7k Redline worries...

[Fidhle007]

Thanks to a recent sofware upgrade my engine now redlines at 7000 rpm but I have to admit, I'm scared to run it that high. Is there any reasoning to my fear or am I just being stupid? Somewhere between 6700 and 6800 my car develops a little bit of a rattle but I think it's my mad tyte exhaust hitting my rear valence....

Just wondering if anyone had any opinions of feed back!

Thanks!
Brendan

[T.Dot E30]

You should not have very much need to rev that high, constant reving to 7k and your bound to break stock rocker arms, so unless u have a built head, i wouldn't do it too many times.

[Fidhle007]

That was exactly my thought. It seems like it would be useful only to have a little more shifting room in the lower gears.

[mode]

i garuntee that if you rev to 7k constantly you will break rockers.....due to VALVE FLOAT. Not "weak rocker arms".

You can do it with stiffer valve springs though.

[MR 325]

My car will go to 7200 or 7300, whatever it is. I usually take it no further than 6500ish considering I have already broken a rocker, lol.

[euroshark]

"mode" must be either Mike or Mr. Dingle... lol

But on the topic at hand, as mode says, you should be safe with performance valve springs from Ireland Engineering, Schrick, etc.

[e30 gangsta]

snapping rockers sucks just keep it safe. And only bounce when needed. ( thats never even @ the track lol )

[rcko]

my

Not much need to go that high. Must of the power is being made in the 5ks. I believe there is not much to loose shifting a tad earlier. Maybe if you ax the extra 500 -700 rpm will let you run a few more cones without having to shift and buy you a few 0.1 seconds.
In my short lived experince with 7k reving chips on a tired old engine, visiting 7k often = busted lower end.

[Fidhle007]

I now have my shiftlight set at 6600 and that seems about perfect, a little more headroom than normal but still not destroying my motor. Yet. :D

[Hadrian]

Has anyone actually experienced valve float on an M20?

[mode]

I have. On two occasions, both resulting in broken rockers. Both intake, the most stressed rocker.(larger mass on the intake valve)

Rev your m20 to 7300 and see what happens.

[e30cbe]

also stock crank is spheroidal cast iron not forged intended to dampen vibrations and provide safe running upto 6700 , if u need to rev higher think of using a forged crank along with upgraded rockers and valve springs - contacting someone like metric mechanic or korman would be a good idea

[AlarmedBread]

My car doesn't pull much above 6k, so I shift around there usually. Go to the dyno and see if it's worth it to be so high in your rev range.

[Fidhle007]

Who needs a dyno when you have a butt and timed quarter mile?

Played around a little with different shift points and finally settled on 6650 for my shift light. I was running 15.7s all evening until the last run when I went up against my buddy in his 328ic e36. I guess the adrenalin and motivation of having something to beat helped because I ran a 15.5. And now my valve need an adjustment...

[Hadrian]

I have. On two occasions, both resulting in broken rockers. Both intake, the most stressed rocker.(larger mass on the intake valve)

Rev your m20 to 7300 and see what happens.

How do you know it ws valve float?