Last edited by PJG1173; 10-09-2012 at 11:06 PM.
87 4Runner, 15" spring lift, 3" body, chevy vortec 355, 5.29 gears, 38.5x15.5x15" Boggers, 280hr, 16168625 running $0D
93 S10, 36x12.5x15 TSL's, custom turbo headers, 266HR cam, p&p vortec heads, $0D Marine MPFI with 8psi boost.
05 Silverado, 2' lift, 4" exhaust, Bully Dog programmer,
Good heads with a fast burn chamber and tight quench will require less timing. People seem to think more is better when it comes to advance but the goal is to make the most power with the least amount of spark advance. When you start spark advance before TDC some of the energy from combustion is wasted as increasing pressure tries to prevent the piston from achieving TDC.it likes alot of timing low but I'm only able to get 26* WOT without knock. I'm assuming this is because of the long duration of my cam. just goes back to every motor is different.
I'm still waiting for the day when in cylinder pressure sensors are part of the hotrodder's tuning arsenal.
All things being the same except the cam i run 33* on my other motor with about 10* less duration. I think the bigger duration cam gets more cylinder filling raising the dcr, and coupled with a tight quench and fast burn chambers is what
is reducing the need for timing.
87 4Runner, 15" spring lift, 3" body, chevy vortec 355, 5.29 gears, 38.5x15.5x15" Boggers, 280hr, 16168625 running $0D
93 S10, 36x12.5x15 TSL's, custom turbo headers, 266HR cam, p&p vortec heads, $0D Marine MPFI with 8psi boost.
05 Silverado, 2' lift, 4" exhaust, Bully Dog programmer,
The WBO2 was $2500 when I first started this game and now it's around 1/10th that price. GM uses active coil current and voltage detection to determine TDC on Ecotec engines and produce a cam sync pulse. And ion spark detecion circuitry can be adapted to measure cylinder pressure as well. We just need to get together and adapt or redesign some OEM circuitry.priced them, it's not going to happen.
87 4Runner, 15" spring lift, 3" body, chevy vortec 355, 5.29 gears, 38.5x15.5x15" Boggers, 280hr, 16168625 running $0D
93 S10, 36x12.5x15 TSL's, custom turbo headers, 266HR cam, p&p vortec heads, $0D Marine MPFI with 8psi boost.
05 Silverado, 2' lift, 4" exhaust, Bully Dog programmer,
I was aware of the ion spark detection capability of many late model coil designs and I believe the current and voltage detection was tied into that technology. But I had no clue that GM or any manufacturer for that matter was using it to determine TDC and produce a cam sync pulse. Of course, I admit that I only paid attention to a fraction of the training courses I took due to the sheer volume of courses it takes to acheive and maintain master tech status. For the time being, I still have access to GM's online database until my old employer decides that my training isn't beneficial to them anymore or until GM realizes that I am no longer employed there. But, as long as I have access, I can still easily obtain part numbers and schematics etc....
1999 GMC Sierra 1500 standard cab long bed 4.8 V8 2WD - A work in progress.
2000 Grand Prix GT sedan 3800 - My new daily driver inherited from the wife via the insurance company totaling it out after a minor collision.
2006 Grand Prix GT sedan 3800 Supercharged - The wife's new grocery getter.
I'm running quite a lot more timing on my truck than the stock OBD2 Vortec tables. More than stock TBI tables too. Mine is actually a LT1/6spd Camaro table with a few degrees pulled out here & there.
80 Camaro Z28 - 550hp AFR 383 / T56 6spd (Holley HP EFI)
91 Beretta "SS" - 260hp 3400 MPFI / HM282 5spd (7730/$A1) sold! for crazy money...but I miss it
94 Silverado Z71 - 300hp Vortec 357 TBI / NV4500 5spd (7427/$0D) gone but not forgotten
96 Beretta "T56" - 4.8 LS RWD swap / 6spd (0411/2156)
01 Silverado 2500HD - stock Vortec 8.1 / ZF6 6spd (0411/8322)
https://www.youtube.com/c/GEARHEADdezign
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