Purple Hornies Glass Packs

[Bob E.]

I've been reading up on the glass pack mod and will be doing that project this winter...finally.   From what I gather, a 2" glass pack (core opening) 18" long is what most are using since the 12" long packs seem too loud and harsh and the 2" opening provides proper back pressure. Consensus seems to be that the Purple Hornies are the glass pack of choice for the best sound so I was going to get those.  So I set out shopping.

One thing I cannot figure out is there is only one model of slip-fit Purple Hornie glass pack and it shows a 3.5" diameter body, 18" long (24" overall length) with 2.25" inlet/outlet.  However, in my search, there was a post that stated that Purple Hornies are 3" diameter and 2" inlet/outlet.  Is there a different model that was maybe discontinued?  Since the Air-Flo stacks are 4" diameter, I'm guessing the 3.5" diameter body will fit ok.  But I'm concerned about the inlet/outlet diameters since the recommendations are to keep the core opening at 2" to maintain adequate back pressure.  From the pics of the glass pack, it appears that the inlet/outlet pipes neck down right at the body of the muffler.  Can someone tell me whether it necks down to 2" through the core?  And finally, is the 2.25" diameter the inside or outside diameter of the inlet/outlet pipes?  I need to know what size reducer pipe I'll need to buy.  Nobody has the Purple Hornies in stock locally so I will have to order them, or I'd just go to the store and measure them.

Thanks in advance for the info.

[Tropic traveler]

I wouldn't get too hung up on a brand of glass pack for your project, they are pretty much all the same. I used plain old muffler shop GP's for my system for my '97. They have been on my bike for over 50,000 miles.
Two inch I.D. is what my research told me to use with the "scoops" or "scallops" facing towards the exhaust flow for proper back pressure. From what I know from my years in the auto parts biz most all mufflers openings are sized as inside diameter so a 2" is what you are looking for. Get them as long as you can as length = deeper tone. I love mine & although not scientific at all my butt dyno says they help in the power department. 




BTW, if the outlet of your GP empties into a truck stack or long extension tip you probably will have a noticeable drone. I had to make a "tip within a tip" set up to get the drone out of my GP set up.
 

[Mr.BubblesVRCCDS0008]

I had purple hornies in my stacks for years never noticed the drone. one day I pulled them out and never replaced them. been running straight from the reducer on the back of the 2ins of the stock collector that I left after removing all the stock muffler for several years now. It pops alittle on deceal but it really isn't too loud unless you want it to be.

[Bob E.]

Thanks for the info guys. I guess I'll skip the purple hornless and just go with whatever I can find with 2" cores. That way I don't have to worry about having enough back pressure and they should be cheaper too.

[frosty]

I have done a few exhaust mods using the Purple hornies. Have turned them both directions. Cant tell any dif in sound. I do use the baffle can in mine. Like to hear the radio. When riding with the Harley boys I'll pull the cans out. Mainly any brand will prob. work. Consid. the dia. for stacks to slide over and if poss. get both or at least one spout end straight. If not can always cut  bent ends of muff off. I used pipe couplers and nipples. I would advise keeping the baffle cans.has some drone cans out.  Never know as old age approaches may want little quiter. Or buyer may want if ever sell.

[Bob E.]

I have done a few exhaust mods using the Purple hornies. Have turned them both directions. Cant tell any dif in sound. I do use the baffle can in mine. Like to hear the radio. When riding with the Harley boys I'll pull the cans out. Mainly any brand will prob. work. Consid. the dia. for stacks to slide over and if poss. get both or at least one spout end straight. If not can always cut  bent ends of muff off. I used pipe couplers and nipples. I would advise keeping the baffle cans.has some drone cans out.  Never know as old age approaches may want little quiter. Or buyer may want if ever sell.

Thanks!   The good thing is that I have a spare set of OEM pipes that I picked up cheap a few years ago for this project.  So I will not be cutting up my good original set in case I don't like the noise.    

I've also I got a set of used Cobras that I got cheap and have had laying around that I never did install.  I gotta get them cleaned up and on the Classifieds.  Does anyone know what they go for these days?  They aren't in bad shape, but clearly not perfect.  I was thinking in the neighborhood of $150 or so.

[Mr.BubblesVRCCDS0008]

Mine really isn't that loud at 3000-3500 rpms in high gear I can hear the radio either on the speakers or thru the headsets. I do have some baffles made from the rear part of the factory mufflers I can slip in for real long trips, but so far only used them once. Maybe when I get older I'll quiet it down.