Im looking to go turbo and looking for around 800rwhp. What are the advantages and disadvantages of t4 setups vs t6 setups. Thanks guys

 

T4 quicker spool, easier to package.
Cons are, lower hp potential,could peak at lower rpm, higher back pressure.
T6 more power potential. Less back pressure.
Cons, physically large so hard to fit, heavy usually requires a brace.

These are very general. We need know primarily engine size, goals, type of car, Trans.

That would help point you in the right direction.

Alex

 

That^ If you can give more info we could help better for your project.

 

Car is 2000 camaro with stock 5.3 with arp rod bolts, head studs, no cam picked out yet. Vic jr efi intake. 6spd for now till I switch to 4l80e this winter. And 3.55 gears. Looking to run 9's. I dont care about a/c

 

A pt88 t4 would meet your goals.

 

A PT76GTS can also do some good work. Pretty instant spool.

 

Ok thanks guys. I noticed you said a t6 spools quicker. What if you got a t6 turbo with the same .96ar as a t4 turbo?

 

IMO if the turbine and aspect ratio are identical they will spool the same. Flange isn't the choke point.

 

alot of factors that effect spool time depened on the rest of your setup, crossover pipe size, crossover length, cam timing, engine timing, etc. on the same setup, you will not notice much difference in a comparable turbo with a t6 flange as opposed to one with a t4. I actually just switched from a 68mm t6 to a 68mm t4. saved over 50#'s off the front and spool time is nearly identical

 

Ok gotcha. Will a gt 91mm be too big for the 5.3?

 

Did you loose any power from the switch?

 

A gt91 will take some time to spool but will make tons of powa

 

Yea I figured that

 

S480 with an 87mm turbine and a 1.10 T6 housing

Build the kit with 2.25 pipe in the crossover.

Go T6 now so if you ever decide to build a bigger motor later you wont have to redo the kit again.

 

I don't have any numbers to compare. the T6 was only on it for a week for testing purposes. Used it because I already had it. only ran it to 5 psi before. I will say that the larger frame turbo did feel much stronger as it was spooling. the smaller turbo, while it seems to make the same boost by the same rpm, it it more "snappy". Like lag, lag, POWER while the larger unit felt like more of a gradual ramp up and then the power really hit

As for the 91, that may be a little big for your setup. It would need a small exhaust A/R to help get it to spool. When it did, you would feel like you have been hit by a train. But it will be a dog until then. This is why big power supras have such a bad wrap. they make amazing numbers on the dyno, but unless they are pulling from a high roll, it is pretty much useless. 5.3's have seemed to get the best result from 68-80mm units, with around a 1.0 a/r, give or take depending on the size of the unit. if you do want a physically larger turbo for the "wow" factor, but still being efficient with your setup, look at the Borg Warner s400 series turbos. can be had pretty cheap, quality units, and look much larger and more intimidating than they are. But they still get the job done. There are members here make 1000+ with them. can be had in either t4 or t6 flange.

BTW as far as the flange is concerned, it isn't a big deal to change, should you decide to later. It literally took me 10 mins to sawzall off my t6 flange, put the t4 flange in place, tack it, and fully weld it. they use roughly the same size opening so my merge fit pretty well still. The biggest difference between the 2 actually is bolt spacing lengthwise. I actually had my t4 bolted to the t6 flange for mock up with it shifted to one side. the narrow way the spacing is the same, but the long way they are about an inch different

 

the t76 with either auto or manual would make a great all around driver on a 5.3 and meet your power goals easily