XLR8NSS

iTrader: (4)

Ok here is the setup.

Stock 2000 5.3L with intercooled 5psi or so.

What type of timing can I run and what is a good A/F ratio to shoot for?

That's not alot of boost so I'm thinking I can probably get away with low 20s on the timing but, really don't know what air fuel ratio to shoot for.

Oh yeah, gas will be 93 pump and temperature here now is around the 90 degree mark. How much advance can I program in for winter like temps(30 or so)?

Crash Dummy

11.8-12.0 AFR and 20 deg for starters and fine tune from there

XLR8NSS

iTrader: (4)

Ok, I will shoot for those number initially.

If I decide to tweak those numbers some which one should I start with? Which one is more important to power(timing or A/F)?

camcojb

More timing will make more power, until you exceed the amount you can run with your boost and octane levels. Getting into detonation will insure a broken engine. An A/F of 11.8-12.2 is plenty safe and won't cost much power.

Another option I've used on the last several blown motors I've done is alcohol injection, especially if you're going to run pump gas. The alcohol on my truck is worth an extra 6-8+ degrees of timing which was 30-40+ rwhp.

Jody

XLR8NSS

iTrader: (4)

I may run a meth kit too if I decide to up the boost some later on. Right now I just want to drive my truck again. It's been on jackstands so long I don't even remember the last time I drove it.

I see your power numbers and have another question. Is that sort of gain standard with an increase in timing like that or will the build level/power level play a role in how much of an increase one can see from added timing?

Thanks in advance.

DanaliHD

iTrader: (5)

my methanol kit must really suck because i can only run 15deg timing if i'm lucky at wot. I don't know how you guys are running 21 or so. whacky!!!

camcojb

When I first started modding the truck I had a race tune for 100 octane and a street pump gas tune. The difference in power between the two was about 32-34 rwhp. The only difference between the two was added timing; they both had the same 11.9:1 A/F and they both ran identical boost.

On my current combo the difference would be more than that because of the high boost I run. Without the alcohol and running on pump gas I would have to pull a LOT of timing out of the truck, and I'd guess it would be 40-50 rwhp difference, maybe more. I quoted the 30-40 rwhp because that's a bit more real-world for a milder combo.

Ideally you start conservative and then add timing until you get into detonation and back it down a couple degrees. Part of this is also reading the plugs with every timing and tuning change, because you can have detonation that you don't hear. Extra boost obviously bumps the power and torque noticeably too, and that's where alky injection, intercoolers, etc come into play; anything that lowers air temps and prevents detonation.

Jody

camcojb

That's more like Lightning timing numbers! They only have 12 degrees stock at WOT, quite a learning curve for me to tune this truck with my experience being in Chevy's.

One thing I do with an alky timing map is ramp it up. I can run nearly race timing numbers (100 octane) with 91 octane pump gas and alky. But with a race curve I might run 20 degrees total, from 2000 rpms and up. With the alky setup and pump gas I (depending on boost) can run maybe 19 degrees, but it's only 12-13 degrees at 2000 rpms and then slowly climbs to 18-19. The real low end WOT timing numbers have to be watched, there's a lot more load on the engine there up until peak torque, than there is up high in the rpm range, which will usually tolerate more timing.

Weight is also an issue. A heavier vehicle like a Denali won't be able to run as much timing as a lighter 1/2 ton standard cab truck.

It also depends on your nozzle size in your alky kit. I had an SMC kit on mine and switched to a Snow Performance MAF kit which I like a lot. One of my SMC nozzles was too small for my modded engine and the larger nozzle was too much, shutting the truck off at WOT on the 2-3 shift. The 625 nozzle on my Snow kit seems perfect for my current combo. I also run straight denatured alcohol, not a water/alky mix. With the Roots type blowers it seems to work better to me, plus gives a bit of an octane boost also. I've run water kits on centrifugals in the past without issue, but the KB screw blower and the stock Roots both ran better on straight alcohol.
Jody

04Denali

I'm new to the meth set up. can anybody recommend a good system. I will be putting in a Radix SC, mid lenth headers, high flow cats, e-fans and a differant t-stat.
aany help would be appreciated
Mark

camcojb

I've used 4 different kits over the years. Best bang for the buck (in my opinion) is the Snow Performance kit. The SMC kit is also nice but more money.

Snow Performance

Jody