Dyno problem

Southwest Montana SCCA discussions for the 2004 season.
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fastneons
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Dyno problem

Postby fastneons » Tue Nov 09, 2004 12:06 pm

I think this is what you were talking about on Saturday Joe. :shock:

http://dinamael.com/vw/movies/r32_dyno_launch.mpg
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Postby JoeE » Tue Nov 09, 2004 3:44 pm

That would be it. :shock:
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Postby RayAR » Tue Nov 09, 2004 10:22 pm

Nice horsepower numbers on the SRT4. Is that Stock or Nick massaged? How much boost?

Hey Joe. Any info on that MR2 in your neighborhood. Even if you have a location so I can look at it. If I don't hear back from you soon I will probably pick up the Cheap Camaro and start building my CP classed ground pounder. I just hate to build another BIG car.
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Postby DaveMk1 » Tue Nov 09, 2004 10:49 pm

Hey Ray,

You might want to give Marty Westland a call and see if he has anything you might want. There are lots of RX 7's and other cool stuff over at Westland Ranch and I think marty might want to move a few.....just my guess.


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Postby RayAR » Tue Nov 09, 2004 11:54 pm

Dave, I like RX7's just not a big fan of the rotary engine especially if it has a lot of miles on it. Just not sure what I want to build.
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Postby JoeE » Wed Nov 10, 2004 8:50 am

RayAR wrote:Hey Joe. Any info on that MR2 in your neighborhood. Even if you have a location so I can look at it.


I rode my bike by this weekend and I didn't see it. It was in a new development off of 25th ave south of the elementry school, in the southeast corner. I'll try to remember to swing by tonight.
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Postby DaveMk1 » Wed Nov 10, 2004 9:48 am

Hi Ray,

I wasn't really suggesting that you get an RX7 but that he has lots of cool stuff there that might be owrth checking out.

Later,

Dave
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Postby fastneons » Wed Nov 10, 2004 5:35 pm

Nice horsepower numbers on the SRT4. Is that Stock or Nick massaged?


Kind of both. It made more hp stock (blue, 12-15psi), but with my free-dollar wastegate mod (red, 15-18psi), it made more torque. So, it's kind of both. btw, Joe, I found out why it holds such a flat torque curve. I'll have to explain it some time.

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Postby RayAR » Wed Nov 10, 2004 7:28 pm

Interesting dyno graph. I wonder if the stock turbo is maxed out and just blowing hot air over 15 PSI. I noticed that it is a little spikey but not as bad as my 344 AWHP dyno run. Pretty sure I was running into spark blowout problems on my run and I was also running lean at just under 12:1 A/F. I felt it was pretty good numbers for just driving it off the street with zero tuning. I would love to try 18PSI on the dyno sometime. I have tried it on the street and the car feels much stronger at 18PSI then 15PSI. :twisted:

BTW, the SRT4 put more power to the wheels stock then the Stealth/VR4. Most stock Stealth TT's/VR4's are getting 220 AWHP. Dosen't help that they have probably the most ineffeciant transaxle, transfer case known to man :x approximatly 27% drivetrain loss.
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Postby fastneons » Wed Nov 10, 2004 10:08 pm

I wonder if the stock turbo is maxed out and just blowing hot air over 15 PSI


Actually, the pressure releif valve has a hard time staying closed. Time to get a stronger spring. And the boost control solenoid is trying to fight back also. I have something in the works to fix that though.
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Postby JoeE » Thu Nov 11, 2004 8:50 am

btw, Joe, I found out why it holds such a flat torque curve. I'll have to explain it some time.

I look forward to that.

Ray, I drove by where that MR2 was and I didn't see it. :(
It was at the end of Snapdragon, east of 25th ave.
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Postby RayAR » Thu Nov 11, 2004 8:53 pm

Thanks Joe, Anyway it looks like I am going to put autocrossing on the backburner next year. That is unless I can sell the Stealth. The money just isen't in the Budget right now with trying to refinance my house and my upcomeing wedding.

