88IntegraLS

Is there really a stock rev limiter?

Some times I get deep into 7000rpm territory when in first gear with my S4 NA, which has a 7k redline, but it never "bounces" off any limit or anything. The buzzer will be going off for a few seconds. This happens mostly when autocrossing when I don't want to shift out of first before going into the next turn.

So . . (I searched and found a bunch of huge threads) . . has anyone ever experienced any kind of rev limit with their stock ECUs?

AE_Racer

iTrader: (1)

I believe on 86-88 it is supposed to be 8500, but i've never had the ***** to take any of my engines that high?

edit: i searched and found this, dunno if its true

truespin88

It doesn't really make a difference if there is or not... the power drops off at 7000rpm or so for an S4 NA.

88IntegraLS

Not when it's ported! I don't even have any exhaust mods and this thing just won't quit. The power starts to fall slightly at 7k rpm but it will keep pulling. I can't wait to get my header installed.

NZConvertible

The S5 Turbo FSM says there's a rev limit at 8500rpm (page F2-75), and that's with a 7000rpm redline, so it's safe to assume the S4 probably has the same rev limit. IMO if you've modified your engine to the point where there really is usable power that high, then you should be seriously considering aftermarket engine management anyway, as it's highly unlikely the stock fuel maps are still suitable.

Luna

I found the rev limit earlier this week. I bounced off of 8000 in second gear. It was really scary.

88IntegraLS

I'll have to get an SAFC. I also don't like spinning the stock flywheel that high. It's just weird because usually you would expect the car to feel out of breath when over-revved. But it does fall off on acceleration by about .05g above 7k.

Scott 89t2

I thought it was surposed to be 7800. but weither it still works is another question when dealing with s4 electronics.

AE_Racer

iTrader: (1)

also dealing with how accurate our old *** tachometers are as to when WE see it cutoff

j9fd3s

iTrader: (3)

i dont think s4 has a rev limit per say, i think it just runs out of processor time around 7800ish

NZConvertible

Keeping in mind any rev limiter is simply part of the ECU's programming, not a separate piece of hardware, I don't see how one could just stop working. That would be no more likely to happen than any other ECU function failing.

SpeedOfLife

iTrader: (16)

Sorry to resurrect, but I thought this was interesting. I've seen a number of different takes on this (and I know different models/years have different fuel cut points). Well, I discovered today that my '87 TII doesn't like passing 7800RPM, haha. I was flying along in third trying to reach 100mph and found that little surprise...

turboIIrotary

iTrader: (9)

mine doesn't either! it scared me when i hit mine i thought i broke something.

arghx

iTrader: (3)

I think there just is a ton of variance in tachometers. I have an 88 T2 with a Power FC standalone. I set my rev limit to 8200rpm. A while back I got on it in first gear, lost traction, and hit the rev limiter, but my tach only said ~7500. Trust me, it was definitely the rev limiter, I heard a huge backfire and a cloud of smoke came out the back. I suspect the tach gets less accurate as rpm's climb.

AreExSevenProject

iTrader: (1)

ive rev limited mine 1 time...8500 rpm...i think it was second gear too...

if you have a tII I wouldnt hit rev limiter bcuz my friend did this and hit fuel cut and it messed his engine up

SpeedOfLife

iTrader: (16)

My tach is precise and accurate. Say, in 5th gear, I'm pulling 70mph at 3k RPM. I pull up to 140mph, and it shows 6k RPM. That's precision. I've compared it with a timing light and with my SAFC-II and it's pretty damned close. That's accuracy. At 7200-7800 RPM I may be 100RPM off at the most, and now that I know it won't pass 7800 I won't shift past 7600.