Single Turbo RX-7's Questions about all aspects of single turbo setups.

Turbo sizing question

Thread Tools
 
Search this Thread
 
Old 10-26-21, 09:03 PM
  #1  
Junior Member
Thread Starter
 
Doctor_25's Avatar
 
Join Date: Sep 2021
Location: NC
Posts: 21
Received 2 Likes on 2 Posts
Turbo sizing question

So I'm going to be turboing my 13b eventually and was trying to get to the 500-700 range, I know the output of a rotary is more than a piston, atleast at higher rpm range, would a g30-770(2.0L to 3.5L) have too much lag. Any suggestions?
Old 10-26-21, 09:46 PM
  #2  
Rotary Motoring

iTrader: (9)
 
BLUE TII's Avatar
 
Join Date: Mar 2001
Location: CA
Posts: 8,211
Received 763 Likes on 505 Posts
G30-770 looks like an alright turbo for 350-450rwhp on a rotary. Not what I would choose by any means.

It should spool amazing with the tiny exhaust side it has if it doesnt choke the rotary out. We have yet to see if the new tiny G series exhaust sides work as well as advertised on a rotary.

For 500-700rwhp on a rotary you are looking for a turbo with a compressor in the 90-95lbs/min flow range.

EFR 9180 is a popular 95lbs/min capable turbo currently that has little lag for its size and a generous size exhaust side.
Old 10-27-21, 05:10 AM
  #3  
F'n Newbie...

iTrader: (6)
 
fendamonky's Avatar
 
Join Date: Sep 2006
Location: Nokesville, Va
Posts: 3,928
Received 313 Likes on 228 Posts
If you're shooting for 500-700whp then I sincerely hope you've overbuilt the hell out of your motor.

Like blue said though, you'll need a BIG turbo for your goals, additionally you'll need lots of fuel, solid spark, e85 or WMI and a good computer if you want to make that power reliably. Plus you'll want to upgrade the rest of your vehicle to suit... it's not a matter of just slapping a turbo on an NA motor and sending it, you're probably looking at $20k plus on the low side to do mostly right.

If a built piston motor can expect 10hp per lb/min of turbo flow, than a well built rotary can expect roughly 7.8hp per lb/min. You may want to go back to the drawing board and adjust expectations.
The following users liked this post:
Rx7bgs366 (11-06-21)
Old 10-27-21, 09:48 AM
  #4  
Junior Member
Thread Starter
 
Doctor_25's Avatar
 
Join Date: Sep 2021
Location: NC
Posts: 21
Received 2 Likes on 2 Posts
Im aware 700 is a far stretch, and im going to dowel the irons and housing, etc. Im more so hoping for around 500 but I guess it doesn't hurt to hope for higher. besides the machining, everything else I'm going to do like the turbo piping, tuning, wiring, etc
Old 10-27-21, 01:52 PM
  #5  
Rotor or no motor

iTrader: (24)
 
R-R-Rx7's Avatar
 
Join Date: Oct 2006
Location: Limassol, CYPRUS
Posts: 3,338
Received 369 Likes on 223 Posts
500 vs 700 are 2 majorly different setups.

for 500(ish) i would probably shoot for an EFR 8374 even though the 8374 will probably be pushed to get those numbers. i havent seen the 8474 in action but the 9180 or 9280 is probably your best bet for a 500+ setup but expect some lag
The following users liked this post:
Howard Coleman (12-07-21)
Old 10-27-21, 08:57 PM
  #6  
Rotary Freak

iTrader: (2)
 
iceman4357's Avatar
 
Join Date: Jan 2004
Location: St.Louis
Posts: 1,879
Received 129 Likes on 73 Posts
You should speak with Skeese. He built and sold a 700rwp+ 2 rotor.

