dual exhaust on an I4

[1996v6corsica]

i have an exhaust question.. figured there would be someone on here with an answer.. at least educated guesses
i want better performing exhaust on my saturn, but i dont want to make it louder... would i see a performance gain by putting on a high flow cat and splitting it just after the cat and running two stock mufflers?
if it would fit down there i guess... would that double the flow? and is roughly twice the flow worth the investment of having a muffler shop rig that up for me?

[VanishingImage]

I doubt a true dual exhaust setup would help 4cyl engines.Theres not enough flow to start with that would be helped with the dual. Even on v6's I have a problem with duals unless the engine is putting out a lot of power. 8cyls need dual because theres more exhaust that needs to be pushed out so the dual exhaust helps it get out,by having a single exhaust on a 8cyl its basically clogging it up and choking it. You can go with a camero style muffler(sits sideways) and run dual outs,not true dual exhaust but you'll keep the performace as well as geating a nice tone...

On my 97(you saw my car at KilKare that one time) I have the 80 series muffler(camero/firebird style) on it with 2.25 piping and dual out with dual tips.Noticed good pick up and go with some noticible torque gains,nothing to brag but something gained. I also run no resonator but would also run no cat but the stupid emissions testing here in Springfield!

[Sweet98GA]

dual is for show on 4 bangers... period... there are no gains from it.. besides its not "true" dual anyway... its a split that just made the gt models look more sporty

[azeniskid]

waste of time and money.. duallies are.

[92CamaroRS]

Originally posted by azeniskid
waste of time and money.. duallies are.


but, that would reduce backpressure, thought you said that was a good thing :???:

[Colin]

Originally posted by 92CamaroRS
but, that would reduce backpressure, thought you said that was a good thing :???: :biggrin:

[1996v6corsica]

im confused.. i know its not true duals.. i know its just split into 2 mufflers.. what im asking is will i get better flow without the foldgers coffee can sound... its a saturn.. i know what it will sound like with a 'high performance' muffler
sometimes i wonder if people only read half of the post before answering

[TA^Guy]

Originally posted by 1996v6corsica
i have an exhaust question.. figured there would be someone on here with an answer.. at least educated guesses
i want better performing exhaust on my saturn, but i dont want to make it louder... would i see a performance gain by putting on a high flow cat and splitting it just after the cat and running two stock mufflers?
if it would fit down there i guess... would that double the flow? and is roughly twice the flow worth the investment of having a muffler shop rig that up for me?
What is the displacement of your Saturn and what mods are you running?

I'm sure a 2.5" exhaust would be sufficient for most NA four cylinders. Anything larger you'll reduce backpressure. A little back pressure is need to help maintain exhaust flow which in turn helps draw air/fuel charge into the cylinder during valve overlap.

Four, six, and even most eight cylinder motors run more efficient with a properly sized single exhaust. It keeps velocity up, and reduces exhaust pluses which results in a smoother, better flowing exhaust. Main reason why I liked running a single 3" exhaust on my Grand National as opposed to a dual 2.5" or 2.75" like many others run.

And ideal setup would be a large exhaust with a valve in it. Since the early '90 Yamaha has been using what they call an 'Exup valve' in their exhaust. It's reduced theflow on the exhaust under low rpm, incressing backpressure and lowend power. When throttle and RPMs incress the valve opens to be less restrictive for great midrange and unrestricted topend flow. The new Corvette ZO6 also yeilds an exhaust simular to this with a muffler thats is less restrictive at higher RPMs.


I would run a 2.5" exhaust with a high flow cat and unrestrictive muffler. But if you want to be trick about it, especially if you have a higher output motor or a turbo you could do something like this. Off your collecter (or after a high flow converter) install and electric exhaust cutout. Inline (when the cutout is closed) run a smaller exhaust like a 2.25". From the cutout side (when the cutout is open) run a larger 2.75". Have them join just before your high flow muffler and from the muffler back run a 2.75" piping. You can use the switch to open it at higher rpm, this way you get best of both worlds. Or even get tricky and use pill style Tach or a progessive activator (like those found in mulitstage nitrous setups) to open it at a set RPM. The small pipe would be enough restriction to add a little backpressure for lower rpm power, and the large dump off would improve higher rpm hp. Then use an arming switch so it's not always operating during daily (normal) driving. You don't have to run the dump pipe back into the muffler, but I think dumping it off unrestrictive is loud and annoying.

