Project Update for July 29, 2011 (1 of 2): Go grab a drink, pull up a chair, and get ready for a long update on the Mustang project. Some of this is a bit tardy, as I've been buried in demolition and construction work at the new Vorshlag shop (we should hopefully be moved in there by mid to late August), and there's a lot of ground to cover so I'm going to post two updates to cover it all. Some of the forums I cross-post this thread onto (namely roadraceautox) have post count limits, so it might turn into 3 or 4 posts on those, but so be it.
Let's touch base on the latest batch of new parts that have been added (or are in the process of going on), that was amassing before my last thread update:
New full length headers + cat pipe weighed 44.5 lbs; the stock bits were 49.6 lbs
The ARH full length 1-7/8" primary headers and X-pipe with cats were installed, and boy are they nice - but a whipping to install. Two of our guys here were working in 105° inside our (old) shop, and that kind of heat. Still, even with a lift and the right tools it took about 10 hours to install these headers. Not the most fun job. The problem is getting access to the stock headers... we saw no less than 3 methods for this car, but the most straightforward was "just pull the front crossmember out". So the engine was held in place while the car was raised on the lift, the steering shaft was disconnected, as were the strut tops, and the K-member was lowered from underneath. ARH swears you can just "partially remove" the rear of the K-member and save time, but we did it this way instead.
Not much to see there, I know... but the sound is better, though still eerily quiet. I guess the stock mufflers are still keeping the sound well under control. At least it made some good gains on the dyno. We took the car to True Street Motorsports in McKinney for a re-turn with the new headers and they found some good gains. The new track tune's "404" whp peak number is +21 whp, which doesn't seem like a
huge jump, but you have to take several factors into consideration: this is using the new "track" tune with the wussy throttle map, which before only made 383 whp (vs 392 whp for the "street tune" with the berserko, stock throttle map). Also, it was
107°F when they did the dyno pulls! We were pressed for time so they didn't do a "street tune" pull, but I suspect it will make another 10 whp, like before. And when it cools down? Yea... it won't suck.
Click dyno graph above for larger image
It has been
crazy hot in Texas for the past month, and even with "SAE correction" factors, dyno numbers still suffer in this kind of heat. He said it was pulling timing on every dyno run, due to the high temps. Picked up power everywhere above 2600 rpm. We'll re-dyno the car with the new mufflers, when temps are more sane, and I suspect we will see a bigger jump. It sure feels a lot faster. The build quality of the entire system was
TOP NOTCH. If you'd like to get some American Racing Headers for your domestic car, let me know -
Vorshlag is an ARH dealer now.
WOT and 45mph drive-by sound tests with "stock everything"
So that same week we did
six sound tests; two tests (WOT in 3rd gear and drive-by at 45mph) for each of three configurations of parts. The First set-up was a re-test with OEM airbox/exhaust (WOT = 87 dB, drive-by = 75 dB ), then with the Steeda Cold Air and tune (WOT = 87 dB, drive-by = 80 dB ), then with the Steeda Cold Air + ARH long tubes and cat X-pipe + tune (WOT = 93 dB, drive-by = 75 dB ).
WOT with Steeda CAI and another with the Steeda CAI + Long Tube headers
As you can see & hear in the 93 dB test video, the car is still damned quiet at Wide Open Throttle with the new headers, and we're putting the sound meter much closer to the car than the SCCA does at Solo events. The steady speed drive-by tests show
no sound increase at all over stock, and driving the car on the highway, it is still absurdly quiet.
I went back and looked at our
February sound tests, also with the car totally stock, and it
was only 82 dB. These tests were made with the same car, same tires, same sound meter, on the same road, meter located in the same location, and it was 5 dB quieter. Can't explain that one. Later this year, possibly after the Watts Link is in (because it adds new exhaust routing challenges), I'll build a custom axle-back exhaust. This will shed some pounds, un-cork some exhaust flow, and probably sound a good deal better. Its still just...
too quiet.
more below...