I agree that 500 and 700 are different animals though.
Old 10-28-21, 10:19 AM
  #7  
Junior Member
Thread Starter
 
Doctor_25's Avatar
 
Join Date: Sep 2021
Location: NC
Posts: 21
Received 2 Likes on 2 Posts
Thanks for all the responce, Ill probably go with the 8374 and stay to the 4-500 ish range, I'm just going to work on some of the drive train upgrades while I have it apart for now.
Old 11-03-21, 06:29 PM
  #8  
@Pettit Racing


iTrader: (1)
 
Manny_Apex's Avatar
 
Join Date: Apr 2012
Location: Palm Bay, FL
Posts: 486
Received 191 Likes on 105 Posts
Trust me my guy, 8374 rotary with the right injectors, spark, IC, fueling, and ECU is A LOT to handle on the streets. It's about as far as I'd go on a street car. My car makes it reliably and I could not even imagine 700. I want no parts of that monster.
The following users liked this post:
Howard Coleman (11-09-21)
Old 11-03-21, 09:07 PM
  #9  
Full Member

 
Brettus's Avatar
 
Join Date: Apr 2010
Location: New Zealand
Posts: 233
Received 36 Likes on 21 Posts
Originally Posted by BLUE TII
G30-770 looks like an alright turbo for 350-450rwhp on a rotary. Not what I would choose by any means.

It should spool amazing with the tiny exhaust side it has if it doesnt choke the rotary out. We have yet to see if the new tiny G series exhaust sides work as well as advertised on a rotary.
.
I have a G30-660 1.01 on my Renesis - they work well. Made 415whp at 15psi with ease . Emap was around 21psi at peak.
Old 11-03-21, 11:10 PM
  #10  
Rotary Motoring

iTrader: (9)
 
BLUE TII's Avatar
 
Join Date: Mar 2001
Location: CA
Posts: 8,211
Received 763 Likes on 505 Posts
I would expect the smaller exhaust wheels to impact power less on a 13B-MSP Renesis because they dont have any intake to exhaust cycle overlap like the older peripheral exhaust port rotaries do.

That is good power for the boost and a lot of boost for 10:1CR Renesis

E85 for fuel I presume?
Old 11-04-21, 12:09 AM
  #11  
Rotary Motoring

iTrader: (9)
 
BLUE TII's Avatar
 
Join Date: Mar 2001
Location: CA
Posts: 8,211
Received 763 Likes on 505 Posts
I see the thread.

E40 fuel.

So that is 360hp Mainline dyno corrected by 1.15 to get it to 415hp Dynojet equivalent?
Old 11-04-21, 12:32 AM
  #12  
Full Member

 
Brettus's Avatar
 
Join Date: Apr 2010
Location: New Zealand
Posts: 233
Received 36 Likes on 21 Posts
Originally Posted by BLUE TII
I would expect the smaller exhaust wheels to impact power less on a 13B-MSP Renesis because they dont have any intake to exhaust cycle overlap like the older peripheral exhaust port rotaries do.

That is good power for the boost and a lot of boost for 10:1CR Renesis

E85 for fuel I presume?
The G30 AR 1.01 flows the same as the 8374 AR 0.92 and that turbo works pretty well .............It's also more efficient than the 8374 so I'd expect emap to be close to what you would see on the 8374 1.05. There are twin scroll T4 1.06 housings for the it now too....someone needs to try it on an REW !
Fuel was E40

Originally Posted by BLUE TII
So that is 360hp Mainline dyno corrected by 1.15 to get it to 415hp Dynojet equivalent?
No the correction is an SAE correction for temp/humidity/pressure and it's 1.15% not 115% . So this is a realistic number.

Last edited by Brettus; 11-04-21 at 12:57 AM.
Old 11-04-21, 09:53 AM
  #13  
Junior Member
Thread Starter
 
Doctor_25's Avatar
 
Join Date: Sep 2021
Location: NC
Posts: 21
Received 2 Likes on 2 Posts
[QUOTE=Brettus;12492475]The G30 AR 1.01 flows the same as the 8374 AR 0.92 and that turbo works pretty well .............It's also more efficient than the 8374 so I'd expect emap to be close to what you would see on the 8374 1.05. There are twin scroll T4 1.06 housings for the it now too....someone needs to try it on an REW !
Fuel was E40

Do you know anything about the 1.01A/R GTX 3582R Gen II, and whether the V-band, or the twin-scroll is more effecient?

