Pro Pipe Dilemma
Seasoned HDF Member
Joined: Aug 2008
Posts: 5,070
Likes: 2,115
From: Ohio
Propipe competition baffles are straight thru with the HO being larger, they have packing and holes like baffle designs but most of the existing exhaust goes out the straight thru hole. I tried a competion baffle in the White Bike and just wasn't right for normal riding and have some ponies. The repair for the competition baffle is to close off the entrance to baffle like more of a standard Propipe baffle since the HO doesn't offer another baffle, just an insert, it will send the pulses into the wrapped area and use the holes in the baffle to create some backpressure in the race type manhole design that will get the lower side back.
Propipes have tendancy to blow out the packing/wrap so needs to be rewraped if the packing is missing, they work slightly better with the packing installed and change the tone of the engine deeper instead of a rat-tat-tat tinney sound but no mistaking the roar of a Propipe when letting the engine eat
Propipes have tendancy to blow out the packing/wrap so needs to be rewraped if the packing is missing, they work slightly better with the packing installed and change the tone of the engine deeper instead of a rat-tat-tat tinney sound but no mistaking the roar of a Propipe when letting the engine eat
Last edited by 1997bagger; Jan 26, 2019 at 11:57 PM.
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Cruiser
Joined: Jun 2008
Posts: 200
Likes: 39
From: Assonet MA
Propipe competition baffles are straight thru with the HO being larger, they have packing and holes like baffle designs but most of the existing exhaust goes out the straight thru hole. I tried a competion baffle in the White Bike and just wasn't right for normal riding and have some ponies. The repair for the competition baffle is to close off the entrance to baffle like more of a standard Propipe baffle since the HO doesn't offer another baffle, just an insert, it will send the pulses into the wrapped area and use the holes in the baffle to create some backpressure in the race type manhole design that will get the lower side back.
Propipes have tendancy to blow out the packing/wrap so needs to be rewraped if the packing is missing, they work slightly better with the packing installed and change the tone of the engine deeper instead of a rat-tat-tat tinney sound but no mistaking the roar of a Propipe when letting the engine eat
Propipes have tendancy to blow out the packing/wrap so needs to be rewraped if the packing is missing, they work slightly better with the packing installed and change the tone of the engine deeper instead of a rat-tat-tat tinney sound but no mistaking the roar of a Propipe when letting the engine eat
Looking at pic #2 it appears the opening is reduced by approx. 50%. about right?
Seasoned HDF Member
Joined: Aug 2008
Posts: 5,070
Likes: 2,115
From: Ohio
Something to think of on hole size is the mass of the Propipe HO chamber area and ponies in the 70 hp range, it would probaly be best to start off with a smaller hole and can open it up with a drill bit without pulling the baffle back out and quicker butt dyno adjustments, mertioned earlier that too much restriction falls off on the top side so will know if it is to small, if the HO is still draining the small ponied Evo with a bigger hole then only a few rows of baffle holes to work with for blocking off.
Many people have gone as far as making a adjustable bolt with a deflector welded to it, drill multiple circle patterned holes in a solid plate in the area we are looking at, they move the deflector closer to the holes to fine tune backpressure and back the bolt away from the holes to lose backpressure. Someone also makes a spring pressure adjustable valve that goes in the same area and opens and closes with exhaust pressure to keep even power.
The Propipe has been around for awhile so many have had several years to tinker with it. I have played with different Proppipe baffles and the smaller stock type baffle with a hole the size of the picture worked for mine but over 100 hp, I would personally start with a smaller hole in a 70 hp engine. You will be basically turning a competition baffle into a more of a conventional Proppipe baffle for street applications.
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Cruiser
Joined: Jun 2008
Posts: 200
Likes: 39
From: Assonet MA
No exact science on the hole size, this is where the tuning comes in. You can start with that size of hole, if it is still to soft in the lower side, a simple hose clamp to block off a row of baffle holes can make a difference on moving the the power tendancies. If you get too much backpressure the engine will pull hard early and fade off on the top side requiring early shifts so that side is easy to know of wrong direction.
Something to think of on hole size is the mass of the Propipe HO chamber area and ponies in the 70 hp range, it would probaly be best to start off with a smaller hole and can open it up with a drill bit without pulling the baffle back out and quicker butt dyno adjustments, mertioned earlier that too much restriction falls off on the top side so will know if it is to small, if the HO is still draining the small ponied Evo with a bigger hole then only a few rows of baffle holes to work with for blocking off.
Many people have gone as far as making a adjustable bolt with a deflector welded to it, drill multiple circle patterned holes in a solid plate in the area we are looking at, they move the deflector closer to the holes to fine tune backpressure and back the bolt away from the holes to lose backpressure. Someone also makes a spring pressure adjustable valve that goes in the same area and opens and closes with exhaust pressure to keep even power.
