Big Shooter

so i took my car up to DB performance to get tuned today and the evo didnt wanna copperate.

it started out with the clutch slipping just a little for a split second when the boost started coming on around 4000rpm. def needs to be replaced but it wasnt horrific.

then came the knocks. i apparently had some bad gas in the car and it was knocking rather badly. so they drained the tank. andy ran across the way and brought back 10 gallons of 92, and put one notch colder plugs in. that took car of almost all of the knocks.

well with these problems aside. shane began making more runs. well after about 22 pulls, and throwing every tune he could think of at it that didnt cause it to detonate, the car was still losing power after 5300rpm

so we checked mechanical: compresion, boost leak test, adjusted cam timing, pulled valve cover off to make sure everything was good under there, ect. nothing seemed to help.

after 6 hours we were stumped. heres my chart. the real line are the first two. sorry i neglected to take a pic of any of the last 20 plus pulls. but i halfass drew the final curve in. the minor blips are off but it follows the curve.

im guessin its just some dumb thing, but if anyone has any idea what could cause this please let me know.


forgot to mention to thank DB for a damn good effort and not charging me a 1000bucks!!!!

turbosmurf02

iTrader: (2)

man sorry for your luck dude...

RoadSpike

iTrader: (5)

You need a better list of your mods and how the psi was going with the tune like 26psi dropping to 21 or something.

Maybe you have some kind of exhaust issue or intake issue based on that curve. Looks almost as if its has a plugged cat in it where it has collapsed the opening and thus creates enough back pressure to loose power as the rpm's climb. That or as in the intake just clogged in some way?

If you do have a cat just take it off and run the open downpipe for a test?

Edit: Anyways good luck on that quest hope you find that missing power soon

Big Shooter

its running 20 psi all the way across the board, no cat its got a testpipe. pulled the intake looking for restrictions...nothing. could a dirty air filter cause this? mine didnt look bad at all, but it def wasnt clean

those are my mods as far as i know. because so far the previous owners have been fairly shady about the whole thing, so i dont know for sure whats done besides what i see. the ect is like silicone hoses and gauges & other pidily stuff

RazorLab

iTrader: (8)

Did you check cam timing? Line up the crank with the cams?

pussywhooped

Minnesota is not too far from here. Why don't you check with AMS for second opinion.

Big Shooter

thats what i thought it was, was the crank timing. they set it to 0 when we were tring to get the car to stop knocking. towards the end they set it back to what it was at. and it still didnt help. i told them to play with it a little but they gave me the impression that it wouldnt affect it enough to fix the problem.

i though that was the primary way of dividing power through out the rpm range was the cam timing.

but on those first two pulls the power doesnt drop off in the high rpm, sure it was knocking badly but i get a feeling it was the gas

mdsevo06

iTrader: (41)

Could be the Knock Sensor, Exhaust hitting the cross bars or Pan, Lifters...etc.

Big Shooter

yeah shane asked if i knew of a loose downpipe or anything. but on a few of the later pulls he had no knocks register at all. also andy & jamie were both kind eough to meditate over my engine bay for a couple pulls and only heard a couple knocks over about 4 pulls.

from what they tell me the ecu will pull timing and correct the knock fast enough that you may only hear one. and you can disable it but he seemed very hesitant to do so seeing how it could lift a head or something

we pulled the valve cover and turned the motor over to watch the cams & lifters. they looked peachy

hey ive got a few vids were can i put em so you guys can watch em. never upladed a vid

RazorLab

iTrader: (8)

So you turned the crank to TDC and the cam gear marks synched up with the valve cover marks?

If I recall correctly on the vishnu gears and/or fidanza, You need to make sure you are running them in the correct hole as there are two. I also know some vishnu gears where machined incorrectly so they had 0 marked on the gears, and not by the notches.

That curve does look like timing is off. Or you have a huge *** restriction somewhere.

Big Shooter

heres the first two pulls.. the real ones. you can see where its knockin but the line seems to me to stay up a little better

RazorLab

iTrader: (8)

Big Shooter, did you do what I mentioned in post #10?

tephra

iTrader: (6)

evoscan log of the dyno run?

is that an 8 or a 9?

Big Shooter

i think it did say evoscan on shanes computer its an 8

razorlab: no sir, i wish i could. i no longer have a garage. so theres a 0 notch on the valve covers that i can line the 0 on the gears up with.

another dumb question that i may already know the answer to. how do i get the motor to TDC?

Big Shooter

and there dyno was made in australia