MCVO Dyno Day - June 23

[GR8_ASP]

Conducted a dyno day in Michigan today. Here are the participants and results.

Vipers starting to arrive at Advanced Chassis Dyno in Troy, MI

Example of a vehicle being raised to the dyno. Wish I could fit one of these bad boys in my garage.

Andy Dafski the dyno owner/operator. Great to work with.

Power curves for all participants. Note this dyno has been proven to be quite realistic and not to overstate hp numbers. Used by Team Viper on several occasions as well.

Torque curves for all participants

The group had lots of fun on a perfect Saturday. Lots of horsepower and exhaust in the air.

 

[GR8_ASP]

Individual results, in order of testing. Power and torque scales are the same for all graphs for easy comparison. Larger sized views of the power/torque curves can be accessed in my gallery.

Ed Gatt - 1995 Rt/10. Several modifications (headers, rocker arms, exhaust, etc)

Tim Sutherland - 2006 SRT-10 Coupe 455 HP, 484 ft-lb

Brian Loose - 2001 GTS 403 hp, 434 ft-lb

Dan Sutherland - 2003 SRT-10 441 hp, 472 lb-ft

 

[GR8_ASP]

Dave Buchesky - 1994 RT/10 Roe SC 520 hp, 594 lb-ft

Terry Turin - 2000 RT/10 418 hp, 443 lb-ft

Ron Stene - 2003 SRT-10 Paxton and Mopar race exhaust 685 hp, 624 lb-ft

Bruce Heckman 2001 GTS Corsa catback 408 hp, 444 lb-ft

Scott Heggie - 1998 GTS Corsa catback 419 hp, 458 lb-ft

Anthony Boutt - 2006 SRT-10 Coupe 441 hp, 457 lb-ft
There was an issue during 2 of the runs where a minor power loss was present starting at 5200 rpm or so and continuing for about 300 rpm. No clear cause. If you have any ideas please post them below.

 

[Steve 00RT/10]

Looks like a good day Ron! Nice job of putting it together. Good numbers for the blower cars. Bo's car did quite well I think--considering there's more to get for him dialing the AFR in. He was running in the mid 10s at G-man in 4th gear when he checked it.

Is it the same guy who owns the dyno place as several yrs. ago?

I'm autocrossing here tomorrow morning. I helped set it up earlier today at the old airport.

Steve

 

[bloose]

Ron,

Nice power, but I don't recall you actually PASSING me this time , not even in the pits.

Seriously though, thanks for arranging everything. It's good to meet more and of the guys each time.

 

[GR8_ASP]

Steve, Dave had his a/f measured. Here is the graph. I do not see much room for leaning out for more power. Maybe under 4500 rpm but not above.

 

[Steve 00RT/10]

How accurate is the tail pipe method -- compared to a **** at the collector? He was reading rich at the track on his meter from the WB sensor at the collector area. Is the additional airflow taken into account so far downstream from the initial exhaust gases?

Steve

 

[Steve 00RT/10]

Our yellow car was tuned down there on a dyno in 2003 using the tail pipe method (554HP/586TQ). Whe we got the car last August, I noticed it would belch black smoke out the back when floored for a second or two. I got the VEC upgraded to be able to log and installed a WB in the collector area, I found the car to be running high 9s to mid 10s AFR with the dyno tune from 03. I have taken out a lot of fuel this spring and pretty much eliminated the black smoke.

From Dave's measured AFR at the dyno, I would probably add a little a fuel after 4500. Too bad he didn't run a log during the run. Would have been interesting to compare the two readings. If I ever get to a dyno again, I will do that. What do you think the temp was?
G-man was hot.

Steve

 

[GR8_ASP]

Steve the temp was 82 degrees for the middle of the day when both Dave and I ran. The correction factor was 1 percent.

As to the end of tailpipe versus at the collector. They should be identical assuming no exhaust leaks allowing air in. Note the EPA uses tailpipe collection. Dave indicated his dash gauge was highly erratic, even in closed loop mode. That does not sound good as in closed loop the reading should be at or near stoichometric. Note the collector **** method is not infallible either. You may be too far upstream and not have a homogeneous mixture.

And yes, at Gingerman with high temps and high underhood temps it would be running somewhat richer. Inlet air temp change would be compensated for but not supercharger exit temperature, thus causing the air to be less dense at any given pressure. The car (or Vec) does not know this and does not compensate for it.

 

[Steve 00RT/10]

Steve the temp was 82 degrees for the middle of the day when both Dave and I ran. The correction factor was 1 percent.

As to the end of tailpipe versus at the collector. They should be identical assuming no exhaust leaks allowing air in. Note the EPA uses tailpipe collection. Dave indicated his dash gauge was highly erratic, even in closed loop mode. That does not sound good as in closed loop the reading should be at or near stoichometric. Note the collector **** method is not infallible either. You may be too far upstream and not have a homogeneous mixture.

And yes, at Gingerman with high temps and high underhood temps it would be running somewhat richer. Inlet air temp change would be compensated for but not supercharger exit temperature, thus causing the air to be less dense at any given pressure. The car (or Vec) does not know this and does not compensate for it.

If I ever get to a dyno, I'll do both and compare the results. My **** is not actually at the collector, but rather the turn out just before going into the side sill. I would guess that to be a homogeneous spot.

I don't think unusual at all for the in car AFR gauge to jump around some in closed loop. Every time you touch the gas, encounter any grade / descent...etc....is not the PCM kicking into the STFT mode and searching for stoichometric? I'd be surprised if his gauge is doing anything out of the ordinary. Even with the EASE diagnostic tool I have, STFT is kind of bouncing all around looking for 14.7. Wouldn't that bouncing around be doing the same thing on the AFR meter? If I run an idle log with the VEC. It's continually running between 14.5 and 15.25 or so...with most in the upper 14s. It never stays in one place.

When first going to WOT, and transition to the VEC programming, the AFR goes a little lean for about 500-750 RPMs before before kicking into the program. The pedal has to be firmly on the floor. If you let up at all, the log/AFR meter will be all over as the PCM trys for closed loop again. Dave really should hook up the laptop and make a few runs. If the tail pipe reading is correct, he should probably add a little fuel up on top.

Steve