(Specs of it)
  • Compressor Wheel Inducer: 62.5mm
  • Compressor Wheel Exducer: 82.5mm
  • Compressor Wheel Trim: 56
  • Turbine Wheel Inducer: 68.0mm
  • Turbine Wheel Exducer: 62.3mm
  • Turbine Wheel Trim: 84
its 82 lb/min flow and 130,000k max turbine speed
Old 11-04-21, 09:55 AM
  #14  
Junior Member
Thread Starter
 
Doctor_25's Avatar
 
Join Date: Sep 2021
Location: NC
Posts: 21
Received 2 Likes on 2 Posts
[QUOTE=Doctor_25;12492511]
Originally Posted by Brettus
The G30 AR 1.01 flows the same as the 8374 AR 0.92 and that turbo works pretty well .............It's also more efficient than the 8374 so I'd expect emap to be close to what you would see on the 8374 1.05. There are twin scroll T4 1.06 housings for the it now too....someone needs to try it on an REW !
Fuel was E40
Do you know anything about the 1.01A/R GTX 3582R Gen II, and whether the V-band, or the twin-scroll is more effecient?

(Specs of it)
  • Compressor Wheel Inducer: 62.5mm
  • Compressor Wheel Exducer: 82.5mm
  • Compressor Wheel Trim: 56
  • Turbine Wheel Inducer: 68.0mm
  • Turbine Wheel Exducer: 62.3mm
  • Turbine Wheel Trim: 84
its 82 lb/min flow and 130,000k max turbine speed

Edit: Disregard my last comment, I messed up the quote part, thought I edited it, ended up posting an entire new comment on accident

Last edited by Doctor_25; 11-04-21 at 10:20 AM.
Old 11-04-21, 12:01 PM
  #15  
Full Member

 
Brettus's Avatar
 
Join Date: Apr 2010
Location: New Zealand
Posts: 233
Received 36 Likes on 21 Posts
Originally Posted by Doctor_25

Do you know anything about the 1.01A/R GTX 3582R Gen II, and whether the V-band, or the twin-scroll is more effecient?
t
I'm pretty sure a twin scroll will be superior on a PP exhaust 13b for almost ANY turbo.
I'd go for a G35-900 over the GTX 3582R gen 2 though . It will spool better and have lower emap.
Old 11-04-21, 12:51 PM
  #16  
10000 RPM Lane

iTrader: (2)
 
TeamRX8's Avatar
 
Join Date: Oct 2006
Location: on the rev limiter
Posts: 2,468
Received 844 Likes on 577 Posts
the G40-900 and 1150 are out now, looking good

the 80% center island has me rethinking a G35 purchase 🤔 wish it was a bit higher Pr though … the 70% efficiency width from 33 lb/min -73 lb/min @ 20 psig isn’t shabby though












Last edited by TeamRX8; 11-04-21 at 01:26 PM.
Old 11-04-21, 09:56 PM
  #17  
Junior Member
Thread Starter
 
Doctor_25's Avatar
 
Join Date: Sep 2021
Location: NC
Posts: 21
Received 2 Likes on 2 Posts
Originally Posted by TeamRX8
the G40-900 and 1150 are out now, looking good

the 80% center island has me rethinking a G35 purchase 🤔 wish it was a bit higher Pr though … the 70% efficiency width from 33 lb/min -73 lb/min @ 20 psig isn’t shabby though











so you think the g-40 might be a better option with the bigger efficiency islands?
Old 11-06-21, 08:13 PM
  #18  
10000 RPM Lane

iTrader: (2)
 
TeamRX8's Avatar
 
Join Date: Oct 2006
Location: on the rev limiter
Posts: 2,468
Received 844 Likes on 577 Posts
Well that depends on where you may be trying to fit it and also where you're real HP goal, overall mod,s and application goal is. Because you are still a bit vague on the details, and the details matter. Not a criticism, just that what you really are trying to achieve doesn't seem clear to me.

