Would true duals like this fit on my '88 FLHTC without major mods? If so would I gain anything from it? I have head pipes with the crossover from a 05 and V&H Twin Slash slipons on it now.

 

No you won't gain anything.
As a matter of fact you will lose just a bit if you go from pipes with a crossover to true duals.

 

Thank you. Just what I needed to know.

 

IMHO, I've found that most true duals wont' give you any gains. In the past, I've found that 2-1's end up being better for performance, and if you get the right ones, have great sound. My evo softail custom ended up loving the cycle shack 2-1.

 

When I put true dual headers on my '90 FLHTC, I can't say I noticed any difference in performance. It was a total pig before, and it's still a total pig after.

 

Sounds like it's time to put a 111 in then!!!!!!!!!!!!

 

I see your running a ThunderJet. what else did you do t the motor? And did you dyno tune it? How old are those pipes, Part#?

 

True Duals will gain in one area and that is the sound is better, a Rinehart TD setup is as about as good it gets in sound. Even a top notch TD system is known for a torque dip right under 2500 rpm where we ride the most, now if you put some go faster products in the 80" the dip won't be noticed as much but never match a 2-1.

Downfall of the 2-1 is you lose some of the Harley sound, looks like crap on a dresser not having the 2 muffler set up. I've always followed the path of buying a used exhaust, people out there have too much money and change pipes like underwear. Last 2 exhausts have been 2-1 and built a ghost pipe set up by cutting the left pipe off the stock exhaust and buying a used muffler to match. Had the Rineharts TD's years ago before the performance bug hit, loved the sound of them but a Harley engine works better with function over sound, if you are not worried about every bit of performance and like a Harley sound then a TD works.

 

I've run the stock pipes, plus TDs and more recently a SuperTrapp 2-into-1. One of the problems I had with the TDs is that our older bikes have a slightly bulkier primary chaincase than later bikes and with the set I had (Samsons) my left pipe never would clear it properly - after a while it would rest it's weary bones on top of the casing and create vibration problems. I never could solve that.

I had the bike dyno set-up with those pipes, which confirms earlier comments about the dip in the torque curve. Later I fitted my SuperTrapp and had it tuned again, which transformed the bike in many more ways than I anticipated, for the better. The torque curve was significantly boosted in the low/mid rev range and the bike was noticeably quicker off the mark and in the gears. In top gear with Mrs B plus the kitchen sink we could outpace a friend riding solo on his BMW GS, even when he changed down a gear or two. No comparison before and after! The real bonus is how much smoother running the engine is - the whole riding experience is greatly improved. No more TDs for us.

As for 2-into-1s, they are things of great beauty and Harleys have used them much longer than those ridiculous twin muffler abominations! There, I've said it!

 

Ya, we can see where your coming from on your view