Hey guys

got my car dynoed today to see what it was doing.

It was discovered that my car is leaning out at the low and high rev ranges. the mid range is ok.

What can cause the car to lean out?

Faulty Fuel Pump? Faulty Fuel Reg?

The only thing i have installed on my car is a Motordyne Iso Thermal Plenum spacer, and a Carbon Fibre Z Tube, and a Sxcexe Grounding Kit

-mark

 

how lean? What numbers did you put down?

 

What were the AF numbers you're concerned about?

 

If you want an accurate answer you need to post the graph.....could be any number of things.

 

sorry for the late reply. i have been speaking with tony hydrazine and due to the weird nature of the dyno graph, he believes it is the dyno operator themselves who have screwed up my dyno run. but here it is for you guys as well.

I got the car dynoed when it was stock and the AFR curve was pretty ok. stayed within 1 range seemed pretty norm made 177kw stock that day...



today i got it dynoed it was all over the place... starting off way up high EVEN HIGHER THAN 19' and coming right down, seems to be ok in the mid range... then getting higher in the higher rev range...
first run made 162kw 2nd run made 158kw and was worse than the run before....



the thing that puzzles me is that the car is driving fine on the street. in the midrange > upper rev range i can really feel the difference the plenum spacer has made. a nice tourque pull it throws me back in the seat.

just wondering wtf is going with my AFR's now, and if i indeed have a problem with the car before i start throwing more money at it. the dyno operator suggested the fuel pump is possibly on the way out.

Oh, and i just remembered, during the dyno run, 1 comment the operator made was that my car was "sticky"..... i run 295 rear tyres on a 19 x 10.5" wide rim. These are new rims that were put on the car AFTER the last dyno run. the last run was with 275 rears on a 10" wide rim

-mark

(one other thing i have noticed is that the 2 graphs in the midrange look very similar... which again is very puzzling because yeh that seems right, but the start / finish of the run is all over the place.........

 

That must be some kind of dyno measurement error.
The A/F goes too high for the engine to run and it is too erratic to be plausible.

The dyno A/F sniffer may of had electrical problems or it was somehow not placed in the exhaust properly.

It looks like your real A/F ratio is probably still in the low/mid 13's.

 

x2

The times I've seen a/f ratios go that high, the engine starts to sputter and simply doesn't make a clean run. Your dyno graph looks very smooth even if it did loose power so I doubt your a/f ratios are THAT bad.

 

thats guys

i dont know if i am just paranoid now or what though i will get it dynoed elsewhere and go from there.

that is why i am puzzled if it still made the power like before... but wtf?

i was looking at a few photos of my car on the dyno... check out the AF Thing in the exhaust... it looks to be not even in there properly?