SLp Dual Dual power output?
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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.
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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
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Just get a cutout, and you're money if you dont want to screw with power
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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.
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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?
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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.
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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
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
Last edited by Badguy7; 08-12-2009 at 08:18 PM.
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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.
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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.
![Name: 100_0962.jpg
Views: 818
Size: 114.0 KB](https://ls1tech.com/forums/attachments/generation-iii-external-engine/621667d1501360787-slp-dual-dual-power-output-100_0962.jpg)
Also Cutout Closed
http://www.youtube.com/watch?v=0Vbo6w0SWaU
Cutout Open
http://www.youtube.com/watch?v=Ed8s0ovoQDU
![Name: 100_0962.jpg
Views: 818
Size: 114.0 KB](https://ls1tech.com/forums/attachments/generation-iii-external-engine/621667d1501360787-slp-dual-dual-power-output-100_0962.jpg)
Also Cutout Closed
http://www.youtube.com/watch?v=0Vbo6w0SWaU
Cutout Open
http://www.youtube.com/watch?v=Ed8s0ovoQDU
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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?
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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.
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.
![](http://i60.photobucket.com/albums/h8/nitroused383/100_0962.jpg)
Also Cutout Closed
http://www.youtube.com/watch?v=0Vbo6w0SWaU
Cutout Open
http://www.youtube.com/watch?v=Ed8s0ovoQDU
![](http://i60.photobucket.com/albums/h8/nitroused383/100_0962.jpg)
Also Cutout Closed
http://www.youtube.com/watch?v=0Vbo6w0SWaU
Cutout Open
http://www.youtube.com/watch?v=Ed8s0ovoQDU
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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.
I am just trying to figure out what I need when I go to the shop.