1999 Silverado/Sierra--Dual Exhaust questions

bob259

Just to set the record straight for everyone, ALL add on aftermarket equipment for late model vehicles must pass and have CARB/EPA approvals before it can be offered to the public. So if it's listed for your vehicle it has passed all the tests, if you are adapting something that is not listed for your vehicle, or you've decide to make it yourself you have broken the law and your vehicle may not pass your state vehicle inspections process.

I have the Borla on my 99 Silverado 5.3 and it not only passes all the test it does not void your mfg. warranty because of its approved rating.

projammer

You didn't read 2sly's post very carefully. You missed the point.

m1685

I have a 2000 6.0 and am going to true dual it with no mufflers and 3-inch pipe. I know ill lose low-end torque, but ill tell you how much. Has anyone done this already?

powerisfun

Isn't that going to be really loud? If it is too loud for you, you can try putting on glass-packs which are almost as good as no muffler (i.e. straight-thru design) but will dampen the sound a bit. Also, Flowtech makes a muffler called the Warlock that has a removable plug that is a straight-through pipe when plug is removed, but is a regular turbo muffler when the plug is in place.
That may be a better option in case you want to take a long trip and don't want to hear that droning exhaust for hours on end.
You can see it at http://www.flowtech.com

-powerisfun

powerisfun

The flowtech website is a bit confusing now that
they were bought out by Holley Performance. I'll give you the direct link:

http://www.flowtech.com/warlock.html

m1685

Thanks for the info about the turbo mufflers and glass packs. I've run both of those in previous trucks of mine. I ran a dual inlet and dual outlet flowmaster on my "old" 350 vortech Tahoe, after I had gotten a ticket for the straight pipes. Im still pretty young, no offense to anybody, and i like being able to rack the pipes off. When I true dualled my old 350 vortec it was loud as anything. It did get a little annoying at hwy speeds, but I liked being able to drop the hammer and everyone hear me coming. I did notice a little loss of power at lower rpms, but not much. My concern with the new 6.0 is that it produces most of its power at high rpms, which the true dual will even raise the peak power to a higher rpm range. I have read some of the other posts that say the true dualled 5.3 really does lose a lot of low end get up and go, I just hope my 6.0 doesn't, but I want it loud. Of course if it is too loud, or i lose too much power Ill probably go with 2 very small turbo mufflers. I do not like the way glass packs sound on the true dualled vortecs. When idling, they sound like they are grasping for air, I mean it sounds like more air is coming out of them than sound is. But thanks again for the replys.

powerisfun

I don't think you'll have a problem with the 6.0L.
Take a look at http://www.gmpowertrain.com and look at the 6.0's torque curve and compare that to the 5.7L's (the best way to compare them is by printing them out and setting one on top of the other and holding it up to the light so you can see both curves). Anyway, the 6.0 has WAY MORE torque than the 5.7L even at the low end. It's just a bonus that it's torque extend further into the high end. I'm the owner of a 5.7L which is a great engine, but I have to admit when something is leagues better and the 6.0L is just that. It's a shame it's only available in a truck that weighs 800lbs more (not counting the forthcoming SS Thunder, that's too impractical for me). By the way, I'm 32 so I'm still young enough to appreciate the sound of a mean engine, but I have a fairly long drive to work each morning (~26 miles) and no muffler(s) would turn me into an old fogey real fast. I have a dual-in/dual-out straight thru design by JCWhitney and it sounds just right for me. Quiet on the highway, but step on the pedal and you'd swear that 350 turns into a big-block.
-powerisfun

m1685

Thanks for the link to the engine specs, Ill print those out and see. Also, I loved my old 350 too. I still wish they had it around. I just opted to spend a little more money and get the 6.0 because I have driven a 5.3, and it did not seem like it had the power like the 350 vortec. They were geared the same too.

powerisfun

I would have done the same in your shoes. The 5.3L is definitely better than the 5.7L in the high range, but I agree with you that the 5.7L is torquier in the low range and I prefer that. Not only that but the torque peak is at 2800 rpm for the 5.7L and that's right where the gearing lands you when you pass or go up a hill so you really feel that boost in power. The 6.0L is not only higher in torque, but it's also a wider curve, so the power is everywhere you want to be.
Since I added a K&N filter, cold-air induction, headers and cat-back, it feels like I've added at least a 10% increase in torque (especially above
2000 rpm, but definitely below too). I also think I widened my torque curve a bit as well. I'm at 5650 ft. altitude, though, and where I work is at 7400 ft., so I'm not feeling all the power of the engine. I can't wait to take it down to a normal altitude to see the added punch it has. I'd like to eventually supercharge it, but we'll see...

