Project Update for April 11, 2011: We had a lot going on the past 2 weeks (prep on 4 of our cars and very busy Vorshlag business) but we still managed to make several changes to the Mustang and then autocross it this past Sunday. Let's take a look at the latest round of mods in this post and talk about the autocross in a post to follow.
First up was the Steeda Cold Air kit that finally arrived, along with the SCT Tuner. This combo-package from Steeda was chock Full Of WIN.
The stock 2011 GT's air inlet box is pretty typical - lots of restrictive accordion style tubing, a closed-element air box, a flat paper element air filter, and weird sound muffling chambers in the inlet tube. There was also the separate "sound tube" silliness that piped sound from the inlet track into the passenger compartment. The stock car is so quiet (81 dB wide open, as tested at an SCCA event!) that this helps you hear the choked up engine sound. The Steeda cold air kit consisted of an all new aluminum MAF housing, a new air inlet tube/elbow all the way to the throttle body, a heat shield that tied into the lower air inlet scoop, a larger lower air scoop piece, and the conical/open element high flow air filter. The kit came with instructions and everything we needed to install it.
I was impressed with the craftsmanship. I've made most of the "cold air" kits on my own personal race cars in the past 20 years, but this car looked a little more complicated with the integral MAF housing in the OEM plastic tube. And with a new higher flowing MAF comes the need for a tune - this has been the standard for Mustangs since the earliest MAF equipped Mustangs 5.0L Mustangs I raced in back in college (MY1986-up). This Steeda kit was not an inexpensive kit, and I am leery of high priced parts that are heavy on the bling and lacking in performance, but this was money well spent. The inlet bell for the MAF housing was a beautifully machined and welded part, and much nicer than I had expected to see (or than I would have made!), with a smoothly tapered inlet bell that has to help air flow. The aluminum heat shield was also very well made and fit perfectly to the new MAF housing, lower inlet scoop, and to the chassis.
AJ had the stock parts out and the new bits back together fairly quickly, but Matt and I snapped some pics of the parts and the install while it was going together. He cleaned up the stock inner fender section under the OEM airbox while it was out (I like my engine bays uber-clean), and it all fit together perfectly. Since its STX-class legal and holds in a little engine heat we removed the plastic OEM "5.0" engine cover piece as well - then cleaned up the hoses and looms underneath. Looks good under there and has
less clutter. We did not re-install the OEM inlet air "sound tube"; I consider that part of the OEM cold air system, so its STX-class legal to modify/remove it, in my eyes. That stupid tube weighed less than 1 pound and is more of a marketing gimmick than performance anything. Plugged the hole in the Steeda inlet tube with a a big rubber plug and hose clamp. Again -
less clutter under the hood.
Will it be too quiet now without the sound tube artificially pumping engine sound into the cabin?
Not hardly! This car SOUNDS GOOD now, and external sound testing shows about a 9dB increase in sound at the SCCA Pro Solo (between my Mustang with OEM airbox and Paul M's identical Mustang with this Steeda cold air) 2 weeks back. See the in-car autocross video below for sounds. We'll plug the 30mm hole in the firewall with some grommet plugs, that Paul found and ordered online, when they arrive.
The SCT Tuner was loaded with a custom Tune Steeda developed for Paul's car as well, which has a more linear throttle response for the drive-by-wire throttle body. Paul was the guinea pig on this mod - he bought this same package and had Steeda tweak the tune a couple of times and we just had them load the same tune for our SCT programmer, as I had driven his car with the same cold air and SCT tune and REALLY liked the improvement. Uploading the tune via the OBD-II port was easy, if not a bit time consuming the first time around (its not nearly as quick as say... a COBB AccessPORT upload, but it has a few more customer-tweakable settings, too). The adjustable speedometer feature (for gearing and/or tire height changes) is a nice feature on this programmer, as is the adjustable rev limit. The OEM limiter is around 6800 rpm and I raised it to 7400 for autocross use (quick bursts up to that limit to avoid a 2-3 shift on some courses), which is plenty safe (the new Boss302 has a 7500 limit). Lots of '11 "Coyote 5.0" Mustang racers are revving stock motors higher than that, but I won't push it further.
This ain't no M54.
We then put on a
heavier part up front - an Eibach 2005-2010 Mustang GT adjustable, hollow swaybar. They supposedly have had a 2011 GT swaybar kit (with 1mm larger front and an adjustable rear bar) coming out since SEMA 2010, but all we have heard after 6 months of trying to buy one is delays and excuses, and I was tired of waiting, so we ordered the adjustable front '05-'10 bar (but not the matching rear, as it wasn't adjustable; we might make our own rear bar at some point to work with some other mods we have planned). Now this front bar is still 35mm OD, which is the exactly the same as the stock 2011 GT front bar, but as you can see the Eibach tubular unit is 3.4 pounds heavier than the stock non-adjustable front unit, so it has to have
thicker wall tubing, which means it should be stiffer at the stiffest settings. And it feels as stiff or stiffer than stock in the "middle" setting we started at - but we need to test this properly and post the numbers up. We'll test the settings on the bar on course at a test-n-tune event later this month. I made sure our tech got the bar installed with no bind in the chassis mounts, which I checked to have "pinky finger effort" to rotate with the end links off. Perfect.... well, almost.
continued below