Dual 2.5" vs single 3inch?
06-28-2015, 05:32 PM
#1
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Dual 2.5" vs single 3inch? I'm extremely intrigued by the hooker 2.5" true duals.... But I'm really curious about how two 2.5" tubes compare to a y-pipe and 3" catback?
I'm guessing that the ARH 1 3/4 headers I have would have to step down from a 3" collector into a 2.5" tube. To me, pinching the exhaust would add some back pressure, and maybe rob some power.
But then I consider the extra area 2x2.5" pipes have to carry the exhaust out the rear.
Can anybody teach this guy a thing or two about the dynamics of exhaust tubing?
I'm guessing that the ARH 1 3/4 headers I have would have to step down from a 3" collector into a 2.5" tube. To me, pinching the exhaust would add some back pressure, and maybe rob some power.
But then I consider the extra area 2x2.5" pipes have to carry the exhaust out the rear.
Can anybody teach this guy a thing or two about the dynamics of exhaust tubing?
06-28-2015, 07:39 PM
#4
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06-28-2015, 07:54 PM
#5
I just installed the bassani true duel and it blows my slp lm2 away. It pulls so much more from down low to high rpm. I have a slp lid, potz tb, shorty headers, ati udp and the bassani. I put down 329 hp and 330tq before the bassani and ati ud pulley. After I did the bassani low all the way to high pulls harder. I don't just chirp second gear it sometimes breaks free now .
06-28-2015, 09:34 PM
#6
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I just installed the bassani true duel and it blows my slp lm2 away. It pulls so much more from down low to high rpm. I have a slp lid, potz tb, shorty headers, ati udp and the bassani. I put down 329 hp and 330tq before the bassani and ati ud pulley. After I did the bassani low all the way to high pulls harder. I don't just chirp second gear it sometimes breaks free now .
06-28-2015, 10:49 PM
#7
One subject that never seems to be mentioned in these TD vs. Y discussions is weight. What is the difference between dragging around a whole 'nother pipe & muffler vs. a single in/out 3.5" Mufflex system? Is the hp gain with TD's positively proportional to the weight difference?
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06-28-2015, 11:51 PM
#8
One subject that never seems to be mentioned in these TD vs. Y discussions is weight. What is the difference between dragging around a whole 'nother pipe & muffler vs. a single in/out 3.5" Mufflex system? Is the hp gain with TD's positively proportional to the weight difference?
06-29-2015, 09:38 AM
#11
I have the bassani as well and theres no doubt the car pulled better than it did when it had a 3" catback. the weight penalty with duals is a decent bit but think about it this way. its common practice that 100lbs is about 10 hp.... theres no way the bassani kit weighs 100 lbs more than a catback and y pipe. between the 2 i'd say a 30lb difference if that. you also have to make sure you're comparing a stainless catback and y to the bassani td system.
you also arent just gaining hp from the larger dia pipe over a 3" but also from the fact the x pipe helps scavenging over a y setup and will improve top end hp. Mrr23 tested the exhaust when it first came out....He had gained 2mph over the stok exhaust which was the same thing he got with a cutout open....it was also dynoed 20whp over a stock catback but I cant find that thread... either way no 3" catback is picking you up 2mph at the track even over a stock exhaust. on nitrous the bassani outperformed the stock exhaust and cutouts even more...
NA times --- stock ----- cutout ---- bassani dual
60ft --------- 2.062 ---- 2.031 ----- 2.028
1/8 ---------- 8.855 ---- 8.729 ----- 8.701
mph --------- 82.34 ---- 83.70 ----- 84.13
1/4 ---------- 13.642 -- 13.449 ---- 13.422
mph --------- 102.66 -- 104.05 ---- 104.22
200 n2o ---- stock ----- cutout ---- bassani dual
60ft --------- 2.004 ----- 2.020 ---- 1.969
1/8 ---------- 7.873 ----- 7.990 ---- 7.739
mph --------- 93.26 ----- 92.16 ---- 95.81
1/4 ---------- 12.056 ---- 12.191 -- 11.814
mph --------- 118.46 ---- 118.20 -- 121.35
Edit: heres the thread with the dynos but they've all been broken links for some time. lsx24 and mrr23 were the ones who tested the system, both gained hp and tq. lsx24 had a magnaflow before which is regarded as one of the best catbacks.
https://ls1tech.com/forums/generatio...exhaust-6.html
you also arent just gaining hp from the larger dia pipe over a 3" but also from the fact the x pipe helps scavenging over a y setup and will improve top end hp. Mrr23 tested the exhaust when it first came out....He had gained 2mph over the stok exhaust which was the same thing he got with a cutout open....it was also dynoed 20whp over a stock catback but I cant find that thread... either way no 3" catback is picking you up 2mph at the track even over a stock exhaust. on nitrous the bassani outperformed the stock exhaust and cutouts even more...
