duragg Posted October 1, 2011 Share Posted October 1, 2011 What causes that Growl during shifting when you let off the gas? My new motor does it a little, some do it a LOT, especially some of the Rebello cars I listen to on the internets. Under acceleration then you shift and as the motor winds down there is a growly "BaAaaaa" Probably not explaining well. I like that sound. My next exhaust will be bigger diameter looking for a deeper sound. Currenly have 6-1 headers then a blown out 18" sausage and straight pipe to the back. Quote Link to comment Share on other sites More sharing options...
duragg Posted October 3, 2011 Author Share Posted October 3, 2011 Bump? Eh, no bother. I just called MSA and ordered their lst "Twice Pipes" kit that was in stock. They didn't have the "Premium" kit. Hard to screw up for $200 bucks anyways. Quote Link to comment Share on other sites More sharing options...
Leon Posted October 3, 2011 Share Posted October 3, 2011 I had my twice pipes built by a really good local exhaust guy who runs his own shop. That sound has a lot to do with the type of muffler(s) you're using. Glasspacks tend to do the trick. You're going to love the sound! Quote Link to comment Share on other sites More sharing options...
duragg Posted October 3, 2011 Author Share Posted October 3, 2011 Funny I was just watching your videos before I placed the order. My system now is some crappy 2" stuff with a glasspack in the middle and nothing else but straight pipe out the back. I should have MSA kit with dual glass packs here tomorrow and will probably just let a local exhaust shop put it on. So you still like the sound? I drive the car about 3 times a month when I want to consume pure Carbon Monoxide so I want it to be loud enough to penetrate the CO induced hypoxia. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted October 3, 2011 Share Posted October 3, 2011 My L28 with triples, headers, and the MSA premium 2.5" system makes the sound. I always called it "exhaust baffle sound" It is a nasty sound, in a good way. Quote Link to comment Share on other sites More sharing options...
duragg Posted October 3, 2011 Author Share Posted October 3, 2011 Your system have the Dynomax superturbo muffler? Is is loud enough? They were out of stock on the 2.5 system or I probably would have gone that way. Twice pipes will be fun to try and I can get it all installed prior to the big show in Phoenix this weekend. For the money I just don't see how one can go wrong with any of them. Quote Link to comment Share on other sites More sharing options...
Leon Posted October 3, 2011 Share Posted October 3, 2011 Funny I was just watching your videos before I placed the order. My system now is some crappy 2" stuff with a glasspack in the middle and nothing else but straight pipe out the back. I should have MSA kit with dual glass packs here tomorrow and will probably just let a local exhaust shop put it on. So you still like the sound? I drive the car about 3 times a month when I want to consume pure Carbon Monoxide so I want it to be loud enough to penetrate the CO induced hypoxia. I love the sound, it's actually hard for me to keep it below 3500rpm just because I want to hear that sweet roar! I have two glasspacks in each pipe, so it's relatively docile on the freeway and around town, but good luck hearing anything else as soon as I open it up. The MSA twice pipes have one (perforated) glasspack per pipe. Loud probably won't begin to describe it! Oh, and post a video up after you get them installed! Quote Link to comment Share on other sites More sharing options...
duragg Posted October 3, 2011 Author Share Posted October 3, 2011 My current setup has to be just as loud or worse? One single 18" glaspack under the driver seat and straight back with nothing else. I wish the twice pipes exited over-under instead of sidexside. Are yours sidexside? Quote Link to comment Share on other sites More sharing options...