[1996v6corsica]

no mods as of yet, after i figure out this exhaust i want to swap in a 5 speed, i hear its pretty easy, since it was an option in the SL2
displacement is a little baby 1.9 liter motor
if i run a high flow cat, then split it after the cat with stock size piping, and ran two stock mufflers, am i going to see the right amount of flow? will it be too little to notice or too much and hurt my lowend?
i dont want to hear my exhaust, thats what im saying

[TA^Guy]

I personally would increase your exhaust by no more that .25"s and run a nice muffler like a Borla. Borla is usually a low tone, unobnoxious sounding muffler with good flow.

Adding dual exhaust is also adding weight. And I know incase of my Grand National my single stainless steel ATR 3" exhaust was 60 pounds lighter than a non-stainless steel Hooker 2.5" dual exhaust.

[Matt95GT]

Originally posted by TA^Guy
I personally would increase your exhaust by no more that .25"s and run a nice muffler like a Borla. Borla is usually a low tone, unobnoxious sounding muffler with good flow.


:agree: I agree.

Although I'd stick with single on your Saturn, dual Borla's are not very heavy at all. Both of mine weighed in at a combined 12~13 lbs in the boxes... which comes out to about 6lbs. per muffler. (2.25" "ProXS" center/offset) It's all the extra piping that accounts for the added weight. (which wasn't a concern of mine since my stock system already was dual)

[matts]

speaking of grand national john, i saw a BEAUTIFUL one the other day. paint was flawless....black and looked just like a mirror. interior was the same way. don't know what he had going on under the hood, but he had him some pretty beefed up street slicks on the back. :gravey:


anyways, i wouldn't even worry about getting bigger pipe, unless it's tiny stuff.....like 1 3/4 or something. maybe mandrel bent from cat back to a nice muffler out some good looking tips.

check on availability for a mandrel bent. my uncle done a cat-back on a new saturn the other day and it didn't turn out very good. too many tight bends and he just has a pressure bender. the guy didn't want to wait or pay for good quality bends. so in turn he got some nasty looking bends.

[RickHigginsHtbr]

Originally posted by TA^Guy

And ideal setup would be a large exhaust with a valve in it. Since the early '90 Yamaha has been using what they call an 'Exup valve' in their exhaust. It's reduced theflow on the exhaust under low rpm, incressing backpressure and lowend power. When throttle and RPMs incress the valve opens to be less restrictive for great midrange and unrestricted topend flow. The new Corvette ZO6 also yeilds an exhaust simular to this with a muffler thats is less restrictive at higher RPMs.


I would run a 2.5" exhaust with a high flow cat and unrestrictive muffler. But if you want to be trick about it, especially if you have a higher output motor or a turbo you could do something like this. Off your collecter (or after a high flow converter) install and electric exhaust cutout. Inline (when the cutout is closed) run a smaller exhaust like a 2.25". From the cutout side (when the cutout is open) run a larger 2.75". Have them join just before your high flow muffler and from the muffler back run a 2.75" piping. You can use the switch to open it at higher rpm, this way you get best of both worlds. Or even get tricky and use pill style Tach or a progessive activator (like those found in mulitstage nitrous setups) to open it at a set RPM. The small pipe would be enough restriction to add a little backpressure for lower rpm power, and the large dump off would improve higher rpm hp. Then use an arming switch so it's not always operating during daily (normal) driving. You don't have to run the dump pipe back into the muffler, but I think dumping it off unrestrictive is loud and annoying.

Yea.... that's what I need on my Turbo T/A... A V8 with a single turbo... So uh, where would I find something like that?