-powerisfun

teaboy022

I recently made the trip to Mieneke Muffler to ask about the dual exhaust. I asked what they did with the trucks and they told me that they will either use one flowmaster muffler and split into two 2 1/2 pipes out the back with 3 1/2 inch chrome tips or put two turbo mufflers side by side and exit out the same way. I've got the 5.3 liter V8 and want to have the sound with a little power increase. I've read the past posts and it sounds like this would lose low end Torque? When asking about performance, they said I wouldn't lose anything. Should i go with this set-up or do something else? I definetly want two chrome tip pipes out the [non-permissible content removed]... looks sweet.

Thanks,
~Teaboy~

m1685

The 5.3 has 2 cats which is y'd into one pipe then goes into the muffler. The posts i read earlier said that when they got rid of the y and went to two separate pipes and mufflers, they thought they did lose some low end power, which it did. You still have the same power, but the range of power is moved up to a higher range, so it seems like you dont have that much power. I personally have not riden in a 5.3 with a true dual, so i dont know the actual difference. I do know you could keep the y pipe into one turbo muffler and then another y pipe for dual chrome tips. That should keep the power, but of course Im not sure. You also could just cut the muffler off and put dual after the single pipe. It would be pretty loud, but nowhere near as loud as a true dual with no muffler. It might cost less to keep it y'd to one pipe then put the dual after one turbo muffler, since not as much pipe will be use. Of course hopefully someone with a 5.3 will answer your question better.

powerisfun

The theory of why it would affect low-end torque is as follows: if you open up the exhaust too much (let's take an extreme example, have big tube headers and two 3 inch exhaust pipes all the way out), then when your engine is at low rpm, the gas flowing out into the tubes will be moving very slowly (because it's low flow thru a big tube). This actually causes a pressure back up (i.e. exhaust gas coming out of the cylinder hits the slow moving gas ahead of it like a brick wall). So instead of improving flow, it hurts the flow (at low rpm). At high rpm, the flow would get moving quickly enough that it's not only not forming a back-up but it would also have a siphoning (scavenging) effect because of the flow momentum of the gas ahead of it.
The muffler(s) basically act(s) as a big slowing point for the gas. The bigger the space (muffler(s)) that the gas flows into, the harder it is to keep the flow momentum going. Two turbo mufflers is a bigger space than one dual-in/dual-out muffler (unless they're really small turbos). The two turbos would be good if you plan on going over 4000 rpm often, but for everything else go with the flowmaster. Either choice will increase high-end torque, so you don't have to worry about that. If it were me, I'd just go with the Flowmaster.
For the record I have a dual-in/dual-out (albeit not Flowmaster) and the torque improvement is awesome all the way across the band. I have the 5.7L engine though.

Good luck whatever you decide.
-powerisfun

teaboy022

Thanks for the earlier posts... that helped alot

Next question I was wondering about was... How loud can I expect this to be?

I would like a deep sound... but not to be real loud. I have a friend with a Ram that is dualled out and it gets annoying after a while. I guess what I am looking for is a system that would look good(dual rear exit chrome tips0, not be too loud, and give me the best performance possible...
Any Suggestions... try something other than flowmaster?

~Teaboy~

m1685

You could go for a 2 chamber flowmaster, i think 40 series. I had a 3 chamber and it was too quiet for me. A loudness of a glasspack is usually halfway inbetween muffler and straights, so it could be a good choice. I did not like the way the glass packs sounded with my old 350 true dual, aka 2 glasspacks. It may sound better with the 5.3???

jweimholt

Hello everyone,

After much thought and research I finally made a decision on an exhaust system.

I went with the above Flowmaster System.
Everything was included.
It was a simple installation.
Took aprox. 2hrs. Was in no hurry.

Interior resonance minimal. Nice mellow exterior sound with noticeable performance gain.

Very pleased with this system.

Jeff

teaboy022

Jeff,

You went with the two chamber flowmaster and it sounds good with very little interior resonance? Thats good to hear...what engine is that on?

The 3 chamber is quieter right...maybe thats the one for me..

Thanks,
~Teaboy~

joelis

Where did you get it, and what was the cost?

