Rear Turbo Kit 001 ;)
#274
Supercharged
Rennlist Member
Rennlist Member
Joined: May 2002
Posts: 18,925
Likes: 65
From: Back in Michigan - Full time!
#275
I take it then, that you have! . The closest I have come to crack is Ledo's pizza here in Maryland. We're fairly certain there is crack in the sauce. it's impossible to stop eating it until it's all gone.
I know what a lot of boost feels like, and how it can be intoxicating. I also know what a lot of boost poorly delivered can do to an engine and transmission. I have blown up both using 25 psi of boost (@ 9:1) in my learning experience. Had a ton of fun in the process, of course. But at 10:1, 7 psi should be plenty, and provide a nice linear power curve, too. I'd say 10 psi max is safe before you have to start reinforcing head gaskets, upgrading fuel pumps, using a rising rate fuel pressure regulator, water injection, etc.
I know what a lot of boost feels like, and how it can be intoxicating. I also know what a lot of boost poorly delivered can do to an engine and transmission. I have blown up both using 25 psi of boost (@ 9:1) in my learning experience. Had a ton of fun in the process, of course. But at 10:1, 7 psi should be plenty, and provide a nice linear power curve, too. I'd say 10 psi max is safe before you have to start reinforcing head gaskets, upgrading fuel pumps, using a rising rate fuel pressure regulator, water injection, etc.
#277
If a '91 9000T 2.3l can do 23psi and get ~130hp/liter (mine has been doing this for years), the 928 should have the same kinds of stress on the heads with a 5.0l at 650hp (which is ~550rwhp with 15% drivetrain loss and probably around 12psi). Bigger injectors, 044 fuel pump and Sharktuning and you are done.
Dan
'91 928GT S/C 475hp/460lb.ft
Dan
'91 928GT S/C 475hp/460lb.ft
#279
If a '91 9000T 2.3l can do 23psi and get ~130hp/liter (mine has been doing this for years), the 928 should have the same kinds of stress on the heads with a 5.0l at 650hp (which is ~550rwhp with 15% drivetrain loss and probably around 12psi). Bigger injectors, 044 fuel pump and Sharktuning and you are done.
Dan
'91 928GT S/C 475hp/460lb.ft
Dan
'91 928GT S/C 475hp/460lb.ft
#280
One thing to keep in mind with the rear turbo setup is that an electronic boost controller can be really effective in tailoring the boost to where you want it. I had one on my GT when I was running the original rear turbo setup and unfortunately didn't play with it as much as I should have...
Like Mike said..check in with JT to see what he can put together for you... he is always "around"...just not here on rennlist etc..
Like Mike said..check in with JT to see what he can put together for you... he is always "around"...just not here on rennlist etc..
#281
I have boost spool envy of Mike's car too!!!! My 62/67 comes on way slower than his! His responds like a twin turbo under the hood! I don't even make full boost until 3000 rpms. His is probably in the 2000 range.
#282
Now at 8.5psi, my 30# injectors are at 85% duty cycle. That's pretty much maxed out. I also am running the 044 pump and removed the FMU. The fmu definitely helps fueling without having to go to larger injectors, but tuning around it is a nightmare! I finally pulled mine. I'm currently installing Meth Injection, and plan on wicking up the timing a bit. I pulled about 4 degrees out of my previous tune (at 6psi) to tune for the 8.5psi I'm currently running. If I can get the power I'm looking for (500whp/tq) with timing, I'll stay here at 8.5 psi.
My car was on jacks this weekend, and my wife asked will I EVER be done tinkering with THIS car? My reply.....................probably not. Once you're not afraid of a certain boost level anymore, it loses it's addition power! The way I see it, I'm still way ahead as far as cost goes. Considering I was looking at a 996TT to modify.
DFJ
Last edited by dragonflyjones; 09-19-2012 at 07:24 PM. Reason: poor Spelling
#283
do not forget there is much more to the formula than PEAK power on a dyno......if you run low compression plus high boost (like a Supra) you end up with a dyno queen.....with no power down low, horrible turbo lag and torque and hp rising at 45' angles together on your dyno chart....this car would be horrible to drive on the street or racetrack.....
The strength of 928's is its wide powerband....a nice low boost turbo that comes in early, is about perfect.....no loss of bottom end, with more midrange and top end...
The strength of 928's is its wide powerband....a nice low boost turbo that comes in early, is about perfect.....no loss of bottom end, with more midrange and top end...
#284
do not forget there is much more to the formula than PEAK power on a dyno......if you run low compression plus high boost (like a Supra) you end up with a dyno queen.....with no power down low, horrible turbo lag and torque and hp rising at 45' angles together on your dyno chart....this car would be horrible to drive on the street or racetrack.....
The strength of 928's is its wide powerband....a nice low boost turbo that comes in early, is about perfect.....no loss of bottom end, with more midrange and top end...
The strength of 928's is its wide powerband....a nice low boost turbo that comes in early, is about perfect.....no loss of bottom end, with more midrange and top end...
#285
Captain Obvious
Super User
Super User
Joined: Aug 2003
Posts: 22,846
Likes: 340
From: Cambridge, Ontario, Canada
do not forget there is much more to the formula than PEAK power on a dyno......if you run low compression plus high boost (like a Supra) you end up with a dyno queen.....with no power down low, horrible turbo lag and torque and hp rising at 45' angles together on your dyno chart....this car would be horrible to drive on the street or racetrack.....
The strength of 928's is its wide powerband....a nice low boost turbo that comes in early, is about perfect.....no loss of bottom end, with more midrange and top end...
The strength of 928's is its wide powerband....a nice low boost turbo that comes in early, is about perfect.....no loss of bottom end, with more midrange and top end...