I'm going in, cover me... (Built 1.8L GT2871)
06-17-2010, 10:52 PM
#42
2 Props,3 Dildos,& 1 Cat
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I have tripod mounted video of several pulls, except my MiniDV camcorder has firewire output which my current PC does not accept. Working on it...
Load dynos are great. For each pull, the operator (Cory) would run the car up to 3000 RPM in fourth gear, light throttle. He would set the dyno to hold that speed, then go to WOT. Turbo would spool, boost would build, but the dyno held the engine speed dead on 3000 RPM. He then released the RPM hold and the ramp run proceeded. That way, each run starts at full spool at that RPM. Also, we did some cruise load timing adjustments to check for MBT. Set it for 3000 rpm, held the throttle so it stayed at 100 kpa, then bumped up timing while watching for torque increases. When the torque quit increasing we stopped bumping up the timing. Also did that at 4000 rpm. Great stuff, should improve cruise mileage. I would have liked to do more of this but we were at 2.5 hours of dyno time as it was.
Load dynos are great. For each pull, the operator (Cory) would run the car up to 3000 RPM in fourth gear, light throttle. He would set the dyno to hold that speed, then go to WOT. Turbo would spool, boost would build, but the dyno held the engine speed dead on 3000 RPM. He then released the RPM hold and the ramp run proceeded. That way, each run starts at full spool at that RPM. Also, we did some cruise load timing adjustments to check for MBT. Set it for 3000 rpm, held the throttle so it stayed at 100 kpa, then bumped up timing while watching for torque increases. When the torque quit increasing we stopped bumping up the timing. Also did that at 4000 rpm. Great stuff, should improve cruise mileage. I would have liked to do more of this but we were at 2.5 hours of dyno time as it was.
The guys that I tuned with had a DD and didn't know the first thing about getting it to hold a steady RPM. the guy had some little **** he kept ******* with while I tried to franticaly tune.
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06-17-2010, 10:57 PM
#43
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Cory really knew what he was doing with the DD, not to mention he knows how to tune a car. Between him and Tim (BEGI) I was in good hands. I need to get that camcorder video posted. You can really hear how well the dyno holds RPM when he goes WOT on the throttle and the turbo spools.
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06-17-2010, 11:48 PM
#45
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With that turbo, you could probably launch starting at about 3K on your first run. Let the clutch out fairly quickly without dumping it, while putting the throttle down at about the same speed or a bit faster. You will probably hit something on the order of a 2.6 on the first run, and it will feel/be slow. Then dial up the RPM from there in about 400RPM increments, same basic technique. It wont kill it, and you will get a feel for how to ratio the clutch out to throttle in to avoid a bog or zooming right ot redline. It becomes intuitive after a half-dozen runs. Perhaps the runway will be a good place to do some practice?
If you over-stage and have to back up, back all the way out and then go back in so that the driveline is loaded up properly.
It doesnt take a hard punishing launch to get a 2.0, it's just tricky, especially in a Miata. But even on the slow runs take a look at your trap. You will probably be in the 108-110 range, which is enough to hit 12s.
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06-17-2010, 11:54 PM
#46
Thanks. Yes it is, it accelerates very well. I'm happy with the power... for now... 
I am tempted to take it to the drag strip next. I have some Nitto drag radials on another set of rims. It would be fun to do a huge smoking burnout, then break into the 13s. If there was a good Miata drag racer (better than me) behind the wheel ***cough*** DVCN ***cough*** I think 12s would be very possible.
I am tempted to take it to the drag strip next. I have some Nitto drag radials on another set of rims. It would be fun to do a huge smoking burnout, then break into the 13s. If there was a good Miata drag racer (better than me) behind the wheel ***cough*** DVCN ***cough*** I think 12s would be very possible.
Would you hand your keys to someone sitting in stands surrounded by empty 16oz'ers? Last time a friend offered up his IS-F but I couldn't grab the keys with a beer in one hand and a corndog in the other.
Congrats on the kickass setup!
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06-18-2010, 01:47 AM
#48
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ZX-Tex
From another boosted Miata looking to go to the track in San Antonio I'm in curious to see what the larger turbo and 22psi will do at the track. Would be nice to check out ur setup.
From another boosted Miata looking to go to the track in San Antonio I'm in curious to see what the larger turbo and 22psi will do at the track. Would be nice to check out ur setup.
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06-18-2010, 02:33 AM
#50
I used to start at 4500 holding, flat foot it till 6500, and ride the clutch out while easing back off the throttle according to tire spin. Felt like high 1.8 to low 1.9's, but no official times (except a decent amount of track time in the past to compare it with).
I probably made 150+ launches that way with the 4 cylinder with the 5 speed and the weak little 7 inch torsen in this 2500 pound pig without a hiccup. Launching seemed to be fine, but I was 3 to 4 powershifts away from a box of neutrals.
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06-18-2010, 08:29 AM
#53
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The guys at York Automotive have a DD and know how to use it. When you were tuning cruise is seemed like he was hold cells pretty good, but I wasn't paying attention when you start doing boost as like you said, seemed like you were just doing pulls.
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06-18-2010, 10:59 AM
#59
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Good question. AIR CONDITIONING! It is getting too hot down here to DD without it. I had to remove the condenser when I was installing the v-mount system, and the stock one will not fit anymore. So I found some Ebay custom double pass units, just need to buy one, mount it, add a dryer, and get some custom lines made. Everything else is already there.
After that, I had this idea about constant torque boost tuning, that is ramp boost up at higher RPMs to hold the torque line flatter above say 5000 rpm. The Adaptronic has closed-loop boost control as a function of RPM so the capability is there. The idea is hold the torque load constant for the drive train and produce/transmit more horsepower with RPM. I definitely have the overhead to do this with the turbo and the injectors. But I have not played with closed loop boost control in the Adaptronic yet so do not hold your breath. It is just a down-the-road idea right now. Yes I know a custom intake would help flatten the torque out as well.
Thanks for the drag racing encouragement. Don't worry, DVCN is working me on the local end to do a manly run at the drag strip, so it could happen. I know he will not drive it himself, he hates driving other people's cars in fear he will blow something up. He knows what he is doing though, his Chinacharger NA has run some impressive times.
After that, I had this idea about constant torque boost tuning, that is ramp boost up at higher RPMs to hold the torque line flatter above say 5000 rpm. The Adaptronic has closed-loop boost control as a function of RPM so the capability is there. The idea is hold the torque load constant for the drive train and produce/transmit more horsepower with RPM. I definitely have the overhead to do this with the turbo and the injectors. But I have not played with closed loop boost control in the Adaptronic yet so do not hold your breath. It is just a down-the-road idea right now. Yes I know a custom intake would help flatten the torque out as well.
Thanks for the drag racing encouragement. Don't worry, DVCN is working me on the local end to do a manly run at the drag strip, so it could happen. I know he will not drive it himself, he hates driving other people's cars in fear he will blow something up. He knows what he is doing though, his Chinacharger NA has run some impressive times.
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