Thanks

unixgod

Thats quite pricey compared to what I have seen the same system for! You should have shopped around some. I won't quote any prices I have seen by memory, but I don't remember any of them being over $300 + shipping. Did you check Summit Racing?

m1685

I would rather go to my local muffler shop and get them to do my muffler work. $110 gets u a dual job plus $15 per chrome tip. They can order any performance muffler and can customize the dual pipes to what u want, out the side or the rear, even 45 degrees. Since I have done so much business with my muffler shop, 4 different vehicles, I get most everything at cost.

wtd

I have a borla side exit system on my 98 ext-cab Z-71 w/5.7L and it sounds great. I have more power at higher rpms. I personally would go with an aftermarket system because most exhaust companies test their systems on each vehicle application. I had a true duel exhaust system put on my truck from a local shop and I lost low end torque and my milage went way down. It also sounded terrible at idle. I had them put back on my stock system and just had the borla put on a couple of weeks ago. For you guys who are thinking of taking off your cats you should know its against federal law to do so and in most cases I think you can't even replace them for 5 years or 50,000 unless they have a problem. There was an article in one of the truck mags that tested the flow of these new generation cats and found that they are all pretty free flowing.

rlangford2

I've got a 4.8L with a 3 chamber 50 series flowmaster. The setup is great. When I first got the muffler, you couldn't even hear the truck idle, but now, 16k miles later, you can. I didn't notice a drop in low end torque, but the motor doesn't have a lot of low end torque when compared to a 350. The muffler is pretty quiet at idle, but when you open the throttle, you get a nice throaty sound that is not too loud. Remember with Flowmasters, 2 chamber mufflers give you a louder sound, as well as more interior resonance. With a 3 chamber, you have less interior resonance, lower overall volume, but a much better tone.(IMHO) I got mine done at a local (atl, ga) muffler shop for about $225, tips included.

Another thing to keep in mind. As your muffler (and your engine, if you have a new truck) breaks in, the sound will get noticeably louder.

Just my opinion,

Ryan

leathal02

my flows put on my '99 Z-71 with the 5.3 engine in it.

The first day when i got them put on, i drove it and it sounded alright, and i took it home for my dad to listen too, he said it sounded like i had a 4 banger.

the next day i started it up.....didnt sound that way, it sound extremely good!!!! especially in the 1400-2500 rpms....it has quite a bit of interior resonance, but thats what i like

I have the flowmaster 50series, but i am not sure if it is 2 or 3 chambers

dsmazz

I had a '99 Sierra with a 5.3 and put a Gibson Sport Truck Cat Back System on it. It sounded cherry. . . for awhile. Then it began to rattle and vibrate. (It was installed by a professional shop.) I took it back and they told me the system was well designed, but tight in a few spots. The rattles and vibrations occurred when the system became hot and expanded.

The resonance inside the cab drove me nuts on long trips. The wife said it embarrassed her when I drove through the addition. She could hear me coming from around the bend.

I traded the beast off last week for a '00 GMC Sierra with a 5.3. Think I'll leave it stock. My mid-life crisis is over, thank God!

rayt2

While waiting for my Y2K Silverado 2500LS Ext. Cab Shortbox 5.3 to be built I am already thinking of exhaust system enhancement. I am leaning towards the Borla system but have concerns of power loss since I'll be towing with this truck and have heard on a few posts that there is possible torque/power loss in low rpm's, that I don't want.
What's your experience ?

Ray T.

bud_light_dude

Don't do a "true dual" setup. If you will be doing extensive towing or towing near tow capacity loads, don't get the single in, dual out either. You will want either just a performace muffler swap or one of the tuned single in, single out custom exhausts. Any of them will be good, Borla (although way too expensive), Gibson, Dynomax (very good), Magnaflow (very good. What I had on my 99 Silverado 5.3l), or even Flowmaster as a last choice.

