21 replies to this topic

[SmacT]

G'day all,

 

It's exhaust time and I am going to have a crack at doing it myself, How hard can it be..? Ha ha.

 

I am going mild steel (could be talked into stainless) 3in with x pipe and under the diff - if it all works I can get more adventurous later.

 

Has anyone successfully used a generic bend/x-pipe kit? There's a few available from Summit and the like, just wondering if a kit is the way to go, or to use welding wire to bend it like I want it, then order the specific bends. 

 

Opinions welcome.

[76lxhatch]

There are two ways to get these things done right - pay a huge amount of money, or do it yourself where you're not time-restricted.

 

I usually just buy three or four 180 degree mandrel bends which can be chopped into multiple pieces to get the required angles. Add a length or two of straight pipe, mufflers and X pipe if that's what you're after. It's only tubing so you can't go too far wrong, some of the cheaper items are substantially thinner but bigger diameter is generally thicker anyway so at 3 inches it should be fine.

[SmacT]

Thanks mate - yes, I have been quoted 5-6k, and I am sure it's worth it, but I am not wanting to spend that coin. I will down the track if need be, but I don't need to get every last hp out of this thing, and you can't see an exhaust when you're driving, so figured, bugger it.

 

Thanks!

[samuel86]

Have a look at Performance Exhaust in Sydney. I've recently build my exhaust using their bends in mild steel. Use a mix of 180, 90, 45 degree bends.

 

They also sell x-pipes.

 

https://www.performanceexhaust.com.au/

[SmacT]

Thanks Samuel, I had checked them out, good to hear a reference.

[76lxhatch]

I have been quoted 5-6k, and I am sure it's worth it, but I am not wanting to spend that coin.

Wow, I don't blame you! Makes me feel really cheap, I'd struggle with spending more than $700-$800 including a good pair of mufflers.

 

I'm definitely an advocate of doing it yourself if you can, the time and care required for a good result is really what it comes down to.

[LCK186]

Hi why waist time and money doing it your self, There Is a mob in Dandynong melb who specalise in the rear pipes they are mandrel bends, up to 3 inch, perfect fit, cost wise by memory around 300  for the pair, i think they also do the lot from extractor back, if you want to make the exhaust yourself at least you can buy the rear with no cuts or welding and do the rest your self, good luck either way you decide  to go

[LJ RB30]

Yeah do it yourself if you can.
Obviously different car but I have a 3” stainless over the diff in my LJ.
All scrap metal from the dairy industry  11544097-E3C1-4A6A-A731-22F9B1CABFB3.jpeg   129.45K   3 downloads  A2124666-597D-4659-8C97-800612305856.jpeg   125.27K   3 downloads

Sorry bout the rotated pic. Too hard to do on phone but you get the idea

[derrin71]

It's not too hard really.

Just take your time.

A height adjustable prop (looks like a really tall jack stand helps). I made a really simple one from offcuts.

Stainless is easy to work with and will last forever. If you aren't looking for Motorex top 10 show quality welding you can just weld it with a normal MIG.

You need centre/offset mufflers. 14inch barrels I think? I can measure if you want. 

Make sure you use the correct HQ style hanger on the rear of the muffler. They are the best and will last forever.

I used to work in an exhaust shop .

[Bruiser]

Just finished another do it yourself exhaust system
Using bits of decent second hand pipes with suitable looking bends to join together
I have a new found respect for exhaust guys now
Front half to first muffler was a doddle
The Back end over the diff and out was a tricky thing predicting where one bend would finish
for the next one to take me where it needed to be in the 3 dimensions and have the rear muffler
sitting straight and clear of everything.
Was good fun, though
Don’ buy one of those $38 exhaust pipe flaring tools off eBay, the thread is the same
shit material as the cheap balancer pullers, and once you fix that the wedges break in half

[derrin71]

I didn’t flare anything. Just used good quality, thick, 2 bolt flange plates.

I have one join at the rear of the Pacemakers and another at the rear of the mufflers. 
Makes it really easy to remove if you need to.

[Bruiser]

Derringer, did you have to butt weld sections together? Need good welding skills for that
I’m right with you that flanges are a good idea
I even flanged for the end of the last header merge and again at the ideal collector length
just in case I get inspired to experiment with chokes or cone shapes or whatever else

* Derrin *

[Bigfella237]

Just copy this and she'll be sweet-as...

