DOHC cam timing-effects, results, data, discussion etc!

[turbovanman²]

Figured I'd post it here as we've hashed SOHC cam timing but SRT, 2.2/2.5 hybrids and TIII setups should all be similar.

So, I have some tri-flow cams, can't remember duration but lift is .396 ish vs stock is .315 ish, have the other numbers at work. Things I noticed with the cams degree'd to the stock centerlines of 121 intake and 105 ex were 12" vacuum at idle, close to 10 in gear, cold start runs like crap-10", major exhaust drone but seemed to run well, best time of 14.7@95, 18psi, 2.3 60ft.

So at the track, all I adjusted was the cam timing, ended up advancing the cams until the MPH stopped climbing and times dropped. Intake ended up at 8 deg and exhaust at 6 deg, nothing changed except that, same boost and ran a 14.0@100mph, 2.3 60ft.

Things I've noticed, exhaust is almost dead quiet on the freeway, no drone, vacuum has picked up to 15" in gear and in park, even cold now its 15", seems alot perkier around town.

So on that note, do you think this will be the ideal settings for high boost etc or should they be put back to the stock centerlines? I seriously didn't think the engine would react like it did.

I also compared my 1/8th mile times to the 12 sec run and I'm 1.2 sec slower and 6 mph slower.

[bakes]

+ this is with a lower stall conv. not the same as the 12 sec. runs last year.

[glhs0426]

Early on GLHS441's TIII Omni had the cams advanced terribly and it had the same effects you described along with: 200psi cranking compression, pushed combustion chambers out of the head, and had something on the order of 21"Hg @ idle. The super quick throttle response was amazing. He stopped hurting so many parts after the cams were degreed. Only the rod bearings were suffering from too much timing after the cams were set. I did not get a chance to play with the timing before he sold the car.

I don't remember exactly what the numbers were but it was something like 98 and 110.

[turbovanman²]

Hmm, interesting. 98 and 110, that's alot on the intake side, only 5 deg on the exhaust.

I'll do a compression test this week, with the cams at 0, I had 150.