View Full Version : power/boost drop off after 125mph
Neanderthal
22-09-2003, 08:53
Had the opportunity to try a flat out trial of my LCR. Pulled like a train right up until ~120-125mph where all of a sudden it was like the REVO was turned off and it had trouble (or it felt like it) accelerating much further. Got to 135mph but it took so long I ran out of track.
Any one else experienced this?
Neanderthal
22-09-2003, 14:31
no one then? :(
Revo Kev
22-09-2003, 15:59
Where were you doing this? What were the conditions like (temps)? What settings were you running in? How long had you been out giving it some stick?
Neanderthal
22-09-2003, 16:40
Yesterday about 1pm so it was pretty warm, 10 mins down the M..Track ;) so the car had been running for 20 mins, although obviously I wasn't thrashing it all that time cause it needs to warm up first. Only got the SPS1 so standard map (wasn't given a choice although I told Vince at Stealth Rcing that I was having to run Normal unleaded when he mapped the car).
Matt
Revo Kev
22-09-2003, 17:43
It sounds as though your ECU was pulling back at the top end,it could be numerous things inadequate air flow, fuel, etc. Is the car performing as normal lower down the Rev/speed range?
It could just be inadequate conditions at the time, if it was very warm then the ECU could have been pulling back if seeing too higher intake temps.
It would be interesting to see if any error codes are present.
I'm not sure what the R will top out at, but I'm sure conditions pending it would be alot more than that.
Are you local then having gone to Stealth?
Neanderthal
22-09-2003, 18:33
Yeah, could have been the conditions, although whilst still un-REVO'd I hit 130 and didn't notice any sudden decrease of power.
I'm in Northampton, phoned up Revo HQ and was pointed in the direction of Vince.
I think that's cos they refer many software 'uploads' from the local area to Vince as he's the most local.
btw - do you have vince's plots to hand from when he did your car?
Mark
Neanderthal
22-09-2003, 19:30
I didn't get it RR'd. Was a bit of short notice for him (I was going on holiday and wanted the car doing for the trip ;) )
RichardBW
23-09-2003, 20:44
Got to 135mph but it took so long I ran out of track.
There must be some of the boys in blue reading this forum (understandably keeping themselves anonymous).
Nearly double the speed limit. This makes worrying reading for someone like myself who has never exceeded the speed limit on a public road.:D
Seriously tho, which gear and at what rpm was the tail off? this is probably more relevant than the mph as it will tell us more as to whether the car has a problem or not.
Neanderthal
24-09-2003, 11:00
it was 6th Gear, full throttle. Didn't take a note of the rpm though as I was concentrating on the track ;)
I'm going to an RR on the 4th Oct, Geoff says's he's coming to that so he'll have a looksee at it :D
Matt
Revo Kev
24-09-2003, 11:48
Actually it was me posting as Geoff on our forum!
I'd been doing some admin stuff using his account and had been automatically logged in as Geoff. I imagine myself and a couple of the other guys from here will be at the RR session.
If you were topping out in 6th and had no more rev's to go then it was definatley down to conditions, have you been out on 'track' since?! and taken note of rev's etc. at top speed?
Neanderthal
24-09-2003, 12:14
Not had the chance to go out on track again as it happens once in a
blue moon :(
Anyways, there were plenty more revs to go on the rev counter, from memory of my run pre-REVO it was 130mph @ 5k revs.
See you at the RR then Kev/Geoff ;)
I get the same problem on my beeza cupra top end dies out about 120 125 mph end of revs in 4th and not much pick up in 5th ?? Last winter had 143mph after just being revo'd now i've got scorp zorst forge dv and intercooler? feels fine 1st to 3rd gears though???
:confused:
:cheers:
Shock_Xe
24-09-2003, 21:05
me too, seems to pull like a train upto 125mph but then creeps upto 140 (slowly) indictaed on speedo and wont go further! Whereas standard 135/140 was seen no probs! See sig for Specs!
The ambient temp over the past couple of months has been substantially higher than those of single figure deg C experienced over winter months.
mark sheerin
24-09-2003, 23:26
I'm no expert but I suspect the ecu will pull boost back at high rpm anyway with the revo code in.
I dont expect my high speed runs to be much quicker with revo if at all due to the ecu winding back.
If you look at the graphs the revo only shows about 5bhp more at 6500rpm than the stock power curve.
Presumably the ecu winds back at high revs with high boost.
Its not a problem for me as top speed testing other than on an airfield is a good way to throw your licence away and the extra power the revo gives to 120mph is perfectly adequate for me anyway...faster than that and my std cupra suspension becomes an issue then anyway.
Interestingly came up to a roundabout today on a dual carriageway..left hand lane.
Alongside me was a tricked up pug 205 1.9gti.
when the traffic cleared we set off...me going round the outside and him near the centre..when we came off he was in the outside lane and me on the inside.
Surprisingly as I thought My leon would struggle with such a technical test..I left the pug for dead round the roundabout and pulled three lengths clear by 70mph.
I honestly thought his lighter car to whoop me round the roundabout and come off ahead..instead he came off two lengths back after having to lift as he was understeering towards my drivers door as we got half way round the roundabout:(
I was well pleased and he was so peed he wouldn't even look at me as we queued side by side at the next roundabout....probably something to do with the huge cheesy grin I had on.
I won't be surprised if it where climate related. Tonight was the 1st night I could remember in the last 3 that the temp actually dropped below 17ºC. The performance difference is pretty incredible.
Shock_Xe
25-09-2003, 00:04
As far as my situation is concerned mines been this way since revo (nearly a year) and has always done this and I have tried in all Temps (Even minus 3 racing a Porsche 911 3.30am) Well the Porsche was more than likely toying with me but still!
RichardBW
25-09-2003, 19:52
All VAG tuners will concentrate mainly on mid range improvements as this is where the stock code is detuned for emissions and economy's benefit. There has to be a compromise somewhere in the tuning of a turbo car, especially one with a relatively small turbo such as the KO3. We could concentrate on the top end of the rev range for high speed purposes but how much use would this be to the average driver, how many people can sustain over 100mph on public roads?
With a tuned car running higher boost it will tend to see warmer intake temps during acceleration, therefore by the time you reach the 120+ speeds the ECU may have retarded ignition to safegaurd the engine. Some may see this as a negative effect but these safety systems are what make the 1.8T such a reliable and tuneable engine. Most of us have been to RR days and seen enough low figures due to heatsoak to know how much this can really affect performance on a car that otherwise drives perfectly on the road.
Neanderthal
25-09-2003, 20:16
Hi Richard,
I hope no one has taken my original post to be knocking REVO cause it wasn't meant to. I was just enquiring as to whether in the REVO code there was a sudden "drop back to normal" boost above a certain speed.
Matt
Shock_Xe
25-09-2003, 21:06
Originally posted by Neanderthal
Hi Richard,
I hope no one has taken my original post to be knocking REVO cause it wasn't meant to. I was just enquiring as to whether in the REVO code there was a sudden "drop back to normal" boost above a certain speed.
Matt
ditto, no complaints! Just didnt seem right! Explanation makes sense!
I don't think it is anything to do with the Revo code. Now mine is more loosened up with over 12k miles it will pull hard to 7000 revs before cut out - about a ton in 3rd.
I am running a superchip, exhaust, and forge dv. I found outside air temps make a big difference. But the strangest thing to me was the amount of miles i started off with (13,000 mls). I now have 23,000mls and the top end is a lot better. I dont kmow if the extra miles or the extra miles on the chip has made a difference. The only way to achieve a good top end and more performance from where you are now is IHI i would think (if you wanted more).:D