I know this is long, but I want to be fair to the shop and give the FULL story.

I went to a shop (XeSSesive Motorsports in Edinburg, Texas) who primarily serves Chevy's as a part of a "dyno day". This is where a group of people get together to dyno their cars at a group discount. The XeSSive Motorsports shop has a Mustang Dyno that they had recently purchased and installed a few weeks before.

Everyone was there to do 2 pulls and get RWHP numbers. MY goal was to get numbers and to data-log using my SCT device and laptop. Runnin' With The Devil (the shop who I get my tunes from) has a "configuration" that records the parameters they want to see during a wide-open-throttle run so that is what I used. I figured, I'd send them the dyno graph as well as the data-log file.

This is how the day went...

1st dyno pull
I signed a "waiver" that basically said "if your junk breaks, it's on you.". After putting some reflective tape of some sort on the crank (I think?) to get an RPM reading, my car was strapped in for the first run. When they started the car, they noticed that the RPM reading wasn't correct so they tried a few things on the dyno machine and eventually decided to plug into my obd port. This was disappointing because the whole reason for me dyno'ing that day was to data-log my run. As they started the first pull, my car almost hopped off the dyno. I had to inform the operator myself.

Video: Car Almost Hops Off Rollers

They re-strapped it and the dyno operator had some trouble in-between gears. I noticed that he wasn't sure where they were but he got into 4th okay. I have a Hurst short-throw with a pool-ball sized shift knob with the typical "H" shift pattern. Anyway, other than taking a bit longer to get thru the gears and to the desired RPM range, everything was normal. I'm used to dyno operators going thru gears pretty quickly and in 4th they'll get it up to the desired RPM and then stomp it until the desired shift point.

This is info for the 1st pull:
Video of 1st Pull | 1st Pull Dyno Graph | 1st Pull Air/Fuel table

As you can see, the air/fuel was a on the lean side.

I ran to the store to buy a bag of ice. The car was sitting maybe 10 minutes before I got back. I let the car sit an additional 10-15 with the ice-bag on top of the blower. There was a huge shop fan (3ft tall?) in front of the car the entire time.

The dyno operator asked if I wanted to try and get the RPM reading off the coil pack wire so that I could data log. I agreed. He started the car and let it run for about 15-20 seconds to see if he could get an RPM reading, No luck. He ended up going with the obd plug again. He started the car again to ensure that the RPM reading was correct for about 10-15 seconds and turned it off. He turned on the car and seemed to have the same trouble. Well, he finally got it into what he THOUGHT was 4th gear and proceeded to pull, realized he was in the wrong gear and lifted.

Here's the info for the 6th gear pull:
Video | Dyno Graph | Air/Fuel Table

The operator seemed a bit confused, and someone mentioned that they thought he was in the wrong gear. I wasn't sure what happened. I thought maybe the dyno was acting up again? He had started/stopped a number of times throughout the time I was on the rollers. He let the car stop and proceeded to pull again, this time in 4th. The only difference was that my numbers were 40hp lower and there was a HUGE puff of smoke that came out of the tailpipes. (See below)

Video: 2nd dyno pull (I didn't bother scanning in the air/fuel table or graph)

That was that. I drove off, parked car and watched the next guy dyno. Turns out he almost pulled that guy's car in 6th as well. After seeing this car and a few others, I paid and left.

Video: Darrell's "Almost" 6th Gear Pull

I turned on A/C and radio shortly after starting the car and drove home. As I parked, I could hear a ticking noise (always turn off the radio and A/C before I turn car off). I didn't think too much of it and decided that I'd let my brother-in-law (who is a good mechanic) hear it later that day since we had a club meeting a couple hours later.

He confirmed that indeed it was probably something major and not an "exhaust leak" or an injector. This all occurred on a Saturday so the shop was closed. I had a fellow cobra owner (owns 3, each around the 600hp mark!) who knows the cars listen to it and he said that it sounded like a tap from a fried piston. I posted to SVT Performance and numerous guys there described the noise exactly how it sounded even though I hadn't posted how it sounded. You can hear it under the hood and in the car, but you can hear it louder UNDER the car on the driver's side. There were both people that have had a "bad dyno" or did high-speed runs in high gear.

I called the shop and emailed the dyno operator.

My Email to the dyno operator:
I've got a problem and I'm not quite sure how to handle it. Saturday, after the dyno, on the way home, I noticed a "ticking" noise. When I parked the car, I got off and the noise was very noticeable from the outside.

Anyway, to make a long story short, I've got a piston/head problem. Everything I've read and seen points to the "6th gear" pull that the car went thru.

I've run the car and dyno'ed it before but I've never been in boost in 6th gear much less FULL boost. Anyway, I'm just trying to see what my options are for my car since it now it has a major issue and is due to what I believe a high boost pass in 6th gear. I didn't go back to the shop because I wanted someone reputable to look at it and MAKE SURE it wasn't due to something else. After I had a mechanic look at it, I *do* have a major head/piston issue.

I wanted to at least inform you and Edgar of what happened and wanted to see if there is something we can do about it. I'm not looking for a new car or trying to get some free money. I'm an honest guy and don't believe in rip-off's or something for nothing.

I guess what I'm trying to see is if the shop/Edgar would be willing to discuss what happened so we could go from there. Like I said, I'm not looking for the shop to finance me a new motor or some ridiculous thing like that, but I'd like to at least chat about what happened to see what options I have.

His response to me:
Hey Nino sorry to hear about your car.. But the thing is that sixth gear pull you keep putting the blame on, honestly i think didnt do it.. i went back the the dyno database to see how high it was reved and how long the pull was.. it was reved to 3789rpms and lasted only 3.71 seconds.. also if i recall correctly after that we stopped and asked you if we restart and you said ok.. so all of this talking about no cool down time in the STMC board is all non sense and giving us a bad name.. how ever i can help you with your car.. i have messed around with ford motors before.. Let me know

 

I decided to call the owner of the shop and see what he'd do about the situation. After phoning the owner of XeSSive Motorsports, Edgar, I was told pretty much the same thing the dyno operator told me. My air/fuel was running lean and that the 6th gear pull wasn't long and he believed that it was a matter of time before the piston failed. Edgar said that he could get me the parts at his cost and that would be the only way he'd be able to help. He was clear that that's pretty much he was willing to do for me. He was nice and very cordial and the conversation never got heated.

What bothered me was that neither the owner OR the dyno operator bothered to even consider that the mistake(s) made that day may have had a hand in my piston failure much less them directly causing it.

What it boils down to is this: What caused the issue?

I believe that since my air/fuel was leaning out in 4th gear, that the 6th gear pull (much more load than 4th gear) caused the piston to fry - Had I shown up, dynoed, let he car cool, dynoed again - I wouldn't have a fried piston.

The shop says it was a combination of my air/fuel and it was "just a matter of time". They didn't feel the 6th gear pull had any more affect on the car than the 4 gear pulls.

I posted it to two of the biggest Mustang/Ford websites and all fingers point to the same place.
HERE is the "ModularFords.Com" discussion.
HERE is the "SVTPerformance.Com" discussion.

I'll never go back to XeSSive motorsports in Edinburg, Texas ever again. In addition, I'll make sure everyone I know with a performance vehicle knows what took place that day.

Here's a thread where Edgar, the owner is taking a shot at me becuase someone was kind of ribbing at him about what happened to me:

Click pic to get large version

[-BACK-]