Leon Posted October 3, 2011 Share Posted October 3, 2011 (edited) The difference between you're current setup and the MSA twice pipes is glasspack location. The dB may not change much, but you might get more drone at cruising speeds. For a long time I envisioned getting the MSA twice pipes, but as close as I got to the getting them, I never pulled the trigger mostly because the rear valence must be cut for the tips to fit the stock location. I had the exhaust builder install twin 2" pipes with slash-cut vertically-stacked tips at the back (Ã la 432), 4 total glasspacks, and 2 O2 bungs all for $300! I definitely could not beat that value, anywhere. One-man shop with 40 years of experience gets the job done right and done quick. Hell, I gave him a $20 tip at the end! Edited October 3, 2011 by Leon Quote Link to comment Share on other sites More sharing options...
duragg Posted October 6, 2011 Author Share Posted October 6, 2011 Twice pipes being installed as we speak at the exhaust shop. Removing a 2" crush-bend straght through with a single blown out 18" cherry bomb in the center. Installing MSA Twice Pipes which by rough calculations will have nearly double the CSA or the old single tweaker pipe. Curious to see how this impacts my header temperatures with improved flow. Doubt they will run any hotter than they do now.. Quote Link to comment Share on other sites More sharing options...
Leon Posted October 6, 2011 Share Posted October 6, 2011 (edited) The cross-sectional area will increase by about 1.5 times and your exhaust temps might drop a tiny bit, but very unlikely that it will be noticeable. AFR and ignition timing affect EGT more than anything else. With that said, we will absolutely need a video once you get it back! I'd love to hear it under load, and how it differs from mine. Edited October 6, 2011 by Leon Quote Link to comment Share on other sites More sharing options...
Xnke Posted October 6, 2011 Share Posted October 6, 2011 My car does that, and does it MUCH more so now that I am not running a glasspack in the tunnel. I didn't notice it with the stock manifold, first picked up on it with the old MSA header I had, with glasspack in the tunnel and turbo style muffler out back, now it's RIGHT THERE with the new Stahl weld-up header and chambered muffler out back. VROOOOOMMMmmuummmmmmmmmumumummm is the sound I get now, rev/decel. I love it. Quote Link to comment Share on other sites More sharing options...
duragg Posted October 6, 2011 Author Share Posted October 6, 2011 I'm not loving the new sound. but need to retune the webers altogether. Its still loud, maybe a slightly more muffled sound to the loud if that makes sense. AFRs are much leaner. Reduced back pressure? Lower ambient air temps? (70f today) For one or both reasons the AFR is about 1 to 1.5 points leaner in all regimes. And I am getting even more exhaust popping at idle, but I think that lean exhaust pops (13.5 - 14). Before I was right at about 12.5 at idle. Quote Link to comment Share on other sites More sharing options...
datsun723 Posted October 8, 2011 Share Posted October 8, 2011 Twice pipes is the only way to go Quote Link to comment Share on other sites More sharing options...
duragg Posted October 8, 2011 Author Share Posted October 8, 2011 They have a neat "dual" sound to them. Its just going to take some work to get the DCOEs back in sync with the Twice's. A friend did a drive past me at full power and WOW, that sucker is loud. Keith Frank from Yahoo Group "Sidedraft CEntral" is helping me with the dial in. I've been tuning to that old exhaust for so many years that this new setup is just a total do-over. Posting a video today. Quote Link to comment Share on other sites More sharing options...
duragg Posted October 8, 2011 Author Share Posted October 8, 2011 I wasn't even drinkin when I made these... DS1 drive by: Forgive the popping and farting. Lots of work to do on rejetting. Lots more videos under my Youtube acct. Quote Link to comment Share on other sites More sharing options...
Leon Posted October 8, 2011 Share Posted October 8, 2011 Damn, you aren't kidding about the popping! Sounds pretty nice though, I like the tone. Quote Link to comment Share on other sites More sharing options...
duragg Posted October 8, 2011 Author Share Posted October 8, 2011 Got a little work to do yet. Its a fun motor. Quote Link to comment Share on other sites More sharing options...
duragg Posted October 8, 2011 Author Share Posted October 8, 2011 Got a little work to do yet. Its a fun motor. Quote Link to comment Share on other sites More sharing options...
zbloke Posted October 8, 2011 Share Posted October 8, 2011 Personally I like an exhaust note that drops to virtual silence off throttle, I am biased though as my setup currently does this....... Quote Link to comment Share on other sites More sharing options...
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