Where are the "cam timing retard mod" 3.4DOHC 1/4

Sinister Fiero · Post by **Sinister Fiero** » Mon Mar 19, 2007 2:24 pm

I just read another thread over on Old Europe about a guy who said he had a 3.4 DOHC engine in his Fiero with the intake and exhaust cam timing retard mods and claimed the engine was making over 300hp.

It just occurred to me that I have not yet seen any 1/4 mile timeslips nor dyno sheets proving the cam retard mod is worthwhile from a drag-performance standpoint.

Has anyone seen such proof? And if so, do you have the URL?

Mach10 · Post by **Mach10** » Mon Mar 19, 2007 2:30 pm

SappySE might have some...

I don't have a lot of faith in this mod. It's entirely possible that it does what it says and more; but seeing as the crowd who normally do it usually can't be arsed to play with the ECM tuning either, I doubt that most people get any benefit at all. :scratch:

whipped · Post by **whipped** » Mon Mar 19, 2007 2:42 pm

I don't think I've ever seen a 13 degree retard dyno or time slip.

except for that one with the short runners/headers that made like 270 whp... but it wasn't exactly a before/after retard.

The Dark Side of Will · Mon Mar 19, 2007 3:03 pm

It was only 24x whp, and included short runner/large plenum intake as well as long tube headers and true duals.

I haven't seen a before/after either. The 240 whp engine sure didn't have a powerband worth bragging about IMO.

Overlap is the cam variable that matches to the ratio of cylinder displacement and port flow. Duration maps to RPM range. With a cam timing mod, the duration isn't changing but the overlap is... Meaning that the overall powerband gets worse. It may make gains on the top end, but those will be accompanied by equal or greater losses on the low end.

Jinxmutt · Post by **Jinxmutt** » Mon Mar 19, 2007 4:25 pm

I haven't ridden in a stock timing 3.4 dohc before so I can't compare but I met up with someone on campus this past friday who did 8* retard and that thing was a dog. I know I"m used to a L67 fiero, but I thought it would have more uumph. Guess its just been too long since i've ridden in a 2.8.

7000 rpms however, is badass..

SappySE107 · Post by **SappySE107** » Mon Mar 19, 2007 9:45 pm

Sinister Fiero · Post by **Sinister Fiero** » Tue Mar 20, 2007 1:00 pm

Ok so we have established there aren't any before/after comparo tests available.

Does anyone have any dyno/track numbers showing what one of these 3.4 DOHC powered Fieros with the cam retard mod done did at the track or at the dyno?

chuck · Post by **chuck** » Wed Mar 28, 2007 9:43 pm

Fieromadman went from a 14.7 to a 13.86 in the quarter with cam timing, new exhaust and an underdrive pulley. Not exactly what you were asking for but i thought it might be worth mentioning.

Sinister Fiero · Post by **Sinister Fiero** » Wed Mar 28, 2007 11:32 pm

chuck wrote:Fieromadman went from a 14.7 to a 13.86 in the quarter with cam timing, new exhaust and an underdrive pulley. Not exactly what you were asking for but i thought it might be worth mentioning.

Ok, but how much of his gains could you attribute to the cam timing mod alone since he also did an exhaust upgrade and underdrive pulley?

For the record my bone stock 3.4 DOHC (1995 eng) w/ 5-speed getrag ran a 14.1 et @ 97mph with a slipping clutch.

FieroWanaBe1 · Post by **FieroWanaBe1** » Thu Mar 29, 2007 9:21 pm

chuck wrote:Fieromadman went from a 14.7 to a 13.86 in the quarter with cam timing, new exhaust and an underdrive pulley. Not exactly what you were asking for but i thought it might be worth mentioning.

but fieromadman also had his chip tuned too, the 14.7 was on bone stock everything, including automatic chip tune (6500rpm redline).