PDA

View Full Version : Mr car on the owners club Rolling Road (Dyno) day



Colonel Mitch
7th June 2009, 10:43 PM
Okay, I know that not many of you are interested in cars here, however some of you are, and with more of you learning to drive that figure is likley to have increased from my last car based thread with the range rover :P

Me and Chris (Target) went down to near liverpool for ClubVR4's (www.clubvr4.com) north west rolling road day.

My dyno graphs are below.

http://i513.photobucket.com/albums/t333/piers1989/flywheelbhp-1.jpg
The above being power at the flywheel, and below being power at the wheels.

http://i513.photobucket.com/albums/t333/piers1989/wheelbhp-1.jpg

This shows me my car has problems, but nothing damaging.

My boost (the wiggly flat line on graph 2) should start lower, peak up to about 0.8, and then tail off to about 0.5, rather than wiggling around 0.5 the whole time, and my AFR (Air:Fuel Ratio) should start at about 14:1 and gradually decrease to around 11:1, maybe a bit more, whereas its dropping right off the scale to what the dyno guy reckoned would be about 7/8:1.

As you can see the boost from the turbos isn't kicking in properly whihc may suggest a turbo or wastegate problem, or a boost leak.

The fueling problem Is hopefully down to the cars computer realising theres a problem and throwing in so a ridiculous amount of fuel (more fuel is safer than less fuel in an engine) to stop damage from something called detonation. This is caused when the AFR is too "lean" (has too much air).

With this much fuel being added I'm loosing power into forcing it all to explode in the cylinder and also loosing power as I am not getting as much boost from the turbos as I should be.

My car should acheive around 260 BHP at the flywheel (Corrected to 276BHP when considering loss in the automatic gearbox) and around 205 BHP at the wheels.

The result of all this technobable is that my car is using so much fuel it is doing about 16 mpg rather than 23 and is loosing power, however 207 BHP is still plenty untill it gets sorted :P

Finally a picture of me and chris with our backes turned to the camera with my car on the rollers (not my picture and somebody else has removed my numberplate from it).
http://www.clubvr4.com/forum/attachment.php?attachmentid=28010&d=1244379749

ez64
7th June 2009, 10:46 PM
He he my car can almost do that :D

Colonel Mitch
7th June 2009, 10:50 PM
He he my car can almost do that :D
But you car doesnt have 4 wheel drive, AYC, ASC, etc

And i can still do 0-60 in under 7 seconds :P

once its fixed ill be +50 bhp too :)

ez64
7th June 2009, 10:53 PM
it does have ASC which I turn off most of the time and it still does 7.3 ish.

Colonel Mitch
7th June 2009, 10:58 PM
it does have ASC which I turn off most of the time and it still does 7.3 ish.

I cant turn my ASC off (and wudnt want to, its REALLY good and makes it alot easier to drive to teh limit safley), my traction control is on anotehr button tho :P

ez64
7th June 2009, 11:05 PM
Mine interfers too much, you know the limit of the car and when you are not near it the car starts twitching which is really annoying.

Colonel Mitch
7th June 2009, 11:13 PM
Mine interfers too much, you know the limit of the car and when you are not near it the car starts twitching which is really annoying.

With my rear all terrain tyres my rear grip is slightly lacking in the dry if you push the car to its extreme around bends (i mean slightly not being sarcastic), but if it gets even slightly wet the rear wheels will spin on any corner or roundabout, which makes the ASC correction extremely hekpful at stopping you crashing :P

Ill get soem road tyres on there when I have some money as the slidefest is a bit lol in the damp atm, though it is awsome fun xD

Target
7th June 2009, 11:21 PM
Yeh u really need to get those tires sorted, was a tad scary goin 80-100 on mway on slight bends in the wet, knowing that doing 30 at a round about nearly made us spin out :P Was fun though and we even saw new GTR when we stopped at the petol station. Be awesome when you have the boost sorted, hopefully bfore i37 :D