In my last build I had quite the dip in torque from 2000-3000 rpm. I know, I know, it's mostly in the RB pipe. They really are not all that good in the low, low end so I thought I would try to do something about it. Some people have used torque nozzles and lolli pops but I don't want to hurt the top end any.
Usually what you do to improve on the bottom end will take away from the top end and vice versa, just like in cams... That's why it so hard to really decide how and where you want your power. Wouldn't it be nice if it was every where across the curve?...... yea baby..... So this is my attempt at achieving my goal. I made this Baffle hoping that it would give me enough back pressure at the bottom to bring the torque on a little sooner but still able to let it breath on top....
I expanded a piece of exhaust pipe and cut in six louvers in a diagonal pattern in hopes of getting a small spiral effect to change the speed of the exhaust gases between the inside of the baffle and the outside of the baffle. It slips inside of the RB baffle and has a securing mount I brazed on. If you notice the louvers are facing upstream towards the head (unlike all pipe manufacturers who face the louvers in the direction of the exhaust). I'm thinking that with the two different speeds of the exhaust gases (Inner and Outer flow) that there would be less chance of reversion back up the pipe. I guess you can actually call it a diverter. Here's some pics. It will sit further in the pipe from what you see in the pic's...
Anyways, my motor is still upstate and am hoping that I'll have it back within the month.... Not going after the top build anymore but a real good bottom end to a great midrange and real good top end. 10.3:1 is the goal for static and am trying to build around that and my experimental cam..... So once Scott is done I'll get the motor back in the bike and bring it back up to him for dyno tuning, hopefully by the end of April....
So After he's done tuning it with the unmodified Rb pipe I will at that point install the Baffle/diverter and do a couple more pulls and see exactly what the difference will be. Same Day, Time, Temp, Dyno etc. So there should not be any disputing of the results..... If my theory works I'll be very happy. If not, all I did was educate myself so no real loss there either... Funny how the older you get the more time you have...
Yea I know, I have too much time on my hands so I figured why not challenge my brain.... who's know's. At least I will have the evidence of whether or not it will be successful....
Last edited by 98hotrodfatboy; 03-09-2017 at 09:26 PM.
very interesting. Don't the gases already flow at different speeds? Wouldn't you also like to know how it would work turned away from the heads? Just asking
very interesting. Don't the gases already flow at different speeds? Wouldn't you also like to know how it would work turned away from the heads? Just asking
NO, with the original baffle in there with the louvers directed away from the heads we already know how that works and at that point it would only be an extension of that baffle.
Bob, When i had my 94 Special out to Hillsides for a thunder jet install and tune I had a RB pipe on it. They had to add to the what amounted to a 1/2" wide piece of flat stock with an L bend. drilled a hole thru and attached that to the inside of the pipe. It helped a lot with the low dip in the torque curve... Your idea is interesting.
Nice work...will be interested to see how it works out. Is one holding bolt enough? Thanks for posting. YD
It should hold fine. When I expanded the pipe diameter it actually will have to be pressed into the existing baffle so the bolt mount is primarily for stabilization.... If anything we'll find out.
Bob, When i had my 94 Special out to Hillsides for a thunder jet install and tune I had a RB pipe on it. They had to add to the what amounted to a 1/2" wide piece of flat stock with an L bend. drilled a hole thru and attached that to the inside of the pipe. It helped a lot with the low dip in the torque curve... Your idea is interesting.
Yea Dave it's funny that you mention that because before doing this I spoke with Scott about picking up the bottom end a little and he recommended a torque nozzle that he was going to machine for fitness in my pipe. So I decided to take it a little further and experiment. We'll see how it works out... I figure if anything I probably saved a couple of hundred for now. If it doesn't work then we'll go his route... Thanx man...
That came out nice... I think the facing the loovers in the opposite direction is going to create huge difference.. I'm curious what it will do to your new curve when you run it. My money is on"too much back pressure"..keep us posted !!
That came out nice... I think the facing the loovers in the opposite direction is going to create huge difference.. I'm curious what it will do to your new curve when you run it. My money is on"too much back pressure"..keep us posted !!
Absolutely.... Because it's at the very end of the pipe I'm pretty sure the exhaust gases will still be able to clear themselves without it building up too much back pressure... I'm quite anxious to see myself...
Last edited by 98hotrodfatboy; 03-11-2017 at 11:28 AM.
03-09-2017, 09:23 PM
Home-Made Baffle
