The Authoritative Galant VR-4 Resource

Join the best E39A 1991-1992 Mitsubishi Galant VR-4 community and document your GVR4 journey.

  • Software Upgraded - Reset Your Password to Login
    In order to log in after the forum software change, you need to reset your password. If you don't have access to the email address you used to register your GVR4.org account, you won't be able to reset your password. In that case, follow the instructions here to regain access to the forum.

Turbo sizing questions

MitsuDriver274

Well-known member
Joined
Jan 20, 2004
Messages
319
Location
Bellingham, WA
I'm going through the process of selecting a turbo, I've definitely decided on the gt28 series but don't know exactly which one to run. Doing some rough estimates at 6k assuming 90% VE and a PR of 2.3 (~20psi) a 4g would flow 439 cfm or 30.7 lb/min. (2.0l*6000rpm*90VE*2.3PR/5660). At 1/2 flow = 15.35, and 1/5th flow (at PR of 1) = 13.35 lb/min




I mapped it out on a gt2860rs map and it looks to small (excuse the crude paint rendition) , did I make a mistake somewhere? And who's running this turbo currently and can give me some feedback on its performance? Doesn't really fall into the middle island all to well.
 

Barnes

Well-known member
Joined
Feb 9, 2003
Messages
6,249
Location
Richland, WA
Any particular reason you picked this turbo as opposed to an Evo3-16g? (I think they are comparable)
 

MitsuDriver274

Well-known member
Joined
Jan 20, 2004
Messages
319
Location
Bellingham, WA
I just picked this turbo to get a base map of where to go, either up or down in size. I'm not planning on making more than 350, but I also want the turbo to be running efficiently. But the main draw to the gt series is the ball bearing center section.

I raced one season with a evo III 16g and another with what apparently was an evo 4 turbo which made much more power on the dyno (218whp => evo3 vs 246whp => "evo 4") that was quite a gain given we were running a 34mm restrictor.

A friend recommended a gt2876r with a .48 housing, but looking at the map it seems a bit too big.
 

MitsuDriver274

Well-known member
Joined
Jan 20, 2004
Messages
319
Location
Bellingham, WA
Quoting MitsuDriver274:
I'm going through the process of selecting a turbo, I've definitely decided on the gt28 series but don't know exactly which one to run. Doing some rough estimates at 6k assuming 90% VE and a PR of 2.3 (~20psi) a 4g would flow 439 cfm or 30.7 lb/min. (2.0l*6000rpm*90VE*2.3PR/5660). At 1/2 flow = 15.35, and 1/5th flow (at PR of 1) = 2.67 lb/min




I mapped it out on a gt2860rs map and it looks to small (excuse the crude paint rendition) , did I make a mistake somewhere? And who's running this turbo currently and can give me some feedback on its performance? Doesn't really fall into the middle island all to well.



Edited: realized I made an error in calc 1/5th flow, changed the map too, comes very close to the surge line now.
 

MitsuDriver274

Well-known member
Joined
Jan 20, 2004
Messages
319
Location
Bellingham, WA
Here's those same numbers on a 2871r
img.php
 

Quoting MitsuDriver274:
I just picked this turbo to get a base map of where to go, either up or down in size. I'm not planning on making more than 350, but I also want the turbo to be running efficiently. But the main draw to the gt series is the ball bearing center section.

I raced one season with a evo III 16g and another with what apparently was an evo 4 turbo which made much more power on the dyno (218whp => evo3 vs 246whp => "evo 4") that was quite a gain given we were running a 34mm restrictor.

A friend recommended a gt2876r with a .48 housing, but looking at the map it seems a bit too big.



Did you make another manifold for the Evo 4 turbo? /ubbthreads/images/graemlins/dunno.gif
 

RayH

Well-known member
Joined
Apr 9, 2001
Messages
2,701
Location
NJ
For reference, I believe the center cartridge and compressor of the 2871R was what was used on the AGP L1R/SS44 turbos. It might have also been used on the FP2544.
 

MitsuDriver274

Well-known member
Joined
Jan 20, 2004
Messages
319
Location
Bellingham, WA
Yea that what I don't understand anything evo 4-9 would spin backwards right? But that is what the shop claimed I wish I had written down the numbers on it. That's why I used quotation marks.
 
Support Vendors who Support the GVR-4 Community
Boosted Fabrication ECM Tuning ExtremePSI Fuel Injector Clinic Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications RixRacing RockAuto RTM Racing STM Tuned

Recent Forum Posts

Recent Classifieds Listings

Top