trying to decide what turbo to buy. I was thinking a r85 or a greddy t78 turbo. anyone have any experience with them? which one spools quicker and has overall best hp potential?

 

The r85 turbo is basically this aspec turbo: https://www.rx7club.com/spec-tuning-154/new-turbo-gt3574-583809/

This based on some measurements blitzed33 posted about the r85.

The greddy is around a 66-67mm compressor wheel, but has huge comp and hotside housings. It'll most likely be laggier than the 3574/r85.

For a street car, you cant go wrong with the GT35R....quick spool, 400 rwhp. If you want to run less than 20 psi, run that. If you're looking at race gas/more than 20 psi, look into the aspec 500R.

 

I am a owner of the R85. Car isnt done yet so cant tell you on spool time. The R85 actually comes from bullseye power. It's a S300 series. Heres 2 pic's of mine. It's a very big turbo. Should put you wherever your looking to go!

http://a459.ac-images.myspacecdn.com...b7b061a9ca.jpg

http://a408.ac-images.myspacecdn.com...1eeda202ff.jpg

 

I had a T78 on my car and loved it. You can easily make around 430-450 on 15psi depending on Air fuel ratio. I do not like that the t78 is an older turbo and parts are hard to come by so I would opt for the R85.

From everything I have seen the R85 seems like the perfect street/track turbo.

Anthony

 

so in the end i could get very good power out of the r85? I want to be able to make around 500 or hp.

 

Absolutely.

 

+1

 

My car made 561 whp at 27 lbs boost with the R85 turbo. It is a 61.5mm compressor wheel and made by borg warner, and I upgraded mine to a S366 or something like that from Bullseye, basically just a larger 66mm compressor wheel but with the exact same turbine wheel and exhaust housing, and it did 610whp on a stock 2mm basic street port at the same boost level. At around 20 lbs it did 500 whp. Spool on the 61mm was at 4500 rpms full 27 lbs boost, which is quite good being a non ball bearing turbo. It is a good street/strip turbo, but you might have to notch the frame because the exhaust housing is so large...but that is a good thing with rotaries, less backpressure The pic of the turbine housings is comparing I believe a GT35R vs the R85's

 

i have owned both...R85 all the way. That bitch pulls like crazy up top and still has throttle response down low. the t78 is a wait for it wait for it baaaaaaaaaaaaam type turbo.

ps: he is looking at my JPR half bridge/R85 combo

 

thanks all well i guess im going to go with the r85. looks like its exactly what i want.

 

R85 for spool T78 for power

 

R85 for spool and power... blitz did 600hp

 

i did 478 @ 17.5lbs someone else did 584 @ 26lbs. do the math!


although i will say ive seen some big numbers out of the R85 but the housing on the greddy is bigger which means it will make more. it might be a little slow but its well worth the wait

IMo if i started over i go with the garrett just for the fact that you can customize the turbo to your fittings with a different compressor to equal the power & spool you want!

 

T78 is a bigger turbo, hands down it will make more power.

 

the T78 is only a 66mm compressor wheel if I am not mistaken, the same size as my S366 was where my car made 610 and was out of breath, but my exhaust housing and turbine was bigger than the T78. So I am not sure that the standard T78 will flow more or make more power than my extended tip borg warner 66mm with 1.15 A/R exhaust housing, hence 610 on a standard street port.

 

there was a thread on mazdarotary having this same discussion and they had a ruler with both turbos and the greddy was bigger than the R85!

if anyone can find it but i cant get in the forums cause im not a member

 

Oh for sure yes the T78 is larger than the R85, i was talking about my upgraded R-85 with the 66mm compressor wheel instead of the standard 61.5mm it comes with.

I maxed the 61mm out at 561, when I upgraded just the compressor in my R85 to the same size as the T78 (66mm), it maxed out at 610 whp.

 

R85 is the newer turbo with the new technology. Smaller it may be, but I'll bet you nobody will make more power with the ancient *** T78.

 

lol..well it seems like the t78 has more power potential but the r85 is a quicker spool. I think for the half bridge that im putting in a quicker spooling turob will be the best bet for my needs right now, but who knows what ill want in the futur.

 

I have the r85 and love it! I would pick it anyday over the Gramps t78...

I'm looking in to going with a 42r. If anyone wants to buy an r85 kit (turbo, manifold, tial 44mm wastegate, downpipe with recirculated wastegate) with a greddy front mount kit that fits perfect let me know!

 

Im thinking of selling my 42R kit. Goin with the big daddy 45R ....Lemmie know if your interested.

 

the t78 may be old but its still a great turbo!
YOU KNOW WHAT! SCREW BOTH. garrett all the way, cheaper too!


ernie what the hell man! you already have the fastest street 2 rotor in the world.

you already beat v8killa PT-76 685hp & scoot T51R 710hp, what more could you want!


YOu know when you beat a hennessey viper ill give you $1000 bucks by paypal!

 

Ernie... your crazy! Anyway, the R85 can produce plenty of power. Dark saying 584hp Blitz saying 561hp and then 610hp with it upgraded. Plenty of power to run a 10sec quarter mile. Said to have good spool time, and a great overall street turbo. I paid 1300$ for mine. I think thats a great deal for something that is capable of around 600hp.