FIX for loss of torque and MPG from dual exhaust
02-17-2009, 02:36 PM
#31
JK Enthusiast
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any larger exhaust system would benefit from a venturi.
it simply creates a small vacume on the back side of it so it will pull the air out. its used quite often in pneumatic systems
it simply creates a small vacume on the back side of it so it will pull the air out. its used quite often in pneumatic systems
02-17-2009, 03:01 PM
#32
JK Enthusiast
Thread Starter
Rubican,
It is worth a shot -- it sure worked for me.
I you call the sales 800 # on the Borla website they should be able to help you.
Tell then the year of your jeep and that you need a venturi to fit a 2 1/2" exhaust system.
See my previous posts in this thread on how and where to install.
It cost me around $24 including shipping.
If you install it - post and let us know if it worked for you.
It is worth a shot -- it sure worked for me.
I you call the sales 800 # on the Borla website they should be able to help you.
Tell then the year of your jeep and that you need a venturi to fit a 2 1/2" exhaust system.
See my previous posts in this thread on how and where to install.
It cost me around $24 including shipping.
If you install it - post and let us know if it worked for you.
02-17-2009, 04:50 PM
#33
JK Super Freak
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There were some posts a while about about people who had installed dual exhaust and loss torque at low RPM and the MPG went down.
Well I installed a dual exhaust system and the same thing happened to me.
I friend of mine told me to call Borla and order a Borla 2 1/2" venturi. I ordered one and had installed at my local shop. It worked great!! The venturi reduces your pipe from 2 1/2" to 2 1/8" for about a 3" inch section of your exhaust pipe.
Torque is back and MPG is at or above factory levels.
It cost for the Borla venturi is $24 and my shop charged me $20 to install.
Very simple install. Slice your pipe ahead of your muffler, slide in the venturi and weld the pipe.
Well I installed a dual exhaust system and the same thing happened to me.
I friend of mine told me to call Borla and order a Borla 2 1/2" venturi. I ordered one and had installed at my local shop. It worked great!! The venturi reduces your pipe from 2 1/2" to 2 1/8" for about a 3" inch section of your exhaust pipe.
Torque is back and MPG is at or above factory levels.
It cost for the Borla venturi is $24 and my shop charged me $20 to install.
Very simple install. Slice your pipe ahead of your muffler, slide in the venturi and weld the pipe.
02-18-2009, 05:04 AM
#34
JK Enthusiast
Thread Starter
nagulator,
I might tend to agree - based on my experience.
But for those looking for an aggressive look and sound........
As Iliinois old Governer would say...."the fix is in"!
I might tend to agree - based on my experience.
But for those looking for an aggressive look and sound........
As Iliinois old Governer would say...."the fix is in"!
02-18-2009, 05:19 AM
#35
I'll even go this far......the venturii effect ain't a new idea. Carburetors have had that as their basis for function for over a hundred years. It WORKS. I think maybe a stock exhaust could possibly show some gains with one, you never know. It's similar to the airplane wing. Air has to speed up to get around an irregular surface. It could actually aid scavenging even in a stock exhaust system. It's so cheap it's worth a try.
02-18-2009, 05:42 PM
#36
JK Enthusiast
Thread Starter
RedneckJeep -
That is exactly my thoughts. I already had the exhaust installed and loved the look and the sound..It was great at top end, but MPG and low end torque went down.
For about $40 I now have better than stock MPG and the torque is back!
That is exactly my thoughts. I already had the exhaust installed and loved the look and the sound..It was great at top end, but MPG and low end torque went down.
For about $40 I now have better than stock MPG and the torque is back!
I'll even go this far......the venturii effect ain't a new idea. Carburetors have had that as their basis for function for over a hundred years. It WORKS. I think maybe a stock exhaust could possibly show some gains with one, you never know. It's similar to the airplane wing. Air has to speed up to get around an irregular surface. It could actually aid scavenging even in a stock exhaust system. It's so cheap it's worth a try.
02-18-2009, 06:55 PM
#37
JK Enthusiast
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what are the thoughts on the Supercharged systems?
I have the Ripp Supercharger and am posting lower mpg's than others, and also feel that low end torque could be improved. Don't get me wrong, the SC made a big difference in low end torque, and even more at high RPM's, but I am thinking that the Magnaflow system I installed might of had an adverse effect on torque. Thoughts?
Best guess is I am pushing around 320 hp at the flywheel and around 217 at the rear wheels. The exhaust system is that from Cooltech which I believe is 2.5" pipes...it really just gets installed in line with the stock system, so whatever the diameter is on stock is the same as what I have now.
Best guess is I am pushing around 320 hp at the flywheel and around 217 at the rear wheels. The exhaust system is that from Cooltech which I believe is 2.5" pipes...it really just gets installed in line with the stock system, so whatever the diameter is on stock is the same as what I have now.
02-18-2009, 07:14 PM
#38
JK Enthusiast
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In the supercharger situation, you really need to get your Jeep into a shop that has a dyno, and the software to modify your fuel management settings, then you can ensure you are properly utilizing all the capability of your system.
02-18-2009, 10:04 PM
#39
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02-19-2009, 11:27 AM
#40
JK Super Freak
wow... is there anyone here from the old school? I use to rebuild mustangs as a hobby... last one was a 71 Mach 1. Here is a history lesson. Back when cars had curves and looked beautiful... we did not have much in terms of emissions. If you slapped duel exhausts, you got 5 to 10% power gains. Throw in a larger carb and headers, and you where up 75hp.
such tragedy! But due to global warming we had to add emissions. By 73, that beautiful 351 went from 375 down to 175hp... a crying shame. Engineers struggled to recapture lost horse power due to back pressure caused by emission controls.
Finally, we figured out how to take advantage of that back pressure and have it work in our favor. The secret is in the timing, cam, mass flow rate, blah blah and more shuff. Now, that being said, if you have duel exhausts, get a computer chip that can compensate for it. You will get more power out of your engine. Change your cam, and you will gain even more power. Throw in a good header and gain even more.
An important note on headers... a good header design times when the air comes together. A safe design is to make the pipes the same length.
If they are not the same length (a problem most shorty's have) then there is a chance that two pipes are competing for the same space at the same time, which reduces performance.
Don't get headers if you don't plan on modifying your engine. Why reduce back pressure if you are not going to take advantage of it. If sound is all you want, get a cherri bomb.
such tragedy! But due to global warming we had to add emissions. By 73, that beautiful 351 went from 375 down to 175hp... a crying shame. Engineers struggled to recapture lost horse power due to back pressure caused by emission controls.
Finally, we figured out how to take advantage of that back pressure and have it work in our favor. The secret is in the timing, cam, mass flow rate, blah blah and more shuff. Now, that being said, if you have duel exhausts, get a computer chip that can compensate for it. You will get more power out of your engine. Change your cam, and you will gain even more power. Throw in a good header and gain even more.
An important note on headers... a good header design times when the air comes together. A safe design is to make the pipes the same length.
If they are not the same length (a problem most shorty's have) then there is a chance that two pipes are competing for the same space at the same time, which reduces performance.
Don't get headers if you don't plan on modifying your engine. Why reduce back pressure if you are not going to take advantage of it. If sound is all you want, get a cherri bomb.