 

[Bruiser]

After spending seven years building it I would probably bang it up parking at the local shops

[gtrboyy]

BestMufflers.com in Carlton usually prices little bit lower than most...dude there also decent to deal with although can be cranky lil' mofo sometimes lol

[SmacT]

Thanks mate - I just find the off the shelf stuff never fits cos all application are different. Drop tank, sway bar, gearbox crossmember, tailshaft etc are all different combos. If you can remember the mob I will =look them up, though! Plus there's the satisfaction of doing it yourself. As well as the tears and frustration! HA ha.

 

Hi why waist time and money doing it your self, There Is a mob in Dandynong melb who specalise in the rear pipes they are mandrel bends, up to 3 inch, perfect fit, cost wise by memory around 300  for the pair, i think they also do the lot from extractor back, if you want to make the exhaust yourself at least you can buy the rear with no cuts or welding and do the rest your self, good luck either way you decide  to go

[SmacT]

Thanks everyone, some great feedback. I figured if I can trim a seat, I can do the exhaust. Ha ha.

Thanks for that Derrin, if you get a chance to measure the mufflers, great! No pressure. 

Big Fella - I am so going to do that.

[derrin71]

14" Barrels. That is what fits under the floor in the correct location. Centre offset, offset goes to the front.

Mine are dynomax straight throughs. I also have cat convertors which also act as mufflers. Without the cat's it would be too loud and attract undue attention.

Mufflers are a lottery. When I was in the industry Dynomax Turbo's were the go for a deep note. Chamber mufflers used to give that thong slapper sound.

All sorts of variables come into play. Even compression ratio. More compression = more bang = more noise.

If someone has more recent exhaust industry experience, please feel free to comment.

Mine was over 25 years ago but at least I got to work on a lot of old school stuff for a bloke who had been doing it since the 70's.

Happy to answer any questions you have.

[yel327]

Gibson make some good stainless resonators and mufflers pages 37-39:

 

Catalog2016v1sm.pdf (gibsonperformance.com)

[SmacT]

thanks Derrin. I was thinking the same with the cats. It's a 10.5:1 comp 383, so interested as to what mufflers will work best. Best guess anyway. Ha ha.

Do I start by posititoning and hs ging the mufflers, add end pipes, then add the x pipe and cats from the header flanges to the mufflers? I will flange the mufflers (rear I assume?).

thanks all for the input. This will be fun! Hopefully.

[derrin71]

My only advice on mufflers sold today would be that if you can see straight through it will be pretty loud if that’s the only silencers you have.

I would position the mufflers first. Some sort of stand to hold them up helps here. I’d cut the pipe ends (nipples) off the front (offset) of the muffler.  Shorten the nipple on the rear as much as you can and weld on a flange on the rear of the muffler (centre). This helps with tailpipe clearance. I also welded a piece of 1” flat bar on the back at the top of the muffler bent at 90 deg to go through the muffler hanger.. You can weld onto where the barrels are joined to the end caps, bent at 90deg to go through the muffler hanger. Do you have both left and right exhaust hangers just in front of the diff?

I don’t have any sort of X-pipe. (Old school) My pipes are completely separate. I cut the ends of the extractors off and welded flanges to them. 
Sounds simple but you then fill in the gap between the extractors and the mufflers.  You may need small bends at the front of the mufflers. Weld the pipes into the front of the mufflers. This will make it one piece between the extractors and the rear of the mufflers.

Hardest bit is to keep it symmetrical. The Original Torana/HQ muffler hangers with new rubbers don’t have much movement so you don’t need a great deal of clearance between the system and the floor. 10mm would be heaps.

Look at as many pics as possible of other Torana systems.

If I was doing mine again I would buy tailpipes already bent and cut/shut them to suit. The tailpipes are the worst bit. I have seen Torana tailpipes advertised on some exhaust parts websites. So many variables but with swaybars, 9” diffs, drop tanks etc.

I would only do 2 1/2” tailpipes . I have seen some guys with 3” pipes over the diff but it isn’t easy to do without knocking and rattling.

I’ve even seen the humps over the diff modified to fit larger tailpipes.

[SmacT]

That's legendary Derrin, thanks.

I am going under the diff to fit the 3in jobbies, but want a swaybar and not finding an easy solution there (fuel filter will foul the kmac I have, so I mounted the bar lower and now there won't be an easy way under the diff either). Ffs.

Okay, will do mufflers first, then fill the gap. Great info, Hope your hatch is still going great, love that car. thanks.