need some help on exhaust

vinny91stang · Dec 11, 2008

alright..I have a fresh 306 in my car which runs great. 12.4 in the 1/4 all motor. only problem is I have horrible exhaust. I have brand new bbk shirty headers which are great but i have an off road h pipe and flowmaster 40s welded into my stock pipes(which was done horribly by the way) Im thinking about getting slp loudmouth cat back. Any thought on the system? Also, one of my friends mentioned spintech. Im just not sure what to do, I love the sound of slp but the cheapest i could find it for was 515.00. any comments would be greatly appreciated.

Vinny

93 LX · Dec 11, 2008

you have to decide on the how the car will be driven and how much you want to hear it. My Capri has flows and its built 305 makes for a ton of noise when driving. Also it gets the cops looking as well. I even has stock cat h-pipe. I cant imagine running an off road h-pipe. I have heard SLPs on cobra's and in my opinion they are so loud that its annoying. Its like riding beside a harley with straight pipes. If you like that then get them if not do more research.

uedlose · Dec 11, 2008

I hate the sound of SLPs sound like glass packs to me and very loud. I like the sound of the Borlas they sound good and I run the Moroso Spiral flows on my wife's car and they sound great and are priced good also very deep sound but the turbo still hushes things down a good bit also. My son wanted SLPs and after lots of talking and lots of sound clips on utube he is gone to get the Borlas

87WhiteStang1 · Dec 11, 2008

Hey Vinny..told ya you'd get some responses on here!

vinny91stang · Dec 12, 2008

87WhiteStang1 said:
Hey Vinny..told ya you'd get some responses on here!

haha yea man you were right..this site is pretty cool

Maryland Stang · Dec 12, 2008

I have 2 chamber Flows with an off-road H pipe and it is louder than sin. They hear me coming from a mile away out in the country. When I go in town there is no hiding from anybody, especially the Po Po. At traffic lights it just sits there idling and you can hear it reverberating off of the buildings on both sides of the street. Like others said, make sure you want your car that loud because the Loudmouths are just like straight pipes with a little tiny resonator just to tune the sound.

dcurtis · Dec 12, 2008

I have a catless h-pipe to a set of 2 chamber flowmasters dumped and people regularly tell me that they can hear me coming from a mile away, cops don't mind it here. They even let all of the hotrods do some hellacious burnouts down main street during parades. Personally I think mac mufflers sound like crap, I say get a new flowmaster exhaust or spintech pro streets, if I decide to change mine, I will deffinetly go with spintech, if you want quieter I don't know, because I like my car fairly loud.

vinny91stang · Dec 12, 2008

well guys thank you for the advice..ive been talked out of getting slp. Ive been told that it messes with the back pressure and would result in a loss of horsepower. Ive decided to get MAC catback

lang williams · Dec 12, 2008

what do you guys think is a compromise in flow/low noise? Are the 3 chamber flow masters much quieter than the 2 chamber?

uedlose · Dec 12, 2008

yes the 3 chamber will be quieter then the 2

ChaosXIW · Dec 12, 2008

I dunno, I don't really like the sound of SLP's. Mac and BBK make nice, fairly inexpensive pipes. Slap some flowmasters(done right) on there and it's good. If you have the CASH, go with Bassani........that's a nice exhaust, but it's a little more that the 515.00 mentioned

PAzYearazzUP · Dec 12, 2008

The deal with exhaust is where do you want your torque? If you clog poop it up and it is quiet, she has a lot of grunt on the bottom. If you open the pipe, she flows faster and you want that more revving up top where you aim for the peak torque = 1/4 Mile exhaust kind of open pipe.

More questions dealing with your exhaust decisions are the cats and the 02 if so installed. You do not want to remove an 02 sensor, being the emissions tuning, and the cat is a must, being; you do not want that removed; especially for the street. And you sure do not want to remove the air pump to the exhaust (fresh air) dump either... These are needed tuning parts if you agree with a little physics theory...

See, you want the hot air to keep moving out of the pipe. Your back pressure is going to be hurt if you remove the cat for example. The cat keeps the pipe 'hot,' so the air pump can throw in fresh air and keep burning the unspent fuel. This reignites the fuel in the pipe so the unspent gas continues to push the 14.7 from reentering.

Again, if theory works in the practical is it works like in the absolute; your high/low pressure is a constant war for HP. Too much flow can send the fresh unspent out the exhausts hot air speed, where that pipe is all about cut and try to gain what torque range you are aiming for. Kind of think like this... Say the car is turned off. Inside the pipe is 14.7psi. If you agree, then that is the high pressure. Low pressure is the hot air moving in a, 'suck the air in the "overlap" causing a vacuum or a sucking action; being is it can push the 14.7 out of the pipe that the 'back pressure" of the 14.7 is trying to refill the exhaust pipe.

