Firstly, I've got a 2.5" redback sports exhaust on my EA. I find it way too loud on the freeway, as the zorst seems to be it's loudest around 2500rpm (which happens to be my cruising speed on the highway).
I do a lot of highway driving as I'm up in Sunbury, and to get anywhere, you have to drive on the highway..
Now for the questions.. Oh, and my EA engine is perfectly stock..
1. If I swap to a 2.25 will the droning on the freeway stop? Will I need a system with 2 mufflers and a resonator to stop the droning?
2. Will I gain low end power at the expense of high end power?
3. If I have a 2.25" zorst, how do I get the exhaust to look bigger at the back? Can they put on a 3"-3.5" dump pipe on the end of a 2.25" exhaust?
1. I've got 2.25" with single lukey high-flow muffler, and it used to drone a little (before i added extractrs) - right on 2500 rpm, but anything above or below that and it sounds sweet. This can be minimised by adding a hotdog at the rear of the system. Doesn't really disrupt air flow, but makes it a fair bit quieter.
2. Pretty much... but not to any MAJOR extent... particularly on a standard motor.
3. Yes, almost any tips that are available for a 2.5" are also available for 2.25".
I have the 2.5 Redback exhaust and I can barely hear the thing when cruising. I Have the high flow muff, and a sports resinator on the rear, thats it.
I found this setup has less drone then my previous exhaust, which was 2.25 with 2 standard muffs, and a 2.5" tailpipe with no resinator. The only difference is that the current exhaust gets loud during hard acceleration.
Might pay to get a resinator on the rear dude.
__________________ CAUTION: Slippery When BOOSTING!
Ive got a 2.5 in sports exhaust only one straight through muffler, and at 110 its quite loud, but then again it dont bother me because I drove to QLD and back several times in an XD that had extractors and one muffler and a 2.25in sports. after a while u get used to it!! hehe.
Well i got a 2.5" cat back exhaust and its a noisy bastard all the time, my ears kill everytime i get outta the car, cause its resonates something shocking.... But im keeping it casue its done wonders for my performance and its noisy than most cars on the road , i guess im just a attention hog!
Well I had a 2 1/4 inch system straight through muffler and hotdog.It was good then I fitted the extrators and it wasn't that much dronier.I have know fitted a 2 1/2 inch system (mandrel bent) extractors back.At first I had 1 straight though muffler (large offset resinator)and a small hotdog 7inch after the cat.I could not drive the thing anywhere as I had a headache within 10min.This lastest a week,I then had another hotdog fitted to the rear just before the tailpipe and also wanted the exhaust moved as it was melting the bumper bar after the dyno run.It was easier to cut the pipe off and start again.This was not too bad around town it was ok but on the highway it was crap.
In the process they melted a bit of the bar with the oxy when they cut the piece off and also offset the hotdog so now it scraped in the centre just after the cat.
So back again.I had a centre section cut out including the small dog and had a 24inch one fitted.They fixed the scraping by repositioning the bends,why didn't they do that in the first place.This was good until I noticed they had put a press bend instead of mandrel and also found out when I jacked up the rear the 24 inch dog hits the tailshaft when the wheels are left to hang.So back again they fitted a mandrel bend and it looks alot better.The hotdog rubbing well I have to live with it.This is starting to sound like what happened to Bass Crazy.
So over a 2 month period my $280 system went to a $450 system in the name of reducment in noise + the distroyed parts of my car.
The result,1 24 inch hotdog,1 offset straight though muffler and 1 12 dog.Its still a pain in the ass after about an hour of driving,So the fix :
Sound deadner in all the doors,under the floor and in parts of the boot.I must say its the best $80 I have spent.The drone is just about gone,a huge improvement.Its from Clark Rubber and is 4mm thick and is a foam material.Its meant to reduce DB's by 7 db which I can say it has,mind you I haven't measured it but my girlfriend is happy with the result too.
O a good quality resinator is a piece of pipe with holes punched in it curving downwards and steel wool incased around it and it is the same size all the way though.If it is 2 1/2 inch then the interal diameter will be exactly that.A bad one when looking down the pipe you will see the hole reduce in size it might be a 2 1/2 inch but interally it could be 2 or even 1 3/4.There is also a criss cross of wires down the centre which slow the airspeed thus meant to reduce the noise.
My exhaust doesn't give me a head ache, and like you said at the start of your post lukey, it's not annoying up to 80k's.. Anything above that starts to resonate in the cabin, and although it doesn't give me a head ache, it can be annoying and I want to get rid of the sound.
So what do you reckon guys? Some sound deadening material?
When you say the doors, do you mean, on the inside of the door trims, or on the metal? Also with the floor, do you have to take all the seats and carpet out to put this on the floor, or do u do it from underneath???
The AutoGuide.com network consists of the largest network of enthusiast-owned enthusiast-operated automotive communities.
AutoGuide.com provides the latest car reviews, auto show coverage, new car prices, and automotive news. The AutoGuide network operates more than 100 automotive forums where our users consult peers for shopping information and advice, and share opinions as a community.