The plan : Do 5 runs, 3 on high boost (20psi peak, 18psi redline) and 2 on low boost (16psi peak, 14psi redline). Expectations are high... lots of people showing up to watch the runs.

Morning comes, I get a 1/4 tank of 103 Octane VP unleaded. I drove on Deerfoot to get to work (a highway that cuts across the city) and manually tweaked the duty cycle to get a more stable boost over the entire rev range, and succesfully got 21psi peak (actually a bit higher than that, my fuel cut is set at a little over 21psi and I hit that twice) and held 18psi up to 6500rpm. Still haven't had good enough weather to get the AVC-R to autolearn... oh well. Car feels great, spinning it's wheels in 3rd gear without much problems when it peaks.

After lunch I picked up some friends to witness the runs. Headed over to Davenport to strap the car on. Got there a bit late, my cousin beat me there, and was already strapping his car down. No biggie, it'll give me a chance to cool off my car. After about an hour, his SLK 32 AMG pulled 284rwhp (330-340hp flywheel), it was my turn. <a href="http://www.virgeweb.com/rage2/SLK32/slk32dyno.wmv" target="_blank">(See the video for this car)</a>.

Now, we all wish plans gets executed without a hitch, but we all know that only happens in a perfect world. First problem : when the car was being strapped on (it was tough!) the CV joint bolts were a bit loose. Probably from my nightly 1/4 mile runs =). After about 1/2 hour of tightening, it was ready to go. The car ran a bit on the dyno to get rid of the snow, and off we go! <a href="http://www.virgeweb.com/rage2/944t/2002-01%20951%20dyno.wmv" target="_blank">(See the video for the 3 runs)</a>.

First run : The blow off valve wasn't adjusted properly, so there was a small leak there. The run was done in 4th gear, I watched from the passenger seat. SDS shows peak boost at 18psi, dropping to 14psi at redline. Duty cycle was at 91% peak. Net result, 339.8rwhp (390.8hp flywheel). No problem, not enough of a load (it's an inertia dyno), so I adjust the duty a little bit more to compensate, ready for another run.

Second run : Again, watched the SDS unit in passenger seat. Peak boost this time was 16psi, dropping to 13psi at redline. Blow off valve was still leaking slightly. Maybe I needed to cool the car down a bit first before doing the run... net result, 308.8rwhp (355.1hp flywheel).

Third run : The blow off valve was adjusted. Car was cooled down for about 10 minutes. This time, I set the duty cycle to 100% above 4500rpm, so the wastegate would be held completely closed. Let's make this one count! Again, watched the SDS unit, peak boost was 17psi, dropping to 14psi at redline. 316.9rwhp (364.4hp flywheel). Very disappointing.

Called it a day from here, and Marc (my mechanic) took a peak and saw a small leak at the intake manifold. Looks like I need an intake gasket. The head seems to be leaking a very small amount of coolant, so the head studs needs to be retorqued (it's about time anyways). My feelings are mixed, I know I'm making around 400hp on pump gas (low boost), but I don't know how much HP I'm making on 103 octane and high boost. Davenport says they'll have an upgrade to their dyno so the drum is loaded by spring time. Since Davenport is the only place with a chassis dyno in town, I'll have to schedule for another dyno run then!

One note, my torque curve seems to be a bit rocky on the graph. We all thought it was a fuel issue, but on the drive home I realized what it was. The AVC-R regulates boost by duty cycle. The duty cycle is the "pulse" that it sends to the wastegate. 50% means in a 40ms "cycle" it pulses for 20ms, 75% would be 30ms, etc. Although it looks rocky on the dyno, you can not feel it on the road. Everyone that I've given rides to have said that the power delivery is very smooth, and the car doesn't feel that fast (till they look at the speedo). And of course on the way home, with my brother watching the SDS, I hit 21psi peak and held it at 18psi without any problems.

Final Results :
Dynorun.001 - 339.8hp, 404.4ft/lbs
Dynorun.002 - 308.8hp, 340.3ft/lbs
Dynorun.003 - 316.9hp, 348.3ft/lbs

BTW - Thanks for showing up Doug, it was nice meeting you =).

 

Rage,

Those torque #'s are awesome! What kind of dyno are those guys running?
Paul

 

[quote]Originally posted by Paul Bloomberg:
<strong>Rage,

Those torque #'s are awesome! What kind of dyno are those guys running?
Paul</strong><hr></blockquote>

Dynojet Model 248 chassis dyno. They're getting a A/F Ratio meter, as well as a Load control upgrade this spring. Makes for great tuning!

