10 replies to this topic

[YellowEvo1]

I want to get a set of crower 272 272 cams, with these cams my rev limit should increase right? If so what is a stock Evo1 bottom end good for??

[WindeX]

I am not sure on the bottom end, but I think you would want go with new valve springs for the 272s. I would love to know the answer to this as currently I am running the stock rev limit and I just love revs

[Entaran]

about 8300. Anything above that = valve bind.

You'll need serious headwork to rev past that including dual valve springs or bee-mad's from ffwd etc etc. ALSO the evo head doesnt' flow enough air to make power at 9k.

[YellowEvo1]

i will be redoing my entire valve train when i get the cams

[YellowEvo1]

my question is about the bottom end. what is a stock bottom end good for?

[Liberoz]

bottom end will all depend on how it has been maintained a stock crank has the potential to withstand more than your pistons and rods, also depending on what clutch your using (heavy) will depend on when / if you spin a bottom end bearing

[VR-4Squid]

as I mentioned to someone else in another thread a couple of days ago, stock oil pumps don't like more than 8000rpm.

other than that the weakest link in the bottom end is most likely the stock rod bolts...

[JAP63]

The amount of torque and horsepower your engine is making will also be a point of consideration here...as greater torque produces more acceleration forces on the crank as it turns around to change direction.....i see a rod bolt being the one to let go, then again, they did skinny the 7 bolt rods down.......anyones guess here, i wouldnt be going a nay past 8 grand.

Another point, a failed bottom end due to rpm usually sees a snapped or buckled rod...a snapped or buckled rod usually exits the block, a block that's had a rod through it always has a hole in it, a block with a hole in it goes in the recycling bin..the point of the story is that if you play with fire, youll risk getting burned, and in this case, its an expensive burn.

Its a true but unfortunate fact that not much can be done on the cheap, and sometimes a forged setup is required.

Edited by JAP63, 19 September 2009 - 02:27 PM.

[YellowEvo1]

sounds like i'll be sticking with the a rev limit of 7 grand.

[BMGTZ]

I have a mines ecu in my red car...........these have the rev limiter raised to the sky. I regularly see 8000rpm on a stock e2 bottom end.......but I have two spare engines as well. soon there will be a stroker in there which will be limited at 7300.

[Entaran]

I stand by my previous statement of 8300.

Although personally I wouldn't be pushing past 7500.