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I have a Supertrapp question for a tiny engine. I could never get my head around that end cap with any number of discs. Seems like a brick wall for the pressure wave. I used a thick stack of discs and end cap for noise concerns when I had more neighbors, now figuring to ditch everything except the packed baffle (its just plain ignorant with an empty cone).

Have the discs and end cap demonstrated more power on the dyno than an uncapped pipe?

80", 10:1, 5.30" x 253 cam, FXD.
 

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I have a Supertrapp question for a tiny engine. I could never get my head around that end cap with any number of discs. Seems like a brick wall for the pressure wave. I used a thick stack of discs and end cap for noise concerns when I had more neighbors, now figuring to ditch everything except the packed baffle (its just plain ignorant with an empty cone).

Have the discs and end cap demonstrated more power on the dyno than an uncapped pipe?

80", 10:1, 5.30" x 253 cam, FXD.
A smaller displacement motor is a whole different story. If you have an open pipe or too many disks you will notice midrange performance will have low torque and a drop in power where you may use it most. Every pipe on all but the big cube motors has an optimal rpm range that it works the best. Only about 1500-2000 rpm window. On a smaller motor you will need a little backpressure. The big bore motors are flowing so much air that if restricted it won't rev up top or make power. Put a standard two into one on big motor and forget getting over 5k itll fall on its face.
 

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Discussion Starter · #24 ·
I have a Supertrapp question for a tiny engine. I could never get my head around that end cap with any number of discs. Seems like a brick wall for the pressure wave. I used a thick stack of discs and end cap for noise concerns when I had more neighbors, now figuring to ditch everything except the packed baffle (its just plain ignorant with an empty cone).

Have the discs and end cap demonstrated more power on the dyno than an uncapped pipe?

80", 10:1, 5.30" x 253 cam, FXD.
So to follow ArcAngels comments -

i had the super trap on my 1340 wide glide also, i do also have the124 S&S in a softail, ok so i have the answer for easy set up for you, i messaged Jeff from super trapp about best disc for the 80 cube,
i had that stupid closed end cap and it suffocated my motor at 4500rpm, i though it had a electrical issue it was go go go then died, so got the open end cap and 8 discs and she went like the clappers, so for noise he said less discs makes it quieter so this combo worked fine, the bike roared when going for it but idle is neighbor friendly, my 80 has S&S heads and barrels and high compression pistons its a goer, it now has 2 into 2 pipes with screaming eagle slip ons and the super trap in on my 124...maybe not my best idea, if you want the best combo for your small block try 8-10 discs open end cap you wont be disappointed. WALKS
 

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Discussion Starter · #25 ·
Hey uhh,,, you can't stir me up,, i am not he most gracious guy and I'm just straight to the point,, sorry it got you wound up,,, nothing i said was intended to berate you,, its just,, i had tried a the system you mentioned,, and it choked my 113 137hp,, old mans retirement motor so bad, i couldn't get past 5k in high gear,,, it pulled well into the 6k rpm neighborhood before the the supertrapp, and did again when it was on the floor,,, i,, was just trying to share my 3xperience with it, and all other 2-1 pipes on big motors...

Its funny you should call me big man,,, lol i'm 6'8" and around 300#,, one old, now deceased friends told me i was as big as a wrestler he called the undertaker,, i had to google it,, lol,,,


Hey ArcAngel did you see FXDRYDR2's question about exhaust on his bike? I think its in the 120 zippers thread
what do you think about Freedom-Performance-Combat-2Into1-Shorty-Exhaust? they have those stepped headers? look a bit radical not sure if they go on the evo
 

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So to follow ArcAngels comments -

i had the super trap on my 1340 wide glide also, i do also have the124 S&S in a softail, ok so i have the answer for easy set up for you, i messaged Jeff from super trapp about best disc for the 80 cube,
i had that stupid closed end cap and it suffocated my motor at 4500rpm, i though it had a electrical issue it was go go go then died, so got the open end cap and 8 discs and she went like the clappers, so for noise he said less discs makes it quieter so this combo worked fine, the bike roared when going for it but idle is neighbor friendly, my 80 has S&S heads and barrels and high compression pistons its a goer, it now has 2 into 2 pipes with screaming eagle slip ons and the super trap in on my 124...maybe not my best idea, if you want the best combo for your small block try 8-10 discs open end cap you wont be disappointed. WALKS
I suppose I should just give up on trying to understand exhausts and do what is recommended. Once the cap is gone I can't get my brain around how the discs can affect performance on bit for better or worse. I have a cap and lots of discs, wish I had access to a dyno!
 

