Dual Exhaust For Beretta

[92Beretta]

Looking for ideas on how to setup custom dual exhaust on my Beretta. Any ideas?

[geoffinbc]

Dual exhaust is not going to help the performance of these engines it will be much too big and you will loose alot of backpressure and low end torque will suffer. Now if you split the exhaust after the cat and muffler it would be a better performing system and you would also have the nice look of dual exhaust.

[StudlyCamaro]

yeha ,i wouldnt run a dual setup either.. not enough cubes to justify it... personally i prefer the look of one tailpipe (although i do have 2 -3 1/2" tips.. i bought a whole catback including a cutout for 20$, the muffler alone was worth twice that much) (i want a spintech single outlet muffler)

[Scott_68B]

I think there is lots of power to be had out of these engines with just a properly designed exhaust system. There is a guy (www.killerbv6.com) who's putting GEN III engines in MGB's and he's getting over 200 hp pretty much by putting well designed headers on an otherwise stock engine.

Scott

[geoffinbc]

There is alot more than just thinking that headers and exhaust will make 200 hp... Most likely that MGB is using a cam that is not affected by a great loss in backpressure.

[Scott_68B]

Nope, all stock internals. This guy is a former engineer for GM, he knows what he's doing.

Scott

[92Beretta]

My thought was to split it after the cat. I had the loss of backpressure in mind. I'm thinking that a turbo muffler after the cat then 2 1/4 - 2 1/2in. pipe with 3in. tips. I think that should give a deeper mellower tone. Can anyone recommend a good yet not overly expensive muffler?

[StudlyCamaro]

dynomax turbo mufflers are like 50ish i think, or the ultraflow is 100ish (the same thing internally, but is stainless not stamped steel) i like the way my ultraflow sounds, its not too terribly loud, but its very mellow

[Cliff8928]

For some reason i don't really buy that whole thing that you NEED much backpressure at all... Has anyone ever actually dyno tested it?

I never really noticed that much difference, between stock, no cat and a glasspack, a cat and a glasspack...

and to finally what i have now, which is a 3" catco cat and one of these



Cliff Scott
89 BerettaGT 3" exhaust, catco hi-flow, CCI 3-disc insert
89 Volvo740 3" cat-back with hooker max-flow muffler

[wiccanferret]

You need to have room for however much exhaust will flow thru the pipes at WOT. No more, no less. More room gives the air a place to cool down (go slower) before exit, and also does not let the air go in a straight line, which will cause the air to bounce around a bunch and slow down (and make the noises that most people think is back pressure). Less room restricts flow out of the motor. If you can get that perfect size for YOUR exhaust with a single pipe, it's a better idea due to the fact that the gap in the exhaust gas between what each manifold has put out will actually cause a vacuum that will yank the next bit out, and just cycle like that. Backpressure is never good. It means air is actually re-entering the motor from the exhaust system. Air bouncing around like a lunatic and going "pop pop pop" can cause a problem, but usually it won't because it's usually in your muffler and it's just bouncing back because there's nothing more coming from behind to push it out.

[92Beretta]

I have heard different examples of 3.1L's with duals. One with 21/4 in Borla and the other with a Cherrybomb glasspack. Both sound really good. The Borla has a better sound at idle than the Cherrybomb but both sound good depending on your taste.

[akira]

In a S-15 you really notice the difference of no back pressure, it's pathetic and gutless. You might not notice as much with the lack of weight in a berreta. Just go with a pipe the size of your colleters. Any bigger is a waste and any smaller is a restriction. Plus when you have a wide open exhaust (no backpressure at all) you will make higher hp but will lose huge amouts of torque in all of your low range rpm's. You need a tuned exhaust, if you go too big with a glasspack you can easily sound like a noisy little honda!! On my 2.8 I have no cat and a straight pipe 2" o.d and use a turbo style muffler (a cheaper 30 dollar one) with a 2"i.d and dump it before the axle. Has an awesome sound, good low end torque (enough to do good brake stands) and decent power on the highway. When I had the same set up with a glasspack instead my inner city fuel mileage went down HUGE! But it was better than my current set up on the highway, but it was way slower off the line. You have to give in one area to gain in the other, more +H.P = -torque with the exhaust when you have small cubes

[wiccanferret]

In a S-15 you really notice the difference of no back pressure, it's pathetic and gutless

[Cliff8928]

Air bouncing around like a lunatic and going "pop pop pop" can cause a problem, but usually it won't because it's usually in your muffler and it's just bouncing back because there's nothing more coming from behind to push it out.

Heh, well it usually only does that when i let off the gas (that makes sense) , so i guess it's not too bad =)

Cliff Scott
89 BerettaGT
89 Volvo740

[skeeterone2]

i have a 92' 3.1 lumina and i put dual glasspacks on it i kept the original pipe diameter and i split the pipe right before the real wheels it sound really beasty and i dont care who you are... borla mufflers and glasspacks are the same thing only one has a shiny cover and costs 4 times as much... i didnt notice a drop in low end at all... i think it is because i use the stock diameter pipe and didnt lose an incredible amount of backpressure... but is still less than what was originaly there with that stupid quiet muffler. and consider this when your looking at mufflers... if you look in em' and they just have a strait though tube that is perfferated it is nothing more than a glasspack. and a glasspack is 30 bucks and turs heads... i have had guys come up to me when im idleing in a parkinglot and ask me what i have in my car because they think it is a V8 and the are astouded to learn that its a 3.1.