factory duals or . . .?

[yucatec]

Dear Panthers,
In March I'll be bringing my 89 CP to Scott to improve the handling. It's an Interstate driver, 13 hours solo or twice that with two drivers. I need a quiet, economical, peppy car - in that order. I'd thought I'd ask Scott to install factory duals. Any suggestions?

Donald McCaig

[mrltd]

The fatory duals are OK at best. They are quiet. If you are planning on keeping the engine stock, they should be adequate.

If you plan on any engine improvements, a 2.25" exhuast is a great all around upgrade, and with a turbo style muffler, will be just as quiet as stock. Scott has put a complete 2.5" exhuast on a lincoln and it sounds just about stock...

[Lincolnmania]

the factory duals are ok......one thing to remember tho is your high mileage cats.......some restriction there i'm sure.........now to replace those convertors with stock converters, youre looking at about $275.00........for about 10 bucks more, you can get a mustang h pipe with cats, and i have a good used set of stock headers here for cheap

also the h pipe for the stock dual exhaust is pricey......around 140 bucks...and it's only 2" pipe.........the midpipes and the extensions i use for the duals runs about 70 bucks total.........even the 2.5" tailpipes are a bargain..........wagon tails are pricey.......about 55 bucks ea........we can use the impala ss tails and have the rear tail section done up at the local exhaust shop like mrltd had his tailpipes done....they look sweet.
as with mufflers, we go with something quiet........cat back the exhaust will be 2.5" but we use a 2.25" catted h pipe and the stock mustang headers so it doesent lose much torque
either way parts prices about equal out, going with the mustang headers and all only adds 2-3 hrs labor

[gadget73]

There are fairly quiet mufflers too, I have a set of inexpensive Summit mufflers on my car, and they really aren't loud at all. It does make some sound, but it doesn't drone at highway speed. I do get some noise right around 40-45 mph if its in overdrive, which does not happen often. I'm running similar exhaust to what Scott described, but I'm using aftermarket headers instead of stock ones. My tailpipes also exit out the back, not at the sides. Not sure how much difference that might make.

[88Vic]

Basically what Mike said, stock duals are ok if you're gonna keep the engine stock. If you plan any mods or a full blown HO conversion, move up to 2.25" or 2.5". I'm sure the 2.5" will benefit at highway speeds, but 2.25" is a good mix or low end torque and some higher end power. I'd go from 4 to 2 cats if I were you, but none at all will make it louder, and illegal if you have to pass a snifer test. I think Mustang shorties, 2 cats, 2.25" h-pipe, and Flowmaster 50's won't be very loud, but I think you'll have to get a custom tailpipe made if you want it 2.25".

[boXman]

Can get a whole dual exhaust on ebay for 160 bucks, that's with an H pipe. I saw it for a sedan tho, not sure if they sell for wagons too.

[OVERKILL]

2.5" exhaust is adequate for most H/C/I Mustangs making over 300RWHP. For a stock HO setup, 2.25" exhaust keeps velocity and exhaust temps up, which helps scavenging and promotes better flow. Too large an exhaust system will cause rapid cooling (and thus expansion) of the exhaust gases and actually will detriment performance. Its all a question of balance.......

While a free-flowing muffler on stock exhaust can help flow, 3" exhaust can cause a sizable reduction in power because it kills velocity and cools the exhaust, making it lazy.

The cheapest route to go with cats is to buy an off-road Mustang H-pipe and weld two 3-way Magnaflow cats into it. They are inexpensive and flow extremely well. This is much cheaper than buying a catted H-pipe.

I'm running stock-style duals (2") with stock manifolds on my HO conversion. Why? Because I had to get it running, its my daily driver. Even with the "restrictive" 2" exhaust, the power gains seemed like the car's HP literally doubled. We'll know when I take it to the track in April. Her previous best is 18-flat, the only change here is the heads, cam, intake, rockers and TB/EGR. The exhaust is the same, the accessories are the same and the gears and tranny are the same. SO, depending on how much faster she is, that will be a good indication of just how much power she picked up. A stock 225HP HO Mustang GT, that weights 3380lbs averages on street tires somewhere around 15-seconds. LX's are faster, and coupes are faster still. On a tire, my 'stang ran a best of 14.2 in stock trim. If the TC, which is at least 1,000lbs heavier manages to break into the 15's on street tires, I would consider that a major accomplishment, given that my buddy's dad's 80's Camaro ran 16-flat Would the car be faster with better exhaust? Maybe. But the stuff that's on there (cat-back) is virtually brand-new, so its not coming off anytime soon. I'm not concerned about shaving 1/10th of a second off the Lincoln by dumping money at it.......Starts to kill the "fun" factor. I have the Capri to be the money pit, and there's only room for one