Rob, I am confused....If your chip is tuned for 6-7lbs of boost, and you are only running 4, isn't the tune supplying more fuel for more boost....So wouldn't you also be a little rich right now???

 

You can't compare results from two different dynos on two different days and come to any reasonable conclusions, IMO. It's a good way to drive yourself crazy, though, so you've got that going for you; which is nice.

 

I agree. You are burning the chip to dump more fuel (and less timing?) to accomodate more air (higher boost). WHen you take away the more air by taking the pulley off, it sems to me that you would be left with more fuel and less timing.

You can't compare results from two different dynos on two different days and come to any reasonable conclusions, IMO. It's a good way to drive yourself crazy, though, so you've got that going for you; which is nice.

Bob Glidden had a quote in National Dragster right before he retired that I cut out and still have. It says "Sometimes it seems like the more you test, the more lost you can get." Seems true to me.

 

yes i realize that i should've taken it to the same dyno. however what if this was my first dyno session ever? what if after putting in my psp chip, filter, 4#, e fan, e-water pump, etc etc i went and dynoed and only pulled a 360 max rwhp??? the AF may be inaccurate but i would definitely be pulling out my hair even more had this been my first dyno session after my mods.

oh well i guess i'll go back to the same place i dynoed first and see the AFs of the PSP. guess i just wasted my 65 bucks not to mention the 2 hour trip (4 hrs roundtrip)....

i just hope no one else goes to that dyno for the first time with a good # of bolt-ons and pulls a crappy 360...i know i'd be crushed with disappointment

 

No matter what you do, the next time you go to the dyno IF you want to take A/F readings the most accurate way is a wideband sensor installed in the system up towards the engine. That means you will have to remove an existing sensor or weld in a new 18 mm bung for the wideband test.

The tail pipe sensors are really inaccurate and can get contaminated with water (a byproduct of cat converters) very easily.
Dale

 

I MEANT RICHER" don't know how I wrote leaner ???
Of course with less pulley I'm richer, thats why I compaired it to his. I have colder plugs and a very rich tune RIGHT NOW and I have no loading up.

Sorry Guy's, thanks for pointing that out

 

yes i won't do the AF via exhaust tips anymore. I believe the first time I dynoed it was accurate and they did not tap the exhaust tips for the AF readings.

however i still don't understand why there is such a huge difference rwhp-wise. i thought SAE-corrected were comparable and that was why there was SAE in the first place. i understand if the margin was immaterial (a couple of hp) and that it was because of the different locations and conditions, but we're talking about a LOT of hp here.

oh well i guess it's back up to naperville sometime when the weather is nice....

 

Maybe you have a vacuum leak. That would likely cause a rich condition.

 

cyntaxx,
Your Mass Air meter could be dirty or contaminated by oil. Have you cleaned and re-oiled your air filter lately? Or you have contaminated or a bad hego sensor or sensors. Any of the mentioned can mess up A/F. Have you pulled a few plugs to see their condition? Is the truck running rough?

lastly, partially blocked or contaminated cats can cause loss of power. I would start at the Mass Air meter first. Then the others. Best of luck!!

 

i will check the mass air. the filter *seems* clean but i will make sure there is no clogging or oil inside. as for the possibility of a vacuum leak or faulty/dirty sensors, i will re-dyno @ FLP in naperville (my original dyno place) before I get into something that requires more scrutiny.

thanks for all the suggestions and i will look into everything i can before i redyno. hopefully it was just inaccurate AF readings from the exhaust tap and not something wrong with the truck.


thanks for all the help guys!