Hi guys just wondered whether anyone could shed any light. On the road an on the dyno the car makes good numbers an seems to go very well but get it to the drag strip an it struugles. The spec of the car is:-

RMW head
RMW cam
RMW race header
Borla street cat back
15%pulley
JCW airbox
GRS intercooler
440cc injectors
Tuned by 1320 autos here in the uk

The car on the dyno constanly makes 270bhp 230whp with good torque figues, on the road it seems to go like the wind but get it on the drag strip with heavy load an it seems to sort of go into limp mode without flaging a light up on the dash. Last time at the strip we reset the ecu an it shaved 0.5 off the et an the car gained 4mph. Is it even possible for the car to go in to limp mode an not put a light on the dash? Could there be a bit of the engine wiring which is being streched under the heavy load? or could it be a faulty ecu? BTW the car is also very rough at idle an has always been?

Can anyone shed any light before i go an pour gas over it an set it a light darn thing?

 

aaaaahhhh, sounds like your revvvv limiter is kicking in..........what's the RMP's at when this is happening

 

Rev limiter is set at 7600revs an it seems according to the timing tickets the car drops off on the back 1/8th.

Also the car often struggles to strat since the install of the RMW race Header

 

CW;2510574]Rev limiter is set at 7600revs an it seems according to the timing tickets the car drops off on the back 1/8th.

Also the car often struggles to strat since the install of the RMW race Header[/quote]


Man, from your sig that's one nice car .

Who lengthened your O2 cable when the header was put on? Look under the car and see if the cable is tight? I have lengthened a bunch for guys that have got that header and it needs about an extra 17".

The header isn't going to cause starting issues but the O2 sensor might.

It may also be something in the tune. Did you car Paul and ask him?

LOngboard

 

belt slippage is my guess!

 

Man, from your sig that's one nice car .

Who lengthened your O2 cable when the header was put on? Look under the car and see if the cable is tight? I have lengthened a bunch for guys that have got that header and it needs about an extra 17".

The header isn't going to cause starting issues but the O2 sensor might.

It may also be something in the tune. Did you car Paul and ask him?

LOngboard[/quote]



Hi Longboard 1320 lengthened the 02 cable. I take it the cable needs to be tight? Cheers for the nice comments

Chris @ 1320 mapped thecar but the cars never really ticked over nicley

Jan any ideas?

Taking the car into work tomorrow to put on the dis machine to read the ecu to see if that throws up any ideas

 

Hi Longboard 1320 lengthened the 02 cable. I take it the cable needs to be tight? Cheers for the nice comments

Chris @ 1320 mapped thecar but the cars never really ticked over nicley

Jan any ideas?

Taking the car into work tomorrow to put on the dis machine to read the ecu to see if that throws up any ideas[/quote]

No you don't want the cable to be tight. Of course you want the O2 sensor tight put the cable should have some slack to it. By tight I mean the cables pulling at a 90 degree angle away from the O2 sensor. You don't want that.

Longboard

 

It'll be intresting to see how they get on today and if they can fin anything, but I believe the car has been like this from day one never performing at the track like it should even pre RMW package being fitted.

As Loui has suggested it seems like an ecu / electrical / sensor issue.

At the BMW show it would only run a 14.7 at 98, exactly what it run before the RMW mods, reset ecu first run 14.7 at 99 then after 4 runs 14.02 at 101.8.

So it seemed not to have time to register a fault and go in un noticed lim mode.

We dyno'd it before the Sat night special and it made 267bhp which is up on what it had before in this configuration and felt good on the road, but could only muster a 14.4 at 99/100. ( could only get 3 runs in due to the amount of people attending )

Just shows that sometimes a dyno doesn't translate to the strip if there is ecu /wiring / sensor issue

Our best plan attack at the moment is waiting for a breaker S to come in and swop wiring sensors / ecu over in one hit and see what happens then.

 

Well the Dis showed absolutley no engine faults, only ABS sensor ones which are probably from it being mapped on the rolling road. Im a bit stumped now. Paul ill ring you in the morning mate the 3 o clock bus dropped off at work an i didnt get chance to give you a call.

On the plus side the drive home was good, it does feel blooming quick on the road