Yukon/Tahoe Performance

[Stepside_fever95]

Got the CMP offset dialed in to 0.1 at 1100 rpm. It runs way better now. Idles smoother, no more bogging off idle, even fixed a harsh tc lockup issue I was having. Really appreciate y'alls help with that.
It's still slow though. Timed a 0-60 at 11s.
No more cmp codes, but I'm getting a knock sensor code. The wire for that got pinched when I replaced the transmission about a year and a half ago. I repaired the wire when I had the engine out so I dunno why it'd be causing issues. I guess I'll have to poke around some.
No o2 codes either, which is weird because I know I used to have one. Still convinced the cats are clogged. CEL is off for now.

Did you have a crankcase angle sensor error relearn (case) done?

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[honkon]

Did you have a crankcase angle sensor error relearn (case) done?

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I haven't, but as I research it I see people talking about needing it because of a P1336 code, which I haven't had.
I also didn't do any sort of tuning or swapping of ECMs.
7.8 is mighty impressive for something as big and old as a GMT400 Suburban. I'd like my Yukon a lot more if it were that quick.

 

[NorthernTahoe]

7.8 seconds for a Suburban with those mods sounds unbelievable. Not saying I don't believe you. That's pretty much the same as my LT1 Caprice stw. I thought my Tahoe was doing OK at 10 seconds (4-door, 4x4, L31, 265/75R16, 3.73:1, under 120k, some tuning, idles great).

 

[Stepside_fever95]

Before tuning it and when I had 32" highway tires I took it to the local 1/8th mile track and it ran even 11s. It feels about the same after the tune with my 33" all terrains. I did take out the spare when I made those passes too for weight reduction and had under an eighth of a tank of fuel too LOL.

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[Stepside_fever95]

I'm really excited to see what a stock lq4 and 3.73 gear swap will do for it.

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[L31MaxExpress]

I'm really excited to see what a stock lq4 and 3.73 gear swap will do for it.

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I just tuned an 04 yesterday. LQ4 with a small cam in a 2004 2500HD. 4L80E with 4.10s. To me it was still a dog until you wrapped the tach all the way up the scale. Once it got in the 3,500-5,500 rpm range it pulled pretty good. With the factory intake, factory intake and exhaust manifolds it fell off drastically higher than 5,500. I have also recently tuned a 1999 crew cab 3500 454 Vortec dually that pulled ALOT better than the 6.0L. Stock 454 would accelerate up the same ramp 10 mph faster at the end of it.

 

[L31MaxExpress]

Before tuning it and when I had 32" highway tires I took it to the local 1/8th mile track and it ran even 11s. It feels about the same after the tune with my 33" all terrains. I did take out the spare when I made those passes too for weight reduction and had under an eighth of a tank of fuel too LOL.

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That is a low 17 second 1/4 mile. I ran a 17.3 @ 78 mph in my bone stock L31 powered Express conversion van with stock sized tires. 5,800 lbs without driver, with a 1/4 tank. 4L60E and 3.42s at the time. When I tuned the black box it went 16.8 @ 81. The stock 96 LT4 cam, 1.6 roller rockers and S10 converter that brake stalled 2,700 rpm dropped that time to a 15.8 @ 86.

 

[Stepside_fever95]

That is a low 17 second 1/4 mile. I ran a 17.3 @ 78 mph in my bone stock L31 powered Express conversion van with stock sized tires. 5,800 lbs without driver, with a 1/4 tank. 4L60E and 3.42s at the time. When I tuned the black box it went 16.8 @ 81. The stock 96 LT4 cam, 1.6 roller rockers and S10 converter that brake stalled 2,700 rpm dropped that time to a 15.8 @ 86.

That is one quick express van! That's awesome!

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[df2x4]

That is one quick express van! That's awesome!

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It probably isn't. Not sure if you saw the thread from earlier but this guy has been caught passing off other people's dyno sheets as his own on other forums. I wouldn't trust a word he says, even if some of it isn't blatant lies.

 

[David89gmc]

Yeah, who would do those expensive mods on a van anyway?

The resources on this site are invaluable and I for one thank you all. The rebuild of my 89 K1500 SLE should go smoothly now.