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Old 09-23-2007, 11:41 PM   #1
WrxRick
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Default STi rev safe to 7500rpm?

I am purposely building my block to withstand the power for a FP RED. I am currently bone stock right now and I plan to go with an Axis Stage 2 shortblock.

I have tried searching to find out an answer, but it seems I can only find part of the answer I'm looking for.

So here it is, What modifications should I do to ensure the safety of revving to 7900rpm in terms of head work? I'd like to keep stock cams for lower torque. I just want to rev a bit more than the stock parameter, since the FP RED will love to rev past 7k.

Thanks for your expertise.
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Old 09-23-2007, 11:55 PM   #2
mick_the_ginge
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Springs, block work and oil system upgrade but IMO if you are going to use the stock cams then their is no point in spinning to 7900. The cams will limit the top end power, TQ going to be plumeting by that rpm
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Old 09-23-2007, 11:58 PM   #3
flycaster
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Are we talking 7.9 or 7.5K here - I'm confused.
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Old 09-24-2007, 12:01 AM   #4
WrxRick
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Sorry for the confusion.
I'll most likely shift right before 8,000rpm each shift. So about 7.9k.

So perhaps 264/264 cams will keep some torque at slightly higher rpms vs. the stock cams.

mick_the_ginge:
by "block work" do you mean porting the heads? Or something else?
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Old 09-24-2007, 12:18 AM   #5
WrxRick
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Here would be my latest up to date question.

What would I need to rev happy to 7900 (no more) besides a Brian Crower spring/retainer kit, and a brian crower camshaft set?

I will have a local shop install this machinery.



Side Note: A big concern I have involves the lack of knowledge that I have as far as aftermarket cams goes. Does adding Brian Crower cams change the power band at all (horsepower) before peak horsepower? Or does it just free up top end horsepower without affecting lower rpm horsepower curve?
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Old 09-24-2007, 12:37 AM   #6
modaddict
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cams shift your powerband to the right. period. Depending on the size of the cams depends on the shift. Port work can also do the same thing.

check this thread out:
http://forums.nasioc.com/forums/show...highlight=past

FWIW my completely stock long block is at 7550. There are people who have gone higher, and there are people who think *I'm* nuts.
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Old 09-24-2007, 12:41 AM   #7
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Fantastic thread find.

Thanks for the info
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Old 09-24-2007, 10:50 AM   #8
blowbyu24
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i wouldn't be as worried with the cams, you should be worried with what rod/main bearings you use!!! and everyone can back me up with that
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Old 09-24-2007, 01:02 PM   #9
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I wouldn't spin to 7900 on factory rods...(axis stage 2)...also wouldn't do it on the factory bearings or factory oiling system.
rods stretch and metal fatigues...not to mention now with heavier forged pistons exerting more force on the bearings and rods

It would be a shame to do the work to just flush it down the drain
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Old 09-24-2007, 01:08 PM   #10
DoctorNick
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7500 on stock block here running a green.
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Old 09-24-2007, 03:22 PM   #11
charliew
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Default 7900

7900, blinking 8200, using a rev limiter at 7500, your still on borrowed time. There is nothing in a wrx or sti that was meant to live past 7000. Just study the threads and use your own judgement it's your money. Who's to say what some stock motors will do. Stock tolerances were not meant to be pushed past 7000. Do you think subaru put an extra 2 grand in the motor just so the folks could play or do you think they tried to hold the cost down and make a neat street car to be used by 40 year olds that want it to last till it's paid for. If you go to bigger cams you are going to spend more time past 6000 and a stock motor wasn't meant to stay there very long. Nice dreams and good luck. I hope you check the oil regularly cause some will dissapear at higher rpms.

Charlie
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