Hi ,
Has anyone had a twin 2-1/2" (from the Cats) fitted ie twin mufflers, twin tailpipes , twin tips? I've talked to a couple of people and it sounds like there might be clearance problems over the diff, and round the H/D towbar?
An exhaust specialist (30 years in the game) would not recommend it, he reckons single 2-1/2" is the way to go. The car is standard ride height and doesn't have the full body kit. I'm looking for a good note, not too noisy in the cabin.Thanks in advance.
Regards,
Gary.

I have twins on mine, and its low, biggest problem I have is it rubs on the body of the car (above the diff) at times. So if yours is standard ride hight I dont think you would have much of an issue providing the exhaust is fitted properley.

if you go twins make sure you get an X pipe. if you go single definetly need to be 3 inch, I would not go 2.5 single.

edit: forgot to mention I have a hayman reece tow bar too

Have you gone and talked to Dave at the place that I went to (exhaust techniques) that I told you about?

They have just put a full twin 2 1/4 stainless on my car and it sounds pretty awesome when you put the foot into it and yet is pretty quiet at idle and also quiet when you are cruising at 120km/hr on the highway. I got them to put on HPC coated pacemaker extractors, high flow cats, magnaflow x-pipe and magnaflow mufflers with twin 3 inch tips. I am pretty happy with it although as I said before in your other thread it does knock a bit on big bumps which I think is where it goes over the diff like what jeffb said above.

If you go and see dave there and talk to him he will probably show you what his AU XR8 ute sounds like (it is the black one on the website) it has a full twin system on it. He has a different brand of mufflers to what I have got and his seems to be a bit more high sounding then mine and also a bit louder.

Hi Phatal,
Yes, I've talked with Dave at Exhaust Techniques, and a few other specialists around town, and I'll be honest with you, I don't want my system to knock on the bodywork no matter how big the bump.
I've sort of narrowed it down to 3 systems that apparently sound great, but are not too awkward to fit. By that I mean, the pipework will clear the diff, and rear axle, clear my H/D towbar, not hit the floor pan etc.
I've learned that 2-1/2" twin is out of the question. 2-1/4" twin is a possibility but risky with potential knocks over bumps. The guys need to check under the car on a hoist before going ahead...and fair enough. A single 2-1/2" system with a straight through Lukey, Berklee or Super Cat is supposed to sound pretty good as well as fairly inexpensive against a twin. And a 2-1/2" to 3" single through a collector is also a go. I'm really only trying to gather information before I start doing the rounds with my Henry. Yourself and the other guys on list are my best source of info because you've been and done it,spent the money already, and you're not trying to sell me anything.
Regards,
Gary

That's cool man I wasn't trying to be pushy or anything, just trying to help you out. Before I got the twin system done the car had a single 3 inch from the first muffler back and it sounded quite good and it didn't knock at all. Since I have got the new twin system though it feels like it has a s**t load more torque especially in the mid range. From standard the EL2 has the 4 into 1 GT extractors and I ditched them in favour of the 4 - 2 -1 pacemakers (PH4000) so Im not sure what has actually given the most power gain, extractors or going from single to twin. As I understand it the twin is the better option as you get a smaller diameter pipe on both sides which keeps the airspeed of the gasses up. Also you actually end up with a bigger cross sectional area with the twins if I calculated it right the twins gets you approx 14.13 inches squared and the single gets approx 9.42 inches squared. So this means you can actually push a larger volume of air through the twins at a faster rate. Thats only my way of thinking anyway, I guess it works like that though.

I wanted a twin system on the AU very much so, but kept getting told its not possible, except on the utes.

Your cars not a ute though is it phatal? Just wondering why you can get the twin setup and garf cant.

one of my mates has an AUIII XR8 Sedan with a twin system

Yeah mine is a sedan. The only reason garf doesn't want to go a twin system is because of the possibility of the exhaust knocking on the diff etc. as it is very close. When I first got mine done it was knocking on the rear sway bar on the left. I got that fixed but it still knocks a bit on large bumps. I think that this is where it goes over the diff. They have actually come from the left turned above the axles and run straight along the axles above the diff and out the back. Also I went for twin 3 inch tips which are a very tight fit in the standard cutouts so they may be knocking as well. Also garf has a Heavy Duty tow bar which would complicate things. By the way that is twin tips exiting on one side.

anyone thought about dump pipes split at the middle and out just infront or behind rear wheels? or would there be a problem with exhaust fumes leaking up into cabin? cause ive seen them on a hill climber commodore, piece of s**t but got the idea from there

No! can do in S.A.......illegal, don't know about the rest of the states. Would solve a s**t load of problems though. Exhaust must exit the rear of the vehicle I'm almost certain.
Regards,
Gary.

thats why ya leave the tail pipe there and you wont notice until you have a good look or your close to it while its going. im thinking bout going twin but stop it just before the diff on both sides and leave existing tail pipe there but not sure how loud it would be