Just reading over some old treads and see that a lot of the ex police cars that some of use have have the Rev Limiter removed. How would this be done and why is it down to the ECU? Mine kicks in a 6,700.


Thanks all.  

My old 3ltr MV6 had a limiter....  :y

Theres no need for it either really cos when it hits the top end the torque is lost. better shifting up a gear at 5k IMO.

The rev limiter is entirely a function of the engine ECU. Above a pre-set RPM it simply cuts the supply to the fuel injectors. Changing the rev limit is therefore a case of changing that particular variable in the engine management firmware, such as by changing the chip in older ECUs or by programming the flash on newer models.

Rev limits are set well above the RPM at peak power, as kris said, so if you're hitting it during driving you probably aren't driving efficiently.

I'd be surprised if they are removed completely :o Set higher perhaps but even then I'd question the need. Power peaks at 6000 rpm so 6700 is plenty unless other tuning work has extended the useful rev range of the engine (unlikely in this case).

Speed limiters perhaps (but on other models. Omega doesn't have one, in Uk market at least AFAIK).

Personally I wouldn't drive a car with a decent engine WITHOUT a rev limiter these days. It's so easy to miss a gear change or have a throttle stick open on you. I'd have trashed several lovingly-built engines by now without them.  :-?::) :-X

Kevin

Kevin Wood wrote on 25. Sep 2007 at 17:26:

Personally I wouldn't drive a car with a decent engine WITHOUT a rev limiter these days. It's so easy to miss a gear change or have a throttle stick open on you. I'd have trashed several lovingly-built engines by now without them.  :-?::) :-X Kevin

Yes, did that on a 1.8i Astra once, hit 1st at 70mph  :-[ - obviously no rev limited could protect engine and valves having a little chat  :'(

TheBoy wrote on 25. Sep 2007 at 18:24:

Kevin Wood wrote on 25. Sep 2007 at 17:26: Personally I wouldn't drive a car with a decent engine WITHOUT a rev limiter these days. It's so easy to miss a gear change or have a throttle stick open on you. I'd have trashed several lovingly-built engines by now without them.  :-?::) :-X Kevin Yes, did that on a 1.8i Astra once, hit 1st at 70mph  :-[ - obviously no rev limited could protect engine and valves having a little chat  :'(

Did the same on a Golf auto.....well on purpose, but didnt think it would do what it did.
I needed to stop from about 70ish pretty damn quick.....and the brakes wernt doing it.....so i pulled the shift from D to 1st to get some engine braking as well.....g/b only went and did what i asked it to do  :o
Went straight in 1st and rev gauge hit the end stop pass the red  :o

I thought it would go for 2nd until slow enough then change to 1st.

However it stopped me blinking fast  :y and didnt seem to damage the engine  :y

Taxi Driver wrote on 25. Sep 2007 at 18:56:

TheBoy wrote on 25. Sep 2007 at 18:24: Kevin Wood wrote on 25. Sep 2007 at 17:26: Personally I wouldn't drive a car with a decent engine WITHOUT a rev limiter these days. It's so easy to miss a gear change or have a throttle stick open on you. I'd have trashed several lovingly-built engines by now without them.  :-?::) :-X Kevin Yes, did that on a 1.8i Astra once, hit 1st at 70mph  :-[ - obviously no rev limited could protect engine and valves having a little chat  :'( Did the same on a Golf auto.....well on purpose, but didnt think it would do what it did. I needed to stop from about 70ish pretty damn quick.....and the brakes wernt doing it.....so i pulled the shift from D to 1st to get some engine braking as well.....g/b only went and did what i asked it to do  :o Went straight in 1st and rev gauge hit the end stop pass the red  :o I thought it would go for 2nd until slow enough then change to 1st. However it stopped me blinking fast  :y and didnt seem to damage the engine  :y

Mine was such a mess, a new engine had to go in.  And the new engine wasn't a patch on the old one (which was bloody quick for a 1.8), so I sold it and got a GTE 2.0 instead...

TheBoy wrote on 25. Sep 2007 at 18:24:

Kevin Wood wrote on 25. Sep 2007 at 17:26: Personally I wouldn't drive a car with a decent engine WITHOUT a rev limiter these days. It's so easy to miss a gear change or have a throttle stick open on you. I'd have trashed several lovingly-built engines by now without them.  :-?::) :-X Kevin Yes, did that on a 1.8i Astra once, hit 1st at 70mph  :-[ - obviously no rev limited could protect engine and valves having a little chat  :'(

I did a simular fook up on my company Astra 1.8.  It was less than a year old (w reg) and while blasting down the A50 at 70mph, i droped to 4th to get some more power and dropped in into 2nd by accident.... oops!

