wow, I didn't realize there weren't any gains what so ever, except sound, when replacing the stock axlebacks to something free-flowing...learn something new everyday. I stand corrected.

 

Yeah, I wouldn't expect any power from mufflers at all. Although my next mod will be boom tubes, I can't stand the look of the stock exhaust.

 

you lose torq normally with new mufflers as the backpressure drops so many feel they 'lose' power actually

 

is it ok to remove the cats ? someone told me the other night that these cars without the cats hurts them as far as gains go, anyone?

 

Hey Replica, see my sig for what the boomtubes will look like, they are loud but sound good. I was still getting a little popping like all the videos you see when they rev it up so I had two 18" glasspacks put in just before the axle and no popping at all. I also felt like I lost a little with the open flow system but the glasspacks fixed that. They have a 2" center and still move plenty of air being two of them compared to one 2.5". Also I have no X or H pipe, just one pipe on each side. Research proved that on a even firing engine the X or H gave little gain unless you put it in just the right place.

Here's a link for pipe info if your interested- https://mustangforums.com/forum/4-0l...crossover.html

 

you can remove the cats but its not really worth it in my opinion especially with minimal mods. I also like the catted sound more

 

Removing the cats AND installing LT's seem to provide a small but sometimes noticeable gain. Add a set of cams to the LT's with no cats (with a good re-tune) and the gains rival adding the CAI & tune from what I've read.

 

The tune does wonders for the auto, even with the stock air box. The intake itself is fine IMO (stock) if I had to do it over, I'd most likly get a KN drop in, larger MAF housing and of course.. a race tune.

Expect greater gains (obviously) with an actual CAI though...

excellent first mod!

 

You will feel the difference with the SCT tune more so than just the CAI (K&N & S&B all others need to be tuned). I tested it myself I had the K&N FIPK and really did NOt notice any difference except at WOT. Versus the tune alone made a better difference in throttle response and in the midrange power band. Together they work well just like Nuke says. they go hand in hand.

Exhaust mods on the S197 really do not work as well as older models ford did a great job with the stock exhaust 2.5in, 2 cats, with hi flow factory mufflers that can support over 400hp as the same mufflers are on the GT500. When removed to only a straight pipe with catted h-pipe only gain 3 horsepower!
Only the stinger or muffler deletes will gain power at the top end less than ~3hp but you will definitely lose mid range torque as a consequence on stock or mild modified stang. Now if you go forced induction you can gain almost 8hp over the stock exhaust with stinger mufflers.

 

I uploaded the tune and wow. It makes quite a difference. I'm still on the stock airbox. Everything, aside from mufflers, is stock.

The throttle response feels like a cable throttle car. Even in 5th, I can stomp the gas and the car jumps to attention. Stock, there was a good half second delay. Another thing that annoyed me about the stock tune was the power delivery being in lumps. That's no longer the case. It pulls really smooth from any RPM. The extended redline up to 6,500 rpm is quite noticeable. I can now do 80 in second gear. Driving to work today, the car had no bogging issues doing 35 mph in 5th. Nice and smooth.

So yeah. If anyone else is wondering about going with a tune on a stock car, go for it. I'm only running the 87 octane tune, and its a night and day difference.