Greddy T78: should I get it? Need advice...

[Reign_Maker]

Ok, so I have the chance to buy a slightly used T78, for a good price... No shaft play, no bent fins, polished comp housing, very nice looking...

Im just wondering, even though its a great price, is it throwing money away? Will it be too big for the 7M to spool it? I dunno waht the AR is, I can find out, but if its too big, could I swap the turbine housing from my turbo?

I was told that a 7M put out 498hp at 18psi with this turbo, however I dont know the supporting mods... I know this is the turbo that GReddy sells to the 2JZ guys in the kits, so its not junk... I just want to get more hp with less boost...

Im going to be doing a complete rebuild over the winter: ffi, 3" IC piping, side to side fmic, 4" exhaust, ss tubular manifold, one piece driveshaft, 750cc injectors, Maft Pro, etc... Im goin for 650-700hp... What do you guys think about this turbo bein the snail for my future set up?

Any advice would be greatly appreciated...

Thanks guys,
jake

 

[IJ.]

Jake: Not sure how old the T78's are or how advanced their tech is but I'd be looking at a GT or GT based turbo I know my little 3540R has opened my eyes as in the past getting a Turbo to support 5>600 rwhp on a 3 litre motor you were sacrificing a LOT of your drivability and ended up with a Lag Monster!

I was reading a few posts on the new GT4067R on SF and it's sounding like a good fit for our motors!

 

[oneandgone]

Ya, I'd definately spend the money for a DBB GTR series turbo instead. Fast spool, great power, and reliable to boot. T=old tech, GTR=new tech.

 

[s383mmber1]

yeah definatly jake!

 

[SP 7M]

I'm in full agreeance with IJ. Unless you don't want much driveability, I would urge you to choose a different turbo. Not that the T78 is "old school," but there are other newer turbos out there that will give you substantial power without letting so much driveability slip away.

It all depends on what you're going for, though, man.

 

[Reign_Maker]

Thanks guys... I definately dont wanna get something that's too laggy... But I definately want something that can make big power quicker... *less boost* I just wonder if I will be sacrificing torque with a bigger turbo...

My fear is, when I go through and do this major over haul, Im going to be limited by the 60-1... I would HATE that, to get on the dyno and run up to 550and be stopped there... I want over 600, and eventually over 700, so I guess I need to research some more...

I was hopin this turbo would work out... It's only $600... But if you guys feel its not worth it, I'll take your word...

Thanks guys, Jake

 

[jbsupra89t]

I was gonna get a T78... many things stopped me, so instead I'm keeping my BB turbo, and dumping a bigger hotside for my craving of power. The T78 is old technology, no two ways about it. Is that to say it's bad? NO. There are just better alternatives to get power, and on SF there was a post with a T78 graph overlaid on one of the BL turbos IIRC. BL made a few RWHP less on the peak, but the area under the curve was killer. I love my ball bearing setup. If you want over 700? Right there I'd look to a different turbo. The 78 could *probably* hit it, but maybe check out the 71mm turbos that are now offered... Good luck.

-J

OK now that I reread that, SP covered almost exactly what I said... oops.

 

[Reign_Maker]

What about this option: what if I just had my current turbo fitted with a 70+mm compressor wheel? Its got a 4" inlet, so there is plenty of room for a bigger wheel...

Any thoughts?

 

[suprabad]

I tend to think that particular turbo (t78) while being an older design would work (i.e. spool up quicker) more successfully on a higher compression motor.

 

[outofstep]

Its all about the newer GT series turbos. Faster spool, more hp per psi, larger islands. Pass on that turbo and try and find a deal on a GT.

 

[garagefujimoto]

the 78 won't be too bad, the wheel spin should help with spool

modding the 60-1 could work, but i would be concerned as to the amount of material left over after milling the housing, and the cost involved in doing so

for a 7M which needs good spool down low compared to JZ, a newer GT series would certainly be the ticket

 

[IJ.]

The GT series are pretty special!
(I was so ready to not believe the hype and figured at the worst they won't be any laggier than a T04)

My GT30R really surprised me but as it has a .63ar turbine housing I told myself that was the reason for instaspool, then I got my 3540R with a 1.06ar fully expecting to start making power at 4500+ which on the new motor wouldn't have bugged me too much as it will rev to 8000.

Very surprised that it goes positive as low as 2200!

 

[IHI-RHC7]

I was hitting 21 psi by a little over 4K with the old T78. but that was running a little on the lean side down low to get the egts up. Power curve wasn't that inpressive, but we did dyno 469 with only 17 psi.. torque peaked at 430 or so, I'd go BB, but that is a pretty good price.

 

[jbsupra89t]

IJ how you like the 1.06? I'm picking up the 1.02 this spring for mine... I've already had positive feedback from one guy on SF, looking for another one =)

-J

 

[IJ.]

JB: I only got to drive it around untuned so didn't get a "feel" for it's full potential but was very surprised at just how responsive it was and how hard the boost hit, I forced myself to back off at 5 psi.

On the Dyno it made 300 rwhp @ 15 psi on 5 cylinders before a faulty injector burnt a piston.

 

[jbsupra89t]

Hmm very nice, that seems to be what I hear, lag doesn't increase a whole lot, and hits hard on the upper end. Thanks!

-J

 

[MRSUPRA]

I the price is cheap and you want big power than it may be a good buy. A PT or SP67 turbo (which is about the same size)would be a better choice because of the newer wheel design and a little better spool-up. Both turbos will max out at a little over 700rwhp. I have heard many people swapping out the turbine housing from the stock .96 to a .81 for better spool.

 

[chevyeater]

Lag schmag. A T78 is a fine turbo and a real good buy used with low miles.

Power comes in between 4-4500 on a 7M (4400 in 4th is full bost on my car and it will make a couple of pounds as low as 2600) so, you'd want to raise the redline for a useable powerband with it. I've ridden in a few T78 2Js with the smaller backhousing T78 and it spools up a bit more gradually, starting earlier and making a few more pounds down low but still hitting full boost around the same RPM as mine (on a modified 7M). Driveability is just fine and you can actually feel the couple of pounds it makes down low. You probably will not win many races starting at 2500 rpm though.

 

[MDCmotorsports]

As chevyeater put it, a T78 will spool "late" (4500) to some people. It is by today's standard "old" technology.

If its cheap, get it. You could always resell it.

If you do get it, I get your old turbo btw.

 

[williamb82]

from what ive seen so far the gt4082 i have will support over 600rwhp and i can garuntee you itll spool a hell of alot faster then the t78. if i were you id check into the gt4067. its a bigger compressor then the gt4088 that blackdevil is using and he made ~560rwhp at 20psi with a 0.81 hotside(and it wasnt a bb turbo either). im going to order a 0.68 hotside for mine and figure with the massive headwork and cams i should be able to spool similar to the upgraded ct i have now and still make a lil over 500rwhp at 20psi on pump gas myself. later ill prolly sell this and buy a larger turbo, or just have it upgraded with the gt4067 compressor wheel and cover. the 88 wouldnt be a big enough of an improvment to warren the cost of the upgrade imho.
william