Jesse Prather":du3i9ezm said:
Any chance it's not the engine but a transmission/transaxle issue? Binding up, bearings, etc.?
I've wondered about that as well, but it's even the same transmission I ran in ITB. (Can't afford to take the alt trans weight penalty and put even more on this thing!) I also have no other reason to think there's something wrong with it. It makes no weird noises, the oil looks fine coming out of it, and we've even ran it at Mid-Ohio test sessions a couple times without problem (except being ITC slow). But no, I haven't actually cracked the trans open or anything.
Greg Gauper":du3i9ezm said:
Any chance there is a problem with the dyno itself?
Maybe do a pull with a different car with previously known good dyno numbers as a baseline?
In line with Jesse's suggestion, check if the front rotors are cold to confirm if you don't have a brake hanging up.
I did even better than that, a completely different dyno! Ran it on a DynaPak a week ago, and then on a DynoJet this past Monday, with the same bad result (within 3whp of eachother).
As for the idea of a brake dragging, I've wondered about that too, but like I said above, we've even ran this thing through 20 minute sessions at Mid-Ohio like this and there's been no evidence of a brake hanging up. Rotors weren't glazed over or excessively hot, and there was no odd pulling or vibration under acceleration or braking.
Kendall Jones":du3i9ezm said:
I'd look at the egt / AF of each exhaust runner through a pull. See if something is happening under load. Hot EGT doesnt always mean lean, could be burning fuel in the exhaust (need to look at AFR as well).
Does the ECU log anything? Look at the tps / ign advance / IAT / vacuum during a pull to see if you're jumping around on the VE table.
Could it be something down the line (sticking caliber, axle bind)? Engine might be making the power but getting lost somewhere else.
Unfortunately, I do not have the ability to monitor EGT's or individual cylinder A/F ratios. Wish I did. With the Hondata S300 system, you basically have 3D mapping of your fuel right there on your laptop while on the dyno, which it and a wide range of other parameters can indeed all be data logged. So far, we haven't been able to identify any issues with any of it. That doesn't mean that there isn't anything to be found, it just means we haven't found anything yet. We've been able to adjust the fuel map from the readings we've been getting from the single wide-band O2 sensor, but honestly, it's readings and the mapping we're having to do to make things look happy really aren't anything wacky. Like, as if it was getting a weak spark or something from the ignition system, and therefore a weak burn with a real rich A/F ratio, causing us to pull a bunch of fuel out of it......no, just not seeing anything like that. Again, I wish I did!
I do really appreciate the thought on it. Nice to hear some other opinions, eventhough it's hijacked the hell out of this thread! :lol:
