Exhaust upgrade? Reply #15 – February 28, 2013, 09:33:23 AM Quote from: ABird;410214Mine has magnaflows after the Y and it runs and sounds very nice. I was glad to find the PO added these. I will add stock or FMS mustang headers and a mustang stock H-pipe for mine, and the engine will stay basically stock. This is basically what I was thinking of for now. I've done a lot to the car this winter and didn't really plan to get into the exhaust this year, however when I discovered the condition of the lers while working under the car I have to at least address that. I currently have stock pipes that are duel exhaust coming from the Y and the pipes are solid. My thought is always if I have to replace something I might as well do it right for the long term. I may or may not get into upgrading the rest of the exhaust from the Y to the heads but it would at least wait until next winter. If I added these lers with 3 inch pipes from the cat or Y back, would I have any hp gain now without doing anything else? http://m.summitracing.com/parts/mpe-11229 I could do this within the budget that I'm looking at, or perhaps someone could suggest a better option. Quote Selected
Exhaust upgrade? Reply #16 – February 28, 2013, 07:35:14 PM After speaking with the exhaust shop I'd be using it sounds like 3 inch would be overkill and harder to work with under the cougar. He though 2 1/2 inch would be better. There are a ton to choose from if I want to go that way and the price for that sized magnaflow through the shop isn't much more then ordering them online and have them installed. I found this one but I'm still researching. http://m.summitracing.com/parts/mpe-11226 Any specific suggestion would be appreciated. And again, does anyone know if I'd see any gain by going 2 1/2 in pipes from the Y back to the 2 1/2 inch Magnaflows while doing nothing else? If so I'd think anything on this stock 5.0 would be noticed.The guy at the shop seemed to suggest flowmasters over magnaflows. I told him I wanted to get something a little throatier then what I had but still wanted to be able to have a normal conversation or enjoy my music. He thought the flowmasters would come closer to that. Abird, how do you feel about how loud your magnaflows are? Quote Selected
Exhaust upgrade? Reply #18 – March 01, 2013, 06:50:26 AM If you want lers and bigger tails to do anything for you, you'll need bigger pipes BEFORE the lers, too. Matter of fact, you'll want to go bigger all the way to the engine. Solution: 1 5/8 shorty headers, 2.5" H or X Pipe (neither has an implicit advantage over the other), 2.5" intermediate pipes, and THEN 2.5" lers and tails. Not simply a loud exhaust like all the posers and billy-bobs, but a performance exhaust. Quote Selected
Exhaust upgrade? Reply #20 – March 01, 2013, 08:29:37 AM Tom, are you talking new high flow cats or just cats in general? I have yet see a dyno where cats vs no cats makes more power. Mind you I have never tried any performance cats, so I can't really comment there, the guy at the dyno told me a good quality high flow cat will make as much power as straight piping, but to be honest, I like the SOUND of straight piped flow through lers. From my experience removing a stock cat gains 18-20ish hp, now if this is because it was plugged or an oem unit I don't know. My skyline gained 50ish hp when I straight piped a 3.5 inch exhaust from turbo back on it, it really made the car a total animal, same with the turbo cougar, it made spool up way quicker and pulled noticably harder I can't say hp cause I never dynoed it with straight pipe. And yeah you are totally right about exhaust sizing, I have had experience with my N/A 347 stroker, went from no x pipe 3 inch exhaust to 2.5 with x pipe, HUGE DIFFERENCE! Quote Selected
Exhaust upgrade? Reply #21 – March 01, 2013, 08:31:01 AM But that's just it, he hasn't got a dual exhaust. He's got a single exhaust, at least effectively. 88 5.0 cars have a 2" y-pipe, and then another y-pipe in reverse, so that even though there are 2 lers and 2 tails, at one point it's just 1 2" pipe between the front Y and the back Y. Most of the restriction he has to worry about is right at the joining of the front Y-pipe.Maybe a 2.5" inch H-pipe system is too big for a stock 5.0SO, but once he's fitted exhaust, you know he won't stop there, nobody ever does. A 2.5" system will be a system he only has to buy once and he can grow into. Otherwise get a 2.25" system made up of extended stock Mustang pipes. I'm telling you, though, nobody ever stops modding once they start. Quote Selected
