New Dyno results

[Superdave]

Did you ever try doing a 1/4 mile run on the dyno to find a rough estimate time?

i'd be afraid that i'd break the tires loose on shifts.. or break something else.. lol

I did play around a little though.. it took 13 sec to go from 55 MPH to 136 MPH in 4th gear, i thought about hitting 5th but running a 140K tranny up to 200MPH didn't sound like a good idea.

[ForcedFirebird]

Man, that was a quick 3rd gear

[1988GTU]

i'd be afraid that i'd break the tires loose on shifts.. or break something else.. lol

I did play around a little though.. it took 13 sec to go from 55 MPH to 136 MPH in 4th gear, i thought about hitting 5th but running a 140K tranny up to 200MPH didn't sound like a good idea.

I have a feeling your car will become a trailer queen.

[01GPGT]

wow vary impresive

my high compretion cammed l67 is only making 270 hp and 265 ft-lbs and i think i have more dumped into the engine.


can't waight untill my 3.4/3400/3500 hybrid project

[Joseph Upson]

The magic number was 26 degrees advance, and i actually lost like 10 HP when i opened up my exhaust cutouts.

That wouldn't have happened if you had a turbo on it.

The cutouts opened probably screwed up the scavenging effect. Never understood it until I disconnected a hose from a check valve on a header used for the AIR injection system and placed my hand over the end of it to confirm the flutter I was hearing was caused by it and felt suction that close to the exhaust outlet, I was amazed expecting it to be blowing air. Coincidently on a TPI camaro after removing a plugged cat and driving up the street with just the "Y" pipe I noticed a considerable loss in low end power that felt like a lot more than the 10 hp you lossed. I didn't know as much then as I do now. Physics is a very important subject to understand.

my high compretion cammed l67 is only making 270 hp and 265 ft-lbs and i think i have more dumped into the engine.
can't waight untill my 3.4/3400/3500 hybrid project

Not to knock the L67, but pound for pound the later 60 degree engines appear to be more efficient and powerful by design rather than fluke and I can't understand why the Fiero owners are even considering installing a naturally aspirated version of the 3800 or the 4.3L V6 in spite of that.

[3400-95-Modified]

Impressive and much smoother than the last run, Now you can actually post those as some hard numbers where before it was a peak number only and not consistent

Makes you wonder though... If your running a 13.29 with that, I wonder how much power Eric's 3500 GT is putting down since he mustered a 13.9 or something like that with an un opened motor.

[Superdave]

i used one of those crummy 1/4 mile estimators and a 13.29 @ 104 is like 245 WHP @ 2900 lbs.. so if that's even remotely accurate then i should be able to break 12's with a good run.

I've got a raincheck from the track, i'm probably going to strip the car to a shell and make it back in a few weeks to try again

[johnnymossville]

Eric is running a 3.73 gear as opposed to Daves 3.30 something. With less HP than Dave is making he is probably getting a little more traction, not to mention that we all know how much difference the gear is going to make. I am still curious what Eric's HP/torque numbers are though.

[Superdave]

3.61 FDR in mine, with LSD

i had the 3.94 diff for a while, i had a hard time breaking into the 13's with it though. I really want to find a '90 GTZ tranny with the 3.61 FDR and the better 1.03 4th.

[IsaacHayes]

The 90 GTZ has a shorter 1st gear too though. Just swap the 4th into your v6 getrag...

Yeah the headers probably need some pipe after the collectors for a decent stretch to keep the velocity going. But there is a beretta that has just a 3400 swap and ran a 14.something with a cutout on stock manifolds. Picked up power because of extra flow, where you lost power because you killed some velocity. Crazy how different designs react. I wonder at which point you should open the cut outs in the exhaust as to not kill the velocity but yet get rid of any potential restriction from bends going to the rear axle/mufflers. Probably won't pick up that much power to be worth it.

Did you ever get higher than 92 kPa with the bigger TB Dave? I noticed from my logs I never get higher than that, but that may be due to other things. Soon I will go from 52mm to 65mm. Big jump LOL.

[Superdave]

all the local trans shops refused to touch the HM282.. lol


Yes, i hit about 98 Kpa depending on the weather at WOT. The engine loves the 75mm TB

my exhaust setup is matched to the engine almost perfectly flow-wise.

[3400-95-Modified]

My next route is the 3.69 gears for my car... 3.42 may be too low with this converter, we'll see.

[sprucegagt]

all the local trans shops refused to touch the HM282.. lol


Yes, i hit about 98 Kpa depending on the weather at WOT. The engine loves the 75mm TB

my exhaust setup is matched to the engine almost perfectly flow-wise.

I think your headers may have been over scavenging with the cutouts open. It just doesn't make sense to me to loose velocity because you lost restriction?

[IsaacHayes]

Hmm, possible that it sucked so much air out of the cylinder that it created a vacuum in the cylinder before compression? heh. I'd say that the pipe right after the collector isn't a restriction, and that it probably helps pull everything out. Now when you get down to the axle and start getting into some of the bends and really long pipe length, then it would be a restriction.

[sprucegagt]

Just saying it's a possibility. How many people here have equal length 32" long headers on a modified big cam 3500? We don't know the limits of the engine or exhaust system and it is possible to have a set of headers scavenge so well that they can pull a bit of the intake charge straight out the exhaust port during cam overlap.