As some of you know I like to dyno and track test all my mods. Yesterday I returned to the same shop I always dyno at, to see if my UR crank pulley really gave me any hp. I did my 3 runs as usual with a/f....I always change my oil and re-charge me filter within days of dynoing my car also just so you guys know.

My current set-up is JWT Pop-charger/Crawford Plenum/Test-pipes/Injen Angled exhaust.....my previous best with this SAE corrected was:

254.04 hp 240.80 ft lbs.

Best pull with the pulley: 254.13 hp 238.52 ft lbs.

As you can see no gains with a small loss of peak TQ. I lost power every where with the pulley from 2k rpm's to 6k rpm's where the pulley barely made more power. Another weird thing, the pulley is making my car run LEAN! The pulley is making me run slighlty richer until 3300 rpm where it leans me out all the way to fuel cut. From 3500-4500 rpm before I was at 14.0 or a little richer, now I am at 14.5 and slightly higher. From then on I am about .5 point leaner all the way to redline.

In closing, for all those people worried about crank pulley failure and whether or not it has an affect on the VQ engine series IMO it is not worth spending $200 and finding out if it does for minimal to no gains. (In my case some loss)

**I know every car is different, and some people might have gotten 5-7whp like is claimed but on my car it did nothing but lean me out and make me lose a little TQ. So I will be taking it off my car, and Ill have the piece of mind of not having to worry about the pulley. BTW, my traps speeds @ the track were the same with and without the pulley, so @ the track it made no difference for me....any comments??

 

how can the crank pulley make you lean?

 

Thanks for info, I had a feeling it wasn't doing much on mine and I just get the feeling that it is adding to too much noise, so I will be taking it off.

 

No clue, I dont understand hot it could do that but my a/f definetely changed. Then again it could just be the shops wideband going to $hit...take it for what it's worth.

 

The ECU is load-based... if it isn't detecting enough load it's not adding enough fuel.

Per say you could then be running lean.

 

If thats the case then people with Tilton clutches and FW's should be pretty lean! Anybody have a/f's with that FW or any other FW? I am about to order a Tilton clutch/fw lol...

 

Exactly...

Have ANY of these guys dyno'd and see their AF results?

Evidence of this has come up from the auto guys getting different TC's, the maps in the ECU just cannot accomodate.

 

Thanks for the info
I dyno my TRACK next week-end with A/F. Very interested to see the results. Actually a bunch of us are dynoing our Z's with all sorts of mods. I am sure many of us will post the results.

Keep everyone posted.

 

My UR pulley is going to come off as well. I did not get a chance to dyno but I can feel the loss of power in just driving the car.

Would the TS ECU reflash help this mod???

 

this whole thread is madness

 

I have always ran on the rich side with everything on umtil the test pipes which leaned it out a bit but still good.

 

So how much time was between these dynos??

Back when our cars were new, we always had to worry about the dynos on a new car being lower cause the car had to break in. Now, our cars are starting to get older, and we have to start thinking about our dynos going down, not cause of mods, but maybe cause they need a tuneup or something that we didn't have to worry about earlier.

 

thanks for the review....how long after the install did you do the dyno...heard it takes a while (week or so) before the ecu to optimize after this mod....rw

 

I drove the car for 3500 miles or 1 month in my case after putting on the pulley before dynoing(I drive a lot)...if the ecu does "compensate" then it would have had more than enough time to do so.

 

alrighty...well that sucks...but we appreciate passing on the info...only positive is at least it didn't hit the pocket book too much....maybe when the ecu programming is figured out you can tune it and get more out of it

 

So how many miles are on your car and how many miles between dynos??

 

Had the car 14 months and I am about to hit 33,000 miles. I put 3500 miles on the car with the crank pulley between my dyno yesterday and my last dyno , which was actually about 1 1/2 months ago...

 

somehow I think the ECU is involved here. How long since your last dyno/mod change? I truly think that after time the ECU is negating some gains. I have reset my ECU a couple times just for the heck of it, and the car seems to start pulling harder after a few hours of driving. No dyno available here to really know the changes though.

 

Sorry, typed up the question but it didn't go through, resubmitted to find many posts already

 

the pulley has nothing to do with load