darkphantom

iTrader: (2)

Was just wondering if theres anything i can do to help spool the Greddy T-78 faster than it already is.
SO far ive gotten a Large street port on the motor and opened the exhaust ports alot more than it already is.

The engine is here but i was thinking if theres anything else i can do to the car/motor/turbo before i put the motor back in. The car will be tunned later on when the engine is in.


I had someone suggested to heatwrap the downpipe. which he quoted will help the spooling better.


Im not complaining about the spoolness of the turbo (just downshift to get the right rpm) but just curious if theres anything i can do to improve it


Thanks guys!

jacobcartmill

iTrader: (6)

what size is the hotside?

darkphantom

iTrader: (2)

Probably Like A .96 Or A 1.1something. Its A Regular T78 Turbo!

pistonsuk

This would help:
https://www.rx7club.com/showthread.p...croll+manifold


Downpipe? How would this help?

Heatwrapping the manifold would maintain more energy in the exhaust and make the turbo spool a little faster and make it more efficient.

Justin

darkphantom

iTrader: (2)

I Appreciate It Justin

RotaryResurrection

iTrader: (8)

When I went from large streetport to mild halfbridgeport my spool time on the t78 dropped around 500 rpm with everything else the same (including wrapped manifold and downpipe).

TT_Rex_7

Havn't seen the exhaust manifold that comes with the T-78 kit, but you could have a custom one made. That would probably help quite a bit with spool. How much would depend on how good/bad the Greddy exhaust manifold is. You don't have to do this with the motor out of the car, so that's a plus. If you throw everything back together, still don't like the spool, this is a route you can take without ripping everything out of the car!

-Alex

Edit: Another thing you could try is running a 4" exhaust from the turbo back.

darkphantom

iTrader: (2)

i have a hks hiper titanium exhaust which is about a 3in. but i havent put the street port engine yet so i havent felt the street port yet. when i had the t78 it was a no port engine

RotaryResurrection

iTrader: (8)

The greddy manifold seems fine to me. Runners are long but not quite equal length. The pipe is fairly thick and not a lot of noise escapes through the pipe walls.

The main thing is fitment. There is really no way that you could improve on manifold design, because there is no where to move the turbo. IF you move it out, the turbo will hit the strut tower. move it in and the downpipe will hit the LIM. Move it back and the turbine housing will hit the LIM. No sense in moving it forward either.

Old Slow Coach

https://www.rx7club.com/rotary-car-performance-77/clr-motorsports-engine-running-412677/

^^^ This a current thread in the Rotary Performance section. Very good info here! Talks about how to use timing (large negative split in the vacuum range of the map) to spool the turbo faster. I recommend reading the entire thread.

EKTwin93

nitrous would spool it pretty darn quick

ErnieT

iTrader: (2)

A full bridge will help too, but thats already a small turbo. Why do you need boost so much sooner? That thing already spools almost instantly.

RotaryResurrection

iTrader: (8)

uh...

t-78...small turbo...spools almost instantly...

RX794

A T78 is considered a very quick spooling turbo, it's a mid range sized turbo(Very comparable to a Garrett T66). If you're having issues spooling it and everything has been installed properly(No exhaust manifold leaks, no boost leaks, etc.) then it's probably due to tuning, if you tune for a rich A/F ratio under low boost then the turbo will take long to spool, make sure your tuning is correct.

RotaryResurrection

iTrader: (8)

There isn't a turbo too much larger than a t78 that will FIT in an FD engine bay without hacking...I'd consider it a medium/larger turbo, personally. The only things larger than that, would be a gt40, 42, t88, and maybe r85.

Yes, I have one on my car. Yes, I've worked on and seen plenty of other turbos installed.

Most t78 cars I've seen with streetports spool around 4000-4300. For me, that's about the limitation of spool time I'll accept.

I'd call a t04S or something a medium turbo, and I'd call a t04E a small one, and both of them spool fast. I would not call a t78 small, or quick spooling.

But, everyone has their own definitions I guess.

BNA_ELLIS

I had a street ported t88 33d come to me already mapped only running 1 bar boost due to fueling limitations. I wasn't happy with full boost being at 5,500rpm
after a bit of playing with the map full boost was at 4,500 at 1 bar of boost.
I wouldn't expect a smaller t78 being to take as long to get to full boost if tuned right.

dhahlen

iTrader: (5)

I had 23 psi at 5500rpm with my TD08 (which is just a hair smaller than a T78).. then again, my tune blew... literally, now i have an AF61r, LOL.

mono4lamar

iTrader: (32)

i was always under impression that my r85 was smaller than the t78... im thinking of upgrading now! oh yeah does anyone know where that link is to the sizing of turbos on here i cant find it.

dhahlen

iTrader: (5)

https://www.rx7club.com/showthread.p...rbo+size+chart

mono4lamar

iTrader: (32)

so any info on a comp. between the r85 and t78? i gotta dig up the specs on the 85 again and i guess compare...

olyrx7

iTrader: (3)

With my Greddy t-88 34D I get 10psi by 4000rpm and full boost by 4700.

So your t-78 should spool a lot sooner, I think an agressive race port would really help and if you want to get serious spool it with nitrous.

dhahlen

iTrader: (5)

You can always go BRAP BRAP BRAP =P

13bmaniac

iTrader: (5)

hello there i have a greddy t-78 wit a large street ported pettit engine i saw 15 psi of boot at 4000rpm i thing is a considerable lag taking the size of the turbo and the size of the rotary engine,also you have a 7500rpm red line considering yo are a conservative guy that dont want to pull harder than that,and yes you will have lag in1 gear but when you hit 2nd is another story,beside you never start a drag race around 1k rpm so if you play a itle bit with your cluth the lag will be a matter of 1 second or so.

i produce 451 hp@15 psi and im more than happy with my t-78

550rwhprex

iTrader: (1)

hey I heard you said your car is running..
9 Darkphantom RX-7 477 hp 2800 lbs 8500 rpm 167 mph 11.6 @ 114mph 5.871 21 psi T $36,669 .

how is your car running if u dont have everything to get it running yet......
lies, lies, lies, lies, lies....

hey dont believe a word this kid says.. anybody that knows him knows that he lies alot....

matty

whats done to your car since itsa making 550rwhp.