NA times --- stock ----- cutout ---- bassani dual
60ft --------- 2.062 ---- 2.031 ----- 2.028
1/8 ---------- 8.855 ---- 8.729 ----- 8.701
mph --------- 82.34 ---- 83.70 ----- 84.13
1/4 ---------- 13.642 -- 13.449 ---- 13.422
mph --------- 102.66 -- 104.05 ---- 104.22
200 n2o ---- stock ----- cutout ---- bassani dual
60ft --------- 2.004 ----- 2.020 ---- 1.969
1/8 ---------- 7.873 ----- 7.990 ---- 7.739
mph --------- 93.26 ----- 92.16 ---- 95.81
1/4 ---------- 12.056 ---- 12.191 -- 11.814
mph --------- 118.46 ---- 118.20 -- 121.35
Edit: heres the thread with the dynos but they've all been broken links for some time. lsx24 and mrr23 were the ones who tested the system, both gained hp and tq. lsx24 had a magnaflow before which is regarded as one of the best catbacks.
https://ls1tech.com/forums/generatio...exhaust-6.html
06-29-2015, 10:35 AM
#12
I like seeing the multiple references to the Bassani system here and know it to be a good product. There's a unique association between the Bassani and Hooker dual systems that is unknown and that is the fact that they were both designed by the same individual (yours truly). I spent 10 years working for Bassani before coming on board here at Holley in 2008 and have fond memories of my time spent there.
06-29-2015, 11:46 AM
#13
http://www.exhaustvideos.com/faq/how...pipe-diameter/
know this, many X pipe systems are designed incorrectly and bash the exhaust flow together resulting in almost no gain on a high end engine setup. a proper X pipe setup should look like two pipes welded right next to eachother, with an opening between both of them allowing flow, and not an actual X like many people see.
an H pipe placed as close to the headers as possible evens out pulses/reversion in the pipes with almost no drawback to flow issues, and smooth flowing Y pipe setup can see gains over many X pipe setups, along with a weight advantage.
know this, many X pipe systems are designed incorrectly and bash the exhaust flow together resulting in almost no gain on a high end engine setup. a proper X pipe setup should look like two pipes welded right next to eachother, with an opening between both of them allowing flow, and not an actual X like many people see.
an H pipe placed as close to the headers as possible evens out pulses/reversion in the pipes with almost no drawback to flow issues, and smooth flowing Y pipe setup can see gains over many X pipe setups, along with a weight advantage.
06-29-2015, 01:39 PM
#14
TECH Resident
Thread Starter
I like seeing the multiple references to the Bassani system here and know it to be a good product. There's a unique association between the Bassani and Hooker dual systems that is unknown and that is the fact that they were both designed by the same individual (yours truly). I spent 10 years working for Bassani before coming on board here at Holley in 2008 and have fond memories of my time spent there.
http://www.exhaustvideos.com/faq/how...pipe-diameter/
know this, many X pipe systems are designed incorrectly and bash the exhaust flow together resulting in almost no gain on a high end engine setup. a proper X pipe setup should look like two pipes welded right next to eachother, with an opening between both of them allowing flow, and not an actual X like many people see.
an H pipe placed as close to the headers as possible evens out pulses/reversion in the pipes with almost no drawback to flow issues, and smooth flowing Y pipe setup can see gains over many X pipe setups, along with a weight advantage.
know this, many X pipe systems are designed incorrectly and bash the exhaust flow together resulting in almost no gain on a high end engine setup. a proper X pipe setup should look like two pipes welded right next to eachother, with an opening between both of them allowing flow, and not an actual X like many people see.
an H pipe placed as close to the headers as possible evens out pulses/reversion in the pipes with almost no drawback to flow issues, and smooth flowing Y pipe setup can see gains over many X pipe setups, along with a weight advantage.
06-29-2015, 03:55 PM
#15
Interesting... This Holley/hooker version is certainly a lot cleaner than that bassani!
I think the main appeal to a dual exhaust is the sound. My Corsa just sounds raspy as heck, even with an ARH Y pipe. I'm also considering a resonator or adding another muffler to the Corsa.... But a dual setup does have its appeal too.
I think the main appeal to a dual exhaust is the sound. My Corsa just sounds raspy as heck, even with an ARH Y pipe. I'm also considering a resonator or adding another muffler to the Corsa.... But a dual setup does have its appeal too.
06-29-2015, 06:25 PM
#17
It's easy to forget things after eleven years and to be honest I don't remember all the details associated with that project. It was a much different gig there and I would typically just ask the man what he wanted (Darryl Bassani) and execute it accordingly. I do remember at the time however that there was nothing else like it available and it worked very well performance wise.