I threw my Yukon on the dyno last weekend as I am starting the teardown this weekend and wanted a baseline number to go by. I street tuned only last year as the truck was AWD, but now with the manual t-case swap I am running 2wd and can put it on the dyno to tune. As of now, I had installed shorty headers, K&N intake and dynomax exhaust on the yukon and tuned last summer. I also have very heavy 24" wheels that I believe hurt the dyno numbers as it put down 272 whp and 312 tq on the dynojet. I kind of hoped it would be higher but figure I'm losing a fair bit from the wheel/tire combination.

This weekend, I'm throwing on some ported 799s with new Z06 springs, a low lift XR265 cam and picked up some longtubes. Also picked up some new 8.1 injectors to make sure I have enough fuel. I had hoped to be close to 400whp with the mods after tuning, but I'll probably have to put the stock 17's back on to get anywhere close. Anyone have any idea on how much the larger wheels will hurt the dyno numbers, I'll probably tune with them on and make a numbers pull after with the factory 17's, and am I out to lunch on my 400 hopes?

 

it think you'll be more likely around 350whp but that's me.

 

^yeah thats what I'd guess. Especially if you're still running the 78mm intake.

 

Post up the dyno graph.. numbers dont mean anything

 

Dang 6.slowwwww I'd be curious to see difference with 17" wheels.

 

Got it done and running, its super rich with the larger injectors so I can't wait for tuning. It is definitely a different animal on the street. Finished up the exhaust today and filled it up with fuel and its off to the dyno tomorrow. Will post up numbers as soon as I get them, I'm going to do a before and after with the 24"s and my 16" winter wheels and tires to see what I'm losing as well. I built the exhaust with V-bands so I might even make an open header pull....lol

 

Well I picked up the truck last night, works really well. Didn't make quite the numbers I was looking for, but I have a few other things I'm going to do to try to get a bit better. Dyno runs were done in second gear with the torque locked. I figure its not that bad considering going through the automatic, transfer case and 24" wheels. I weighed a wheel and tire and it was 110 lbs last time they were off. Plus I need to upgrade the exhaust a bit, have 3" duals back reduced to 2.5" muffler inlets and one 3" tailpipe....lol.

Anyway, here's the graph, and below is my run from the last weekend, I was wrong on my previous numbers, I guess it was a torque spike that gave it 312 that he fixed up with the smoothing.



And a quick video of the last pass

 

that's not bad though, a solid improvement over your previous numbers

 

Pretty solid!

 

I like it.. Mo powa...