Exhaust upgrade? Reply #22 – March 01, 2013, 08:49:19 AM It sounds like the consensus is that I'd have no gain in hp by going 2.5 inch from the cat back and going to the Magnaflow would only give me a louder exhaust. This makes sense and it's why asked the question in my first post. Whereever my narrowest point or greatest restriction is would determine how much flow I could get and this would be at the Y. I don't think I'd want to go with just the cat and no lers, I'm afraid that would be too loud. I thought the Y was greater then 2 inch but if that's the case what if I cut the Y and extended straight true dual all the way back? I guess I'd either have to go without the cat or add 2 new cats to do this. Going without the cat might keep me within the budget I want, adding 2 cats along with the 2 new lers and pipes would likely put me over $500. I'll run this idea by the exhaust shop guy though.Would I see a gain from this???? Quote Selected
Exhaust upgrade? Reply #23 – March 01, 2013, 03:12:21 PM You will LOSE with a true dual exhaust! When I first bought the cougar the exhaust was rotten and blowing on the gas tank, so I hacksawed it off just behind the cat. It was a noticeable gain cutting off the rotten exhaust and it wasn't very loud at all. Then I decided to go true dual exhaust with side pipes and cherry bombs, well that dropped the power so much I took it off after a week. I can say an x pipe or h pipe is really needed on the 5.0 engines for equalizing exhaust pressure, a constant feed of flow works better than starting and stopping the exhaust pulses having each sides flow disrupted waiting for the other side's cylinders to fire (at least that is the way I think of it). It is easier to maintain motion or flow than it is to start and stop it. You are not going to notice the difference by seat of the pants from 2.25" to 2.5" cat back exhaust. Plus I like the SOUND of the larger exhaust better, plus you can grow into it.You can go with 2 cats INSTEAD of lers!! That might be something to think of, you are emissions legal and make more power than most lers! That is something I might try I am really curious now! Quote Selected
Exhaust upgrade? Reply #24 – March 01, 2013, 03:41:36 PM What about a larger pipe at the Y along with a single larger Cat so the intersection didn't restrict so much. Then go with larger pipes and lers. That would be less expensive and less labor then changing to and H pipe and I'd only be out 1 cat instead of 2. Quote Selected
Exhaust upgrade? Reply #25 – March 01, 2013, 04:31:48 PM Just find a Mustang guy throwing out a stock H-pipe and stock headers, then buy some intermediate pipes for a Mark VII. Even the Mark VII stock H-pipe (smaller than Mustang) would be better than trying to fab a better double Y-pipe. The Mark VII pipe is probably harder to find. The intermediate pipes are dirt cheap and Mustang guys practically GIVE away their stock headers. Quote Selected
Exhaust upgrade? Reply #27 – March 02, 2013, 01:14:05 AM Tom:When you say modern cats don't restrict what about a 25 year old cat in my cougar? Any improvement in going to a new cat? Quote Selected
Exhaust upgrade? Reply #29 – March 02, 2013, 03:25:03 PM Tom,It wasn't simply cutting off the cat, I did 3' downpipe which eliminated 2 precats, removed the cat, ler and resonater. I went to 3.5 mandrel bent exhaust all the way to 4 inches for the last 2 feet. The cats were so plugged the boost was only hitting 12psi with the boost restrictor removed. The boost went to 18psi after. It was a substantial improvment, same with the cougar, the turbo t/a, and the grand national ALL GAINED quite noticeably from straight piping. I do agree with you, as my n/a 347 made most power through the x-pipe exhaust, more power than straight headers AND true dual 3'exhaust. I will be trying an xpipe 3' exhaust with 2 high flow cats instead of lers on the cougar when the motor goes back in it this spring.PS: Keep in mind I am no mechanic, no tuner, just some redneck hick who does stupid stuff to cars that blow them up all the time. I can only say from personal experiences. Quote Selected
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