Low bolt-on dyno #'s
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From: Dallas/CS/Nacogdoches
Low bolt-on dyno #'s Well took my 2000 SS to the dyno today and was not too thirlled with the results. A couple of weird things happened on the 3 pulls. By that I mean each run gained me progressively more and more HP and TQ. I guess its because on the 1st run the car's temp read at 155 degress so it was at closed loop. But by the 3rd and best run the temp was at 185.
Two important factors I think for why the car dynoes so low was the air temp on the dyno sheet said it was 95.5 degrees outside and also the A/F was consistantly right around 14:1 Look below
run 1: 308RWHP 315 RWTQ A/F at 14.2:1
run 2: 319.5 RWHP and 323.85 TQ A/F 14.2:1
run 3: 323 RWHP and 329 TQ A/F 14.0:1
Why do you think its this low? I've seen 2000''s dyno at least like 335 with LT's and ORY. MY mods are in my sig and I will add that it was mail order tuned for the LT's and ported TB by wait4me
Alright fellas tell me where to go from here
Two important factors I think for why the car dynoes so low was the air temp on the dyno sheet said it was 95.5 degrees outside and also the A/F was consistantly right around 14:1 Look below
run 1: 308RWHP 315 RWTQ A/F at 14.2:1
run 2: 319.5 RWHP and 323.85 TQ A/F 14.2:1
run 3: 323 RWHP and 329 TQ A/F 14.0:1
Why do you think its this low? I've seen 2000''s dyno at least like 335 with LT's and ORY. MY mods are in my sig and I will add that it was mail order tuned for the LT's and ported TB by wait4me
Alright fellas tell me where to go from here
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From: Dallas/CS/Nacogdoches
No I don't have an ls6. Just can't afford to get one right now.
With the a/f on target how much can I expect to pick up. Also the temp on the dyno sheet said 95.5 degrees. I'm propably going re dyno back in like November/December wehn its cooler here in Texas. What can I expect to gain from lower temps as well?
With the a/f on target how much can I expect to pick up. Also the temp on the dyno sheet said 95.5 degrees. I'm propably going re dyno back in like November/December wehn its cooler here in Texas. What can I expect to gain from lower temps as well?
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those numbers arent bad at all. I would take them with the mods that you have. However..that AFR aint gonna cut it. You may lose some power due to richening up, but it(although, if you were getting any knock due to detonation, you would have actually lost some, tho we can tell cause you dont have any scans). Take those numbers, richen it up some and go.
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Open/closed loop operation wasn't a factor in this equation. When you go WOT, the car goes into an open loop state since the PCM isn't taking any feedback the narrow band O2 sensors are giving it.
Have you touched the MAF sensor at all? You are running really lean WOT, which usually isn't how it works when you have headers. With headers, you run lean cruising around town, which means your trims are positive, which means your PCM starts dumping fuel damn near indiscriminately into the engine at WOT to keep everything running safe. If anything, it should be running rich, unless you have done some stuff to the MAF sensor (which will make your tune really whacky). Hell, when is the last time you cleaned it? Do you have any exhaust leaks, or vacuum leaks?
Something isn't adding up here...when I did some WOT runs after just getting my wideband O2 installed (LC1), my AFR was dipping all the way down to 11.2 in spots.
Have you touched the MAF sensor at all? You are running really lean WOT, which usually isn't how it works when you have headers. With headers, you run lean cruising around town, which means your trims are positive, which means your PCM starts dumping fuel damn near indiscriminately into the engine at WOT to keep everything running safe. If anything, it should be running rich, unless you have done some stuff to the MAF sensor (which will make your tune really whacky). Hell, when is the last time you cleaned it? Do you have any exhaust leaks, or vacuum leaks?
Something isn't adding up here...when I did some WOT runs after just getting my wideband O2 installed (LC1), my AFR was dipping all the way down to 11.2 in spots.
If it was just ported, the air was still being metered...it just didn't know what the hell to make of it. The MAF table is just a set of "look up" values that correlates Hz to a set amount of airflow. These airflow values are calibrated on a screened, unported MAF in the stock intake tract. Change that stuff, and these values aren't right anymore, causing the problems.
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From: Dallas/CS/Nacogdoches
Thanks fellas, I'll check for leaks tonight at my buddies house. I'll look at the MAF as well and see if its ported. I've only had this car for a couple months so I haven'te really pulled the MAF to look at it up close. I know its descreened though. A guy at the dyno said I might be losing a little bit because of the fact there was no hose clamp around the throttle body. I'm gonna clamp that first and then check the MAF
All I was hoping for was around like 335RWHP. I think thats possible with a/f correction and cooler weather.
thanks fellas
All I was hoping for was around like 335RWHP. I think thats possible with a/f correction and cooler weather.
thanks fellas
Eh...sadly enough, I've forgotten to tighten the clamp around the TB a couple of times, and the effects were negligible. MAF mods will throw things further out of whack than people think...
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From: Dallas/CS/Nacogdoches
Well u guys were right......I inspected the MAF a little closer a little while ago and it is a ported MAF. I didn't even know it was until I got up close and looked at it.
So alll I need to do is find a stock one or trade.......anyone wanna trade a ported MAF for a stock one? LOL!
What can I expect the a/f to come down to with a stock MAF? power gains as well?
So alll I need to do is find a stock one or trade.......anyone wanna trade a ported MAF for a stock one? LOL!
What can I expect the a/f to come down to with a stock MAF? power gains as well?
I dynoed 306 with a ported MAF and had two very serious power drop offs after 5200rpm. My car hated the ported MAF. My friend had some stock MAF ends so we put them on my MAF. I dynoed 317 after that with just a cutout and lid on a 99. I can't say for sure whether you will get that much back, but I'd say there is a good possibility you could get another 4-5. Like I said, hard to tell because my car responded terribly to it. It wasn't hard for my car to get noticeably better.
I'm honestly not surprised you found a ported MAF in there...there usually has to be something really wrong for these cars to run that lean on a stock tune. Put the stocker back on, and I'd guess you'll be around 330 RWHP or so...A/F should come back down to around 12.5-13.0 depending on how the PCM reacts. Running that lean, you were probably experience some knock retard as well...