Bigschwerm

iTrader: (26)

Ive searched all over and never really got a good answer on this.

Here is my current setup minus the tranny mods:

Air Aid Intake tube with K&N filter and modified stock air box

OBX Long Tubes and y pipe/3" pipe off of Y pipe through 3"x12" summit glasspack dumped right before the back axle...a straight shot.

Crane 1.8 ratio Gold Race Roller Rockers /LS6 springs http://www.chevyhiperformance.com/te...rms/index.html

Nelson Tune 93 octane

My question is since i don't have any head work ect. done to the motor do you think the exhaust will support the airflow having the summit glasspack?

Just want to to see some of your experiences (trial and error ect...) and opinions on what works and what don't.

What I noticed so far is a loss of low end grunt with the addition of the headers and the new exhaust setup...I am waiting on the updated tune from Nelson which shipped out today.I know a good stall and gears will help out but maybe a good muffler would gain some low end back?

budhayes3

iTrader: (19)

A lot of guys report a loss in low end after installing long tubes, especially with a 3" y-pipe. The larger diameter pipe reduces the scavenging affect and the exhaust has less velocity and actually doesn't evacuate the cylinders as quickly as before. In a stock or mild setup, most long tubes and larger diameter exhaust isn't really suited, but as you do more mods, you'll find the exhaust to be necessary. If a cam and head work, or FI is in your future, you'll find the exhaust setup to be better suited to your set up. A different muffler may or may not help, I'm going to guess not, as the larger primaries and larger diameter y-pipe is probably where you're currently mismatched. My recommendation to you is to do a cam, converter, and gears to match the exhaust

rel3rd

iTrader: (42)

I have similar combo:
Longtubes & ORY
3" exhaust
Airaid intake tube with modded stock airbox
ported throttle body
93 octane MAF only tune by me, using HPTuners
(Although MAF only is just an experiment that seems to be working and make the truck more responsive than stock VE/MAF combo. FWIW, VE is well within + or - 5% on the fuel trims and MAF is less than 2% off so I have no idea why it "seems" to be more responsive now)

anyway...

My truck runs MUCH BETTER with two mufflers inline, as opposed to any type "supposed" free flowing setup it's had so far.

I went from 1 into 2 two chamber Flowmaster with stock manifolds and cats,

to...

Ebay longtubes and their Y pipe with mini resonators with same catback (way too loud and raspy)

to...

Summit 3" I.D. 18" Bullet glasspack inline (with everything else the same)

to...

3" center in/out Hooker AeroChamber inline (to replace the Summit bullet and sounded decent IMO)

to...

Removing the Flowmaster and replacing it with an open "Y" pipe (basically just using the Hooker AeroChamber, but it was raspy at anything above cruise rpm, or while accelerating)

to...

Present setup (and hopefully the last one, LOL)

Ebay longtubes with their matching Y pipe
Hooker AeroChamber inline on the "I" pipe (under cab)
Dynomax SuperTurbo 1 into 2 muffler and dual tailpipes

This is by far the quietest that my truck has ever been since the header swap.
It is also by far the best it has run at any rpm.

With it opened up previously and much louder it only SOUNDED like it was faster, but now it actually feels like it is...without all the noise...

If you have the Ebay/OBX headers, than you have a 2.5" tubed Y pipe (with 3" outlet) and recently debatable sized primary tubes (either 1-5/8" or 1-3/4"), so I'd seriously doubt that you'd lose anything due to the headers themselves. I'd bet money any low end losses you now have are due to the "now too open" exhaust system that you have.

To answer your question, I'd all but guarantee that your present combo will indeed run better with a real muffler on it.

budhayes3

iTrader: (19)

That makes sense rel3rd...I didn't realize that the y pipe was 2.5, and if the primaries are 1 5/8, the straight through muffler may be the major culprit then. A different muffler, or series of mufflers like you mentioned, might actually do the trick

Bigschwerm

iTrader: (26)

Thanks for help Gents! I will play around with the setup a little..try a dynomax bullet in front the glass pack and see how that works out..if not i seen the summit fully welded turbo mufflers are pretty decent in the muffler shootouts.

Bigschwerm

iTrader: (26)

Update: Recieved my nelson tune from UPS this morning and promply installed it before i went to work....I drove around during lunch and took about a 40 mile drive after work to let it dial itself in. It is alot better now! Im still goint to mount a new muffler later on but for this friday night im going to get some practice runs in at the track.

Thanks again guys for the help!

KleenHall

i have the same exhaust on my truck but stock manifolds and cats,and it dumps in front of the tire... its loud
i can tell you there will a difference in the low end, there is a torque loss
and you will probabaly have a terrible rasp sound to it w/o cats

you need more cubes to justify 3" collectors and y pipe