Safely rev higher

[GlacierFreeze]

I have a '97 240sx and I'm planning on turboing it by the end of the year. I was wondering about how I could make the engine have a higher redline safely. I wanted to move the redline from 6500rpm to 7000rpm. I tried searching and found a little bit about it but wasn't satisfied enough with what I found.

I was wondering if anyone could give me any info on what all I would have to do to safely be able to rev to 7000rpm, like what all parts I'll have to upgrade or strengthen or what not. Thanks.

[DuffMan]

for only 7000 you probably just need valve springs. S13's could rev that high stock.

[fleaf]

Originally posted by DuffMan
for only 7000 you probably just need valve springs. S13's could rev that high stock.

true...my s13's redline is at 6900 (92 coupe) with the original ka24de (122k). They only made redline at 6500 for the s14's mainly for security. But yeah, it's able to reach 6900, I do it everyday :D

edit: pic
- might be kinda hard to see cause of the sunlight
http://204.210.51.14/pictures/240sx/240sx%20034.jpg

[Jeff240sx]

JWT bumps up the rev-limiter to 7500 rpms with their ecu reprogram. The stock valve springs are fairly good.
-Jeff

[andrave]

I think the problem isn't with revving that high, but with making power that high... the stock ka doesn't make power that high in the revband.

[GlacierFreeze]

Wow I didn't know the JWT reprogram bumped it up that high or at all for that matter. Thanks for telling me that. Yeah I know about the poor power band of the KA. I was going to put better cams in whenever I turbo it. Thanks for the feedback guys.

P.S. What would be some good specs for a set of cams going into a turbo KA for the 7500rpm redline? I don't know too much about cams when it comes to figuring what duration and lift are good and where they make power. Thanks.

[andrave]

its gonna take more than just cams.
but for a good set of cams for the de, PDM racing just released some that offer a really nice curve.

[AKADriver]

For a turbo application you want something mild... a set of cams with too much overlap will be slow to build boost and end up bleeding off boost on the top end.

"Turbo" grind aftermarket cams tend to set the intake more aggressive than the exhaust. I don't know of anyone selling a set like this for the 240SX off-hand, all the KA cam sets I'm seeing are designed for N/A power.

S14 cams are the most conservative factory cams, just installing '91-early '93 S13 cams is a good mild upgrade that should extend your powerband to the 6000s. You might try working with someone that sells reground cams like PDM to see if you could get a mild reground intake cam and match it with a stock S13 exhaust cam... or perhaps two different regrinds (hot intake, mild exhaust).

But, bounce that idea off some other people first, 'cuz I'm no engine building guru. :) This is just what I've picked up from researching aftermarket cams for other cars.

[Tuck&Poke]

cams for a turbocharged motor IIRC they dont require an extreme cam profile. you will definately need something better and more aggressive than stock. you dont want to high of a lift or too long of a duration. w/ a long duration you can loose boost as it escapes through the exhaust port. i dont know too much about the measurements of cams blah blah.