T78 is with a divided exhaust housing as is the manifold. The actual A/R is 17cm^2 IIRC, which is around 1A/R. It will however spool like a .81 because of the divided housing.

A T78 will spool a little slower than a PTE67, but it should make more top end power because of the free flowing exhaust side..

 

I have a T78 turbo kit on my 6speed and with a stock motor I made 510whp at 18-19psi on 93oct. and with C16 I made 650whp/600wtq at 28-29psi. Once you hit 4500rpm you better hold on Actual compressor size I believe is 65.x mm

 

has anyone converted/adapted the t-78 4 bolt exhaust side to the more popular vband?

 

http://www.atpturbo.com/Merchant2/m.../Merchant2/merchant.mvc?Screen=PROD&Product_Code=ATP-FLS-028&Category_Code=GTBB

 

i think the t78 is the same wheel as the t67.
The t78 has a bigger exhaust wheel than the T67. The t78 is a 1.00a/r exh housing which is NOT the same as an 81a/r exh housing.

 

isn't a T67 a 67mm turbo? A T78 is actually 65.x mm.

 

The T67 (PTE67, SP67, BL67,etc) is actually 66.7mm (inducer) / 84.0mm (exducer)

The Greddy T78 a 66.0 mm (inducer) / 90.0 mm (exducer)

Not the same wheel!!!

Mike

 

What are the Power differences between these??????

 

My car made 656 whp and 565 lb ft torque uncorrected at 24.5 lbs boost it has a pte67mm dbb and full boost 4100-4200 rpms, and 400 lb ft by 4K, this was on 93 pump gas and 50/50 mix water methanol conservative tune.

 

Those are very strong numbers for that turbo. What hot side and an s compressor housing I assume? How big of a meth injector were you running and how much timing?

Seems like that water/meth is pump gas boost's dream child. That or your corrected numbers are way different. What was ambient?

Ian

 

What's the compressor cover on your 67mm DBB P Trim Blitzed? Is it a S cover (.70 a/r) or H cover (.75 a/r)? Strong numbers! The two turbos have small differences in wheel size and turbine wheel size and also the T78 runs a far bigger a/r. I would take the PTE version anyday because of the newer technology and price. Might as well grab a PT68RHPS with a .81 a/r and make a little more power than the T78 and the 67P DBB.

 

Thanks, I have the H cover.

 

I personally prefer the power delivery of Mitsu/Greddy turbos. They ramp up soo fast that the power surge is incredible. It does make it harder to drive due to traction problems with the huge power surge but it feels awesome. I know T78's have made 700+whp as have t67's but I would say both are good for right about that. Ideally I would do a T88H kit with the 50mm header and bigger WG plus the T78 14cm2 turbo. That combo would be awesome. That is the turbo in the FD RX7 kit and it would probably spool faster and with the bigger WG make about the same power.

Later

 

Thanks for the reply!

 

I would NOT run the t78 past the year 2002. Damn that thing is LAZY and there are a ahndful of turbos out there that make a lot more power than that and spool ~500rpm sooner.
I make 722rwhp/598rwtq on a 6 speed, STOCK CAMS. 67dbb, 28lbs. Now I have a ported head that will make more power.

t78s are for sale all day long, it does not mean you should buy one.

 

After owning a pte71gts and getting the joy of sending it back to precision for repair right out of the box was fun to say the least. Only took 6-7 weeks too :hay:

My only problem I have with the new dbb turbos is they are not rebuildable and your $1300 investment is damn near worthless after it takes a dump and with precisions reliability I wouldnt feel too comfortable.

Its understood that the greddy has a huge exhaust housing paired with a smaller compressor wheel, so yea it will slightly lazy but will make up for it on the big end..til this day still no magic turbos jus tons of size options and now dbb is rather inexpensive..

I think the mitsu/greddy t-78 reliability from all the info I've gathered (last long as hell as someone already mentioned) paired with its powerband is jus want I want out of my set-up..

might be old tech but look at the hks t51r, still a hell of a turbo compared to all the "new" technology thats out now..

 

IMO, The Greddy T78 turbo is the most fun turbo for a street car... I have driven just about every other combo and still love the T78. It spools a bit later than the others, but when it comes on it is FUN... I know it is old school, but still my #1 ! My next choice would be a GT4088.

 

I agree with this. Plus, there is no comparison between reliability between GReddy and PTE. GReddy hands down. This so-called old technology related to GReddy turbos is an internet myth, IMO. Get yourself a 67 mm journal bearing PTE turbo with a 1.0 A/R (if such a turbo exists) and see if outperforms the GReddy.

I do not know if the stickie still exists, but BLK MGK had a T-78 with a .84, ditched it to buy a "quicker spooling turbo that makes as much, if not more, power" and went back to the T-78 after his apples to apples testing proved its superiority. It shouldn't be a surprise to anyone that a DBB PTE 67 mm turbo, with a .68 or .81 A/R can outspool a journal bearing T-78 with a 1.0 A/R, but that is an apples to oranges comparison, not apples to apples.

