Valve Spring Issue on D1SC 347
There's your problem, @ 130lbs you're just bleeding off your boost, not enough pressure to keep the valves closed. I had the same issues with my AFR 225's w/ standard springs which were rated at 135lbs closed seat pressure, I ended swapping the springs for their optional higher rate springs and solved all the valve float problems.
I believe i'm going to change my springs to PRC Gold Dual Xtreme's in about 2 weeks. I planned on running 100% methanol when I ordered the kit, but my tuner said I needed 50/50 so thats what I did. Seemed to work very well dropping intake temps 40+ degrees and he added a good bit of timing.
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I can't remember exactly, but I think it's 155lbs @ the seat and 428lbs@ .650lift. It's not really that high of a rate compared to other springs that I've seen around here, but I did'nt want the hassle of pulling the heads off to have the seat machined for a bigger diameter springs.
I can't remember exactly, but I think it's 155lbs @ the seat and 428lbs@ .650lift. It's not really that high of a rate compared to other springs that I've seen around here, but I did'nt want the hassle of pulling the heads off to have the seat machined for a bigger diameter springs.
Spring Pressure Closed: 155 lbs. @ 1.800"
Spring Pressure Open: 410 lbs. @ 1.140"
Coil Bind: 1.090"
You might want to try 100% meth though before you swap out valvesprings just to rule it out. Bob
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I'm nearly 100% positive thats not causing the problem. If it were, the car would get extremely rich right after the meth kicks, which is probably around 3000rpms. All the symptoms point towards valve float.
I am now looking to invest in the Livernois Motorsports LS dual valve spring. Its rated at .690 lift and has 150lbs of closed seat pressure. If that doesn't solve it, i will try 100% meth just to humor you.
I am now looking to invest in the Livernois Motorsports LS dual valve spring. Its rated at .690 lift and has 150lbs of closed seat pressure. If that doesn't solve it, i will try 100% meth just to humor you.
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Verdad Gallardo To any of you who were still following this thread the problems have been resolved.
To start out, all the springs were changed to Livernois Super Duty springs (150lbs seat pressure). This didn't fix the problem though. Symptoms were still the same.
So I called Bob and we talked about it for a while and he convinced me to try a shorter belt and I also purchased a new idler pulley from him since mine was a little dinged up from the previous owner. I also went with 100% meth instead of the 50/50 mix.
Car got back on the rollers last Wednesday and put down an impressive 730hp 640tq. I was pretty happy with these results. It made 17lbs of boost.
Graph can be viewed from my tuners website here: Dyno Graph
Hopefully those of you who had an interest in this thread will remember these problems and be able to point someone else in the right direction if you see a problem like this arise again. Thanks.
To start out, all the springs were changed to Livernois Super Duty springs (150lbs seat pressure). This didn't fix the problem though. Symptoms were still the same.
So I called Bob and we talked about it for a while and he convinced me to try a shorter belt and I also purchased a new idler pulley from him since mine was a little dinged up from the previous owner. I also went with 100% meth instead of the 50/50 mix.
Car got back on the rollers last Wednesday and put down an impressive 730hp 640tq. I was pretty happy with these results. It made 17lbs of boost.
Graph can be viewed from my tuners website here: Dyno Graph
Hopefully those of you who had an interest in this thread will remember these problems and be able to point someone else in the right direction if you see a problem like this arise again. Thanks.
To any of you who were still following this thread the problems have been resolved.
To start out, all the springs were changed to Livernois Super Duty springs (150lbs seat pressure). This didn't fix the problem though. Symptoms were still the same.
So I called Bob and we talked about it for a while and he convinced me to try a shorter belt and I also purchased a new idler pulley from him since mine was a little dinged up from the previous owner. I also went with 100% meth instead of the 50/50 mix.
Car got back on the rollers last Wednesday and put down an impressive 730hp 640tq. I was pretty happy with these results. It made 17lbs of boost.
Graph can be viewed from my tuners website here: Dyno Graph
Hopefully those of you who had an interest in this thread will remember these problems and be able to point someone else in the right direction if you see a problem like this arise again. Thanks.
To start out, all the springs were changed to Livernois Super Duty springs (150lbs seat pressure). This didn't fix the problem though. Symptoms were still the same.
So I called Bob and we talked about it for a while and he convinced me to try a shorter belt and I also purchased a new idler pulley from him since mine was a little dinged up from the previous owner. I also went with 100% meth instead of the 50/50 mix.
Car got back on the rollers last Wednesday and put down an impressive 730hp 640tq. I was pretty happy with these results. It made 17lbs of boost.
Graph can be viewed from my tuners website here: Dyno Graph
Hopefully those of you who had an interest in this thread will remember these problems and be able to point someone else in the right direction if you see a problem like this arise again. Thanks.
__________________
ATI ProCharger and Moser Sales 260 672-2076
PM's disabled, please e-mail me
E-mail: brutespeed@gmail.comob@brutespeed.com
https://brutespeed.com/ Link to website
ATI ProCharger and Moser Sales 260 672-2076
PM's disabled, please e-mail me
E-mail: brutespeed@gmail.comob@brutespeed.com
https://brutespeed.com/ Link to website
Yea, its a little more than I was hoping for. In the near future, i'm going to swap the LS6 intake for a LS2 and upgrade to a Nick Williams TB, change my exhaust to a setup with cutouts and also upgrade to a larger intercooler. Hopefully drop it to 14psi.
