Outer Limits 4x4 Board

I have been collecting info about what exhaust system I should get and have some conflicting opinions.

One place said 2in or 2 1/4in with a choice of three mufflers (can swap at no cost if I don't like the sound).

Another place said 2 1/4in with a good muffler would be noisy but not noticable from inside the cabin. 2in would obviously be quieter. Extractors would make minimal power difference due to existing manifold.

Another place said extractors a must due to cracking plus 2in exhaust as 2 1/4 would drive me nuts. He said he drove a 2.6 Rodeo for 10yrs and he had extractors with 2in and muffler and still had to put a long resonator at the front to stop it droning on the hway.

Got another quote of a 2 1/2in system mandrel bend with tri flow muffler and resonator. Bit pricey being mandrel bend but he seemed to know what he was talking about. Interesting that others said to stay 2in though.

I am aware of the manifold cracking problem but mine is fine AFAIK.

The Jackaroo World website used to have on it that 2 1/4in was recommended but I can't find that particular page now.

My existing system is very rusty (the pipe) and has some small leaks. AFAIK it is the original system. The pipe measures 2in OD and the muffler is pretty much in front of the LHS rear wheel. It is not loud at all but louder than it used to be so I am presuming the muffler might be knackered. Would another 1/4in really make it heaps noisier???


HELP ME OUT PLEASE.

Hi Ute,

My 2.6 petrol pajero has extractors and a 2 1/4" exhaust, with a "hot dog" and a single "semi interference" muffler.
Straight through mufflers are too noisy, semi interference still flow well but are a fair bit quieter, and the "hot dog" kills the resonation or "droning"
Having travelled in a 2.6 pajero with the same exhaust, less the hotdog, I would never be without one! I was wearing earplugs in the car whilst towing a large trailer!

The piping inside a semi interference is arranged like this If you can use a little bit of imagination!

inlet[-------
----------]outlet

Cheers, Dean

Tas_Dean wrote:Having travelled in a 2.6 pajero with the same exhaust, less the hotdog, I would never be without one! I was wearing earplugs in the car whilst towing a large trailer!

Thanks for that. I'm beginning to see that I'll be getting a resonator regardless of the rest of the setup.

How loud is yours currently? Can you hear it with the windows up? I've been told a ute driver is less affected by exhaust noise than a wagon driver. I guess that is due to having a seperate front and rear compartment.

I'm certainly thinking that the 2 1/4in + resonator + muffler of some kind is going to get the nod.

Thanks

The two inch tube will be enough, unless you regularly hold above 4,500RPM.

The extractors will help, use a Redline straight through LARGE resonator (same size as muffler) in the front and a smaller resonator at the back to get rid of the droning.

If you rev harder (and I mean for extended periods and not just peak) go the bigger tubing.

Thanks up2nogood.

I remember a friend of mine had a 1.4L 120Y and he only had two resonators.

What benefit would you think I would gain from a 2in with 2 resonators as opposed to my current (original) system of 2in and one muffler?

My motor sits on 3000rpm at 100km/h (bit less currently with 31in tyres) and I doubt I have ever had it to 4000rpm as it doesn't rev too freely and does not like to go that high at all. Would the system you suggest expel the gases faster and thus allow the motor to rev easier?

One of the exhaust guys I spoke to said he has done quite a few Rodeos and reckons that Holdens in general put out more than average emmisions so benefit from a larger free flowing exhaust.

Thanks

2" will be enough, given 2.5" is enough for a stocko 5 litre.

The muffler is the major restriction on a Rodeo. They are a huge triple flow restrictive POC.

What I mentioned is pretty much straight through and will do the job well. And as you don't rev the tits off it you don't need bigger.

Well one of my questions to the exhaust people was 'is it better to get a larger diameter exhaust and a more restrictive muffler to quieten it OR a smaller diameter pipe and a less restrictive muffler?'

I never really thought about having two resonators and no mufflers and no one has suggested it to me. I'll be asking more questions tomorrow. Hopefully I'll have a system by the weekend as we are going away. Would be great to test it out then.

You can't reallyhear mine with the windows up, unless I'm pushing up high revs (ie past 4 1/2 thou). there is a huge change in capacity between 2" and 21/4", and again a huge change between 2 1/4 and 2 1/2". Just because 2 1/2" is "enough" for a 5 litre, doesn't necessarily mean 2" is enough for a 2.6 4cyl.
To make that statement clearer, when holden made hx v8 utes, out of the factory you had a choice between one single 2 1/4" (i think) exhaust, or twin 2" exhausts. There was almost no difference in the two systems caapacity!

If your spending your hard earned, I'd put 2 1/4 in straight up, as you don't want to spend all that cash and then be wondering if you should have put the extra 1/4" in!

When I had my exhaust fitted, I said to a small, private exhaust shop "I want an exhaust that will give me good performance, without being too loud." He fitted pacemaker extractors, 2 1/4" all through, with a hot dog in the middle and a semi interference muffler at the back. He refused to fit a straight through muffler, because it would be too loud and I'd be shitty with him. All up, fitted, $550, and he designed it well, keeping all parts up as high as possible so I don't knock it around (as much!) offroad.

Cheers, Dean

I'm booked in at a place this afternoon for 2 1/4in pipe and a muffler. The place said that they will fit a few mufflers until I get a sound I like. Not getting a resonator straight away as they said they will charge the same to fit the resonator whether or not it is fitted now or later. So we will see how it goes without first.
Not getting extractors yet either as general consensus seems to be that the Rodeo manifold isn't too bad to begin with. It is already 4-2-1. I will keep my feelers out for some 2nd hand extractors.

My last two cars had extractors but standard pipe etc so this is my first experience with getting an aftermarket exhaust system. So I'm just learning at the moment. So thanks all for your input and I'll let you know how it all progresses.

OK I got some gear fitted this afternoon. 2 1/4in with a tri flow muffler. The shop said they reckon it needs a resonator after hearing it but they never actually drove it further than the workshop to the carpark.

My feeling is that it works really well. When you put your foot down in 1st gear it now rockets off the line and is revving at 4500rpm before you can blink. A fairly unachievable rpm level before the new system. In fact the car feels like it pulls better in all gears.
The only time the noise becomes annoying is when the engine is labouring like when you put your foot down at 40km/h in 4th gear. I think of it as an audible reminder to change down a gear
I also took it for a run on the freeway and was surpised that I couldn't hear it at all.

Best of all I should be able to fit my 31in spare under the tray now

Overall I am quite happy.

Thanks all.

Utemad wrote:The only time the noise becomes annoying is when the engine is labouring like when you put your foot down at 40km/h in 4th gear. I think of it as an audible reminder to change down a gear

Just got a resonator fitted today. Exhaust was fine on the highway where I do most of my kms but annoyng around town when the engine is allowed to labour a little. That drone is completely gone now.