I'm curious about which numbers apply to the 8v heads and which to the 12v heads. I know some of this was raised earlier
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Well from my experience there is no point revving the 4G15 past about 6000rpm unless you have a hot cam in there. I find that changing at around 5800 in my 4G15 Excel drops it smack bang in the middle of the peak in the torque curve. It chirps second with sticky Dunlop rubber when I change at this point. If I go higher, less torque & no chirp & slower.
The 4G15 is an undersquare motor not designed for revs, more for mid-range torque. The 4G61 is very oversquare and hence has low torque but revs to the moon.
Redline on the '93 Excel is at 6200rpm - although this version never made it to the US and is MAP based rather than MAFS.
the version in the excel is also 8 valve and as far as i have seen, no 12 valve motors ever went in them in the U.S. Porting is way different on 12 valve motors. I'm sure the power band would be affected. I believe 12 valve version was introduced in in some 90's and on 91' models.
look in my photo album for comparison pics:
http://photos.yahoo.com/socrateez@prodigy.net
but I'm a little uncertain what applyies to my tired 8v and what doesnt.
red-line (dash tach) is marked at 6000 on my car (90 plymocolt 200gt) and I've always approached that line rather cautiously (she's my daily driver, cant risk screwin the pooch, ya know?), but this threads got me interested in pushing it. in this post,
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Very true Jason. I find with my 4G15 powered car that I need to rev to about 6500rpm to make sure that the 1-2 & 2-3 shifts stay in the power band which is above 4000rpm. Given that, I wound the valve lash in (one good thing about solid lifters) from .15/.25mm (inlet/exhaust) to .08/.18mm which woke up the top end a little to make revving it more worthwhile. I checked compression before and after and it was the same (If they are wound in too far you will loose compression and power).
xlr8 suggest 6500 is optimal. true for a 8v as well? (very stock)
sorry for the ramble
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no tach), but it's at 37 MPH in a 4 spd car. I bounce off it all the time autocrossing the car. It's much faster to stay in first and use the limiter than shift and lug the car.
, the mechanical limits of the 4g15 at 9000rpm is about 2 months of hard driving. then the weakest link is the cam which snapped in half. and the retainers tht held them in got stripped out(fukcing aluminum heads). I picked up a new cam out of another csm and some epoxy, and I was back on the road. 2-3 cyl running and all, it lasted another 2 months before meeting the maker. BTW i was trying to kill the engine due to a new 4g63t purchase. So short story, 9000 is the mechanical limit for this car!
