Making sense of a RR graph
Discussion
I got my car put on a rolling road yesterday, and the results was a little disappointing to say the least. It is a 1.8i mk1, so should be around the 130bhp area maybe slightly under.....i got 105bhp with 85bhp at the wheels(rollers)
When it came off the guy who ran it said my afr was slightly lean and that it should be between 12.5-13 and was on 13.5
I have put the graph below for Guessed flywheel power and the AFR, if anyone could make any sense and let me know if there is a problem and what would be able to fix it i would appreciate the help a lot!
When it came off the guy who ran it said my afr was slightly lean and that it should be between 12.5-13 and was on 13.5
I have put the graph below for Guessed flywheel power and the AFR, if anyone could make any sense and let me know if there is a problem and what would be able to fix it i would appreciate the help a lot!
Munter said:
Ok then. Either he was joking and it wasn't his best comedy moment. Or I wouldn't believe a thing that guy said!
Well the rest of the results of cars running that day weren't great, seemed a big variation on there. Had a DC2 integra show up 156hp instead of the 190 or so it should have. Wondering whether to ignore it and just run elsewhere next time!Well if everybody was low I'd suggest the dyno was reading low, and there's probably not much wrong with your car. They are never perfectly accurate. Does seem quite a variation between expected and measured results.
Might be worth posting in the Engines and Drivetrain section. See if a real expert responds.
Might be worth posting in the Engines and Drivetrain section. See if a real expert responds.
Sounds like a duff dyno maybe. And did he actually look under your bonnet? Distributor!?
That said - when did you last check your timing.
You can see at 4200rpm where the ecu goes from closed loop (is taking lambda measurements and adjusting injector duty to suit, to hold good afr) to just "chuck loads of fuel in and hope for the best" where it runs rich.
That said - when did you last check your timing.
You can see at 4200rpm where the ecu goes from closed loop (is taking lambda measurements and adjusting injector duty to suit, to hold good afr) to just "chuck loads of fuel in and hope for the best" where it runs rich.
The AFR looks about right to me. 14.7:1 when in closed loop and not going richer than 13:1 when in open loop. Check the timing - should be 10BTDC and can be adjusted to 14BTDC for as bit of extra go. Also make sure that the cam timing wasn't screwed up when the belt was changed. It's easy to get it one tooth out and there won't be much to show for it other than a bit of a drop in power.
Drop Vixpy an email and mention to him who the dyno operator was. Get his professional opinion
Drop Vixpy an email and mention to him who the dyno operator was. Get his professional opinion
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