it's rated at 700 hp but I could be wrong. I'll upgrade if needed.

Tranny: I realize the Tremec 3550 will not get the job done. The Tremec "Viper" tranny was recommended. I'm told I can get this tranny with a lower 1st gear (numerically higher) & this should help build rpms quicker do to the rear gear change of 3.37 or 3.55's...ANYONE HAVE COMMENTS OR SUGGESTIONS ABOUT THIS PIECE OF THE PUZZLE?

Power Delivery: I have a stock 1974 351w block. The internals are all forged & balanced but Woody at FordStrokers.com recommended I limit my rwhp to 700...perhaps I'll only need 10'ish psi? What I'm really curious about is the rwtq at LOW rpms...like 2000 & 2500??? Right now I make 361 rwtq at 2350 rpms, 404 rwtq at 4600 rpms & 408 rwhp at 5650 rpms (This is on a Mustang Dyno...I've been told the Dynoject reads about 12% higher than the Mustang Dyno)

I'm hoping that with the right turbo set up instead of making 361 rwtq at 2350, I'll be in the 500 rwtq at that rpm...is this possible??? If not then what is your guess at rwtq at 2350 rpms with the right turbo setup???

Can someone post thier dyno graph with thier 351+ cubic inch turbo build!!??

Thanks,
Jim
 

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I'm about to put a Precision gt4708 (80mm) with a T4 .96 AR. It's actually a T5 hotside they call it. Same size as a T6 but with a T4 size where it bolts up to the manifold. I'm putting this on a brand new 408 I have with AFR 205's, Victor 5.8 efi. I'll let you know how it works out, my buddy who builds 3000+ hp turbo cars said I shouldn't have any issues with this turbo on my 408 so we will see.
Ive never seen one of these turbos so I have no comment, but do keep us posted on your results. Im interested to see how it works out for you.

The PT88 is a true T4 exhaust housing, and that will be very small on a big 408. Im sure his car would boost almost instantly and then fall on its face near 5000. Back preassure is going to be an issue.
 

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Ive never seen one of these turbos so I have no comment, but do keep us posted on your results. Im interested to see how it works out for you.

The PT88 is a true T4 exhaust housing, and that will be very small on a big 408. Im sure his car would boost almost instantly and then fall on its face near 5000. Back preassure is going to be an issue.

Yeah I'm hoping to have the whole setup in the car and running by late July or early August. If it doesn't even up working out then I'll sell it and go to an 88 with a T6 flange and just cut and weld a T6 flange on to my on3 kit. But I think this setup I'm going with should work out but only time will tell.
 

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Jersey True Street Guy
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I have a b&g kit with a pt88/47 turbo, which is good for another 200 hp over a pt88.

There are a lot if variables besides cubic inches. Make sure you go through all if the details with Brian. He will give you the right guidance.

I am making 1000 rwhp with a t4 based 88 and B&G kit. Everybody talks about the necessity of a t6 flange but I have not yet had a backpressure problem on this setup. My more pressing issue is pressure drop through intercooler.

Traction, yes.

You don't want instantaneous spool on a high powered street car, makes it harder to drive.
 

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I have a b&g kit with a pt88/47 turbo, which is good for another 200 hp over a pt88.

There are a lot if variables besides cubic inches. Make sure you go through all if the details with Brian. He will give you the right guidance.

I am making 1000 rwhp with a t4 based 88 and B&G kit. Everybody talks about the necessity of a t6 flange but I have not yet had a backpressure problem on this setup. My more pressing issue is pressure drop through intercooler.

Traction, yes.

You don't want instantaneous spool on a high powered street car, makes it harder to drive.
How big is your motor? Big inch Windsor?
 
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