Just my opinion on my experience. Hope it helps.

powerisfun

I could be wrong because I'm going by my '98 Sierra with 5.7L vortec, but I think all the new trucks have two catalytic converters which lead into a huge muffler (dual-in, single-out). My only point is that single-in, single-out is not really an option (unless you use a Y-connector to adjoin the two inpipes) on the new trucks (or the '96-'98's for that matter).
-powerisfun

bud_light_dude

No. These new 99's and up have go to a single pipe at the y and have O2 sensors in such a way that it is tricky to go with true duals without screwing with the computer. It can be done, but most shops won't do it because of the work involved. The muffler is a huge muffler and is single in, single out. If you don't want to lose the low end torque, you will need to use a less restrictive muffler, but stay with the single in, single out setup. If you do go with a single in, dual out, if it is done right, you won't lose significant low end torque, but you will lose some. One the pre 99 models, it was less critical to go with a dual out setup because the low end torque of the 350 5.7l was higher at the low end and the change in torque by the seat of the pants was far less noticeable.

leathal02

the 5.3L

and i just had the 50 series flowmaster put on mine. Great sound, very impressed from my standpoint

but anyhow,i called up flowmaster to find out which muffler to actually get, and they told me this one that i have, but they said that on their exhaust kit, it is single in dual out, but it has 2.5" pipes out the back.
On my truck i have it dualed out the back, but the custom shop put 2 1/4" pipes out the back. Maybe that helped on what your talking about because i didnt fell any change in low end torque, but possibly a increase.

either way, i have what i wanted!!!!

bud_light_dude

Yeah, it sounds like they knew what they were doing. The 2 1/4 inch pipe diameter probably compensated for the dual out setup. My shop used 2 1/2 inch which is pretty close to the same. They could have used 2 1/4 inch, but the 2 1/4 inch pipe is a lesser grade aluminum and is pretty much standard across the industry. Not much difference, but could mean the difference of a couple of years longevity.

bob259

rayt2 - I haven't experienced any loss of low end power or torque with the Borla set up. In fact I believe it has improved, that was also true for the Gibson I had.

powerisfun

Okay, sorry for the confusion. I should have known that it would be changed for '99. Someone told me that they still have the dual cats and I figured the rest must be the same as well.
Yeah, the 5.7L torque curve is definitely different than the 5.3/4.8. Much peakier, which is nice in some respects but not so nice in others. It's great when you're climbing a hill in lower gear at ~2800 rpm because that's the engine's sweet spot (torque peak) and you really feel the extra torque as you get pinned to the seat back. Kick it into lower gear, though, at an rpm of ~4000 and it feels like the engine suddenly becomes a six cylinder. I added headers and a dual-in/dual-out performance exhaust to help with the higher end torque and it did help quite a bit, but it's still wanting at high rpms for my taste. I may have to consider a centrifugal supercharger to help add some torque to the high-end (We've got a lot of steep hills here in New Mexico, so power is really appreciated).

-powerisfun

obyone

after installing gibson catback single out on '00 LS ext cab 5.3l with Airaid already installed. Added Granatelli MAF, ten minute install, and remarkable low end seat of the pants results. Of course a supercharger would have beat it, but for $320.00 versus $ 3000.00 it was best investment that I made. My opinion anyway.

m1685

Just put straights on my 2000 6.0, true dual and boy is it loud. I love it, but i doubt my neighbors feel the same way. My recommendation, true dual straights with the 6.0 is way too loud, I would try glass packs or small mufflers.

Epaminondas

Just ordered a 2000 Silverado 1500 LT extended cab. I'm after fuel economy, with higher Horse/torque with as little noise as possible! What's the best option? Thanks.

bud_light_dude

Jardine, Gibson, or Borla, and in that order of torque/hp increase and cost.

Jardines are hard to find, but make the best power. Gibson are a little cheaper and are second to quoted power increases. Borla is about the same as Gibson on the power, but are extremely expensive! All can be had in a just slghtly increased tone.

If it were me, I would go with the Gibson, simply because they are more readily found and have a lot of bang for the buck for someone who doesn't want all the interior resonance.

obyone

produces an irritating resonance in the cab at about 1700 to 2200 rpm. Cruising on the freeway at 60 is rather annoying. Everyone says that Gibson's are the quietest, for me just not quiet enough. Oh yeah, don't know if these make a difference but I also got JBA headers, Airaid intake with Granatelli MAF on '00 LS xcab 5.3 2wd.

bud_light_dude

A header swap on these trucks alone will give you quite a bit of additional interior tone, even with the stock muffler. The swept sides are louder than their single in, single out mufflers and provide less low end torque. As matter of fact, Gibson even states on their web site and on their product that the swept sides are not recommended for anyone towing with their truck due to the slight loss of low end torque with the increase being more in the mid to upper end of the rpm band.

obyone

the swept side is a single in single out system for maximum performance. I had installed the airaid first, the headers second, and the Gibson's last. I drove the truck in between each install to see the difference. While the airaid and the headers increased sound. It was minimal compared to the resonance from the Gibsons. The Gibson's came with two clamps to hold muffler in place. I even tried welding the muffler on in case there was any exhaust leaks. Still the same irritating resonance.

m1685

On my 97 tahoe I had a dual inlet/outlet Flowmaster with the pipes angled out the rear. When I punched the gas, The engine made more noise than the pipes did. At Hwy speed, 65 or 70, the resonance was irritating. Even when you reved the engine, the pipes did not sound that much louder than stock. I think it had to be the three chamber muffler. Final thought, even if you want a liitle more noise coming from the pipes, your gonna hear it in the cab.

bud_light_dude

Yeah, I think I was thinking of the Super Truck Gibson set up. You are correct. My bad.

