dual exit via y-pipe, not duals from the exhaust ports back.

 

Thanks for the opinions keep them coming!!

 

I prefer to take my advice on this sort of thing from engineering texts, not self-help books...

Sure, but the car's total weight is a much, much bigger number. If you make a very small percentage change to weight, you'll get a correspondingly small percentage change to performance. It's delusional to expect anything different. If I said I gained 1% power and claimed it made a HUGE difference to performance, you'd tell me I'm an idiot.

Sure they do, but they're also expensive (the ones that work anyway), add restriction and are barely used. All they do is reduce noise while cruising; the exhaust is still just as loud under full load.

Because on a dual system each muffler only has to deal with half of the noise energy, so each muffler is more effective.

Despite overwhelming anecdotal evidence to the contrary?

Best answer yet. When you weed out the dodgy engineering opinions about weight and performance, all that's left is personal preference for appearance, noise and cost. Get what you like the look and sound of and can afford.

Sure thing Mr. McCarthy...

I assume you're talking about your single system that ended up quiet due to it's deliberately restrictive design. If you're happy with it that's great for you, but most turbo owners wouldn't really consider a single 2.5" pipe a "performance" system.

Who said anything about experimenting? This isn't rocket science. By properly sized I simply mean the two parallel pipes are sized to have the same or preferably less restriction than a single pipe. For example, two 2.5" pipes will flow considerably better than one 3" pipe, but two 2.25" pipes will flow less. Which would you choose? Not hard is it?

That's right, one muffler in parallel with another, sharing the exhaust flow and the noise energy and hence able to be more effective at reducing sound.

I have no problem with your opinion about cost and sound, but your opinion doesn't outweigh the engineering facts nor the practical experience of others.

I have no idea what "potential" flow issues you mean. Potential implies an accidental or unintended restriction, which you’re unlikely to find in any off-the-shelf system or one build by a competent exhaust builder. I'm not really interested in ghetto systems cobbled together by some wannabe welder

While cruisin' with the homies...

You've choked your engine's flow to compensate for insufficient wastegate flow. IMO that's not doing it right. No offence, but your exhaust's quietness is a minor upside to a design compromise you made to reduce boost, not a breakthrough in performance exhaust design.

Nobody ever said there was a "need", only that there are proven advantages to splitting into two mufflers. Do you think it's a coincedince that as manufacturers search for more power while noise restrictions get tighter, more and more new cars with all different engine types are appearing with dual rear mufflers? I don't...

 

Sure it's not a large percentage of the total, but does that mean that no one should ever remove any weight if it's not 200+lbs? If you remove/change a few things here and there that each save 10, 20, 30lbs then pretty soon you've got a car that's significantly lighter.

 

IMO, to call a car "significantly" lighter it'd need to loose 10% of its weight, which is between 260 and 300lb depending on model. You'd need to remove a lot of those 10, 20, 30lb items to get there, meaning you end up with a stripped out ****-box. A few people like driving pseudo-racecars on the road, but those people aren't normal. Buying a lighter car would be much smarter.

 

Not to be facetious, but I didn't know noise energy was a scientific term. How does it work?

 

Touche!

A. with stock turbo, there is no need to go 3"
B. with stock turbo, there is no 'wastegate control'
C. there was no compromise. By lowering boost, I've done exactly what I wanted to do. No boost creep, no over-boost, quiet exhaust (relative), single with great flow.

-communist gangsta

 

u'll notice the weight if u are under the car trying to get some suspension work done / dropping the gas tank

there aint many car around this price is turbo / rwd / handles as good with as much room

 

I know it's not a particularly accurate scientific term, but I think it'll do for this discussion. Sound is a form of energy after all.

Even with the stock turbo, you'll get more power and quicker response with a 3" exhaust that you will with a 2.5" one. Those are things I like, which is why I no longer have a 2.5" exhaust.

Not really sure what you're getting at there...

That's all fine except for the "great flow" bit. Sorry but I think you're deluding yourself if you think an exhaust restriction that reduces boost from 16 to 8psi isn't a compromise. The fact that boost went down so much is irrefutable proof that flow is also considerably lower. As I mentioned above, I didn't need to compromise my exhaust system to keep boost down to the same level, and I guarantee my exhaust is far less restrictive than yours.

Nah, it's not that heavy. I've just swapped my whole exhaust recently (and then swapped the rear half back!), in the garage lying on my back under the car, on my own, holding it up in place with my knees while trying to hook the mounts on. What fun...

 

So it's not that difficult and those pounds can add up quickly to be 100lbs or more. Say you've got an S4TII, going single, 30lbs, steel to aluminum hood, 20lbs, stock to 'vert wheels, 40lbs, stock to light flywheel, 15lbs. There, we're over 100lbs and we've changed 3 things and the car's not a "stripped out ****-box".

It's a pretty dumb argument you're having, basically saying that if it's not 250-300lbs then don't bother, because you're not going to find anything to remove that's 300lbs, so therefore we shouldn't care about weight at all? It's a fact that lighter cars get better gas milage, accelerate faster, stop shorter and turn better than a heavy one does. Sure it's a matter of scale and 300lbs will make more difference than 30lbs, but if you can save weight then I think you should do so wherever you can, because as I just showed, it can all add up pretty quickly.

 

Depends what you remove. You'll lose more than that if you're replacing the stock system. All I've ever claimed is that the weight difference between a single-muffler and a dual-muffler system using the same type of mufflers will be ~20lb.

Two examples of weight reduction with no disadvantages. Well done. Although unless you're lucky and get a good deal on an aluminium hood painted the right colour, it's an expensive way to lose 20lb.

Yay, smaller wheels with higher profile tires. Who the hell want that for their TII?

