First Dyno Experience... :(
02-13-2012, 07:55 AM
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First Dyno Experience... :( went to dyno day at the shop in town saturday and came out pretty dissappointed from my first dyno with my T/A. over all it ended up doing 256hp/314tq...
and ITS A 2001 LS1..WTF it ran so lean that by the time it got to 6000rpm the ratio was at 18:1.. does it just need a good tune or is this something more serious?
and ITS A 2001 LS1..WTF it ran so lean that by the time it got to 6000rpm the ratio was at 18:1.. does it just need a good tune or is this something more serious? 
02-13-2012, 08:04 AM
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wow.... something is really off, just by looking at what you have in your sig i dont think any of those would effect it so much to throw it off that far, im guessing you dont have a check engine light correct? It would be wise to have a tuner hook up and see what is going on with your car.
02-13-2012, 08:44 AM
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An 02 sensor should not cause you to go lean at WOT. When in PE, STFTs cut out and LTFTs only alter fueling if they are positive.
OP, was this a tailpipe sniffer giving you 18:1?
OP, was this a tailpipe sniffer giving you 18:1?
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02-13-2012, 09:13 AM
#9
Why would you dyno a car with a known 02 problem? I would think you'd want the car in as nice of mechanical shape as possible for your dyno run.
Retunes/dyno time are much more expensive than an 02 sensor.
Retunes/dyno time are much more expensive than an 02 sensor.
02-13-2012, 09:29 AM
#10
Well o2 sensors do not come into play at WOT, there it depends on a predetermined loop. Now the o2 sensor will screw up normal driving wwhich should be corrected before the dyno. Also if its going that lean ONLY up top then I suggest you take a good look at fuel pressure get a gauge and strap it to you car and do go some street pulls if it drops below 55psi for longer than a couple seconds while your in it then the fuel pump is toast. an o2 will not cause it to go lean if anything it will cause it to run rich.
02-13-2012, 10:41 AM
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02 sensors feedback is only used in part throttle situations - not WOT. Thus a bad O2 sensor will not affect WOT performance since WOT is in open loop mode, not closed loop. I'm going to go with fuel pump as well. Considering your torque is significantly higher, I would say the pump leans it out as the RPMs climb, and hence the drastic difference between the two numbers.
02-13-2012, 10:45 AM
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my main concern is the health of the car. i have to fix the o2 censor this month anyway because its inspection month. if i also need a fuel pump to correct the problem i want to go ahead and get that done before spring.
02-13-2012, 11:23 AM
#17
went to dyno day at the shop in town saturday and came out pretty dissappointed from my first dyno with my T/A. over all it ended up doing 256hp/314tq... and ITS A 2001 LS1..WTF it ran so lean that by the time it got to 6000rpm the ratio was at 18:1.. does it just need a good tune or is this something more serious?
and ITS A 2001 LS1..WTF it ran so lean that by the time it got to 6000rpm the ratio was at 18:1.. does it just need a good tune or is this something more serious?sounds about right for a stock LS1 that has never been touched and its 11 years old
sounds like your AFR may be correct...for that tailpipe..
I've found that you can get different AFR readings from different tailpipes...
at low rpm they both tend to flow similar, but as rpm goes up and pressures rise, you get the problem that the exhaust doesnt want to make a 180* turn to go back to the other side, so it comes out of one pipe more than the other.
usually one will read correct, and the other will read way lean.
and noticing your signature... you have a cutout... does it seal all the way? does it seal correctly at WOT and high rpm's?
that could be skewing your readings as well.
you can also look at your narrowband readings to get an idea if the dyno wideband is in the right area
if its really 18:1, you will see your narrowband o2's below 450mv by quite a bit
if its richer than 14.7 it should be above 450mv..
most people equate 13's being somewhere in the 800~900mv range(its not correct, but its a ballpark guess at best that will at least tell you that you are on the rich side of 14.7)
it is not accurate, and you cannot use it for tuning WOT, but it can tell you if you are really lean like the dyno wideband is showing
also, 18:1 naturally aspirated wont hurt anything, its just not gonna make good power..
the stock settings will see knock, and pull timing...it will be fine..
people have run around for years on a stock tune being lean with no issues.
With the K&N Air filter, its also a possibility that you have a Dirty MAF as the oils tend to get sucked off of the filter and dirty the MAF making it read incorrectly...
you may just need to clean the MAF...
buy a couple cans of MAF cleaner form the parts store and go to town on it..
also, take out the K&N and look at it...if you can touch it and oil comes off on your fingers, then it is far too much oil on it...which is typical if you pulled it out of the box and just put it in
I always start by buying teh K&N kit, and cleaning all the oil off of it, and then spraying on a much lighter coat than what it came with out of the box...
Does the car have fresh plugs in it? new oil? or did you just buy it and take it to the dyno without doing normal maintenance items..
I cant tell you the number of tunes I've done that started off like yours...with a little maintenance and cleaning, it picked up 20 or 30 HP
also, what brand of dyno...all of them read different...
I have one locally that we call the heartbreaker... a stock LS1 will barely do 240HP..LOL...but we all know differently...its good for solid state tuning and its the only eddy current dyno in town, and it lends to being able to add a load to do a longer pull on a really short gear car to get proper data to be able to make an informed change to the tune. spark mapping also tends to translate better to the street/track for that reason.
if I want big #'s, theres a really really old dynojet within an hour drive that will make even the slowest car a dyno queen..
unfortunatley, theres just not enough data in your first post to say what is wrong...
I would bet on the simple fixes I mentioned above...
clean MAF, less oil on the K&N, new plugs, fresh oil, try the other tailpipe to check AFR.
Last edited by soundengineer; 02-13-2012 at 11:28 AM.
02-13-2012, 12:06 PM
#20
Staging Lane
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the k&n filter does have a good amount of oil on it from past times taking it out. im getting fresh plugs in today and i will clean the maf if that will help. oil was changed on january 28, 2012. i just got the cutout about a week ago and it seems to be fine. i definitely want a tune because i want to make more power later down the road. thanks for the help.