Got the car on a dyno after my cam install, and the numbers are pretty low. 250hp/260ft lbs. I should be at least 275hp, and over 290tq from what I've seen.
He showed me that there was a difference in fuel trim between bank 1 and bank 2 of 17%, so it would be pointless to try to get power out of it until it's fixed. It's not throwing any codes though, which is good... but makes finding the problem a little harder.
He got the idle and the driveability locked in, though. Full throttle AFR's are 12.1, it starts right up and idles at 800, runs really smooth and feels like it pulls harder than it did before I put the cams in, but the numbers on the dyno are definitely off. When I'm driving, I don't feel a miss or knocking or any breaking up. It's not blatantly obvious to me that there's an issue.
He thinks it's a spark problem and told me to put new plugs in and front O2 sensors because maybe I fouled them up by running the car untuned for a few days. But I don't know if that would make a 30hp difference. What else could cause a bank-to-bank difference in fuel trim like that? An exhaust leak on one side before the front O2 sensor maybe? I just want to cover all the bases before I go back and try again next week.
All types of dynamometers have different characteristics, the important part is to always use the same type (same dyno when tuning) if you want to come close to comparing apples and apples. They are just convenient tools for measuring engine output while doing initial rounds of tuning.
Very few are calibrated to any standard, and none to any real world standard (which would I suppose be putting some sort of "standard" output vehicle on the rollers).
Optimal engine tuning does not even require a dynamometer, just some mechanism for evaluating relative performance. This can be a dynamometer, one of the accelerometer based tools like those from G-Tech (I still use a very old G-Tech Pro), a stop watch and lines on a back road, or even a well-tuned butt-dyno.
I (and many racers that retune between runs and now dynamically during races) would argue that those in which the vehicle is actually in motion on an actual roadway are the best...
Brent is the man. Sorry to hear you had a bad day today. But at least you figured it out. Im gonna go see him tomorrow. I believe he can give you corrected numbers if you really wanted them seeing that his dyno dynamics reads lower than most dynos.
I'll get some pictures, they're pretty trashed. The gap on them was .060, they're all brown like the color of rust, and the electrodes are gone. Just over 71,000 miles on the engine and I'm pretty sure these are the plugs that came from the factory in 2001.
I can believe it. I had a plug closed and a cop messed up and got a base dyno of 275. Fixed those and got 312 the next weekend. Never came up with any codes
I can believe it. I had a plug closed and a cop messed up and got a base dyno of 275. Fixed those and got 312 the next weekend. Never came up with any codes
Electrodes are gone? If a cam was 180* out could it hit the plugs?? Hopefully that's not the case.
Op when you going back for a dyno?
I still think the o2 for wot was either him not knowing or you mis understood him. Pretty basic knowing o2's go in open loop and are basically useless at wot.
Electrodes are gone? You mean the ground straps? I've put one of my cams in 180 out (on purpose because I thought it was 180 out to begin with) and I never had any problems with the plugs with a flat top piston and a PI head.
Mine still ran with the cam 180 out. Hell mine ran with the passenger side injectors not even firing lol (which is what was happening when I changed the cam to 180 out trying to diagnose it) Didn't hit any valves or plugs or anything, and I have pretty big cams in mine.
If those were gone then yea definitely could be a big issue. I hope that's all it was man!
IMO tuner should have pulled the plugs. I know it's not his job, but idk IMO like my tuner he wants to cover all the basics rather then sending you home thinking worse case scenario.
He would have charged me more than I would have been willing to pay. It was safe to drive on, just down on power. He really was right though, he called it 100%. When I say that it's night and day difference after plugs, I wish you could have felt what I felt. The car's never pushed me back in the seat before, and it does now until redline. Second gear rolling burnouts from the throttle. Can't wait to get back on the rollers. I think you guys will be surprised.
Nothing of significance, I ordered a set of OEM COPs last week but they haven't come in yet.
The car drives fine so I'm holding off going to the dyno for a bit until I'm sure that I'll have no issues. I still plan on changing the front O2 sensors and making sure the exhaust is tight when the weather gets a little nicer.
The only problem I have is that it stalls out on a cold start if I don't give it a little gas for a few seconds.
i remember last May i was disappointed as hell, i was at an open house at RDP and they were doing free dyno runs.. they had the new camaros putting down mid 300's, s197 kenne belle at 430's. subaru i was surprised 190's. so i went on and felt embarassed when i put down 263 hp.... but with just bolt ons you really cant expec much.. so eventually i will get a s/c... but until then i will enjoy cruising. although i was surprised that a tiburon suped up was 230's
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