The Propipe has been around for awhile so many have had several years to tinker with it. I have played with different Proppipe baffles and the smaller stock type baffle with a hole the size of the picture worked for mine but over 100 hp, I would personally start with a smaller hole in a 70 hp engine. You will be basically turning a competition baffle into a more of a conventional Proppipe baffle for street applications.
Something to think of on hole size is the mass of the Propipe HO chamber area and ponies in the 70 hp range, it would probaly be best to start off with a smaller hole and can open it up with a drill bit without pulling the baffle back out and quicker butt dyno adjustments, mertioned earlier that too much restriction falls off on the top side so will know if it is to small, if the HO is still draining the small ponied Evo with a bigger hole then only a few rows of baffle holes to work with for blocking off.
Many people have gone as far as making a adjustable bolt with a deflector welded to it, drill multiple circle patterned holes in a solid plate in the area we are looking at, they move the deflector closer to the holes to fine tune backpressure and back the bolt away from the holes to lose backpressure. Someone also makes a spring pressure adjustable valve that goes in the same area and opens and closes with exhaust pressure to keep even power.
The Propipe has been around for awhile so many have had several years to tinker with it. I have played with different Proppipe baffles and the smaller stock type baffle with a hole the size of the picture worked for mine but over 100 hp, I would personally start with a smaller hole in a 70 hp engine. You will be basically turning a competition baffle into a more of a conventional Proppipe baffle for street applications.
Road Warrior
Joined: Nov 2007
Posts: 1,641
Likes: 4
From: south of Boston
for your setup, this seems a bit rich ... dale typically sends out the carbs on the rich side as a base
Ok, since this is a public forum and all topics are concidered debateable plus I can't take it no more. Why would a Propipe that has no reversion with a scavaging design need a air altering lollipop to help reduce reversion? This compares to a guy with a 12" johnson buying a ***** pump, I'll never know about a 12" johnson but know Propipes can only have pulse collision (reversion) when you have too much backpressure by either owner modification or by trying to blow a big cube engine down the baffles throat.
The issue with the OP's high output is the manhole cover opening size is leaning out the engine, three things can happen: (1) tune the engine to the pipe best as possible as members have suggested, (2) slowly add backpressure which also raises AFR's or richens combustion by a less scavenging effect, (3) install a big motor in front of it or I guess there is a 4th of installing a exhaust system that is more suitable out of the box for a 70 hp engine. I know what I would try to do If I enjoyed the looks and sound of the high ouput and already owned it.
The issue with the OP's high output is the manhole cover opening size is leaning out the engine, three things can happen: (1) tune the engine to the pipe best as possible as members have suggested, (2) slowly add backpressure which also raises AFR's or richens combustion by a less scavenging effect, (3) install a big motor in front of it or I guess there is a 4th of installing a exhaust system that is more suitable out of the box for a 70 hp engine. I know what I would try to do If I enjoyed the looks and sound of the high ouput and already owned it.
They were designed & tested to increase low and mid range power in open duals & 2-1-2 pipes by increasing the exhaust gas velocity AND limiting engine pumping loss, that is an inevitable negative side effect when back pressure is increased.
We wrongly assumed that the high end 2-1 pipes would not benefit from the W TTI's. We made this assumption because we figured that these big companies had spent time & money to make sure they had the optimum exhaust gas velocity and minimum engine pumping loss on their High Performance pipes.
Your premise that the "Propipe has no reversion" is not one that I accept after looking at it's design and hearing what the OP is experiencing.
btw, comparing the W series of the TTI with a lollipop is like comparing a moped with a Big Twin Harley...they both got two wheels, but are very different.
Well, we have ended up with dozens upon dozens of folks with RB Racing LSR's, Thunderheaders, Bassini Road Rage and other 2-1 performance pipes report back to us that they experienced a noticeable increase in low and mid range torque when using the TTI's.
I don't know of any with the ProPipe off hand. Below are a couple of links to real world data.
https://www.hdforums.com/forum/sport...derheader.html
https://www.hdforums.com/forum/engin...sapointed.html
"Went for a ride and did some tuning with the Thunder Torque Insert installed. It did bring back a noticeable amount of low to midrange torque with out hurting the top end pull.
The smart tune tables backed this up showing an increase in the low to mid range VE. "Quite a bit in some areas." ...
I would say the Thunder Torque Insert works well with the RB Racing LSR pipe and has mine more in tune with my setup."
I agree with you, increasing back pressure can absolutely help the low and mid range torque. But I prefer to find a way to improve the torque without increasing back pressure, for above stated reasons.
Another thing we can probably agree on...it is amazing the hundreds of millions of $ in the HD exhaust market, and most of them are terribly inefficient.
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Last edited by DK Custom; Dec 25, 2013 at 05:56 PM.
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