Outer Limits 4x4 Board

I am planning to get a turbo fitted to my GQ soon. I also want to fit a free flowing exaust to get the best out of the motor. I will be getting a new mig soon so I thought I would have a go at my own exaust.

Do I buy some mandrell bends and weld into place or create my own bends by cutting small wedges and welding together till I get the right angle.

I saw this done by Garland on many years ago on his Jackaroo. Which way is best?

I've just done something similar to my exhaust - we bought four 90 degree mandrell bends and a few metres of straight - much easier than stuffing around with cutting wedges and making your own bends - that would take forever.

Not a bad idea mate you could tuck it up nice and high, away from danger.

Mines fairly well stuffed around the main muffler from rock rash etc.

the best way to weld an exhaust together is to tack it with a MIG and then oxy weld it or TIG it.

the reason for this is you dont get as much build up (penetration) inside the pipe itself which leads to turbulence, what you want is laminar flow.

also oxy welding is a very malleable weld so it can handle vibrations, nocks and abuse a lot better than MIG or TIG.

Thanks for the coments, I was thinking of using 2.5inch with a straight through muff. Could go 3inch if it would be better, but don't want it too loud as it is used to drop the kids off to school during the week.

Greg, what did the mandrell bends cost you and where did you get them from?

Faithilbilly, I thought that tig welds would be the same as mig welds so long as the amps are set correctly. I used to use a tig welder about 10 years ago with stainless steel and mild steel but my experiance with migs is very limited. I am planing to get a mig as that seems to be the most popular for all round work nowdays. I want to use if for general mild steel construclions thus thought the speed of a mig would also be better.

Any opinions welcome

bundyrum4x4 wrote:Greg, what did the mandrell bends cost you and where did you get them from?

I got them from the muffler man (malvern rd prahran)... bends are about $15 each i think but mine were 2.25"...

The people there are pretty good - you can get brand new / second hand mufflers / cat's from them too.

The 90 degree bends come with about 10 - 20 cms of straigh on each end too.

Cheers

Go see Andew at ON TRACK 4X4, exhausts are a pain in the toosh.

Is your GQ diesel??

If so, go the 3 inch!! They sound so fat! I'm getting a turbo on mine when I finally sell my pajero. I'll be going 3 inch straight through. They sound like big trucks and when you pump the accelerator going up hill climbs they sound awesome.

Just my thoughts but.

yep, its a diesel.

I like the idear of a 3inch but I would end up in the dog house again if it's too loud.

if you want your exhaust to sound loud - it may be easier (and cheaper) to just wind down the windows ... once we had mine built we found it was too loud and my girlfriend and i had to drive around with ear plugs in - not too pleasent i'm afraid - we had to put a silencer in the exhaust tip to keep the noise down a little.

you wont need much of a muffler with a turbo as the turbo does most of the muffling. definately go wid the 3" pipe and let it breath !!! 2.5 is next best if ya watchin $$$$$

We have GQ, had turbo fitted, came with 2.5", Turbo quietened it down heaps. I went and got muffler taken off and replaced with a hot dog just so I could hear it. And I use it to drop off the kids throughout the week.

Effectively the MIG and TIG process are the same.

But you have more control over "penetration" (I am using this term very broadly), with a TIG, i.e. Stuff on the other side of the weld. But it is still has a defined heat affected zone (HAZ),

Generally a weld itself wont crack, it will be the area each side of it, i.e. HAZ

with oxy welding you have still have HAZ affected base material but the HAZ is progressive and spread over a larger area ,so in a high vibration environment (exhaust) they have a much less tendency to crack, also the "penetration" is much less than a MIG

With exhaust systems for turbos you need the least amount of resistance as resistance adds to lag, slower spool up time, and generally lower boost.

In reference to welders I use a MIG an Arc/ or stick and an Oxy set, but the MIG is the one we use most.

buy a denco turbo they come with mandrel bent exhaust.