 

Rage,

Nice runs on the dyno.
Davenport is not the only place in town with a dyno. Western Motorsports also has one, along with another place which I think is called Calgary Sports Cars. IF you like, I will get the name for you.

James

 

Yes that would be great. I still have some 103 left in the tank... =)

 

How about posting your dyno-sheets for us? I'm interested in the shape of the curves. Thanks.

 

My scanner broke, so the graphs will have to wait. Basically, it's a smooth climb up to 4400rpm where the small boost spike gave it the torque peak (404.4 ft/lbs). Then it slowly drops. It looks really rocky. Here's a quick "plot" of the torque curve. You should be able to draw up a graph in Excel.

3000 - 145

(it's a linear climb here to 4400rpm)

4400 - 404
4500 - 380
4600 - 362
4700 - 361
4800 - 340
4900 - 364
5000 - 343
5100 - 350
5200 - 324
5300 - 355
5400 - 347
5500 - 340
5600 - 333
5700 - 339
5800 - 331
5900 - 320
6000 - 312

 

Alright, did some work and plotted my torque curve. Calculated my HP based on the equation HP = (TQ*RPM)/5252. Found something REALLY strange...

On the WinPEP Dynojet graph, the HP is dropping at the same rate as HP. Hell, it didn't even match up at 5252rpm!

When I made my own graph, my HP curve barely dropped (it actually went up). My Max HP was 368hp @ 5700hp, not 340hp @ 4400rpm as indicated by the WinPEP graph. Is the dynojet software measuring HP differently? Or is this a bug/configuration problem on the part of WinPEP? I'm looking at everbody's dyno charts and they all intersect at 5252rpm, the ones I got are off by 60.

Here's what my calculated HP/TQ graph looks like :

Edit : Problem solved. See post below.

 

Thanks for the informative post, and the video.

What type of blow off valve are you running?
Ahmet

 

Rage2, it could be that the chart you got on your dyno run had difference scaling on the TQ & HP curves. On might be from 0-400HP and the other 0-500TQ.

What's with the wavy torque curve? You might be getting some ignition-retard from knocking.

 

[quote]Originally posted by Danno:
<strong>Rage2, it could be that the chart you got on your dyno run had difference scaling on the TQ & HP curves. On might be from 0-400HP and the other 0-500TQ.

What's with the wavy torque curve? You might be getting some ignition-retard from knocking.</strong><hr></blockquote>

Problem found! Their graphing software was outdated, and the scales were completely off on both TQ and HP =). I got the proper raw data from them and made my own graphs.

The rockyness isn't ignition retard, I watched for that from passenger seat and there was no retard at all. It doesn't look as rocky on my graph, so I think their software was just crappy. Here are the 3 charts of the 3 runs. Hope I'll be able to make a full boost run on a loaded dyno soon.

 

[quote]Originally posted by over1g:
<strong>Thanks for the informative post, and the video.

What type of blow off valve are you running?
Ahmet</strong><hr></blockquote>

Using a MAS Dump Valve from Demon Tweaks. Cheap, $70US shipped, adjustable from 0.8bar to 2.2bar. Mine's now set to 1.6bar.

 

Nice job! Looks like you would make a lot more power if that AVC-R would just work correctly. Try going with a maunal boost controller (like SFR's) to get a handle on the boost situation (if only for comparison's sake). Truthfully, I have heard more crap about that AVC-R than any other boost controller. Good luck and let us know how the car does on pump gas also if you get the chance.

 

[quote]Originally posted by aka 951:
<strong>Nice job! Looks like you would make a lot more power if that AVC-R would just work correctly. Try going with a maunal boost controller (like SFR's) to get a handle on the boost situation (if only for comparison's sake). Truthfully, I have heard more crap about that AVC-R than any other boost controller. Good luck and let us know how the car does on pump gas also if you get the chance.</strong><hr></blockquote>

Actually it's not a boost controller problem, it's the dyno problem, not enough load to generate high boost. The AVC-R works great once you understand how it works and how to program it properly.

 

I have a manual boost controller on my car, and had similar problems when I put my car on the dyno. Not enough of a load, and even though my controller was set to 16psi, I was only boosting to 14psi. It wasn't really a problem though, I just adjusted the controller slightly during the first dyno pull, to bring the boost up to where I wanted it. After that initial adjustment, it was hitting the boost I wanted, and sitting there right up to redline.