Hey all,

I'm currently in the middle of getting to 500whp, the meth kit is on its way and i'm still working on sourcing the rest of the fuel system.

I have been reading alot in this section, and it seems that everyone is always talking about what the gt35r can do.

My car came with the Greddy T78, and nobody really ever brings that up. I'm just wondering why. Now there is no way I'm switching yet, as from what I've read it should be able to do 500whp. I'm just curious why its never mentioned.

Is it just outdated/overpriced? I know its an older journal bearing turbo. I have searched, and the only comparison that I could find was to a gt35r, and it seems that they are basically the same power-wise but the gt35r spools a bit quicker. Is this accurate? If not, what newer kit would one compare it to?

 

the only thing i've heard about the greddy turbo's are that they are very expensive to rebuild almost the cost of a new one but in power margins i think it will do 500 horse.
the gt35r are just ball bearing and give a quicker spool , but are smaller in size compared to the t-78 ,it all depends on what your going to do with your car
if your gonna do the 1/4 mile the t78 will do since it can go 20+psi.the gt35r's faster in spool so it will be a very responsive car boost wise great for circuit racing or any type of road racing. also since you have a meth kit on the way i think your detonation safe. if you didn't already have a turbo then there would be a decision that had to be made by you but since you already have the t-78 just max it out and see what it will do
Just my opinion .

 

thats what I plan on doing, I was just wondering why they don't seem too common, its gt35r this gt42r that haha.

And I don't think a rebuild is that expensive, I had 2 shops give me quotes for about $400 with shipping included.

 

The t-78 will hit 500rwhp. No question about it. they are ery reliable turbos

 

A friend of mine (turbor1) had a hard time getting the GT35 to go over 22 psi or so. It ran out of compressor and he is upgrading to a larger turbo.

I have seen the T78s have no issues going to 30psi easily and holding it through the rpm range.

Yes, they are older but I always liked the greddy turbos...I have a T88 34D and on 20psi it went 10.8 easily...

Anthony

 

They are old, not the newest, but they perform and are reliable.

 

Get a T04Z (ball bearing T04R/Garrett T67, not to be confused with Greddy/Mitsu T67). it's a little bit smaller than the T78 but will be more responsive and easier to rebuild

 

Greddy T78 is one of my favorite turbo's of all time. They are very reliable and you can turn them up and they take it like a champ! we ran 24+ psi on one for years and when it was taken off it was still like new! barely any play and the blades were not stressed.

they are just old technology which forces noobs to disregard them immediately since the GT series turbos are out now and doing well.

 

I used the T-78 on both my RX-7's. Its old but fine for 500HP. All things equal the T-78 will smoke a GT35R. The transient response is better on the GT35R but the T-78 spools right away if you are in the right gear.

 

as far as ability, they`re not really comparable, the 35R falls off at mid 20 psi and 65 lbs/min, the T-78 will do 30 psi and 80+ lbs/min. Old tech, yes, but you would think that Greddy did some testing to make sure it worked well on the 13b.

 

Gusfd3s made 548whp at 22psi on e85 with his T78 (my old one).
Stay with it and replace it when you want more power!

 

This is all great news, I missed out on doing the research to go single because the car came with it. Looks like I'll be sticking with it for a while, I don't think I'll ever push the engine past 22psi (with meth) on pump gas.

Just purchased a fuel system, once that gets here I think I'll be all set to finish breaking in the engine and get tuned.

 

well post some vids of the car really exited to see this project come ALIVE

 

take a look at my sig.

boost # 3700, full boost at 4400rpm. made 478 @ 6000rpms on 17psi. 520 @ 17psi @ 7800rpms

the thing i like about he turbo is when it spools it doesnt stop spooling

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not that many talk about the turbo cause the kit is around 4k and peoples budgets are kinda on the low!

plus theres the garretts that ive seen people fall in love with!

 

I dont get how people are having trouble with 35/40 and boost?

I have done a few at over 25psi no worries.
Only thing is all had water injection so maybe that is playing a part.

 

we had 28psi dropping to 26psi, but it made the same power as 22 psi..
just over 500hp is what we were able to get out of the GT35.

 

I take it you're talking pre turbo? In which case yes, it would most certainly be "playing a part"......

-J

 

Pre turbo of course.
On one car we got to 28psi and power was still climbing.
Ive looked at compressor maps and it shouldnt be doing anything but it isnt the case. Turbo is working excellent.

Ill post a dyno sheet once the car is sorted to show what its doing up their.

 

Ray made over 600rwhp with a T78 on his own RX7 back in the day and ran 9's (w/ juice)with it.

 

I have a Greddy T78 on my track car and am very pleased with it. I don't run a crazy amount of boost as it is a track car. Sure it's a big single that is laggier than a GT35R but as Jason said, as long as you are in the right gear boost is always there. It's a non issue for me as I'm never at a dead stop. I think mine was rebuilt by Majestic Turbo's in TX a few years ago for around $500.