I love my true duals but i wanna quiet them down a tad. Ran across the cone inserts that they have at Jegs.com and summitracing.com. Im curious as to how much backpressure they will add. Im thinking they wouldnt hurt flow that much. Its basically a screen. Any thoughts?

 

TTT. I thought some people had them here. Anyone. I need some input on these. They seem like they would work well with true duals without hurting performance.

 

No they'd be a good idea. I havent personally used them, but some buddy's have and they add a bit of backpressure to an already open exhaust (like a true dual setup)



I wouldn't think they'd hurt performance any more than a high flow cat would...if even that much...

 

Thats what i was thinking. If it were on a 3in single exhaust system I probably wouldnt do it but since its on my true duals and it already doesnt have much backpressure, I would think they would'nt hurt much if any at all. Even if they did hurt only a couple HP would be worth trading off for alot quieter true dual system. BTW, thanks for the reply. I did a search on these cone inserts and all the post's 9only like 5) ended up with hardly any responses. I figured more people had went with the inserts by now.

 

if even it doesnt work it would be worth the small investment just to see if it works

 

Problem is they are not cheap. I bought a pair of the Dynatech 3" cones already mounted in the 90-deg turndowns. They are now $80 each in JEG's..... I think I paid way less than that a year ago..... maybe $60 each.

I never tried them. My idea was to stick them on if my exhaust system did not meet the noise 90dB limit at Englishtown/Raceway Park, but is passed tech with just the plain turndowns on it (Borla XR-1 shorty on each header collector, 3" pipe back to the axle, 90-deg turndown).

I had also intended to try them on the dyno last time I checked the tune, but we found some problems and spent most of the time fixing those problems, and had no time for an extra pull with the Dynatech cones.

The reason they use the perforated "cone" is to make the open area of the perforations the same as the cross-section of the pipe, so HP losses should be minimal. I would have liked to see what they did on an 800HP nitrous pull..... maybe next time.

 

I'm using a single 3" Vortex insert cone diffuser in my setup that I got from Jegs for $60. I've got SLP single cat headers & y-pipe, offroad pipe/cutout, Borla catback. I had been using the cone in my ORP right after the cutout before the S bend in the catback. I hated the way the exhaust sounded without the cat in there, I thought all that crackling, popping noise it made under decelleration sounded nasty. The cone took out almost all of the bad sounds I didn't like, but the exhaust still sounds very raw and mean. I was going to due some testing of how much it effects the backpressure at the track by running the cutout open then closed but didn't get the chance last year, last time I just ran it with the cutout open. Just this weekend I was in the process of moving the cone to the rear of the exhaust, I'm putting it in right before the Y at the Borla muffler. I'm pretty sure it will be less of a restriction at the end of the exhaust where exhaust gasses are less dense, well see.

 

I'm with Greg on this,
I have Jet-Hot LT's and an ORP, and flowmaster.
Without the cone the exhaust sounded like crap, way too raspy for my taste. I added the cone right before the muffler and it has quited down the rasp substantially. According to vortech, it is not supposed to any hardly any backpressure because the holes in the cone add up to a bigger area than the 3" pipe does. Makes sense I guess.
Good luck.

 

Great. Thanks for the replies. I'm gonna buy some to put in my true duals. I'll make some soundclips as soon as I do.