my G37 is Redlining 8200Rpms 5at
06-14-2010, 11:46 AM
#46
Yeah, I'm sure it is just a high reading. But I did see a dyno graph of someone who used a tuner to raise the limiter and power did drop off dramatically. I just can't find it now. I'm pretty sure it was on this site somewhere....
06-14-2010, 11:52 AM
#47
IIRC, at 8k rpm, torque drops off another 12-13% from 7500 RPM. However, again, the gearing dropoff between gears is still bigger than that torque loss, so it is 'faster' to use the higher redline.
IMO, I wouldn't go that high on a regular basis, since its not proven to be safe, and the connecting rods are generally considered to be the weak link in the engine.
IMO, I wouldn't go that high on a regular basis, since its not proven to be safe, and the connecting rods are generally considered to be the weak link in the engine.
06-14-2010, 02:52 PM
#49
Average piston speed at stock redline is already roughly 70.5 ft/second. This is about the same piston speed as a Carrera GT, Carrera GT3, Murcielago, etc. Don't you think they'd love to make more power up top too? None of those cars are known for their low end grunt.
MotoGP and F1 cars see piston speeds of about 82 ft/s. They also have a much shorter stroke, partially to accommodate the stratospheric redlines.
If it really was safe to go past 7500, why isn't it there from the factory? Because it reduces longevity.
Better safe than sorry in this case. I'd rather not pay for a new crate motor.
06-14-2010, 05:12 PM
#52
I realize that...what I'm saying is that I don't know if there are stiffer springs used because of the VVEL system. I know that guys who run high RPM engines typically swap stiffer valve springs to eliminate valve float.
06-14-2010, 06:26 PM
#53
Honestly, 8000 RPM really comes down to how overbuilt the motor is. Can it do it? Yes. Can it do it fine? Yes. Will it hurt longevity? Definitely.
I know a few guys who regularly rev up to 8k, and they're still okay. However, they also don't skimp on everything, and have every supporting mod that they think is necessary to support this.
Mathematically, the speeds aren't TOO high... I'd go as far as saying that float wouldn't become an issue quite yet. Does anyone make stiffer springs for the VQ?
I know a few guys who regularly rev up to 8k, and they're still okay. However, they also don't skimp on everything, and have every supporting mod that they think is necessary to support this.
Mathematically, the speeds aren't TOO high... I'd go as far as saying that float wouldn't become an issue quite yet. Does anyone make stiffer springs for the VQ?
06-14-2010, 07:16 PM
#55
I haven't heard of anything valvetrain wise being made. It's a voodoo witchcraft thing to try and dial in the VVEL after anything has been touched. That's another reason why we probably haven't seen any type of head work.
I agree about the setpoints from the factory being dialed in to create "longevity", but I don't like factory setpoints. In my mind they are playing a numbers game. This is nothing new. If they have can boost reliability, emissions, gas mileage, safety, or any other number of measurable items by just 0.001%, that is huge numbers when talking about making hundreds of thousands of cars. I'll take take the risk of 0.001% if it means more performance.
My 96' Ram has a MOPAR computer that bumped up the rev limiter and shift points and reduced torque management and it made a hell of a difference. That's a factory computer replacing another factory computer. You can't use the "engineers know best" arguement when the engineers don't have the final say and the number crunchers do. At least that's the way I see it.
I agree about the setpoints from the factory being dialed in to create "longevity", but I don't like factory setpoints. In my mind they are playing a numbers game. This is nothing new. If they have can boost reliability, emissions, gas mileage, safety, or any other number of measurable items by just 0.001%, that is huge numbers when talking about making hundreds of thousands of cars. I'll take take the risk of 0.001% if it means more performance.
My 96' Ram has a MOPAR computer that bumped up the rev limiter and shift points and reduced torque management and it made a hell of a difference. That's a factory computer replacing another factory computer. You can't use the "engineers know best" arguement when the engineers don't have the final say and the number crunchers do. At least that's the way I see it.
06-14-2010, 10:25 PM
#57
I haven't heard of anything valvetrain wise being made. It's a voodoo witchcraft thing to try and dial in the VVEL after anything has been touched. That's another reason why we probably haven't seen any type of head work.
I agree about the setpoints from the factory being dialed in to create "longevity", but I don't like factory setpoints. In my mind they are playing a numbers game. This is nothing new. If they have can boost reliability, emissions, gas mileage, safety, or any other number of measurable items by just 0.001%, that is huge numbers when talking about making hundreds of thousands of cars. I'll take take the risk of 0.001% if it means more performance.
My 96' Ram has a MOPAR computer that bumped up the rev limiter and shift points and reduced torque management and it made a hell of a difference. That's a factory computer replacing another factory computer. You can't use the "engineers know best" arguement when the engineers don't have the final say and the number crunchers do. At least that's the way I see it.
I agree about the setpoints from the factory being dialed in to create "longevity", but I don't like factory setpoints. In my mind they are playing a numbers game. This is nothing new. If they have can boost reliability, emissions, gas mileage, safety, or any other number of measurable items by just 0.001%, that is huge numbers when talking about making hundreds of thousands of cars. I'll take take the risk of 0.001% if it means more performance.
My 96' Ram has a MOPAR computer that bumped up the rev limiter and shift points and reduced torque management and it made a hell of a difference. That's a factory computer replacing another factory computer. You can't use the "engineers know best" arguement when the engineers don't have the final say and the number crunchers do. At least that's the way I see it.
06-16-2010, 03:56 PM
#58
It doesn't seem to make sense that you are redlining past about 7600k rpms max, unless you are slipping a lot between gears or the tires are losing traction transferring less power, I can't really see it going up that high. I know in a Lexus GS400 A/T we have, sometimes it goes a few notches past redline when I go WOT in the snow but I only do that occasionally.
Off Topic, but hey Chaldean Habibi, do you have a any family-friends out in Metro Detroit? Tons of Chaldeans here, lol. I hear there's some in AZ and SoCal too though.
Off Topic, but hey Chaldean Habibi, do you have a any family-friends out in Metro Detroit? Tons of Chaldeans here, lol. I hear there's some in AZ and SoCal too though.
06-16-2010, 05:26 PM
#59
Well before hand when i first got my car i could've rev in netural all the way redline and got an update and now it stops at 5000rmp. However if i put it in 1st on stand still i can redline. I redline my car once or twice...you feel a lost in power and wouldn't have the same effect when shifting up as oppose to switching right before redline which is sick
06-17-2010, 02:13 AM
#60
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i think what im going to do to solve the problem with the power loss is get it dynoed and see what comes up im not really worried about anything happening to the engine ill go to the dealer and say what happen then have them deal with it (saying i never rev high of course) anyone know where i can get dynoed in san diego for a good price
Last edited by KhaldeanHabibi; 11-12-2011 at 11:25 AM.
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