Which Turbo to Lower Back Pressure and still spool early
03-24-2014, 07:04 PM
#1
TECH Apprentice
Thread Starter
Which Turbo to Lower Back Pressure and still spool early Hi
I have a Holden Commodore (a 4 door with same platform as a 2004-6 GTO) with a custom STS style rear mount single turbo. It was an STS supplied upgraded unit with ball bearings. It worked fine on the old LS1 but on the new repowered LS3 it shows massive back pressure and is down 150rwhp on what a bigger turbo would produce.
I was going to run the new Borg Warner EFR 9180 as they are state of art and BW claim that it would give me the added 150rwhp and still spool as early. The downside is that it will require water cooling - which I can do but it is obviously a bit of extra work in the back of the car and I'd run a waterless self-contained cooling tank and radiator/fan set-up.
Before I commit to that I thought there may be someone here who can vouch for a top quality alternative that is proven very good at spooling early (I'd like 2psi from a dig on 2800rpm stall) as the current car can produce 300rwhp from 2600rpm and it'd be a shame to lose bottom end. BUT also I want to reduce back pressure and gain top end.... I know compromise, but what I have is too restrictive
LS3 has mild Calloway cam (218/222 @ 050), tight quench 040 gaskets for around 10.7:1, ARP bolts etc; 4 into 1 headers and free flowing exhaust and intake - there's no room for improvement in back pressure from the plumbing. Kurt Urban steam system, Aquamist water/meth, E-boost 2 controller, can't get less than 10psi peak due to back pressure no matter what spring in the wastegate
The STS turbo is a 75 T4E/T4V P-trim BB (67mm size) with a 0.81 A/R housing
I'd like something really efficient at low boost (blows lots of CFM at low boost yet will still spool from around 2500rpm.
Anyone?
or should I just go with the EFR 9180? I know they're expensive but that is ok if they're good for my application. My concern is they're really designed to do well at 30psi or more, and I'll not run more than 10-12psi given both a non forged engine, high compression, and the fact I'll be traction limited by tire size anyway.
I have a Holden Commodore (a 4 door with same platform as a 2004-6 GTO) with a custom STS style rear mount single turbo. It was an STS supplied upgraded unit with ball bearings. It worked fine on the old LS1 but on the new repowered LS3 it shows massive back pressure and is down 150rwhp on what a bigger turbo would produce.
I was going to run the new Borg Warner EFR 9180 as they are state of art and BW claim that it would give me the added 150rwhp and still spool as early. The downside is that it will require water cooling - which I can do but it is obviously a bit of extra work in the back of the car and I'd run a waterless self-contained cooling tank and radiator/fan set-up.
Before I commit to that I thought there may be someone here who can vouch for a top quality alternative that is proven very good at spooling early (I'd like 2psi from a dig on 2800rpm stall) as the current car can produce 300rwhp from 2600rpm and it'd be a shame to lose bottom end. BUT also I want to reduce back pressure and gain top end.... I know compromise, but what I have is too restrictive
LS3 has mild Calloway cam (218/222 @ 050), tight quench 040 gaskets for around 10.7:1, ARP bolts etc; 4 into 1 headers and free flowing exhaust and intake - there's no room for improvement in back pressure from the plumbing. Kurt Urban steam system, Aquamist water/meth, E-boost 2 controller, can't get less than 10psi peak due to back pressure no matter what spring in the wastegate
The STS turbo is a 75 T4E/T4V P-trim BB (67mm size) with a 0.81 A/R housing
I'd like something really efficient at low boost (blows lots of CFM at low boost yet will still spool from around 2500rpm.
Anyone?
or should I just go with the EFR 9180? I know they're expensive but that is ok if they're good for my application. My concern is they're really designed to do well at 30psi or more, and I'll not run more than 10-12psi given both a non forged engine, high compression, and the fact I'll be traction limited by tire size anyway.
03-24-2014, 07:09 PM
#2
TECH Apprentice
Thread Starter
Single turbo BTW, pump gas, and currently makes 510rwhp when it should be 650rwhp at 10psi. Fuel supply will support 650rwhp easily (2 x 044 pumps and ID725 injectors)
Only a baby compared to many here but its a fun car that is good at road tracks and can still get 30mpg on the drive home
thanks :-)
Only a baby compared to many here but its a fun car that is good at road tracks and can still get 30mpg on the drive home
thanks :-)
03-25-2014, 11:57 PM
#4
TECH Apprentice
Thread Starter
