370 w/S91 spooling question
Take the turbo off the setup in your imagination. Now look at your combo. You have no air velocity because you have a short runner intake on an over sized head for the cubes that you are running and on top of that, you got really low compression. Not to mention that you haven't told us the cam size. So if you ran a combo like this without a turbo, you can see how it would need a monster cam and TONS of RPMs to really get going. You haven't told us the AR on the turbo either but I'm guessing it's a T6 housing with a 1.1+ AR and add tube headers to the mix and you got a max effort combo.
Solutions:
Without changing the combo all around, you could bump up your part throttle timing (off boost) into the 40's*. That'll help. A long runner composite intake would also help but it would choke off the heads up top. Switching to a 225 head would be the best fit IMO. Wrapping the headers really good will also help.
No, I have not yet. I just got the car running.
I did mention earlier that it is a 1.32. The Cam specs are as follows- @ .05 Intake duration is 235.5 Lift is .59774
Exhaust duration is 234 Lift is .59975
Lobe separation is 115.9
My plan all along has been to rev his engine up to 8k rpms, I had a 408 and switched to this engine to take advantage of using rpms and getting a little more Longevity out of it then the 408. The reason this should last longer even at a higher rev is because it has a WAY better rod to crank ratio which puts the piston on a lot lesser of an angle causing less friction and wear. Basically I was looking for a car to be Really nasty on the track (max effort as you put it) and still have some street duty. I am not planning on street racing it though.
That might be an option as long as it doesn't choke up the top end. We'll see how it all pans out after we get it fully tuned. I'm still not ruling out that it's only running on 7 cylinders. I will pull the plugs out on monday and do a visual inspection to see if one looks a little different then others...
Thanks for all the useful replies guys!
It's the chicken and the egg. Everybody thinks that air velocity doesn't matter in a turbo setup. That is incorrect. You need exhaust pressure to turn the turbo. In order to have sufficient exh pressure, you need to make a little NA power first.
Take the turbo off the setup in your imagination. Now look at your combo. You have no air velocity because you have a short runner intake on an over sized head for the cubes that you are running and on top of that, you got really low compression. Not to mention that you haven't told us the cam size. So if you ran a combo like this without a turbo, you can see how it would need a monster cam and TONS of RPMs to really get going. You haven't told us the AR on the turbo either but I'm guessing it's a T6 housing with a 1.1+ AR and add tube headers to the mix and you got a max effort combo.
Solutions:
Without changing the combo all around, you could bump up your part throttle timing (off boost) into the 40's*. That'll help. A long runner composite intake would also help but it would choke off the heads up top. Switching to a 225 head would be the best fit IMO. Wrapping the headers really good will also help.
Take the turbo off the setup in your imagination. Now look at your combo. You have no air velocity because you have a short runner intake on an over sized head for the cubes that you are running and on top of that, you got really low compression. Not to mention that you haven't told us the cam size. So if you ran a combo like this without a turbo, you can see how it would need a monster cam and TONS of RPMs to really get going. You haven't told us the AR on the turbo either but I'm guessing it's a T6 housing with a 1.1+ AR and add tube headers to the mix and you got a max effort combo.
Solutions:
Without changing the combo all around, you could bump up your part throttle timing (off boost) into the 40's*. That'll help. A long runner composite intake would also help but it would choke off the heads up top. Switching to a 225 head would be the best fit IMO. Wrapping the headers really good will also help.
Exhaust duration is 234 Lift is .59975
Lobe separation is 115.9
My plan all along has been to rev his engine up to 8k rpms, I had a 408 and switched to this engine to take advantage of using rpms and getting a little more Longevity out of it then the 408. The reason this should last longer even at a higher rev is because it has a WAY better rod to crank ratio which puts the piston on a lot lesser of an angle causing less friction and wear. Basically I was looking for a car to be Really nasty on the track (max effort as you put it) and still have some street duty. I am not planning on street racing it though.
Thanks for all the useful replies guys!