Ended up with a few bent valves and a gearbox strip...  ::)

TheBoy wrote on 25. Sep 2007 at 19:02:

Taxi Driver wrote on 25. Sep 2007 at 18:56: TheBoy wrote on 25. Sep 2007 at 18:24: Kevin Wood wrote on 25. Sep 2007 at 17:26: Personally I wouldn't drive a car with a decent engine WITHOUT a rev limiter these days. It's so easy to miss a gear change or have a throttle stick open on you. I'd have trashed several lovingly-built engines by now without them.  :-?::) :-X Kevin Yes, did that on a 1.8i Astra once, hit 1st at 70mph  :-[ - obviously no rev limited could protect engine and valves having a little chat  :'( Did the same on a Golf auto.....well on purpose, but didnt think it would do what it did. I needed to stop from about 70ish pretty damn quick.....and the brakes wernt doing it.....so i pulled the shift from D to 1st to get some engine braking as well.....g/b only went and did what i asked it to do  :o Went straight in 1st and rev gauge hit the end stop pass the red  :o I thought it would go for 2nd until slow enough then change to 1st. However it stopped me blinking fast  :y and didnt seem to damage the engine  :y Mine was such a mess, a new engine had to go in.  And the new engine wasn't a patch on the old one (which was bloody quick for a 1.8), so I sold it and got a GTE 2.0 instead...

Much better choice  :y

Tho slamming g/b's auto or manuals into 1st at that kinda speed......rev limiters are like a chocolate fireguard!  ;D

Hmmmm wonders....what the omega will do if 1st selected at motorway speeds  :-/

Any offers  ;D

I used to take my Sunbeam almost to the other side of the red line it came off cam at 7200rpm (in top)

Many years ago ... (early 70's) .. the father of the GF of the time had a Jensen FF ....  4 wheel drive, about a 6 litre V8, ally body ... was one of the first cars ever to have maxaret anti-skid system ....

He was driving down the A1 near Ripon (dual carriageway) apparently at around 130mph - damned fast for the 70's!!) when someone pulled in front of him, he hit the brakes and the pedal went straight to the floor .. so he forced it into 2nd :( and dropped the clutch  !!

Apparently there was a very loud BANG and the car stopped almost instantly with the back wheels locked !!

The engine and whole transmission was a complete wreck, but the most amazing thing was 8 very neat round holes in the ally bonnet, all 8 plugs had stripped out and gone like bullets through the metal !

When they tried to rebuild it, complete new drive train, they could not get it to handle properly so it went back, eventually, to Jensen where it was scrapped ... the whole chassis was twisted out of shape.

Some students at Ripon Uni did some calculations and the figures for the instant RPM reached and the stresses they reckon the pistons got were more like telephone numbers than engineering data !!

The Westfield throttle pedal is hinged at the bottom and has only a few mm of clearance above the floor. If you get in with shingle stuck to your feet eventually a stone will get trapped under the pedal when you least expect it :o

First time it happened was on a short section of dual carriageway which I entered flat out in 3rd. Went to change up, already going pretty rapidly, and engine started bouncing off the limiter @ 7500 RPM  :o. Quickly grabbed the next gear and, whist the next roundabout loomed, fumbled for the ignition switch.

No drama in the end but it woke me up!

One of these days I'll make a small hole in the floor under the pedal.

Kevin

Many years ago I was issued with a Vx Novavan 1.5 diesel as a company vehicle.  I drove the thing flat out in 3rd gear from Bodmin to Exeter in the vain hope that i would blow the darn thing up and get an Astra as a replacement.  Didn't work though  >:(

Taxi Driver wrote on 25. Sep 2007 at 19:17:

Hmmmm wonders....what the omega will do if 1st selected at motorway speeds  :-/

Omega ECU will not change down until it can....

TheBoy wrote on 25. Sep 2007 at 21:58:

Taxi Driver wrote on 25. Sep 2007 at 19:17: Hmmmm wonders....what the omega will do if 1st selected at motorway speeds  :-/ Omega ECU will not change down until it can....

I have done manual downshifts, with the 2.0 you can't even get 2nd in 70 until you are down to 67, found this on A30 hills while towing.

friend of mine works for a VW Van dealership.....

Just had a caddy van in with a blown diesel engine VW have agreed to replace it under warranty, a few of them have blown up with monumental results.......

This one van they had to replace the bonnet and one of the wings as well as having the inner arches repaired, the engine literally sent shards of engine all over the place, the official story if the engine just blew up, the truth is an aggrieved employee dropped it from top speed in 5th into 1st, the diff has shattered and nearly all the engine mounts have been ripped apart........

Jay w wrote on 25. Sep 2007 at 22:21:

friend of mine works for a VW Van dealership..... Just had a caddy van in with a blown diesel engine VW have agreed to replace it under warranty, a few of them have blown up with monumental results....... This one van they had to replace the bonnet and one of the wings as well as having the inner arches repaired, the engine literally sent shards of engine all over the place, the official story if the engine just blew up, the truth is an aggrieved employee dropped it from top speed in 5th into 1st, the diff has shattered and nearly all the engine mounts have been ripped apart........

Good advert for auto boxes :(

IrmscherKris wrote on 25. Sep 2007 at 11:37:

My old 3ltr MV6 had a limiter....  :y Theres no need for it either really cos when it hits the top end the torque is lost. better shifting up a gear at 5k IMO.

The problem with that is that the wide ratios on the Omega's box mean that you drop right out of the power band on the next gear. I usually rev to over 6k before shifting up when caning it, yes it's over the peak power RPM but you make up for that by keeping it in the power band for the next gear.

I do wish the ratios on the Omega were closer though, it really is crying out for a 6 speeder IMO.