I got my car dyno'ed yesterday and here is the sheet. Something is deff. wrong here. The guy had the meter in my tailpipe. Is this the reason it is off. I called my tuner and he said it shouldn't be that way. Any help will be appreciated. My car doesn't have any ping's or anything like that. It seems to be running great.

 

Got cats ?

 

yeah. Everything I have is in my Sig.

 

get back on the dyno and fix your PE ratio. Also, put this in the tuning section.

 

Placing a wideband after the cats can give you a false reading of about .5 off on the lean side. I've also heard that placing it in the tailpipe reduces accuracy.

Re'

 

have you cleaned your MAF lately?

 

you might also want to ask them when the last time they changed that sensor, if it's been too long, their readings will be off..

 

No my MAF hasn't been cleaned. I only have 23k on my car total. I'm sure it was just a false reading because my car is running great I also don't think I would have put up those numbers if it were that lean.

 

The leaner the A/F ratio, the more HP you produce, for a normally asperated stock engine, the WOT A/F ratio should be 13.5.

You are running way to lean.

My stock motor 01 Z28 with the above stated A/F ratio dyno - 291RWHP/340RWTQ (3.73 & 3000 stall)

SteveC

 

It was a false reading. If I ran that motor that lean it would melt a piston. Also having it too lean you loose HP and TQ or so I was told.

 

Think about it this way, why do people super charge their engine? what are they introducing? MORE AIR, then they up the size of the injectors (as to not run too lean), and set the A/F ratio @ 11 and hope for the best.

GM sets their stock A/F ratio's lean to get more horsepower out of the engine.

SteveC

 

my tuner tuned mine to 12.6. Just have them put a wideband before the cat. It sucked cuz they hadto weld a bung into my ORY but, whatever tey have to do to get it right is what i said. At least now i can hook one up whenever i want. I would def say your readings are super off, you would be frying plugs at 16:1

 

wow if your car was that lean it would probably have popped! and very big shame on your tuner for not killing the run and figuring out what went wrong!

be afraid... be VERY afraid!!!

 

What is with the oscillation in the graphs? Is the car surges when you drive it? Only curious. Thank you.

 

Good point "uncle ray" They should have stopped the run once they saw those numbers. I am skepticle because of where the sensor was located thoo. I would really suggest just having the bung welded in the exaust, and having them hook up there wideband to that.

 

my tuner here uses a $800 sensor in the pipe. if you want to really pay for a tune he has a $1200 SENSOR AS WELL!!! VERY DETAILED AND SENSATIVE! i would say your tuner is probably using a cheap sensor, or his has been fouled.

may be the dyno too. mine uses dyno dynamics... its the best/ most detailed.

 

Like I said before it was a false read. These were just DYNO pulls at a local shop not a dyno tuner. My car is running great and I'm sure its not lean. Just look how inconsistent the A/F ratio is. I later went back to the dyno guy and he said he thought I didn't have Cat's and that those readings were completely False because I have them. My tuner (MadZ28) said that there is no way its that lean and he really knows what he's talking about. I've been driving on this tune for nearly 6 months. If anything was going to happen it would have already happened.