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| Dyno Tuning |
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So, pretty much I decided to say "fuck it", and go to the dyno to tune the car, despite not having the money for it. Ehhhh...whatever. It'll turn up somewhere. The only dyno I know of in Gainesville is the one at Rollins Automotive (352-335-7223). A word of caution if you're going to do business with them. The place is owned by the Rollins family, and as far as I can tell, there are two sons, a mother and a father. The mother and father are really cool, nice people. Real chilled out and helpful. I don't know about one of the sons, but the other one, who looks kind of like someone beat the retard into him a bit when he was young or something, is a flaming cock. When Chris, my boy with the nitrous SW2, went into the place to get a part for something a while ago, the guy actually started talking shit about, "you know, we don't DO much with imports, especially four cylinders...blahblahblah." First of all, you fucking 'tard, Saturns are NOT imports, despite the opinions of many beer belly growing, BBQ stained wife beater wearing, "Proud Member of the NRA" bumper sticker having fucks who think anything other than a 5000 pound muscle car with a 454 or a 350 is an import. Second of all, if you talk shit to your fucking CUSTOMERS, you'll soon not only be a retarded country fuck, but an unemployed asshole, as well. That being said, Rollins DOES have good products and as long as you don't deal with the piece of shit son, you'll probably be good to go. The guy who worked with me on the dyno was not actually in the family, but really knew what he was talking about and ran the car very well during the dyno runs. My boy, D The Master Plan Big Money Man, came to help out and experience the beauty of a good dyno session.
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As we walked back to the dyno behind the store building, he was just finishing hooking the car up. He had a wide band O2 sensor stuck up into the tailpipe and a couple of connectors latched onto the spark plug wires to get a tach reading.
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Next to the actual dyno was a computer that had digital speed and tach gauges, and a colored bar that ran across the bottom of the screen that displayed the air fuel ratio, both in number form and graphically, on the bar. He did the runs in 4th gear, and flooring it from about 1800 to 6500 RPM. We would do a run, and then he would pull up the graphs for horsepower, torque, and air fuel ratio. We would decide which points to make changes to, I'd go make them, and we'd make another run. All in all, we probably did 10 or 11 runs in the hour I was there.
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Some problems arose during the tuning that you should be aware of when tuning one of these cars on a dyno. The engine got VERY hot at one point. The guy running the car didn't realize that when my coolant temp gauge reads anywhere near half, the car is close to overheating. I also messed up and didn't check it when I went in to change the tuning. So, anyway, after a decently successful run, I made some small changes and he made another run. However, the second one I could tell was fucked up from the start. When he floored it, the A/F went to about 15, and then dropped to 14 or so as the computer tried to lean it out. I wasn't sure what to do, so I didn't say anything except "oh shit." By the time it got to about 4500 RPM, though, the A/F was still at like 14.5 and I shouted for him to shut it down. He did, but not before it detonated. Let me tell you...detonation is, along with the sound of a snowboard being gouged out by underlying rocks, the WORST sound EVER. It sounds like pennies being shaked realllllly fast inside a paint can. You just KNOW it's fucking shit up bad. So anyway, he shut it down immediately, and I started wigging out. The head was making a ticking sound and the car was idling at like 850 RPM, as opposed to it's normal 1070 or so. So I go in and check the temp gauge and it's almost at the half mark. I turn on the A/C to get the fans going, and it helps some. The idle comes back up and the ticking goes away. It was probably due to the oil thinning out too much from the heat and not being able to lube up the lifters well enough, making them tick. The detonation was probably also due to the heat, as a super hot engine is much more prone to detonation than one at normal operating temperature. Nothing seemed to be broken, though, so we went on. In the end, we came up with this profile for the AFC. The largest change was at the 5500 RPM point, where I cut fuel almost a quarter. When we started, the A/F ratio at that point was so low, it was off the scale. The scale only goes down to 10:1, and this was less than that. When we were done, it was around 12.5, so that's better. One should note that the tuning job I did was pretty bad. The A/F ratio throughout the RPM range isn't very flat, nor it is generally close to 12.8 or 12.9, where I was shooting for. However, it's a lot better than before. All in all, we picked up about 8 HP in the lower RPMs, and about 10-12 in the higher RPMs. The biggest change of all was the 18 foot-pounds of torque gained at 2900 RPM. Hahahaha...awesome. You can check out the graph for horsepower plotted against torque, as well as the one for horsepower plotted against A/F ratio. The blue lines were the results of the last run we did. Awesome.
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