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Here's the thing it also depends on how you ride. If your crusing with the boys mostly mid range running and shifting that backpressure will help keep the bike with midrange torque and smooth power. If your one of those who likes to chug to hear each cylinder hit one at a time like many older bagger guys do (lugging is bad for motor) and shift at 2400 rpm again back pressure helps performance. If you leave rubber going light to light, drive like you're on fire and can't sleep without the sound of a v-twin hitting 6k the back pressure is not for you and hence the drag pipes now come into play. Get air in get air out fast! Drag pipes are for 4500rpm up. Now throw drag pipes on the other two scenarios they will hate them. Thats the best way to explain this......now on a big bore motor witch usually has a mid to upper rpm cam and huge volume of air the principles change a little. Torque is everywhere so if it runs a bit sloppy down low its less noticeable but up top past 4k its all about flow and getting that air out fast. Any restriction will not let it rev. Can't rev all the power of those high rpm cams is left on the table.
Again ALL pipes make their best power in less than a 2k window of rpm. So your best choice is to get the one that works best where you ride most. There is no one best choice to fit all. It is based solely on what you plan to do with it. The Superbtrap with disks is adjustable to a point you can vary that pressure. Above 5k on a big bore? No you'd be beter off cutting it off with a Sawzall before they tee together or it won't rev over 5k.....cold harsh facts...
 

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Discussion Starter · #29 ·
Here's the thing it also depends on how you ride. If your crusing with the boys mostly mid range running and shifting that backpressure will help keep the bike with midrange torque and smooth power. If your one of those who likes to chug to hear each cylinder hit one at a time like many older bagger guys do (lugging is bad for motor) and shift at 2400 rpm again back pressure helps performance. If you leave rubber going light to light, drive like you're on fire and can't sleep without the sound of a v-twin hitting 6k the back pressure is not for you and hence the drag pipes now come into play. Get air in get air out fast! Drag pipes are for 4500rpm up. Now throw drag pipes on the other two scenarios they will hate them. Thats the best way to explain this......now on a big bore motor witch usually has a mid to upper rpm cam and huge volume of air the principles change a little. Torque is everywhere so if it runs a bit sloppy down low its less noticeable but up top past 4k its all about flow and getting that air out fast. Any restriction will not let it rev. Can't rev all the power of those high rpm cams is left on the table.
Again ALL pipes make their best power in less than a 2k window of rpm. So your best choice is to get the one that works best where you ride most. There is no one best choice to fit all. It is based solely on what you plan to do with it. The Superbtrap with disks is adjustable to a point you can vary that pressure. Above 5k on a big bore? No you'd be beter off cutting it off with a Sawzall before they tee together or it won't rev over 5k.....cold harsh facts...
i do get it your pushing out massive pressure on a big bore and its restricted after 5000, but how much it matters depends on weather you needing it to run at top power and as you say how you ride it, mine revs to 6000 no issues but i went for a quick ride the other day to see if i could notice it and i think i actually can just, one of my buddies has the same pipe on his 120R night train and he also has no issue hitting the limiter in the late 5000's cant tell, my springer also had the super trapp with limiter set at 5800 rpm 110 cube 120-121ft pound the dyno guys mentioned nothing about it loosing power as i would of been turfed it if they did, but in saying that i guess they tune to what you ask for, me rolling Burn out but motor safe mode.
 

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Discussion Starter · #30 ·
I suppose I should just give up on trying to understand exhausts and do what is recommended. Once the cap is gone I can't get my brain around how the discs can affect performance on bit for better or worse. I have a cap and lots of discs, wish I had access to a dyno!
i'm not sure how small your bike is but if its a 80 cube, go the open end cap 10 discs that's a good set man, i ran it like that perfect if you think the power drops off add 5 and do it again or remove 5 and do it again. sounds like it might be fun doing those little power experiments
 

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i do get it your pushing out massive pressure on a big bore and its restricted after 5000, but how much it matters depends on weather you needing it to run at top power and as you say how you ride it, mine revs to 6000 no issues but i went for a quick ride the other day to see if i could notice it and i think i actually can just, one of my buddies has the same pipe on his 120R night train and he also has no issue hitting the limiter in the late 5000's cant tell, my springer also had the super trapp with limiter set at 5800 rpm 110 cube 120-121ft pound the dyno guys mentioned nothing about it loosing power as i would of been turfed it if they did, but in saying that i guess they tune to what you ask for, me rolling Burn out but motor safe mode.
Slight correction on that statement..... it will still rev but not make any big power up top.
 

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ArcAngel,,, great video,, all your friends were dots in the mirror getting smaller,, its like the intro to the old star trek series,, when they go to warp drive.. there and gone in the same second,, that was a quick bike,, before the bottle...