So, with that constant pressure/back into the pipe, it is a heat/speed/14.7 war of the HP/Torque move. It is that stink king pipe you gotta figure out is which one hits the spot?

old_blue · Dec 12, 2008

I love the sounds of a 2 chambered flowmaster with o/r h-pipe. had them on my old 89.

on my current 88 i have a stainless steal mac muffler now, but would rather the flowmasters. I will switch to them one day.

57fairlane · Dec 12, 2008

MACs are alright but they will be loud at WOT.

Make sure you run tailpipes . . .

cenok is family · Dec 12, 2008

SPINTECH's FTMFW!

here's a little idle/rev clip of my car

POS hedman longtubes, offroad 2.5" H pipe and dumped spintech prostreet mufflers.

YouTube - 87 mustang GT 308ci, thumpers, afm n-412 cam, cobra intake

Mac-man · Dec 14, 2008

i had the mac cat-back and it sounded awesome had a real nice tone to it, but like previously stated it got fairly loud at WOT.... had a good agreessive tone as well

rbonella · Dec 15, 2008

exhaust

vinny91stang said:
alright..I have a fresh 306 in my car which runs great. 12.4 in the 1/4 all motor. only problem is I have horrible exhaust. I have brand new bbk shirty headers which are great but i have an off road h pipe and flowmaster 40s welded into my stock pipes(which was done horribly by the way) Im thinking about getting slp loudmouth cat back. Any thought on the system? Also, one of my friends mentioned spintech. Im just not sure what to do, I love the sound of slp but the cheapest i could find it for was 515.00. any comments would be greatly appreciated.

Vinny

i agree with 93lx. slp's are raspy and too loud. these pushrod motors sound so good, slp simply ruins that. Who ever said glass packs earlier nailed it! I run long tubes, h pipe no cats, and 3 chamber flowmasters. 2 chambers are a little bit louder, but I think (only an opinion) 3 chambers have a nice loud sound quality to them. 5.0's like backpressure, and a nice cam will only make things sound better! I love a nice loud exhaust just as much as anyone else, but too loud can get real annoying especially if you run turn downs. My friend bought some magnaflows recently....too expensive, sound like a chevy truck!

7upstang91 · Dec 15, 2008

the slp sounds like s*** on a ford! I have the Flowmaster cats on one of mine. And glasspack dumps on the other. whats wrong with glasspacks?

347HO · Dec 15, 2008

PAzYearazzUP said:
The deal with exhaust is where do you want your torque? If you clog poop it up and it is quiet, she has a lot of grunt on the bottom. If you open the pipe, she flows faster and you want that more revving up top where you aim for the peak torque = 1/4 Mile exhaust kind of open pipe.

More questions dealing with your exhaust decisions are the cats and the 02 if so installed. You do not want to remove an 02 sensor, being the emissions tuning, and the cat is a must, being; you do not want that removed; especially for the street. And you sure do not want to remove the air pump to the exhaust (fresh air) dump either... These are needed tuning parts if you agree with a little physics theory...

See, you want the hot air to keep moving out of the pipe. Your back pressure is going to be hurt if you remove the cat for example. The cat keeps the pipe 'hot,' so the air pump can throw in fresh air and keep burning the unspent fuel. This reignites the fuel in the pipe so the unspent gas continues to push the 14.7 from reentering.

Again, if theory works in the practical is it works like in the absolute; your high/low pressure is a constant war for HP. Too much flow can send the fresh unspent out the exhausts hot air speed, where that pipe is all about cut and try to gain what torque range you are aiming for. Kind of think like this... Say the car is turned off. Inside the pipe is 14.7psi. If you agree, then that is the high pressure. Low pressure is the hot air moving in a, 'suck the air in the "overlap" causing a vacuum or a sucking action; being is it can push the 14.7 out of the pipe that the 'back pressure" of the 14.7 is trying to refill the exhaust pipe.

So, with that constant pressure/back into the pipe, it is a heat/speed/14.7 war of the HP/Torque move. It is that stink king pipe you gotta figure out is which one hits the spot?

Backpressure is NEVER a good thing.
In my experience, backpressure is like holding in a huge fart... that aint good.

irish · Dec 16, 2008

I like the way mine sounded before I took it apart (again)

Video of mustang - Photobucket - Video and Image Hosting

Equal length ceramic shorties, 2.5 offroad H pipe and mandrel bent 2.5 all the way out the back through magnaflows.

Matt

need some help on exhaust

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