Long tubes vs. O/R pipe

einehund

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As the title states, has anyone gone from just an Off-road pipe to Long tubes? Without the catalysts, I have to know that exhaust is flowing better than with stock pipes, but does anyone think that it flows close to what long tubes do? I would like to drop a bit of boost pressure and pick up some power, but not sure if long tubes would be worth it over the o/r h-pipe.

As a side question, i believe that at WOT the car is a tad rich from 4500-6000. Would going to long tubes, and the slight increase in airflow even out the AFR, which should increase power a bit by itself.
 

CD07GT500

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The gains will be about 25whp with a 650-700hp combo with 1 7/8x3”.
 

MastaAce03

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Long tubes aren’t the best bang for the buck since they’re relatively expensive part and the cost of install is higher for the amount of of power gained on a street car. Having said that, nothing beats the sounds of long tubes and the right exhaust. If you do it, do it for the sound rather than the power gained. If you really want to gain power and lose boost pressure, go cams.


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PM-Performance

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OP: Have you ever seen what the stock manifolds look like? lol They are pretty pitiful. Deff get longtubes. Yes they are expensive, but IMHO LT and OR midpipe are pretty considerable when making decent power.
Exhaust does not change airflow. Your AFR does not get affected by exhaust changes within reason unless you have an open dump right around your sensor and throws things off.
 

einehund

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Long tubes aren’t the best bang for the buck since they’re relatively expensive part and the cost of install is higher for the amount of of power gained on a street car. Having said that, nothing beats the sounds of long tubes and the right exhaust. If you do it, do it for the sound rather than the power gained. If you really want to gain power and lose boost pressure, go cams.

Cams are in the plan as well, but budgeting is limited, which is why I was asking the benefit/cost factor of the long tubes.
 

PM-Performance

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Cams are in the plan as well, but budgeting is limited, which is why I was asking the benefit/cost factor of the long tubes.
IMHO, if you aren't a full bolt on car, cams should not be before opening up the exhaust. Just my opinion though.
For reference this is what stock manifolds look like

img_92001_zps71f0b7f0-jpg.578272
 

axo250

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I recently went from an O/R-X to 1 7/8” long tubes with kooks green cats and nsr cams. I’m running a vmp 2.5” pulley on the stock ‘11 supercharger and measured around 12.5psi per the tuner. It does still peg the oem gauge at 15 but I question its accuracy. Unfortunately no before cams/headers dyno run for comparison but I believe it should have been in the 15psi range beforehand.
 

Islandcat

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On same mustang Dyno and corrected numbers I went from 605 rwhp to 645 rwhp by going from o/r h-pipe to kooks headers and o/r h-pipe. Now before anyone starts calling bs on that my tuner did go more aggressive on the timing ( 2 more degrees I think) with the long tubes which is probably a big part of it.

Regardless, my car felt a lot stronger after the long tubes went on. I was never happy with the power below 3,000 on the other setup. The long tubes fixed that. Car pulls hard from down low all the way to redline now. It was definitely worth the cost for me.
 

einehund

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On same mustang Dyno and corrected numbers I went from 605 rwhp to 645 rwhp by going from o/r h-pipe to kooks headers and o/r h-pipe. Now before anyone starts calling bs on that my tuner did go more aggressive on the timing ( 2 more degrees I think) with the long tubes which is probably a big part of it.

Regardless, my car felt a lot stronger after the long tubes went on. I was never happy with the power below 3,000 on the other setup. The long tubes fixed that. Car pulls hard from down low all the way to redline now. It was definitely worth the cost for me.
Exactly the kind of real world data i was looking for. What was the pressure drop between the two set ups?
 

Islandcat

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Exactly the kind of real world data i was looking for. What was the pressure drop between the two set ups?

I think I was at 18 or so without longtubes. After the long tubes I think it is high 15 to right at 16 if I remember correctly.

Also I forgot to put in original post that the long tubes made a tremendous difference in torque. I think that’s why I like it so much. I think it was 40-50 lbs better thru most of rev range if I remember correctly

Edit: I have a non ported trinity tvs with a 2.4 upper and stock lower. Currently in shop getting port work so I am guessing I will gain some boost back
 

einehund

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I think I was at 18 or so without longtubes. After the long tubes I think it is high 15 to right at 16 if I remember correctly.

Also I forgot to put in original post that the long tubes made a tremendous difference in torque. I think that’s why I like it so much. I think it was 40-50 lbs better thru most of rev range if I remember correctly

Edit: I have a non ported trinity tvs with a 2.4 upper and stock lower. Currently in shop getting port work so I am guessing I will gain some boost back
I'm currently sitting at a little over 20lbs of boost, so i'm about at the limit i want to be without having to switch to e85 or use additives. Dropping the pressure would be a good thing!
 

Islandcat

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I forgot I had a copy of my Dyno on phone. I attached it for you. Those are the two runs , manifolds vs long tubes. No other changes.

Unfortunately I don’t see anything about the boost. Like I said it was a good 2 lbs for sure. That would be great for you to get you to 18 lbs or a lil lower
 

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Jam421

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My '13 made 24rwhp with AMR H-Pipe headers, Hi-Flo Cats + tune. Already had 2.4 upper & VMP 67. Headers were louder + way deeper and did drop 1psi boost to 16.5. Guys here will tell us anything on the exhaust side that lowers back pressure helps reduce boost. Remarkably, when I added a larger CAI + KB Mono Blade my boost was not effected. I'd only guess with stock exhaust we might have seen slight boost increase with the intake mods?
Regarding OR pipe? My buddy had FBO's on his '08. During a Trinity swap (stock 2.67upper + 10% lower) boost seemed very high. ..18-18.5.psi. Turns out his cats were breaking and began to clog. Cats were hogged out on a bench. We expected tune revision but not required. Boost did drop to safer 17psi. Sound was deeper & louder but surprisingly no HP gain on the dyno.
 
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PM-Performance

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I'm currently sitting at a little over 20lbs of boost, so i'm about at the limit i want to be without having to switch to e85 or use additives. Dropping the pressure would be a good thing!

what mods do you have that you are seeing 20? I assume a stock lower though?
Consistent 20? Or just when cold out?
 

einehund

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what mods do you have that you are seeing 20? I assume a stock lower though?
Consistent 20? Or just when cold out?
Vmp gen2r w/ 2.6, IW 10% lower, JLT 123 and the twin 65 Ford Racing throttle body. The 20.3 psi was discovered during the street tuning at sea level on a 65ish degree evening with lower humidity, so I'd say that the 20 psi is pretty consistent.
 

GT500_012308

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If you are keeping the car for a while do it.
The sound alone is worth it. Cant beat the sound I had a off road X to start with when I went to LT's its literally night and day difference.
 

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