But I didn't say removing 100lb would have that result, did I? Don't make stuff up to suit your argument, it only weakens it further. Where's the other 150-200lb coming from?

Actually I didn't say that at all. You're jumping to that conclusion to make an argument (again). You said it was easy to make a car "significantly" lighter. To me, that's how much weight you'd need to loose before you can claim a significant effect on performance. If you'd said losing 100lb will result in a small improvement in performance, I'd have agreed with you.

All completely true, but you're missing the point that nearly everything you take off the same to save weight will be a compromise if some sort. Each part you consider removing should be looked at on its own merits rather than some over-riding crusade to lose weight. Some things will have little to no disadvantage, but IMO with the exhaust (that's the thread topic remember, not hoods and wheels) the advantages of a dual system outweigh the very small weight penalty.

 

Apexi GT SPec Or N1 I have both never put the N1 on my car but I put the GT Spec **** looks bad *** didnt finish with the piping soo I cant tell u how it sounds but it looks bad ***

 

Maybe you didn't say those things in as many words, but you've been implying that it's not worth it because it's "only" 20 or 30lbs and that if it's not a bunch more weight all at once then it's not worth it. My point is simply that you can do some things that don't necessarily compromise the comfort of the car and still save a bunch of weight and it'll have advantages, so why the heck not? To me 100lbs is pretty significant. Then there's a bunch more things that'll have a fairly minimal impact on the civility that'll save more weight. Maybe it's not 10%, but it'll be noticable to almost anyone who's paying attention and loosing weight is always a worthy goal within your broader plans and expectations of the car.

Ok so maybe people don't want 15's, but even if you just go to S5TII wheels you'll save 20lbs, and going to lighter aftermarket ones can save you more.

For me, when I weighed my car it was 2850lbs (heavy street wheels, big sways, roll bar), and it needs to go on a diet for better track performance, so evey bit counts, and 20lbs in one fell swoop is a good start.

 

How about N/A with single exhaust out on driver or passenger, does it matter. what is the overeall benefit besides weight.

 

This thread is about exhausts. Go back and read the last sentance in my previous post which is what I think about this topic. I'm not interested in debating the worth of other parts here.

16lb actually.

 

Yes, it's about exhausts, I was just trying to address the general impression you seemed to be giving that weight losses of this magnitude weren't really important, whereas I'm saying that in the overall scope of the car it can add up to a decent loss of weight. The car's a system after all and we need to look at it as such.

Ok, 16lbs, I missrememberd, I thought they were 16lbs, they're 17.

 

IMO the whole "it all adds up" argument is just a bit retarded. Every weight-loss mod you make should be done on it's own merits, not as apart of some mindlessly-repeated mantra. If the advantages don't outweigh the disadvantages, look elsewhere.

BTW, I noticed you said earlier you were going to replace your RB system with a 2.5" single system. Will the weight lost be worth the power loss that's going to cause?

One more thing, that 100lb you so easily saved before is about the same weight you gain every time you refill the fuel tank. I can't say I've ever noticed enough of a performance loss to make me want to put less fuel in the tank.

 

I read that they had to redesign the spark plugs for F1 cars because for their size, spark plugs were the heaviest part on the whole car... so they made them much smaller, and each one costs about $65 dollars.

So obviously if you're serious about going fast, every ounce counts.

 

Sounds like a fanciful story to me...

 

i have both a corksport single and a borla dual set and i enjoy them both the single is on my n/a right now (since the TII isn't running) with stock cats and it sounds great, only slightly louder than the borla set.

 

That's only $3 more expensive then a single spark plug for my Honda Insight..

I don't think that anyone here was disagreeing with that. The major point is that in a street application, there is a point of diminishing returns at which time the compromises to save another 20-30 LBs are too great on a car that is driven somewhat daily. It is a matter of personal opinion though. I can't ever imagine how someone can drive a car without an interior on a regular basis. Feels like a tin can, looks like some junker they just pulled out of the wrecking yard, etc. My interior is sort of half done and it still kills me every time I get into the car to look at bare floors, no center console and no rear upholstery. Does it save weight? Sure. Probably 30 LBs considering the weight of the carpet underpadding and all the trim. Would I ever feel that on the street? Never. And if I did, I would be driving so far into the illegal range that I would have to be stupid to do so. If I really cared, I would turn the boost up 0.5 PSI.

Now that being said, if it's a track car then this discussion is also moot as it should have a megaphone exiting behind the front passenger tire.

Neither exhaust, when properly designed, will make more power then the other type. The compromise then is how it looks, and how much noise it makes compared to how much it weighs. In a street application, putting up with the extra noise a single exhaust generates seems crazy.

I'm also willing to bet that a lot of those who like single exhaust have never heard something as elegant and well designed as the Racing Beat turbo-back dual system. Only a bit louder then stock, yet can support some very high power levels.

 

Many supercars, the Lotus Elise/Exige and some others come with essentially no interiors, just the bare carbon body showing through, they must be crappy

I do agree that a stripped out car probably isn't the best for daily driving, and I did say that weight loss is good within the larger scope of your goals of the modifications, I didn't say you should necessaily do it just for the weight loss alone.

I might go 2.5", I might go larger, but the pre-silenser is 2.5"and header outlets all seem to be that size anyway. I've got an NA, not a turbo, so 3" is likely overkill.

 

Actually, no. It was covered pretty thoroughly in Race Car Engineering mag about a year ago.

 

You certainly wouldn't catch me using one of those cars as a daily driver.

 

Ok....Ok... I finally got that Gt Spec set up on my N/A it looks bad **** alsoo sounds sooooooooooo nice omg !!!!!!!! Get It NOW !!!!!!