3.4 V6 Exhaust

[MikeJak]

looking for some info and possibly some direct experiences...
I have a LWB with the 3.4 V6 and in the last few weeks it has developed a rumble under acceleration that disappears once you back off the accelerator, sounds very much like some lose baffles in the muffler resonating.
I have seen that milners have some very reasonably priced tail pipe and mid box in SS but the centre box is for the diesel, I have seen mention of fitting the middle box from a diesel by cutting about 10 inches from it and fit a joining piece...or get a shop to cut it and fit a flange to the cat?
Anyone gone that route? Very little info on the petrol engines.. guess not many around
I can weld but don't have a welder atm so can't fit a new flange myself, was thinging of cutting the muffler and adding a slip joint and a flange adapter to connecting it to the cat. done lots of work on cars but never much on exhausts.. what do we think?
cheers!

 

[MODVRS]

My experience so far is welding in a new flexi-pipe in the cat section to avoid buying the whole thing for £1500 and that was ten years ago. I keep an eye out for replacement sections but they are expensive e.g.

Silencer

Euro4x4parts - Silencer

www.euro4x4parts.com

I've resigned myself to either bodging what's there or getting a custom stainless system when the time comes. A few folks on here have done it, I can probably dig out the places they used if you need them. Autodoc list a couple of pattern parts (centre box £80) but they've shown no availability for a long time.

 

[MODVRS]

By the way, if you decide to investigate the "power valve" in the centre box be very careful with the nuts as they love to snap off.

 

[MikeJak]

thanks MODVRS! I'm hoping the cat is still good really, also because they are impossible to find new it seems as only European market had the cat and you probably know as well as me how few petrol there are in Europe... fitting an aftermarket cat sounds like an absolute gambel on emissions...
I think the issue I have is the mid box. I think mine is already a (very cheap) aftermarket muffler from teh previous owner as it doesn't have the power valve (it's at the front of the original mid box/muffler, right?) and the noise happens at teh rpm range where the valve should theoretically open..
full stainless systems have gone up hugly in price in teh last few years, although I would really like eventually to change the down pipes from the headers to the cat as teh Y joint has that crazy restriction...

the Milners SS is quite appealing for a cat back if I can modify the mid box to fit...

 

[MODVRS]

I see the link didn't go to the right product

And yes power valve on the front, can't believe it does anything useful

 

[MikeJak]

yes, mine is definitely already an aftermarket one, don't have the valve..damn, 846Euro... I tink was listed for 300GBP on amayama with shipping...

I think I may try the diesel midbox for the diesel from milners, https://www.milneroffroad.com/toyota-land-cruiser-5-door-3-diesel-from-1996-to-2003-kzj95/product/exhaust-pipes-components-exht-ex/exhaust-pipe-centre-box-ss-ex0029/EX0029
chop the flange and part of the pipe from my current muffler to connect to the cat and butt connect them with a sleeve...

 

[chadr]

Worthwhile investigating how much a custom SS exhaust would be - even it's only cat-back for the time being. I would imagine price-wise it's fairly comparable with imported OEM parts.

The "Y" joint (2-into-1) from the manifolds, which is roughly under bulkhead, will also eventually give up the ghost and will probably need replacing in the future.

I replaced the whole exhaust (cat-back) initially and a few years later also replaced the front "Y" section - probably documented it on this forum too.

 

[AndycruiserguyLomas]

I had the exhaust replaced in 2 visits on my V6. This was the second visit, the twin into one which cost £320 to be made and fitted. The rear half was made previously at a cost of £450.

I couldn't get a mild steel replacement anywhere so this was my only avenue. I did find it a touch noisier so I wrapped the rear half with exhaust bandage and that worked well.

 

[MikeJak]

thanks for the input, the SS costs don't sound exhorbitant will likely investigate, where did you get it done? Did you keep it 2.25" or did you size up? the Y pipe is still in pretty good condition on mine but I know eventually will need to be made and will have to be a custom one. wonder if there is a bit of gain getting rid of that awful Y joint, looks really restricted. are you still on original cat?
I'll probably give a shop a call, any suggestions hertfordshire way?
thanks!

 

[MikeJak]

Just had a quote back from a local radflo fitter… 995£ for the cat back…
Sounds a bit much I think!

 

[MikeJak]

just reporting back... done the exhaust mid box last weekend, I ended up grafting in the SS diesel mid box from Milners, looks well made, 304 stainless, and chep enough. had to cut about 10" off the front pipe and couple it with the front end of the old mid box (flanges were different so couldn't re use the one from the milners box. intended to use a coupler but with the angles I could not get the joint on a straight portion so ended up just welding it on. works a treat, sounds quiet but quite guttural when accelerating and doesn't have as much flat spot around the 2400 rpm spot

 

[MODVRS]

Did you mig weld the stainless pipe to the mild steel flange with normal mig wire and gas or something special? I'm never sure what you should do?

 

[MikeJak]

yeah... well... was a bit of a gamble and not ideal but it is a fairly mild quality SS (304 I think) so it took the weld fine with regular wire and co-argon. if it had been a more fancy stainless would have been more complicated.. I'll probably give it a coat of high temp paint to protect the weld a bit

 

[MODVRS]

Thanks, I'll have a go with more confidence when the time comes

 

[MikeJak]

Thanks, I'll have a go with more confidence when the time comes

No worries, next I would like to figure out (without rush luckily) is the headers to cat section, always thought the y pipe joining from the headers is a huge restriction but custom costs are just ridiculous