396ci LT4, YSI and 15lb of boost dyno result :(
03-14-2010, 11:26 AM
#26
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diff cams can cause diff amounts of vacuum, i got bout 12" at idle, i think your cr is too low, and the cam is costing you a few! something is def wrong, i made 670 thru a th400 at 14psi with 120 degree intake temps, with a 385, small cam stock ported heads, and bone stock lt1 intake! and with a 75mm turbo!
Last edited by 4SFEDZ; 03-14-2010 at 11:41 AM.
03-14-2010, 12:00 PM
#28
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Cam is fine, blowers love overlap-don't let anyone tell you anything different.
I tested a cam with 81 degrees of overlap and a cam with 58 degress of overlap-guess which one won.
Slap on a 8" crank pulley and hold on. If you can up the CR that would help too-I would go at least 9.5.
I tested a cam with 81 degrees of overlap and a cam with 58 degress of overlap-guess which one won.
Slap on a 8" crank pulley and hold on. If you can up the CR that would help too-I would go at least 9.5.
03-14-2010, 12:19 PM
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Cam is fine, blowers love overlap-don't let anyone tell you anything different.
I tested a cam with 81 degrees of overlap and a cam with 58 degress of overlap-guess which one won.
Slap on a 8" crank pulley and hold on. If you can up the CR that would help too-I would go at least 9.5.
I tested a cam with 81 degrees of overlap and a cam with 58 degress of overlap-guess which one won.
Slap on a 8" crank pulley and hold on. If you can up the CR that would help too-I would go at least 9.5.
03-15-2010, 12:58 PM
#32
the bump in compression is where your gonna feel the seat of the pants difference.
putting blowers and turbos on stock comp. cars pull hella hard because of our relatively high CR. obviously the only reason for lowering it would be the safety and reliability aspect of it but i would say start they and at least get it to 9 which is relatively safe on the boost you have now so there wouldnt be any changes there and then youll for sure be in a good ballpark to work from regarding a cam and what not because with the difference youll feel and see you might not want to swap cams
putting blowers and turbos on stock comp. cars pull hella hard because of our relatively high CR. obviously the only reason for lowering it would be the safety and reliability aspect of it but i would say start they and at least get it to 9 which is relatively safe on the boost you have now so there wouldnt be any changes there and then youll for sure be in a good ballpark to work from regarding a cam and what not because with the difference youll feel and see you might not want to swap cams
03-15-2010, 03:25 PM
#33
I think the cam is fine. The CR is a bit low but IMO you will only feel that off boost. Sounds like you are using the Commander 950 Pro, right? Are you using the 950 to control your timing? I also have the 950 and use it to control my timing. At 6000rpm and 12# of boost I have pulled timing back to the 24 degree range. My 383 SBC/T-trim put down 632rwhp with a locked 'verter at ~6300rpm.
The 8" crank pulley will help, then you can go a step up on the blower pulley and avoid slip. I would definitely check valvesprings. Are you using the AFR-8000 ones that come stock with the 227s?
Jim
The 8" crank pulley will help, then you can go a step up on the blower pulley and avoid slip. I would definitely check valvesprings. Are you using the AFR-8000 ones that come stock with the 227s?
Jim
03-15-2010, 04:10 PM
#34
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I am using Wideband Commander part#DJ-15-7001. Its not controling the timing.I was looking at the log file of my FAST ecu classic Sequential- which doesnt have N2O control- and the N2O retard timing was between 12 and 20 deg. I dont know whay that is on the log.I didnt alter the N2O retard parameters because I thought this option is disabled anyway.
About the valvesprings, I have no idea.Thay asked me what camshaft I have so they can install the right springs and I e-mailed them the cam specs.
I have Dynatech Vortex Insert Cones at the headers collectors, I might take them out and see what happens.Also I thinking of reworking the 3'' y-pipe and installing the flowmaster y-collector 3'' in 4''out.
I am also using stock spark plugs acdelco# 41-943 and stock gap.
About the valvesprings, I have no idea.Thay asked me what camshaft I have so they can install the right springs and I e-mailed them the cam specs.
I have Dynatech Vortex Insert Cones at the headers collectors, I might take them out and see what happens.Also I thinking of reworking the 3'' y-pipe and installing the flowmaster y-collector 3'' in 4''out.
I am also using stock spark plugs acdelco# 41-943 and stock gap.
03-16-2010, 12:47 PM
#36
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i agree with the posts about the aftercooler. you should at least check it out. i doubt it was really intended to support a YSI with the cubic inch motor you are running. there is a point were it might start to hurt you're performance instead of help.
03-16-2010, 08:12 PM
#37
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Some older books say that every full point drop in compression will reduce total power by 3%.
My 8:1 348 cid LS1 made 680rwhp, 18 psi, ysi, th400, 9", slicks, 9.40@143 with belt slippage.
If the guy has low compression he can up the timing and run a bit more boost...
My 8:1 348 cid LS1 made 680rwhp, 18 psi, ysi, th400, 9", slicks, 9.40@143 with belt slippage.
If the guy has low compression he can up the timing and run a bit more boost...
03-16-2010, 08:24 PM
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