Batty200, having had a number of GReddy turbos over the years, I agree with your post as well.

Ken.

 

I dont think there is a better bang for your buck turbo kit better than the greddy T78 setup. Because of the interesting compressor/hotside combo the turbo still has good spool for the street and good top end punch. One of the guys on island had one and it hits hard. Plus they last forever damn near. One of the few old school turbos that is still a great combo today.

 

Hau and BLKMGK both had logs and dyno comparos showing that the T78 was doing all the things people said it couldnt do. I know right about 4K rpm the T78 comes alive and kicks your ass! I have a 4banger so a t3/t67 combo will have to suffuce for spool otherwise I would do a T78. I am shooting for 700whp (made 603whp on a 61mm) and I need all the spool help I can get.

Ken,

Being a DSMer I have a lot of experience with the smaller Mitsu turbos along with Hau's T78 Supra and I love it.

SO SP60,

Where else will a 3500-4000 street price kit come close? Especially considering the Greddy comes with that HUGE WG and a TUBULAR manifold for so cheap. One of the few times greddy is the "bargain".

Later

 

Damn, I miss BLKMGK, that guy had some interesting posts and posted only the facts, not opinions. My friend Ron (Supra400hptt) on the forums here had the T78 set up and it was a great street turbo. I don't think you can go wrong either way, but it would be interesting if someone would do a comparison though. I know Waynecar had a T-78 with the .84 hotside and ran numbers 10.6X@130mph or so at only 22lbs of boost on stock fuel/meth. He was making a lot of power with that set up.

Steve

 

I friend of mine from the RX-7 community had his T-78 compressor wheel upgraded by a US turbo shop after FOD-ing it. The shop commented on how insanely beefy the internals of these Mitsu (Greddy) turbos are compared to some of the US stuff out there.

 

Did the T78 kit with 1.0a/r about 6-7 years ago and loved it. Was having a hard time finding a boost leak (turned out to be the EBC solenoid) and re-fit the compressor housing thinking it may have been coming from there. I didn't get it on good and it popped off munching the compressor wheel.

So, since I had it for few years I decided to try one the "new gen" turbos. I got the precision 67dbb with .68a/r and a new DP.

The 67 does not feel like it spools anywhere near 500rpm sooner. It does spool a bit sooner, but definitely lacks the top end of the T78.

IMO the Greddy kit is a quality kit that is complete. Everything fits without grinding or hacking anything else.

If I had a choice right now between a T78 kit with the smaller A/R or vendor 67 kit, I'd take the greddy. I think the only issue with the greddy kit is that I had to send some parts out to be jet-hot coated. No biggie.

 

It's realy nice to hear that you guys like the T-78, I have just bought one and can't wait to get it out on the road

 

Does anyone have any dyno sheets of the T-78? Ive tried searching but it doesnt come up with anything. Whats the most power recorded with this turbo with supporting mods?

 

Go to t04r.com. There are many T78 dyno graphs posted. I believe the highest number recorded to be mid 700s with a built motor and aftermarket intake manifold.

Steve

 

thanks Steve. I didnt even know to4r was still up, i thought it was taken down a long time ago. Ill check it out.

Between the Greddy T-78 kit and the PHR stage 2+ turbo kit, which one would you guys say is the best street turbo? Does anyone have any experience with both?

EDIT: I found a dyno chart on t04r of a phr stage 2+ single kit with stock engine at 26 psi. He made 627 rwhp and 580 ftlb torque. I then found a dyno chart of a t-78 on a stock engine at 26psi and it made 630 rwhp and 565 ftlbs torque.

Heres the phr stage 2+ dyno chart:

And heres the T-78 dyno chart:

Looks like the phr kit spools a little quicker then the t-78 and makes as much power up top. Ive heard that the phr stage 2+ is the ultimate street turbo, and ive also heard that the t-78 is a great street turbo, so i was hoping someone has experienced both and give their feedback and comments on them? The Greddy T-78 kit can be had for $4000, and the Phr kit costs $5300, so at a cost point of view, the greddy kit seems like the better buy because for 1300 more, your only getting a turbo that looks like it spools a little quicker. What do you guys think?

 

That T-78 a/f ratio seems a bit lean at 13.5 up top.....

 

The PHR 2+ is overall a nicer kit, heat-coated manifold & turbine housing, drop-down (Greddy 4 row style) IC pipe, DBB turbo. Good stuff.

The question is, are you willing to pay substantially more for it than the T78 kit? The Greddy is one of the great bang for the buck kits going.

 

For reference, here is my ucorrected dyno with a pte 67mm dbb turbo w/.81 a/r hot side, stock long block with only hks 264 cams on 93 octane pump gas and 50/50 water meth at 24 lbs boost...with race gas, a aftermarket intake manifold, and high boost, I know it would be well over 700 whp

 

A T78 will do about 650-700 on a stock engine with race gas (6 speed). I got my car down to a 9.7 1/4 mile time with a TH400, T78 and 150 shot... It is a great turbo for using nitrous too, the big housings really help.