Gt4788
tinkerd on here has a done, M6 4788, and I was impressed with it.
408 iron and 317s, pump gas, no meth, 13* IIRC he made 800/800 on 14/15 psi-
race gas and 20 psi, same timing, made 900.
If he adds timing and a bit more boost, itll make 1000 no problem.
Do a search, and it should give you a good idea.
It doesnt seem to light until 3800-4200, so keep that in mind. Its like a smaller 67mm on a supra, takes a bit to get lit, then its full steam.
Louis
408 iron and 317s, pump gas, no meth, 13* IIRC he made 800/800 on 14/15 psi-
race gas and 20 psi, same timing, made 900.
If he adds timing and a bit more boost, itll make 1000 no problem.
Do a search, and it should give you a good idea.
It doesnt seem to light until 3800-4200, so keep that in mind. Its like a smaller 67mm on a supra, takes a bit to get lit, then its full steam.
Louis
tinkerd on here has a done, M6 4788, and I was impressed with it.
408 iron and 317s, pump gas, no meth, 13* IIRC he made 800/800 on 14/15 psi-
race gas and 20 psi, same timing, made 900.
If he adds timing and a bit more boost, itll make 1000 no problem.
Do a search, and it should give you a good idea.
It doesnt seem to light until 3800-4200, so keep that in mind. Its like a smaller 67mm on a supra, takes a bit to get lit, then its full steam.
Louis
408 iron and 317s, pump gas, no meth, 13* IIRC he made 800/800 on 14/15 psi-
race gas and 20 psi, same timing, made 900.
If he adds timing and a bit more boost, itll make 1000 no problem.
Do a search, and it should give you a good idea.
It doesnt seem to light until 3800-4200, so keep that in mind. Its like a smaller 67mm on a supra, takes a bit to get lit, then its full steam.
Louis
Thread Starter
Launching!
Joined: Jan 2011
Posts: 250
Likes: 0
From: vegas
Yah I did, Precision told me 1.08
For some reason I think I should go bigger and then tinkerd told me he has a .96
So I have no clue I'm flip a coin and see what happens
For some reason I think I should go bigger and then tinkerd told me he has a .96
So I have no clue I'm flip a coin and see what happens
Last edited by konceptracin; Jan 7, 2012 at 06:37 PM. Reason: .....
I would go with the 1.08 if that is what Precision told you. You have to understand my motor has more done to it. With AFR 225 heads. So you're not compare apples to apples. I am thinking the larger the A/R the more lag you will get. So 1.08 is what I would do. If you are going to play on the street. With what you have, that is what I would do. Now if you comment to track only I would say go bigger and get a trans brake and 2 step. To aid in laughing it.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?
Pouria Savadkouei
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Are you using the gt4788? What A/R is yours? What computer are you using? It is my understanding that the bigger you go with the A/R the more lag you will see. If it is to much for what you have. Being that yours is a 434CI you wouldn't have to much lag at all. But as I said previously, I was told this stuff a long time ago so my input might be wrong. I think I am right about that tho. It's hard to compare with konceptracin setup. A 434Ci VS a 408CI That's a bit more motor than a 408CI. I would like to hear more about your setup. PM me with the 411 on it.
My point that I trying to get at is this. If the turbo or A/R is to big and he has problems getting into boost. It just won't be no fun. If he is doing a track only car heck yes go to a gt55.
turbine housing is easily changed, if you dont like it.
.96- Tight A/R turbine housing, in relation to singles. Will spool quickly, but top end power will suffer.
1.08, 30-40 hp difference, with little laggier boost ramp, carries top end a little further.
1.36 Noticeable difference in both spool and power production at high RPM. turbine flows much better than .96, however, due to this, we lose the ability to light it at low rpm.
.96- Tight A/R turbine housing, in relation to singles. Will spool quickly, but top end power will suffer.
1.08, 30-40 hp difference, with little laggier boost ramp, carries top end a little further.
1.36 Noticeable difference in both spool and power production at high RPM. turbine flows much better than .96, however, due to this, we lose the ability to light it at low rpm.
Thread Starter
Launching!
Joined: Jan 2011
Posts: 250
Likes: 0
From: vegas
turbine housing is easily changed, if you dont like it.
.96- Tight A/R turbine housing, in relation to singles. Will spool quickly, but top end power will suffer.
1.08, 30-40 hp difference, with little laggier boost ramp, carries top end a little further.
1.36 Noticeable difference in both spool and power production at high RPM. turbine flows much better than .96, however, due to this, we lose the ability to light it at low rpm.
.96- Tight A/R turbine housing, in relation to singles. Will spool quickly, but top end power will suffer.
1.08, 30-40 hp difference, with little laggier boost ramp, carries top end a little further.
1.36 Noticeable difference in both spool and power production at high RPM. turbine flows much better than .96, however, due to this, we lose the ability to light it at low rpm.
Yeah the housing can be changed, that's the good part!
I'm thinking about going in-between the .96 and the 1.36 and see what happens!
On The Tree
Joined: Jan 2012
Posts: 131
Likes: 0
From: sydney australia
hi mate i,m running a 408ci iron block setup with a bw s400 with the 1.32 ar rear and reckon its spot on comes on around 3000rpm and just pulls like a train !!! as you said if its mainly for the track !!!! 1.36 ar !!!! cheers
Thread Starter
Launching!
Joined: Jan 2011
Posts: 250
Likes: 0
From: vegas
A/r is only one factor. Turbine size is another. The bw 96mm 1.32 with a 88 compressor won't spool the same as a 1.36 housing on a gt4788. Another thing people talk about on the 4788 is the back pressure and that the turbine wheel is too small to suport the compressor
Which would lead to not enough torque to drive the compressor, so its two fold, which I can see. Higher back pressure, and slower spool because there isnt enough turbine to drive the wheel.