Next Catfish Engine Build
#21
Elite Member
![](/mt2011/images_td/ranks/supporter1.gif)
Thread Starter
iTrader: (2)
Join Date: Dec 2011
Location: SoCal
Posts: 2,561
Total Cats: 488
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
GTX2867R and low boost because you bought the wrong pistons.
Smaller turbos that would spool faster need to make more pressure to achieve the same power but make more heat. You can't handle as much heat because you chose a higher compression piston. Therefore your car will be a slower spooling compromise.
For a serious car, I would use the 2867 at high boost with the lower compression pistons. And if it was track only, i'd consider e85.
Smaller turbos that would spool faster need to make more pressure to achieve the same power but make more heat. You can't handle as much heat because you chose a higher compression piston. Therefore your car will be a slower spooling compromise.
For a serious car, I would use the 2867 at high boost with the lower compression pistons. And if it was track only, i'd consider e85.
![](https://www.miataturbo.net/images/smilies/smile.gif)
So it's a compromise, and I don't actually mind a little boost lag as it's not really an issue at track rpm's, and is more fun than anything on the street. Compromises always mean that someone else's choice is better...for them.
No, we're planning a "serious" track car now that should end up with a 5:1 horsepower to weight ratio, but I'll start a new build thread when that happens.
#22
2 Props,3 Dildos,& 1 Cat
![](/mt2011/images_td/ranks/supporter1.gif)
![](/mt2011/images_td/ranks/smod.png)
iTrader: (8)
Join Date: Jun 2005
Location: Fake Virginia
Posts: 19,338
Total Cats: 573
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
I'd err on the side of a larger turbo than a 2560 if you want a little boost delay on the street. I abslutely loved the whooshiness of my 2876 on my 01. Plus you can run fairly low boost levels and get monster power.
I also have a theory that reducing boost response helps real world MPG but ... no data to back that up.
I also have a theory that reducing boost response helps real world MPG but ... no data to back that up.
#23
Former Vendor
![](/mt2011/images_td/ranks/supporter1.gif)
iTrader: (31)
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 15,442
Total Cats: 2,103
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
No surprise. 9.5:1 might be what you want for a low-boost responsive Rotrex. Everyone with any turbo experience understands that 8.6 motors make more torque with a turbo than 9.0 motors because you can run more timing with lower compression, especially on pump gas.
9.5 is the bastard child of compression ratios - not high enough to take advantage of E85, and too high to work well on pump gas. I don't know why Supertech makes that piston, honestly.
9.5 is the bastard child of compression ratios - not high enough to take advantage of E85, and too high to work well on pump gas. I don't know why Supertech makes that piston, honestly.
#24
Former Vendor
![](/mt2011/images_td/ranks/supporter1.gif)
iTrader: (31)
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 15,442
Total Cats: 2,103
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
This is like turbo BP 101, when did everyone suddenly forget that 8.6:1 is good and 9.5:1 is garbage? WTF?
#25
Elite Member
![](/mt2011/images_td/ranks/supporter1.gif)
Thread Starter
iTrader: (2)
Join Date: Dec 2011
Location: SoCal
Posts: 2,561
Total Cats: 488
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
No surprise. 9.5:1 might be what you want for a low-boost responsive Rotrex. Everyone with any turbo experience understands that 8.6 motors make more torque with a turbo than 9.0 motors because you can run more timing with lower compression, especially on pump gas.
9.5 is the bastard child of compression ratios - not high enough to take advantage of E85, and too high to work well on pump gas. I don't know why Supertech makes that piston, honestly.
9.5 is the bastard child of compression ratios - not high enough to take advantage of E85, and too high to work well on pump gas. I don't know why Supertech makes that piston, honestly.
![](https://www.miataturbo.net/images/smilies/smile.gif)
#27
Elite Member
![](/mt2011/images_td/ranks/supporter1.gif)
Thread Starter
iTrader: (2)
Join Date: Dec 2011
Location: SoCal
Posts: 2,561
Total Cats: 488
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
![](https://www.miataturbo.net/images/smilies/smile.gif)
No, don't really want to mess with E85 and will run premium only, or race gas at the track. I know, California premium is cat ****.
Thread
Thread Starter
Forum
Replies
Last Post