The G40 is about 2" longer overall than the G35, so there's that. Due to some inconsistency in how Garrett does the flange chart dimensions, it's not as easy to assess the width and height, but it seems they may be close though slightly larger than the G35 there as well.

In addition to the wide compressor efficiency range, the G40 turbine reaches as low or lower than the G35 turbines at the far left of the low Pr range (about 22 - 23 lb/min @ 1.3 Pr for the 0.85 AR T4, about equal with the G30 1.01 AR VB Brettus is using!), yet it also outflows sooner and greater than the G35 1.06 AR T4 turbine (the only G35 divided T4 choice) from there as well. The G40-900 looks like it has a lot of rotary potential for a 450 - 600 whp top end, but how responsive you want it to be on the low end, fuel type, porting, etc. etc. is all going to matter. Those are my thoughts any way, not really so much intended as specific advice for your situation. The G40 release just came out a day or two before I posted about it, so perhaps some people were not so aware of the choice.
Old 11-07-21, 02:02 PM
  #19  
Full Member

 
Brettus's Avatar
 
Join Date: Apr 2010
Location: New Zealand
Posts: 233
Received 36 Likes on 21 Posts
Really interesting that Garrett thought they needed another series between the G35 and G42. Not only that ...but they went away from the single entry theme straight to twin scroll housings only. Would be interested to know what their thinking was .
Old 11-07-21, 05:50 PM
  #20  
10000 RPM Lane

iTrader: (2)
 
TeamRX8's Avatar
 
Join Date: Oct 2006
Location: on the rev limiter
Posts: 2,468
Received 844 Likes on 577 Posts
They discussed releasing it a year ago as a G40-1000/1050

https://www.rx7club.com/single-turbo...150-a-1148267/


It’s also not the same -900 compressor assembly as the smaller G30/35; different compressor exducer, trim, and AR …



.

.
​​​​​​​
Old 11-07-21, 09:15 PM
  #21  
Rotary Motoring

iTrader: (9)
 
BLUE TII's Avatar
 
Join Date: Mar 2001
Location: CA
Posts: 8,211
Received 763 Likes on 505 Posts
G40-900 looks amazing for a 2 rotor.
Old 11-08-21, 01:02 AM
  #22  
Arrogant Wankeler

 
Slides's Avatar
 
Join Date: Nov 2006
Location: Newcastle NSW Australia
Posts: 704
Received 113 Likes on 92 Posts
Wish they would have thrown a 67-69mm comp inducer option in there too.
Old 11-08-21, 05:59 PM
  #23  
10000 RPM Lane

iTrader: (2)
 
TeamRX8's Avatar
 
Join Date: Oct 2006
Location: on the rev limiter
Posts: 2,468
Received 844 Likes on 577 Posts
I doubt the response difference justifies that over the 71mm inducer of the G40-1150
Old 11-08-21, 06:17 PM
  #24  
Arrogant Wankeler

 
Slides's Avatar
 
Join Date: Nov 2006
Location: Newcastle NSW Australia
Posts: 704
Received 113 Likes on 92 Posts
Originally Posted by TeamRX8
I doubt the response difference justifies that over the 71mm inducer of the G40-1150
It's not just the inertia of the wheel though, lower trim means more pressure at less shaft speed, should make a noticeable difference. I feel that flow rate (achieved on modern circa 68mm inducers ) would be a good balance for "I don't want to shred my factory case gearbox/aftermarket gearset the first time I go out" vs I put in a T56 may as well go to a G42 and 3 bar boost.
Old 11-08-21, 06:28 PM
  #25  
10000 RPM Lane

iTrader: (2)
 
TeamRX8's Avatar
 
Join Date: Oct 2006
Location: on the rev limiter
Posts: 2,468
Received 844 Likes on 577 Posts
So then what's wrong with the G35-1050 with 68mm inducer and the 1.06 divided T4 housing?
The following users liked this post:
Howard Coleman (12-07-21)


Quick Reply: Turbo sizing question



All times are GMT -5. The time now is 04:30 AM.