continued from above
We were not happy with the day's results, at all. You can hear that at the end of my Run 3 video. But when you add up the comic amount of things going wrong - steering shudder, the full stiff rear shock, the massively overheated tires, and loud suspension noise up front - I guess we couldn't expect more than we got. We did see another data point in an ongoing trend at this SCCA event - AST shocks were on all 5 of the top 5 in PAX results, and 11 of the top 15, and these were all Vorshlag/AST testers.
So we have a lot of new parts here this week to install and test, and another 2-day Divisional autocross this coming weekend. We've got to see some serious improvement in the car, and soon, or it will be a blood bath at Nationals and we might have to wait until we get the car further developed before we take it to Lincoln. But I'm not giving up just yet - just look at what's going on the car this week:
- ARH full length 1-7/8" primary headers and X-pipe with cats, good for 30 whp everywhere. Those are going on today (giant pain in the ass install). See picture, below right
- New PCM tune for the added power and exhaust flow from the headers
- Moton Clubsport double adjustable monotube shocks with remote reservoirs and custom valving, plus custom upper rear mounts (to mount these "eye to eye" shocks in the stock location). This is why we had the custom valved ASTs off - to verify valving ranges for the new Motons to match
- D-Force 18x10" wheels with 265/40/18 Yokohama AD08 tires (for street testing and some test-n-tune autocross runs, as these are not STX legal) - see picture, below left
We've also taken the car as close to "stock" as possible this week, so we could swing by the Ford dealer to have them try to install that so called "fix" for the electronic steering (TSB 10-16-4). So we put the stock airbox back on, the stock tune, pulled ALL of the decals off, slapped on the stock wheels, and took it to the local Ford dealer. They couldn't get the EPAS program to stick on our 2011 GT, and then we found out this TSB's software update only works on the 2011 Mustang GT500's EPAS module. They also "couldn't duplicate the steering shudder issue", and left the car with all sorts of
AdvanceTrac fault codes lit up (that they cleared, after I pointed them out).
De-stickered and back to "stock", at least for a day
Frustrated, I brought the car back and did some more digging. It appears the "new" EPAS programming issued in TSB 10-16-4 will never fix this issue on our GT at all - from what
this article says, this TSB is simply turning the "Active nibble" programming ON for short build run of 2011 GT500 Mustangs that inadvertently had it turned OFF at the factory (see more
here). I'd rather have this active electronic nonsense in the power steering turned off completely, but that's a fight for another day.
Steering Shudder Test #2 - click for video
In the mean time I did some more road testing and now can make it go into "shudder mode" at will, and made another video showing this on the way back from the dealership (their techs were all at lunch when I picked up the car). I sent them
this video (above left) and hopefully they can get to the bottom of this. Again, this is the only problem we've seen on the Mustang, nobody else with a 2011 GT has had it do it
this badly, and we may have done this inadvertently, ourselves, while performing other work on the car. This seems to be a problem unique to this car, at least to this degree.
Header install is easier with the entire K-member out of the way
Since we had the stock airbox and tune on for the day, we did WOT and 45mph drive by Sound Tests with that set-up, then 2 more with the Steeda cold air and custom SCT tune back on. We'll do another 2 tests with the new headers on, later this week or next, then I'll post up all of those Sound Test videos/results. I'll throw another update up soon, maybe after we have the headers and tune on and have more dyno numbers to report, or after this weekend's Divisional - depends on how busy we get. The long tube header install is well underway, with the K-member completely out of the car to gain access to the stock headers. Supposed to be a "5 hour job", but we'll see.
Thanks,