supertrick_05 Posted January 19, 2010 Report Share Posted January 19, 2010 I'm trying to plan out my new exhaust system. I know I want 2.5" tubing. What I'm not sure of is a few things... 1. If I get a custom downpipe made, will running w/o a cat post any problems as to the car running properly? I live in MN, so no inspections 2. Does mandrel bending REALLY have that much more flow than the crimped bends? Like noticably in power gains? I'm not sure if I want to run w/o a cat or not...I want to get maximum flow, but don't want an obnoxiously loud car either. Thanks! Quote Link to comment Share on other sites More sharing options...
carkhz316 Posted January 19, 2010 Report Share Posted January 19, 2010 Coming from experience with exhaust to your specs (92 Z34, 2.5" mandrel) If you have little or no mufflers, a cat will make a noticable difference, sound wise. At least on mine it did. I could care less about having no inspections as well (MN, woot). Quote Link to comment Share on other sites More sharing options...
19Cutlass94 Posted January 19, 2010 Report Share Posted January 19, 2010 search! This exhaust shit has been covered so many times Quote Link to comment Share on other sites More sharing options...
supertrick_05 Posted January 19, 2010 Author Report Share Posted January 19, 2010 I did search, and I didn't see anyone ask if mandrel bends have anymore gains than crimp bends, and if no cat makes a difference either, sooooo...yeah. I'm unsure about my muffler choice yet, but I swear I saw a Grand Prix or two on here with a Camaro/Firebird-style muffler (sideways mount style) with the dual outlets. I'd kinda like to do that instead of buying two mufflers. Quote Link to comment Share on other sites More sharing options...
19Cutlass94 Posted January 19, 2010 Report Share Posted January 19, 2010 yes mandrel bent will give more gains becasue it flows more since the crimped area is smaller than mandrel bent. However youll never notice a different. Quote Link to comment Share on other sites More sharing options...
supertrick_05 Posted January 19, 2010 Author Report Share Posted January 19, 2010 Ok, so if I cared about every single HP number on a dyno sheet, use mandrel bends. If I do, I'll just buy the mandrel bent pieces and weld it up myself, but I'll probably get a custom downpipe fabbed up. Quote Link to comment Share on other sites More sharing options...
DaveFromColorado Posted January 20, 2010 Report Share Posted January 20, 2010 I noticed a big difference when I got rid of the cat on my old Z34 ... The lower end didn't change too much, but I noticed quite a bit of a difference up on the top. I toyed around with the idea of gutting out the upper intake but my trans. crapped out on me, so i got a different car all together. The LQ1 I had was just too tired anymore anyhow. --Dave. Quote Link to comment Share on other sites More sharing options...
GOT2B GM Posted January 20, 2010 Report Share Posted January 20, 2010 I don't think you'll be able to get a f-body style muffler to fit due to the spare tire well being in the way. Quote Link to comment Share on other sites More sharing options...
Artemis Posted January 20, 2010 Report Share Posted January 20, 2010 Custom DP is probably not worthwhile, I believe stock DP on a LQ1 is already 2.5" and flows pretty well. As for mendrel bent 2.5", I have it, I think it sounds better. Performance wise, I swear it made a little difference but that's probably just in my head. Quote Link to comment Share on other sites More sharing options...
sloick Posted January 20, 2010 Report Share Posted January 20, 2010 in all honesty i dont think mandrel bends will make any difference on your car. increasing from 2.25 to 2.5 will probably though. i would get rid of the cat, but thats just me. Quote Link to comment Share on other sites More sharing options...
supertrick_05 Posted January 20, 2010 Author Report Share Posted January 20, 2010 Custom DP is probably not worthwhile, I believe stock DP on a LQ1 is already 2.5" and flows pretty well. As for mendrel bent 2.5", I have it, I think it sounds better. Performance wise, I swear it made a little difference but that's probably just in my head. Well a custom downpipe withOUT the cat is what I'm after. Just a solid piece of pipe. Also, would you happen to have a sound clip of your exhaust? If not, would it be possible to get one? I have yet to hear an LQ1 car with a good-sounding exhaust. in all honesty i dont think mandrel bends will make any difference on your car. increasing from 2.25 to 2.5 will probably though. i would get rid of the cat, but thats just me. I plan on going withOUT a cat...if I don't like it, I'll get a Magnaflow universal unit. Quote Link to comment Share on other sites More sharing options...
