Mustang Bullitt Forum banner

1 - 5 of 5 Posts

·
Registered
Joined
·
12 Posts
Discussion Starter #1
I just purchased her from a dealer, in November, with 25,200 miles. The dealer did not have too much info on the mods, or history. My plan was to just get a clean stock Bullitt and do just some minor mods – FR500 exhaust, tune, that’s about it. However, the previous owner had extensively modified the engine:

C&L Racer CAI 95mm MAF
GT500 60mm Throttle Body
FRPP Intake
FRPP Hot Rod Cams
Long-tube headers (unk make)
X-pipe, cats deleted (unk make)
FRPP FR500S Exhaust (then) (now – M-5230-GTB)
Hurst Shifter
Tune (then - unk) (now – SCT custom tuned 93 octane)

This sucker is loud and fast!

That’s way more than I planned on doing, and not much more left other than porting and/or forced induction! I knew the car must have had an aftermarket tune with all these mods. The dealer had no idea, tuner device, and I saw no decal or other indicator. So, I planned on getting a tuner device, going to a local shop and have a new custom tune written as clean start and get a bead on the dyno numbers.

Unfortunately, I did not get a baseline with the car as-is. I also had the shop change the FR500s back to the Bullitt-style mufflers M-5230-GTB. Why? The existing set up was too loud! Now I like loud exhaust, and I don’t want a quiet car, but the headers, no cats, and FR500s were LOUD! Like Volume 11 under WOT. Idle was loud but “tolerable”, but once you crossed 3K, watch out, the sound was a painful crack. I figured moving to the Bullitt-style cat-backs would dial it back a few.

So as listed above with new Bullitt-style instead of FR500s, and custom tune:

333 HP – 259 TQ

Note on Dyno: This was on a “Mustang” dyno, not a Dynojet dyno. The tuner explained that Mustang typically reads lower than the Dynojet, and they use a ballpark correction factor of 12% to estimate Dynojet numbers. The printout includes “Est Dynojet HP” of 375 RWHP,but he warned this a guestimate and not gospel, and that crank HP would be higher still, for either Mustang or Dynojet, with about 10%+ for manual drivetrain loss. He said he preferred Mustang dynos over Dynojets for tuning purposes. I don’t race or care to chase numbers, I just wanted a clean tune and the tuner recommended a dyno-based tune, rather than a canned or e-mailed type tune. The new tune is much better (streetable) than the old unknown tune, though I have no notion of the old HP numbers to compare. I noticed more mid-range oomph with the new tune.

Note on M-5230-GTB exhaust: They are much quieter than the FR500s! I’m starting to think too quiet. I wanted go dial down from 11 to 7-8, I went to 5-6! I’m going to live with it for a while, but the drop in loudness was more significant than I thought. I may need find something in between. Maybe it’s just because I was going from something so loud.
Note on Hot Rod Cams: Awesome! I would have never sprung to get them if I hadn’t experienced them- $700+ for the cams alone. The total install must be way over $1K. But damn, the chop, the idle, the roar, the shake, the smell! This is my favorite mod – I love them! I know they’re not efficient or cost-effective, but they do work with my mods, and add a lot to the muscle car experience.

(I'll post the actual dyno sheet when I reach enough posts to add images)

Now on to wheels and suspension . . .
 

·
Administrator
Joined
·
6,381 Posts
Between the stock Bullit mufflers and the KRs for the GT500, these are probably the most popular options to retain the tone of the exhaust sound, with the later being louder, at least with the stock H-pipe. That said, enjoy your ownership experience and when it comes to your suspension, keep us updated on your choices. Good luck!
 

·
Registered
Joined
·
12 Posts
Discussion Starter #3
Thanks Tony! Maybe the b Bullitt muffler will grow on me . . . I still have FR500s to switch back too.
 

·
Registered
Joined
·
14 Posts
I have been considering the FR500S setup for mine too. I was wondering if there was a way to run long tubes but still retain the h pipe and stock exhaust?
 
1 - 5 of 5 Posts
Top