Join Date: Feb 2009
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Yeah, I should've added...
On stock timing, you have a lot of power from spool-up until 2500RPM and above that, it tends to taper off quite a bit. However on these engines, the best power zones are between like 2200 and 3500RPM.
When you advance timing, (of course, it depends on how much, but let's use 17º as a happy medium) it will greatly improve the revs from 2000-3200+ (depends on if you have HD exh valve springs). It will drop power a little bit below 1800 and it's around the same between 1800-2000.
Above 2000 though, advanced timing really helps.
And honestly, those high revs are really where it's at... especially after you get bigger injectors.
The headgasket and high EGT's are the only real concerns unless you're really turning high revs, above like 3700RPMs. And the headgasket is a touchy subject. Some people swear that either highly advanced timing (18º or over) or high drive pressures (differential between exhaust "drive" pressure and intake "boost" pressure) hurts the HG, but it's really a matter boost pressures and also letting the engine (head & block both) warm-up to at least 165-170º before exceeding 20PSI boost.
Nitrous is also up for debate as to whether IT hurts a stock HG. I know 12-valve mechanics who have run 25º timing, nitrous and a 66mm turbo (pushing 60# boost) on a stock HG & headbolts. They are crazy, but they prove it's a soft-science.
Also, a couple of those guys don't believe in re-torquing the stock headbolts. They just leave it how it is because they believe that can actually increase the risk of HG failure (stretching old screws and disturbing the gasket as well).
I don't know... my point is just that you can do alot more to these things than you think.
98' 12v QCLB 4x4 216k, S363/68/.83 + S478/87/1.1, Steed T4 manifold + JGS gate, Levi's Blankets, A1 studs, Goerend, 5x18 SAC, 042DV, 2095, 4GSK, TerraG 295/17's on 4thGen 6-spokes
Last edited by Algae Eater; 07-16-2010 at 01:53 PM.