Artemis Posted January 21, 2010 Report Share Posted January 21, 2010 Custom DP is probably not worthwhile, I believe stock DP on a LQ1 is already 2.5" and flows pretty well. As for mendrel bent 2.5", I have it, I think it sounds better. Performance wise, I swear it made a little difference but that's probably just in my head. Well a custom downpipe withOUT the cat is what I'm after. Just a solid piece of pipe. Also, would you happen to have a sound clip of your exhaust? If not, would it be possible to get one? I have yet to hear an LQ1 car with a good-sounding exhaust. Since when do LQ1's not sound great? Especially in the upper range when they scream! Don't have a video camera, but might be able to get a sound clip if a friend records it. Won't be until this weekend though.... the GP is getting a facelift. Quote Link to comment Share on other sites More sharing options...
jake91 Posted January 21, 2010 Report Share Posted January 21, 2010 make sure to watch them with good speakers it sounds like shit on laptop speakers start watching at 0:40 all rasp went away and the sound got a bit deeper and louder after 500 miles that is just mufflers Quote Link to comment Share on other sites More sharing options...
jake91 Posted January 21, 2010 Report Share Posted January 21, 2010 this car has full 3 in catback with magnaflow which is overkill for a dohc Quote Link to comment Share on other sites More sharing options...
jake91 Posted January 21, 2010 Report Share Posted January 21, 2010 and this is 2.5 catback http://s110.photobucket.com/albums/n81/GTP_MuNkY/GP%20Engine/exhaust%20upgrade%20part%202/?action=view¤t=CIMG4225.flv Quote Link to comment Share on other sites More sharing options...
supertrick_05 Posted January 21, 2010 Author Report Share Posted January 21, 2010 Ok, your car doesn't sound bad, and either does that last GTP...actually sound pretty damn good! I never saw your videos before. The ones I've heard on YouTube sounded like shit. So yours has no cat or resonator? Just mufflers? I wanna know what that GTP has for exhaust components... Quote Link to comment Share on other sites More sharing options...
xtremerevolution Posted January 21, 2010 Report Share Posted January 21, 2010 Ok, your car doesn't sound bad, and either does that last GTP...actually sound pretty damn good! I never saw your videos before. The ones I've heard on YouTube sounded like shit. So yours has no cat or resonator? Just mufflers? I wanna know what that GTP has for exhaust components... In response to a previous post of yours, I have heard plenty of 3.4L LQ1's sound terrible. They can sound uncomfortably raspy without a cat and resonator. As for the video with the 3" pipe, don't assume that a bigger pipe will yield a better performance. There are plenty of cases where going with too big of a pipe will actually hurt performance. I can't speak from personal experience since the Regal has 2.5" all the way back, but I do know many guys with Jags (5.3L V12 engines) with dual exhausts with an x-pipe and they put down better numbers at the track with dual 2" pipes (stock) or 2.25" pipes than with dual 2.5 or dual 3" pipes. Just pointing out an example so you don't put in a massive pipe to make it sound deeper and then wonder why your car feels slower. The engines are obviously different, but the same principles should apply. Quote Link to comment Share on other sites More sharing options...
supertrick_05 Posted January 21, 2010 Author Report Share Posted January 21, 2010 Yeah I know...I read a few things on the exhaust sizes and know that 2.5 is the biggest and most recommended size for the LQ1. I just PM'd GTP_MuNkY to see what his exhaust components are. I was pretty impressed with how nice his sounded. Quote Link to comment Share on other sites More sharing options...
jake91 Posted January 22, 2010 Report Share Posted January 22, 2010 mine is all stock cat resonator, ect. with new mufflers. with these cars you always want a resonator or they are raspy, but they sound much better with out a cat. i wouldnt have one if we didnt have emmisions Quote Link to comment Share on other sites More sharing options...
supertrick_05 Posted January 22, 2010 Author Report Share Posted January 22, 2010 So basically if I got a custom 2.5" downpipe w/ cat delete, a resonator, and (2) Magnaflow mufflers, I would have a great-sounding car? I've never had Magnaflows on a car before. I've dealt with Thrush (glasspacks), Flo-Pro, and XLerator mufflers. I gotta see what my options are, but now I know what I want for an exhaust...just need to decide on a muffler. Thanks guys! Quote Link to comment Share on other sites More sharing options...
jake91 Posted January 22, 2010 Report Share Posted January 22, 2010 get a 18-24in glasspack and use it a s a resonator that works really well Quote Link to comment Share on other sites More sharing options...
jake91 Posted January 22, 2010 Report Share Posted January 22, 2010 this is the muffler i went with http://www.amazon.com/MagnaFlow-12216-Finish-Stainless-Muffler/dp/B001EG683W/ref=sr_1_26? Quote Link to comment Share on other sites More sharing options...
GOT2B GM Posted January 22, 2010 Report Share Posted January 22, 2010 Jamie (Gtpmunky) has 2.5" piping to the Y, Walker cat, 18" Vibrant resonator, a stamped steel Y pipe, 2.25" Magnaflows Quote Link to comment Share on other sites More sharing options...
CSI_MuNkY Posted January 22, 2010 Report Share Posted January 22, 2010 Jamie (Gtpmunky) has 2.5" piping to the Y, Walker cat, 18" Vibrant resonator, a stamped steel Y pipe, 2.25" Magnaflows I PM'd him already Jamie Quote Link to comment Share on other sites More sharing options...
GOT2B GM Posted January 22, 2010 Report Share Posted January 22, 2010 well now everyone knows Quote Link to comment Share on other sites More sharing options...
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