Rev limiter

[Terry Field]

1999 1.8 K series

I seem to remember reading somewhere that the K series installation includes a built in rev limiter.

Is that correct?

[paul richards]

Yes. Standard 1.8 k with mems ecu included a rev limiter (at least it did on my 140 bhp 1.8 supersport)

[K7 VCT]

Have u never  found it.....

[Toby S]

Early 1400 K Supersport has a one - 7,600rpm, rev counter that only goes up to 7,000 (original VDO guage same as off the x-flow), but a handy change up light which comes on at 7,400

[Terry Field]

#3 Not knowingly, but I missed a gear today which prompted the question!!
 

Do we know if the limit on the 1.4 and the 1.8 are the same?

Thanks for the advice chaps

 

 

[SLR No.77]

1.4 is higher.

 

 

[john milner]

You might want to download some free software and have a look at the definite number.

https://andrewrevill.co.uk/MEMS3Flasher.htm

 

[Roger Ford]

1999 is EU2 so may be different, but the EU3 certainly had a limiter. When you say "missed a gear" did you rev it in neutral, or did you put it into 3rd instead of 5th, or something similar. You will still over-rev the engine if that happens, limiter or not, but that said I did it several times (with some scary numbers in the ACES memory) but it never did any obvious harm.

[paul richards]

Looking at my old catalogues it seems the 1.8 and 1.6 Supersports both had maximum rpm of 7600 with shift light warning at 7400. SLR max rpm 8000 with shift light warning at 7750. No mention of max revs for non supersport or VVC but I seem to recall they had a rev limiter but no shift light. 

[Golf Juliet Tango]

My rev limiter won't travel in the Seven.

[Terry Field]

Stephen, I have the same problem!

I revved it hard in neutral, although I caught it before it got too high, but it just raised the question in my mind.
 

Why will the limiter not work when the car is in neutral? I fitted an after market limiter in my old XFlow, and that certainly worked in neutral.

#9 Paul, there is no shift light.

#7 Thanks John, but I am not going down that route - way beyond my pay grade! 
 

Thanks for all,the comments.

 

[Ray Pearce]

Yes, it has got a rev limiter.

It does work in neutral but won't help if you buzz the engine by changing down a gear rather than up.

I think it will be fine - a quick blip in neutral with the limiter doing it's job will have no ill effects.

[Roger Ford]

Also in neutral there's no load on the engine. I could be wrong, but I think high revs at low load is much safer than high revs at full load.

[Geoff Brown]

Rev limit is lower than either 1.4 or 1.8. I do believe that 1.8s have lunched themselves due to persistent revving to the limit.

Probably due to the change in stroke to achieve 1800cc ?

[John Vine]

#14 I do believe that 1.8s have lunched themselves due to persistent revving to the limit.

Oily recommended keeping a 1.8K with standard (non-Trophy160) pistons below 7300 for fear of damaging the piston lands.

That always worried me with my 1.8K SS-R, which had its limiter set to 7600.

JV

[paul richards]

Terry. I think the shift light was only fitted to supersport versions. Also I don't think blipping the throttle in neutral will test the rev limiter. The limiter simply cuts the spark. I'm sure that you can blip the throttle and momentum will take it over the rev limit despite the spark cutting. In the same manner that you can over rev the engine by changing into a lower gear too early.

[aerobod - near CYYC]

Assuming there isn't a mechanical downshift to another gear, momentum of the mechanical components of the engine will delay the revs dropping, but will not cause any increase in revs without a source of fuel and ignition.

[John Vine]

#17:  That's a good example of the First Law of Thermodynamics (or, at the very least, the law of Conservation of Energy). 

JV

[Gridgway]

#16 to be pedantic, acceleration has no momentum.  The rate you reduce the force is the rate that acceleration decreases.

The effect of revs going higher "at the limit" will be due to the capabilities of the rev limiter to reduce the force (from the bangs) to zero at the right point quickly enough.  I think that most limiters are very good at that, although some employ a soft cutting regime.