Pulled the spark plugs last night. Its firing on all 8 cylinders. We are gonna play with the tune aome more and try some of the stuff you all recommended. I'll post up results later.
Pulled the spark plugs last night. Its firing on all 8 cylinders. We are gonna play with the tune some more and try some of the stuff you all recommended. I'll post up results later.
I did mention earlier that it is a 1.32. The Cam specs are as follows- @ .05 Intake duration is 235.5 Lift is .59774
Exhaust duration is 234 Lift is .59975
Lobe separation is 115.9
My plan all along has been to rev his engine up to 8k rpms, I had a 408 and switched to this engine to take advantage of using rpms and getting a little more Longevity out of it then the 408. The reason this should last longer even at a higher rev is because it has a WAY better rod to crank ratio which puts the piston on a lot lesser of an angle causing less friction and wear. Basically I was looking for a car to be Really nasty on the track (max effort as you put it) and still have some street duty. I am not planning on street racing it though.
Exhaust duration is 234 Lift is .59975
Lobe separation is 115.9
My plan all along has been to rev his engine up to 8k rpms, I had a 408 and switched to this engine to take advantage of using rpms and getting a little more Longevity out of it then the 408. The reason this should last longer even at a higher rev is because it has a WAY better rod to crank ratio which puts the piston on a lot lesser of an angle causing less friction and wear. Basically I was looking for a car to be Really nasty on the track (max effort as you put it) and still have some street duty. I am not planning on street racing it though.
Are you using a three step?
as the others stated you need to get the timing in the high thirty to 40* range also lean it out.
If your just stabbing the throttle on a cold turbo on the street then that is why you are seeing the turbo spool later.
as the others stated you need to get the timing in the high thirty to 40* range also lean it out.
If your just stabbing the throttle on a cold turbo on the street then that is why you are seeing the turbo spool later.
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Verdad Gallardo . And as far as the timing and you guys saying to bring it up now to High 30's to 40*, is that at WOT right before going into boost and then ramp it down, or at part throttle only? What would you guys say max timing should be on only 6-10 psi while actually in boost?
Just to make sure were on the same page I will go through my launch.
First the burnout, the burnout heats the turbo up and helps to spool. I stop the car a foot away from the first beam and activate the first step. I footbrake hard and floor the car it goes to 2900 rpm, around 40* of timing and around 14+ AFR. as I foot brake into the first beam and stage to the second I will have built over three # of boost the car is floored the entire time. This usualy takes four to five seconds. When the second bulb activates I hit the transbrake and it goes on the second step which is 4100 to 4400 rpm. in 7-8 tenths of a second I am at launch boost of 8-11 psi. the AFR has dropped to the low 12's and the timing is in the 25* range. This is only possible beacause I have the turbo heated up before I go to the second step. If I hit the transbrake with a cold turbo and go right to 4400 it will take 3-4 seconds to build boost. You said you have a two step but are you actually using it? The first step has to be as high as you can hold the car footbraking. You have a lot to work with on your tune before you go messing with the converter and a like.
First the burnout, the burnout heats the turbo up and helps to spool. I stop the car a foot away from the first beam and activate the first step. I footbrake hard and floor the car it goes to 2900 rpm, around 40* of timing and around 14+ AFR. as I foot brake into the first beam and stage to the second I will have built over three # of boost the car is floored the entire time. This usualy takes four to five seconds. When the second bulb activates I hit the transbrake and it goes on the second step which is 4100 to 4400 rpm. in 7-8 tenths of a second I am at launch boost of 8-11 psi. the AFR has dropped to the low 12's and the timing is in the 25* range. This is only possible beacause I have the turbo heated up before I go to the second step. If I hit the transbrake with a cold turbo and go right to 4400 it will take 3-4 seconds to build boost. You said you have a two step but are you actually using it? The first step has to be as high as you can hold the car footbraking. You have a lot to work with on your tune before you go messing with the converter and a like.
Just to make sure were on the same page I will go through my launch.
