Doubtful on 91oct, unless you have a full exhaust.

 

Yes, he crushed it, but that didn't change the weird boost fluctuations.

The MBC has been taken apart several times and was also oiled. Doing this only helps with the boost spike issue that happened to a few people, but Josh has a completely different problem that I've never heard of nor seen before. His boost goes up, then drops, then slowly climbs back up again. From what Chris described, his did the same thing on the dyno, which is why he hit peak boost at 4750 instead of 3250. We plan on doing boost leak tests, but we also are going to switch my old Hallman Pro on there to see if the same characteristics exist. If so, then we'll re-install the UNOS and do a pressure test. If nothing comes of that, we'll check the install of the hoses and such.

 

I actually agree with Wurlytalon on something!

 

Here's my bone stock baseline on the same dyno for reference, also a IX:





FYI, I think cij911 hit a peak torque of 294 ft-lbs on another run, but didn't hit as high of a whp on that run as the 300.7whp run.

He gained almost 50whp/50wtq from upping the boost and the flash alone

Now post up the graphs cij!!!! I know you're technically and otherwise challenged, but come on!

 

OK, here are the pics that cij911 sent me to post up. Two boost/afr plots and the dyno run with the best whp.

FYI, the boost was source by tee'ing off of the intake manifold->bov line which fed the map sensor for the mustang dyno. AFR was read by tailpipe sniffer. They actually offered to put sensor in the stock cat bung but would have to charge for the time to hook that all up. They said in their experience on that dyno, the tailpipe wideband usually reads .2-.3 higher (leaner) than in the cat-back pipe.

 

The car feels great, but the graphs tell you it could be a little better....Still we have made huge improvements....Look forward to your revisions / advice....(Please see the original post, it now has the graphs.) Thanks Al

 

the graph shows exactly how the boost is behaving. This is what Josh has been saying. It ramps up without spiking, lowers slightly, then rises back up before doing the natural taper. I'm certain that if the boost spiked normally that the WTQ would be over 300 without question, and that dip wouldn't be there right at 3500. It's amazing how early the turbo spools with the MIVEC head.

Just to be sure, this was in 3rd gear, right?

 

4th!!! I tried to have the tech do 3rd on my car but he kept saying 4th was closer to 1:1 and it's safe blah blah so whatever we let him. Then for consistency of reference, we did Chris' runs in 4th too ... hitting 106MPH on the dyno!

 

Oh, crap...that's not right. 4th heatsoaks the FMIC and causes higher underhood temps. Hmm, well that throws everything off. The runs should all be done in 3rd gear. That is the standard by which we all do our dynos. Bah.

 

Ha. I seriously argued with the tech for 2 minutes over the 3rd/4th decision. He said they always try to do closest to 1:1 whereas I had heard buschur doing 3rd in the Evo. Ultimately I let him win since he was operating the device ...

I think the boost behavior that it shows remains valid though?

 

Yeah! Loud noises! LOUD NOISES!!!!

 

War --

Why the boost issue? What about the AFR? Do you think Al can make some tweaks to correct? I would love to get the numbers a bit better....Thanks a ton

 

I don't know what's up with the boost. I thought only Josh was experiencing that. We need to pinpoint the cause and ERADIC8 it. We need to troubleshoot by switching to the Hallman first, then checking all the boost lines/installation second.

As for the AFR, I'm not sure. It could have been a problem with 4th gear and the coolant temperatures. Al will need to comment on that.

 

Thats a little extreme warr, in most cases its not going to throw off more than a handful of horsepower. Just because the pull lasts for a few extra seconds doesn't mean you will start sucking in hotter air, unless the dyno facility isn't well ventilated.

A lot of tuners prefer 4th gear pulls because tunes can be thrown off between a dyno and the road, they find the best results with the gear ratio closest to 1:1

In most cases (that i've personally seen) a 3rd gear pull will read slightly higher

 

Call it extreme if you want, but when we have tested 4th gear pulls, it throws off the timing, AFRs, and the power significantly, especially after doing several of them. The pull is MUCH longer. Plus, since none of the rest of us do 4th gear pulls, then we can't do direct comparisons.

The difference between my 3rd and 4th gear pulls were 10whp/10wtq, and the curves on the 4th gear pulls were erratic and choppy.