99monguse

I am going to install a used SLp Dual Dual on my 99 SS with 420rwhp..mods in sig. I had a SLP LM1 and it soundes like a$$. I am curious as to how much power the Dual Dual hogs from a free-flowing set-up like the LM1. I dont' race anymore, but I don't want to lose a lot of power either. I may install a power cutout in the I-pipe if the companies have fixed the leakage problems they once had and the issues with the drive units dying on them.

ls2 bait

iTrader: (11)

i made 4.5 hp with an open cutout vs my dual dual on motor and i made 6 more hp on nitrous. so imo it flows DAMN good.

Relapse

iTrader: (4)

if i remember correctly someone mentioned the muffler has a smaller hole for airflow within it to make it quieter, but also more restricting(I have no evidence but my brain, which has been tampered with)
Just get a cutout, and you're money if you dont want to screw with power

DANOZ28

iTrader: (1)

SLP DUAL / DUAL is a very quiet muffler. that doesnt mean it doesnt flow well. its all about sound. thats also about $500 i think. a lower cost reasonably quiet / high flow is my edelbrock RPM cat back. no rasp. i paid $250, i think you can buy for less than $350 now. the web guys here like hooker or magnaflow but those are louder than mine. just my 2 cents.

99monguse

I got this for $120.00 plus $40.00 in shipping! My understanding is the "cone of silence", the small hole you're referring to was on the 96-97 SLP Dual Duals on the SS, FIREHAWK and WS6 LT1s...not the 98-up Ls1s. I was also debating the EDELBROCK system too but isn't that just aluiminzed pipe?

DaveX

The SLP dual/dual flows very well. It was common knowledge a few years ago. IMO it's also the best muffler out there for a heads/cam/headers/ory car if you want it to sound fairly quiet until you get on it. Unfortunately they no longer make it.

RS_SS69

iTrader: (31)

It flows really really well but by no means the best flowing out there, I now run the hooker catback and gained about 10rwhp from the swap.

Badguy7

iTrader: (6)

My car used to have the dual/dual muffler on it. I swapped it out for the Lm2 setup. I felt the car open up alot more, i never have dyno'd the car or anything so i cant say just how much but it was noticeable to me. Does it flow better then a regular z28 stock exhaust?? Im sure it does, but its also due to the 3" I-Pipe you get with that dual/dual muffler setup, compared to the 2.5" you get with the regular stock setup. Atleast i think it was 2.5 or was it less?? Not to sure...

I can tell you that with my longtubes & ory, it was pretty damn quiet till you got on it. I think i may have a video of just revving it up with the dual/dual still on the car before i swapped to the lm2. I just wanted something louder overall, not just when i get on it. Very stealthy setup though, i would hear truck exhaust over mine @ idle in traffic. Get the cutout if you go this route, you will lose some power.

EDIT: Here's the video, so you getta feel for the sound. I also show ground clearance with the BBK longtubes and ORY pipe for ppl who wanted to see this.
http://vids.myspace.com/index.cfm?fu...deoid=51915927

SLOW 94 LT1

iTrader: (4)

I made +10 rwhp with my cutout from my SLP D/D on my cam only SS. LTs/ORY. Was expecting around that much of a difference.

toadzq8

iTrader: (43)

I have a 2000SS with small cam, ARH's W/ORY and cutout. I am putting down 390RWHP corrected. There is only 5HP diff between cut out open and closed, I would say that the dual-dual flows darn well. and don't make a lot of noise until you get your foot in it. SLP got it right on this one, shame they don't make them any more.

Nitroused383

iTrader: (10)

My car has the factory dual dual exhaust and the I pipe that goes over the axle looks to be a restrictive POS! Its all kinked and folds down real small, I think that is the main restriction but I gain around 15hp with my cutout open. Everytime I run at the track I gain 1-2 mph just from opening the cutout. Here is my dyno graph, you can tell which one has the cutout open. I absolutely love my dual dual and would not trade it for anything. It is real loud when you get on it but crusing around town it sounds great.



Also Cutout Closed

http://www.youtube.com/watch?v=0Vbo6w0SWaU

Cutout Open

http://www.youtube.com/watch?v=Ed8s0ovoQDU

99monguse

I was thinking about having a new 3 inch y-pipe made (using the flowmaster merge) and then using a 3 inch intermediate pipe and 3 inch over axle pipe and then reduce down to the original mufflers size. Isn't the SLP Dual Dual tubing 2.75 inch; its not 3 inch right?

toadzq8

iTrader: (43)

I did relace the SLP over the axel pipe with a 3" Magnaflow piece that was not crimped for clearance like the factory pipe, that may have made a bit of diff in my case.

toadzq8

iTrader: (43)

It's 3" past the merge to the muffler, 2.5" duals out the back.

99monguse

Oh...ok, I thought it was 2.75 like the OE tubing, but I guess not. Now I havn't received it yet but I do see several posts about the i-pipe and over-axle pipes are crimped; is that right? So basically the entire SLP DD is 3 inch EXCEPT for the tailpipes with are 2.5??

I am just trying to figure out what I need when I go to the shop.

Nitroused383

iTrader: (10)

I do not think the the factory crimped I pipe that goes over the axle is 3". I can measure it this weekend but if I recall correctly it is smaller than 3".