I thought the Gibson singles setups were pretty tame as far as interior res.

powerisfun

I also installed headers on my truck. They are from Flowtech. One question I have for you is did your headers come with any kind of gasket/donut for the collector-to-headpipe connection. Mine didn't and didn't have anything in the instructions involving one. The stock exhaust manifold also didn't have one, so maybe it's not needed, but I'm getting an exhaust-ticking sound similar to a sound my '81 Blazer had when the donut needed replaced. I used some copper sealant between the joints, but I'm still getting the sound. Is this just a characteristic of headers?
It's not that loud or bothersome, I just would rather not have a sound like that coming out of my "new" truck (it's over a year old, but I still call it new). Thanks.
-powerisfun

rayt2

BUD: I just found another cat back exhaust sytem listed for 99/00 Silverado's TriFlow @ $699.00 it blows away Borla as being the most expensive.

POWER: I would contact Flow Tech on this gasket question, a exhaust leak only gets worse as time goes by because it is slowly eroding the material where it is escaping the exhaust system (path of least resistance).
Just my thoughts.

Ray T.

richardm

There should be a exhaust gasket availible from flowtech. You Mr. gasket may have something that will work also. The ones that you get from victor, detroit gasket and most other gasket companys are to thin.The reason the manifold didn't need the gasket is it is machined surface.

obyone

The JBA headers came with 4 gaskets; two to connect to the y pipe and two to connect to the head. the ticking is definitely an exhaust leak. I would contact flowtech to see if gaskets are available as the two previous posts recommend.

How did you decide on which brand of headers to buy?

powerisfun

Thanks for the reply. I had a feeling that there were supposed to be gaskets there. The fact that the exhaust manifold didn't have any down there and the kit didn't come with any (with no mention of them in the directions) threw me, though.
I chose the Flowtechs mainly because the price was only $159 + $7 shipping thru Summit Racing. That was the best deal I could find. At the time I just figured headers are headers, they all look the same and have the same tube diameters... I got what I paid for, apparently.
The fire-cone on the JBA's sounds like a good thing and I probably should have just went with them. Live and learn!
Thanks again.
-powerisfun

heimy

I put dual pipes on my '96 Tahoe a while back. Sounds great, with glasspacks and separately dual from engine to tailpipes. However, the cat converters burned out at 40,000 miles, both of them. Coincidence? OK, a question. I like both Chevy and Ford (must make me unique), and have a '00 Ford SuperDuty coming this month with V10. I've heard that putting dual exhaust on a Ford V10 makes it sound like a lawnmower. Anybody heard one, have one, or know anything about that?

rayt2

need to go to a FORD topic page for info on their trucks exhaust questions this forum answers questions on Chevy/GMC as the title denotes.... So you would not get an unbiased opinion of FORDs here.

Ray T.

bud_light_dude

You are correct. I do not personally own a V10, but know many who do. No matter what exhaust system you put on either Ford or Dodge's V10, it will sound wheezy. Those engines are both torquey stump pullers, but just don't sound as good as the good ole' American V8's.

You must take the good with the bad I guess. Some don't like the louder rumbly exhaust tones anyway.

heimy

Had to start somewhere, rayt2. My topic search didn't find a Ford dual exhaust, but did find Chevy.

Anybody got anything on why my 96 Tahoe's cats burned out after I installed dual exhaust?

rayt2

while seemingly waiting forever to get my truck you just happened to be in the wrong place at the wrong time. I have seen some late model FORD pickups w/dual exhaust set ups exiting the rear & from my opinion they sounded all right, they were not the V-10's however.

Cats burned out on your Tahoe? that seems odd I wonder if it was defective from the start, I never had any problems w/the catalytic on my 88 4.3 ext cab and had over 130000 miles on it when I sold it.

Ray T.