First the burnout, the burnout heats the turbo up and helps to spool. I stop the car a foot away from the first beam and activate the first step. I footbrake hard and floor the car it goes to 2900 rpm, around 40* of timing and around 14+ AFR. as I foot brake into the first beam and stage to the second I will have built over three # of boost the car is floored the entire time. This usualy takes four to five seconds. When the second bulb activates I hit the transbrake and it goes on the second step which is 4100 to 4400 rpm. in 7-8 tenths of a second I am at launch boost of 8-11 psi. the AFR has dropped to the low 12's and the timing is in the 25* range. This is only possible beacause I have the turbo heated up before I go to the second step. If I hit the transbrake with a cold turbo and go right to 4400 it will take 3-4 seconds to build boost. You said you have a two step but are you actually using it? The first step has to be as high as you can hold the car footbraking. You have a lot to work with on your tune before you go messing with the converter and a like.
First the burnout, the burnout heats the turbo up and helps to spool. I stop the car a foot away from the first beam and activate the first step. I footbrake hard and floor the car it goes to 2900 rpm, around 40* of timing and around 14+ AFR. as I foot brake into the first beam and stage to the second I will have built over three # of boost the car is floored the entire time. This usualy takes four to five seconds. When the second bulb activates I hit the transbrake and it goes on the second step which is 4100 to 4400 rpm. in 7-8 tenths of a second I am at launch boost of 8-11 psi. the AFR has dropped to the low 12's and the timing is in the 25* range. This is only possible beacause I have the turbo heated up before I go to the second step. If I hit the transbrake with a cold turbo and go right to 4400 it will take 3-4 seconds to build boost. You said you have a two step but are you actually using it? The first step has to be as high as you can hold the car footbraking. You have a lot to work with on your tune before you go messing with the converter and a like.
I am chicken to run 40* at 8-11psi of boost. Besides From the time I hit the trans brake and go to the second step until I am at full launch boost is only .7 to .8 tenths of a second. I have a full second from the time the second guy stages until the tree goes green on a pro tree.
Just to make sure were on the same page I will go through my launch.
First the burnout, the burnout heats the turbo up and helps to spool. I stop the car a foot away from the first beam and activate the first step. I footbrake hard and floor the car it goes to 2900 rpm, around 40* of timing and around 14+ AFR. as I foot brake into the first beam and stage to the second I will have built over three # of boost the car is floored the entire time. This usualy takes four to five seconds. When the second bulb activates I hit the transbrake and it goes on the second step which is 4100 to 4400 rpm. in 7-8 tenths of a second I am at launch boost of 8-11 psi. the AFR has dropped to the low 12's and the timing is in the 25* range. This is only possible beacause I have the turbo heated up before I go to the second step. If I hit the transbrake with a cold turbo and go right to 4400 it will take 3-4 seconds to build boost. You said you have a two step but are you actually using it? The first step has to be as high as you can hold the car footbraking. You have a lot to work with on your tune before you go messing with the converter and a like.
First the burnout, the burnout heats the turbo up and helps to spool. I stop the car a foot away from the first beam and activate the first step. I footbrake hard and floor the car it goes to 2900 rpm, around 40* of timing and around 14+ AFR. as I foot brake into the first beam and stage to the second I will have built over three # of boost the car is floored the entire time. This usualy takes four to five seconds. When the second bulb activates I hit the transbrake and it goes on the second step which is 4100 to 4400 rpm. in 7-8 tenths of a second I am at launch boost of 8-11 psi. the AFR has dropped to the low 12's and the timing is in the 25* range. This is only possible beacause I have the turbo heated up before I go to the second step. If I hit the transbrake with a cold turbo and go right to 4400 it will take 3-4 seconds to build boost. You said you have a two step but are you actually using it? The first step has to be as high as you can hold the car footbraking. You have a lot to work with on your tune before you go messing with the converter and a like.
Plus. I'm thinking you are gonna lay the smack down on me. haha Sweet. Well, if I ever change my setup it will be for one of Shearers setups. I really like them. Unfortunately I spent my money on this OFI one that i've had to modify quite a bit and I lost a lot of money to him too. Thanks for the info!