Just a temporary racing setback. I might break the Stealth out of retirement if it dosen't sell next spring, just for the Ice garden events or if we happen to find a large curbless lot to run on(Roskie). Even if I do run the Stealth you won't be seeing my 6000 RPM launches anymore. I finally found the clutch disengagement problem that I have been struggling with for the past 2 1/2 years and ended up installing a factory Mitsubishi clutch. It was a bad aftermarket pressure plate that caused my problems. You should have seen the clutch disk, I am amazed it hooked up at all. At least I got more then a year out of this disk. :roll:
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Postby rkaiser » Fri Nov 12, 2004 7:31 pm

Is the SRT-4 running a tad rich? Looks like you start to loose some torque at the point where your A/F goes rich at 50-55 mph. Also your power comes down a bit at that same point.

Impressive dyno numbers though!
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Postby fastneons » Fri Nov 12, 2004 9:46 pm

Is the SRT-4 running a tad rich?


That's what I originally thought too, but then Joe explained to me that for a turbo car that is about right. He said that tuners usually shoot for 11:1. It could be to compensate for the extra heat of a forced induction car. Maybe Joe can enlighten us.

Also, I would disregard the red run, because that is the computer trying to compensate for the extra boost caused by the free-dollar mod. The srt-4 factory computer shoots for a maximum torque(say 250, that is also the short answer for the flat torque curve), instead of maximum boost (say 15psi), and when you surpass the torque it wants to shoot for, it tends to go haywire. It pulls timing, dumps extra fuel, and tends to just go into super-protect mode. It also goes into a modified protect mode near the redline, that is why it tends to go rich (blue run) at the end of the run. The stage 1, 2, and 3r kits fix that though.
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Postby rkaiser » Fri Nov 12, 2004 10:01 pm

I don't think over all it's over fueling, it just seems like it reaches 10:1 A/F ratio really quickly. Looks like it's just running rich very early. Here is a dyno plot of the Cossie - look at the red A/F ratio. It was fairly properly tuned at this point (ignore the blue lines)

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Postby fastneons » Fri Nov 12, 2004 10:10 pm

Here is a dyno plot of the Cossie - look at the red A/F ratio.


That's the difference between a stock ecu on the neon (conservative), and an aftermarket stand alone on the Cossie (fairly aggressive).
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Postby JoeE » Sat Nov 13, 2004 11:06 am

fastneons wrote:Joe explained to me that for a turbo car that is about right. He said that tuners usually shoot for 11:1. It could be to compensate for the extra heat of a forced induction car. Maybe Joe can enlighten us.

I showed our forced induction expert in Vegas your graph. He said it is a bit rich. Pulling some fuel would smooth the curve and increase the torque some. He told me some #'s, but I don't remember exactly what he said, it was something like 6% less fuel.
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Postby RayAR » Sat Nov 13, 2004 12:22 pm

I had to dig out my dyno chart. I was right at 12:1 AF ratio on both pulls. Very lean, I am amazed it got the horsepower it did. Very flat torque curve but unfortunatly the chart was printed in seconds instead of MPH. From 5 seconds in the run until 14 seconds it was over 325 lb/ft of torque. I am thinking that it is from about 3500RPM to 6000RPM, From 10-18 seconds it was over 300 AWHP, probably around 4500RPM to redline. Torque stayed right around 350 lb/ft from 8 to 12 seconds peaking at 360lb/ft. I would say 4000 RPM to the point the the horsepower and torque curves cross I believe that is 5250RPM then the torque starts to drop off with only 250 lb/ft at redline. horsepower stayed level from 5250 rpm till redline in the 340 horsepower range peaking at 344 AWHP.

Very jagged dyno chart from 6 seconds in the run till the end, Probably 4000 RPM on up. The best way to describe it is take a look at the Spanish peaks :shock: . Considering how lean I was I wonder how much knock it had. If I had a scanner I would post it.
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Postby JoeE » Sat Nov 13, 2004 6:40 pm

Wow, I printed Nicks with MPH instead of RPM. And I did Ray's in Time? You would think I would be a little better with the software, wouldn't you? :roll:
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