Stock motor-safe redline?
04-08-2009, 02:40 AM
#1
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Stock motor-safe redline?
I have an 05 MSM with a stock engine(for now)and upgraded turbo and supporting mods including a Hydra.
I know this all relative but where do people set their redline for reasonable safety on a stock motor? I know many rod failures(the motors weakest point) occur due to stretch at TDC.
I am current running a tune of about 250/250. I have the redline set at 7200 mostly to make 1st gear more useable.
Do you think this is a reasonable redline? If not where would you set it?
I know this all relative but where do people set their redline for reasonable safety on a stock motor? I know many rod failures(the motors weakest point) occur due to stretch at TDC.
I am current running a tune of about 250/250. I have the redline set at 7200 mostly to make 1st gear more useable.
Do you think this is a reasonable redline? If not where would you set it?
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04-08-2009, 04:15 AM
#3
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On a stock harmonic balancer, the OPGs are pretty much 100% safe below 300whp or 8000rpm. I would worry about stock rods past 7800 or so, as well as the valvetrain in that range. Past 8k, you need uprated valve springs, rods, and possibly billet OPGs.
Having said that, I have my hard cut set at 7200 on my stock 99 motor for longevity, even though it's still making power through to 7500 or so.
Having said that, I have my hard cut set at 7200 on my stock 99 motor for longevity, even though it's still making power through to 7500 or so.
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04-08-2009, 11:01 AM
#4
I didn't find that I needed anything above 7k on the street. I was willing to sacrifice a bit for engine longevity. I set my soft cut at 6800 and hard cut at 7000. I hit it occasionally taking a long stab in second... but never missed the extra couple hundred RPM I could have had.
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04-08-2009, 11:56 AM
#6
I have mine set at 7500.. no problems. There were a couple of guys here in Ga that funked with the stock ECU on STOCK n/a Miatas and were revving a little over 8,000RPM and were saying how it was all reliable... both of them have funked their motos within a year of doing it 
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04-08-2009, 12:00 PM
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Ok it sounds like I am in relatively safe territory. Savington, you mentioned on the "stock" harmonic balancer that the oil pump gears were safe up to a certain RPM. Does something like the ATI balancer make that big a difference for longevity/durability of the oil pump? I guess I hope it would for $600.
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04-08-2009, 01:24 PM
#9
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I think changing to an aftermarket pulley that does not have a harmonic damper has been generally linked to oil pump failure. Specifically, the aluminum "underdrive" pulleys that you see from time to time are of a solid construction and do not incorporate a damper. I'd imagine that the ATI unit would be good as gold in this regard.
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04-08-2009, 02:46 PM
#10
I think changing to an aftermarket pulley that does not have a harmonic damper has been generally linked to oil pump failure. Specifically, the aluminum "underdrive" pulleys that you see from time to time are of a solid construction and do not incorporate a damper. I'd imagine that the ATI unit would be good as gold in this regard.
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04-08-2009, 03:11 PM
#12
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in the meantime, I will maintain my plan to install both billet gears and ATI pulley.
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