World's first FT86 Anti-Reversion,(A/R) Header
 

I had been swapping out intake and exhaust parts for the best low-end torque and best mileage. When I opened up the exhaust with over pipe, mid pipe, and muffler, I would lose about 5 MPG. I could accelerate quicker, but only if I shift down. The low-end torque was not there for traffic acceleration. That is, quickly accelerating 5-10 MPH. That's where the V6's and V8's rule. When I run the stock exhaust the low-end torque is there, but the high-end power suffers. Back-pressure is required for better MPG and torque, but power suffers at high RPM's. After much research I learned that engines DON'T just pump air in a steady stream. They pulse at varying RPM's and varying velocities. If the RPM never varied the perfect manifold would be easy to design, but since it does, therein lies the problem. The best low-end torque is produced by a hot, high-velocity flow, through a narrow, straight pipe. I found a nice 4/2/1 header with accessible center flange bolts,(they didn't cover the center bolt with a primary) and bought 4 Harley A/R cones, then got replacement flanges and had a shop cut off the existing flanges and counter-sink the A/R cones into the new flanges and weld onto the header. See Pics below. I just got installed today and man is it fun! It pulls from 2000 RPM's all the way up to redline. If the power drops off at redline, I couldn't tell. More torque AND more power! The cure for the automatic FT86 is here! :burnrubber:

Do you have any dynos to back this up?

Wow that looks nice

DAT ASS

I'm going to dyno test it in the next few weeks. Have to find a dyno that will test down to 1000 RPM's to show improvement in low-end torque. All the headers I've tried before made it run like a 2-stroke dirt bike, no power down low, but once it's wound up it moved OK. Just OK. Remember I'm driving an A/T so my gearing is way taller than a manual's. I'll post video's once I get them. It's hard to believe this isn't FI the way it drives now. The torque dip is gone completely and it accelerates like it's supercharged. I'll have to find someone else in the Portland/Vancouver area to bear witness to my claims. Who should I ask to test drive it?

Try Wryann at VIP Performance, Portland. He has a dyne shop and a FRS.

I wanna drive this magic torque beast!

PM me your phone number. I'll call and set something up. I'm in Portland all the time.

Interesting. Theoretically you should be able to minimise the reversion with a tune and headers with the right length of runner. It depends a little on why you are lacking torque down low tho. Traditionally if you had a lot of overlap with your cams you could adjust the length of your runners to add some reversion at low RPM to help the air fuel mix in your cylinder and to also scavange from the cyinder at higher RPM. However VVTI makes this fairly redundant.

I am looking forward to seeing the dyno results. A quick google showed mixed opinions in the Harley world. Good on you for giving it a go OP.

Very interested in before/after dyno sheets.

FWIW my AT FRS gained 10-15 ft lbs between 3-7k rpm with just a Borla UEL header, HFC front pipe and a tune. There was no loss of tq or mpg.


IMO you need a tune.

I have been using the OpenFlash tablet for tuning, and even when I had the turbo I noticed the same thing, when I installed larger aftermarket exhaust I lost low-end torque and MPG. I've had catted and catless headers midpipes, flow-through and restrictive mufflers, and the results have always been the same, the less back-pressure there is, the less torque and MPG, regardless of which tune I was running. Maybe this A/R header is finally giving enough restriction for me to run a free-flowing exhaust. I don't know why it works, but it definitely works. I'll try getting some video today.

interesting! keep us posted.

AKA torque cones....These have been around forever..Any Harely rider that's been around a while will recognize them. Here is a dyno http://www.nrhsperformance.com/tech_arcones.shtml

I'm pretty sure there's a good reason why none of the mfg use these "torque cones". Guess some dynos will be able to explain!