*7M Crank RPM Limit*
- Thread starter IJ.
- Start date
His bottom end is much the same as mine!
Very different thing flashing to 8+K for a few seconds compared to holding it there at the top end!
One of the guys here runs an LPG system like mine in a drag car and has no issues at 600rwhp during a pass yet mine runs horribly lean after 20>30 seconds!
Very different thing flashing to 8+K for a few seconds compared to holding it there at the top end!
One of the guys here runs an LPG system like mine in a drag car and has no issues at 600rwhp during a pass yet mine runs horribly lean after 20>30 seconds!
IJ,
Just how long are you holding it at 8,000 rpm?
Also, my shortblock is similar to yours (7M, Pauters, JE's and a lot of care) but no crankwork other then align bore and hone and new clevites.
Based on your experiences with your engine, how do you think it will behave using the Brian Crower 272's and a GT35R T4? Both as a street car and on the top end. With the turbo, I am undecided about turbine a/r but will be either 0.68 or 0.82. What would you suggest keeping in mind that it is T4?
Jim
Just how long are you holding it at 8,000 rpm?
Also, my shortblock is similar to yours (7M, Pauters, JE's and a lot of care) but no crankwork other then align bore and hone and new clevites.
Based on your experiences with your engine, how do you think it will behave using the Brian Crower 272's and a GT35R T4? Both as a street car and on the top end. With the turbo, I am undecided about turbine a/r but will be either 0.68 or 0.82. What would you suggest keeping in mind that it is T4?
Jim
My shift light is at 10,000rpm it depends on the race somethimes I hit the rev limer at 10,200rpm but normally I change gear at 9200 -9500 that is were I have the power peak.
My crank is Factory 6MCrank balance.I will go for a steel one next year as I am going to hit her with NOS.
My crank is Factory 6MCrank balance.I will go for a steel one next year as I am going to hit her with NOS.
Jim: No difference between the T3 flanged and T4 flanged 3540R other than the flange size/shape!
Depends on how long the road is!
8000 in each gear then hold for awhile in 4th before shifting to 5th.
Same nozzle size same wheel and trims!
All depends on how hard you're going to rev it and how much boost as these will affect the flow through the motor and I think if revving hard/high boost you're going to choke the exhaust with a .63.
Mibrum: What valve springs are you using and how are they holding up?
I'll post some pics of my 7M crank once it's back from being lightened!
Depends on how long the road is!
8000 in each gear then hold for awhile in 4th before shifting to 5th.
Same nozzle size same wheel and trims!
All depends on how hard you're going to rev it and how much boost as these will affect the flow through the motor and I think if revving hard/high boost you're going to choke the exhaust with a .63.
Mibrum: What valve springs are you using and how are they holding up?
I'll post some pics of my 7M crank once it's back from being lightened!
Gary: Thanks I thought you were running Ferrera's just wanted to double check!
Quite a few of my inners are tight inside the outers and I think this is what caused the failure at 8000!
Quite a few of my inners are tight inside the outers and I think this is what caused the failure at 8000!
Update!
I'm very pleased with the performance of my lightened 7M crank
We pulled 2.7kgs/5.9lbs out of it and coupled with the ATI Damper and JE pistons it's made a HUGE difference to engine response and off boost performance.
I'm very pleased with the performance of my lightened 7M crank
We pulled 2.7kgs/5.9lbs out of it and coupled with the ATI Damper and JE pistons it's made a HUGE difference to engine response and off boost performance.
why the bolts on #3? is that how they come (arp stuff i'm assuming)? not too familiar with the 7m internerals..
I had mine set at 7200 on the dyno, and it had barely started to drop off in hp at that point. That was with a stock head, and stock crank and rods, Ross pistons, everything balanced, gt4082.
This time around I have Eagle rods, Arias pistons, shorter stroke, 1mm os ss valves, titanium retainers, Comp Cams 975 springs, mild p&p, and everything is getting balanced, including the pp and flywheel.
So we'll see how high it can rev pretty soon, I'm going to set the redline by what the dyno says.
This time around I have Eagle rods, Arias pistons, shorter stroke, 1mm os ss valves, titanium retainers, Comp Cams 975 springs, mild p&p, and everything is getting balanced, including the pp and flywheel.
So we'll see how high it can rev pretty soon, I'm going to set the redline by what the dyno says.
With my old IC setup it would plateau around the 7000 mark but the new setup is still heading upwards by 7500 limiter.