Walks,,, you can try the supertrapp pipe,, if you find the wall annoying,, its just another hole in your pocket if you dont want to put up with hitting it.
You will find it revs so quickly,, you will be past 6k before you realize it,, if you don't already know this
 

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i'm not sure how small your bike is but if its a 80 cube, go the open end cap 10 discs that's a good set man, i ran it like that perfect if you think the power drops off add 5 and do it again or remove 5 and do it again. sounds like it might be fun doing those little power experiments
It's a well built 80". 9.5:1, P&P heads, 0.530 x 252 cam, good ignition system, HSR42 and all the little bits necessary to support that stuff (springs, tappets, roller rockers, etc). On paper I'd say it's worth between 80-90 hp optimally tuned (there's the fun, right?).
 

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FWIW, TT and AA are spot-on with all the input given here. IME with a beast 117 and a very strong 124 -- there's only so much torque you can use down low and a big motor set up more for mid/high power is a lot more enjoyable on the street than any other option with a big motor. That's my opinion based on many thousands of dollars and real world experience. My 124, 640/1.7, 11.5, Baisley-headed dyna has all I need up to 4500, and in normal traffic, I rarely go over 3500. Over that and it's pulling real good and at 4500 it's a monster. My 117, 11.2, 9b was a hair-trigger beast that could break the rear loose from low to mid all too easily and was a bike only for an experienced rider. It was tiresome to ride.

Exhaust in a big motor has a huge influence on power delivery and "fun" factor. Big motors are different animals that don't track with what smaller motors do or how they respond. I ran and tested a number of pipes on the street and on the dyno - pro pipe, couple D&Ds, custom-built Burns 2:1, and am now running a set of 2" straight pipes. So far they're the closest to nirvana. I'm still tinkering around but the thing to remember is: big motors are different.

You saw how strongly Arc's pulled in the vid - that's how they run. Forget all the internet chatter and listen to the guys who know. AA and TT are telling you right. Forget about losing a few TQ or HP low to mid - you'll have too much to use anyway. Maximize mid to high. You'll enjoy riding the bike and when you do have room to stretch its legs, it'll pull harder than you expect. My $.02.
 

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Discussion Starter · #35 ·
It's a well built 80". 9.5:1, P&P heads, 0.530 x 252 cam, good ignition system, HSR42 and all the little bits necessary to support that stuff (springs, tappets, roller rockers, etc). On paper I'd say it's worth between 80-90 hp optimally tuned (there's the fun, right?).
similar to mine, beside i have S&S parts and higher compression i think that 8-10 discs are perfect on your build, mine hits the limiter before i have time to shift with that combo not feeling of restriction
 

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Discussion Starter · #36 ·
ArcAngel,,, great video,, all your friends were dots in the mirror getting smaller,, its like the intro to the old star trek series,, when they go to warp drive.. there and gone in the same second,, that was a quick bike,, before the bottle...

Walks,,, you can try the supertrapp pipe,, if you find the wall annoying,, its just another hole in your pocket if you dont want to put up with hitting it.
You will find it revs so quickly,, you will be past 6k before you realize it,, if you don't already know this
same as it does with the 80 cube does snap snap snap, i get the picture now if i want the beast to rock and roll - got to open it up
 

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Discussion Starter · #37 ·
FWIW, TT and AA are spot-on with all the input given here. IME with a beast 117 and a very strong 124 -- there's only so much torque you can use down low and a big motor set up more for mid/high power is a lot more enjoyable on the street than any other option with a big motor. That's my opinion based on many thousands of dollars and real world experience. My 124, 640/1.7, 11.5, Baisley-headed dyna has all I need up to 4500, and in normal traffic, I rarely go over 3500. Over that and it's pulling real good and at 4500 it's a monster. My 117, 11.2, 9b was a hair-trigger beast that could break the rear loose from low to mid all too easily and was a bike only for an experienced rider. It was tiresome to ride.

Exhaust in a big motor has a huge influence on power delivery and "fun" factor. Big motors are different animals that don't track with what smaller motors do or how they respond. I ran and tested a number of pipes on the street and on the dyno - pro pipe, couple D&Ds, custom-built Burns 2:1, and am now running a set of 2" straight pipes. So far they're the closest to nirvana. I'm still tinkering around but the thing to remember is: big motors are different.

You saw how strongly Arc's pulled in the vid - that's how they run. Forget all the internet chatter and listen to the guys who know. AA and TT are telling you right. Forget about losing a few TQ or HP low to mid - you'll have too much to use anyway. Maximize mid to high. You'll enjoy riding the bike and when you do have room to stretch its legs, it'll pull harder than you expect. My $.02.
your 2 inch straight pipes are $$$ brought or made, i don't particularly want to spend another 900 bucks but i do wants it to rip in the rpms all the way past 6
 

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Oh you'll love this... after all the BS with 2:1s, the 2:2s were off-the-shelf Kustom Krome or somebody like them and were all of $89.00... Still had the stock exhaust shields from when the bike was new and they fit. So after all was said and done, an $89.00 set of straight pipes, cut flush at 33" IIRC, with back pressure via two bolts -- outperformed all the others. I have the cancelled checks and dyno sheets to prove it LOL!!
 
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