Side-exit exhaust on an 80-Series

[MikesVX80]

I see plenty of people with side exit exhausts on their 80-Series, and am considering doing the same on my '93 4.2 1HD-T to free up the breathing and make the most of the fuel pump tweaks. I would like it to exit just in front of the rear O/S wheel, under the door/sill (rather than out over the back axle as standard). Before I set to it with the angle grinder and welder, perhaps some of you guys can help me with the following:

- Do you remove both the centre box and rear silencer, or just one or t'other?
- What routing do you take (some pictures underneath would be great)?
- Can this all be fabricated using parts from the existing system, or are new bits required? Mine is a relatively new system, so would like to reuse as much as possible.
- Does this cause any problems come MOT time? Mine is a 1993 car, not sure how this affects the emissions tests or any deviations from standard spec in the UK.
- People say they sound much better without the silencer(s) in place, are they intrusively loud at motorway speeds?

I'm looking to achieve something like this:



Thanks

 

[Towpack]

I had a SS 3" bore made up from turbo back. Perhaps a little on the low side for serious of roading but I don't so no issue. You can just se the silencer. Forward of that is another silencer or resonator as the exhaust place called it. Plan was to just go with this but too loud for me so the second silencer was fitted. No problems at MOT time. Thought I had some closeups of the system somewhere but can't locate them.




Edit...

Here we are:

 

[MikesVX80]

That's great, thanks Towpack! Pretty much exactly where I want mine to exit. I intend on keeping the resonator that is behind the O/S front wheel (shown in your second pic, the first close-up), what I can't decide is whether to keep the centre box or not. I'm told removing it releases quite a bit more power, which would be a real bonus when the car is loaded up!

Do you know if the last mounting bracket (visible in your last pic, just before the pipe bends and exits sideways) is from the original system? I'm not with the car so can't check, but I would assume so!

Cheers,

Mike

 

[chapel gate]

Have you just taken that cruiser out of its box towpack? Credit to yer.

 

[stumog]

I have kept the one front box and then come off that with a 3" straight through sliencer this is then mounted to the running board. It's not the best but works well and I think it's one of the best things I have done to mine. Sorry no pictures of it but we'll pleased. The way mine is does mean you can't run rock sliders as it currently is. I may change it a bit in the future.
Stu

 

[MikesVX80]

OK, thanks. Looks like most people keep the front (centre) box and just ditch the rear silencer - my only concern is this is unlikely to give any performance gain. Did you guys notice any difference?

 

[Gary820]

Mine comes out behind the wheel but it's petrol so have 2 cats and a silencer. 2.5" diameter pipe. I would've prob squashed it if came out in front of the wheel tbh, the sliders have taken some punishment where the pipe would be.

Ditched the rear silencer and a free flow main one fitted, Def noticed a difference but again not an oil burner

 

[stumog]

I got rid of the rear silencer and the massive heavy middle one. Made a massive difference the turbo spools up so much better now.
Would like to come straight off the turbo with 3" and only 1 straight through sliencer but not yet.

 

[Towpack]

That's great, thanks Towpack! Pretty much exactly where I want mine to exit. I intend on keeping the resonator that is behind the O/S front wheel (shown in your second pic, the first close-up), what I can't decide is whether to keep the centre box or not. I'm told removing it releases quite a bit more power, which would be a real bonus when the car is loaded up!

Do you know if the last mounting bracket (visible in your last pic, just before the pipe bends and exits sideways) is from the original system? I'm not with the car so can't check, but I would assume so!

Cheers,

Mike

The pic under the wheel arch is the flex joint not the resonator. That sits between the flex and the silencer visible in the pics. AFAIK all the mounts were new.

 

[MikesVX80]

Gary - did consider that, but really want it exiting infront of the rear wheel

I got rid of the rear silencer and the massive heavy middle one. Made a massive difference the turbo spools up so much better now.
Would like to come straight off the turbo with 3" and only 1 straight through sliencer but not yet.

Hi Stu, so which one is the front box you mentioned in your previous post? AFAIK there's only a centre box and rear silencer?

The pic under the wheel arch is the flex joint not the resonator. That sits between the flex and the silencer visible in the pics. AFAIK all the mounts were new.

Aaah, so there's a resonator between that flex joint and the centre silencer?

 

[stumog]

On a standard 80 there is 3 boxes. Front one just by the pedals/ drivers feet large cylinder one in front of the rear axel the a small tail box one. I have only kept the one under the pedals drivers feet one. Mine is a 91 so could be different not sure.

 

[StarCruiser]

Same as mine Stu.

The pipe exits the turbo then through a flexi and heads for the first box which is outside the chassis rails. The pipe then hops over the right hand chassis rail to connect with the main box inside the chassis and beneath the back seats. Then the pipe goes up and over the back axle where it is squashed quite nastily and goes into the third box outside the chassis in the right rear corner. There is a clamp fixing bracket just after the connection to the turbo, then each box has a rubber mount in compression (I.e. The bracket from the exhaust sits above the support bracket with a bolted rubber flexi mount in between rather than a hanger like most cars) and there are 2 bolted flange joints between box 1 and 2, and 2 and 3 fairly close to box 2.

I've read a lot on here about the squashed pipe being a source of resistance as it is only the same size pipe as the rest and is quite well squashed. If I were going to exit after the rear wheel, I would have this squashed part made from larger section pipe before squashing so that it retained at least the same cross section as the (preferred) 3" stainless tubing used. A lot more work IMO but I do think the look of the petrol one above is nice and I like the idea of keeping it all out the way above the chassis (something the OE one fails on here as the front of the middle box gets a beating). However, of course, the straighter the whole exhaust is, the better it will breathe. So those that have had (and there is a thread on here about this) a performance exhaust in stainless made up at Pro Speed in Cardiff, have one box and all but the final exit between the chassis rails in front of the rear wheel. This area I feel is open to damage as it ends up forward of the rear trailing arm mounting on the chassis which always seems to get hit.

 

[Chris]

The squashed bit is the culprit. It really is the main restriction. I have done a couple of these home made jobs and not found the boxes particularly restrictive. On the silver one, I took them all out. On this one I have just removed the middle and small rear can. I made the new side exhaust mostly from the bits I cut out, but I did need a section from Jetex. 2.5 tube. Just to fill in where the centre (heavy) box sat. Without the squashed bit the engine breathes so much better. it's an immediate improvement. I'd like a nice stainless custom system, but truly I doubt that it would actually add much more over the chop job. This isn't a Lambo, it's just a big truck engine. Maybe if you had the header redesigned and everything smoothed out and done in 3" you might technically add a bit, but just chopping bits out probably makes the same difference near as dammit. It's a cheap way to see if you like it before committing the cash.

 

[Gary820]

No squashed bit on mine, 2.5" pipe fits through the gap. Going in for headers soon and a free flow cat, front pipe is getting a bit tatty and old so will go full stainless. Needs an oxygen sensor which looks unlikely to come out so will do all at the same time.

 

[MikesVX80]

OK, thanks guys. Mine has a very recent new mild steel exhaust system, so I will go and check this weekend what the silencer arrangement is; I think it is just a centre box under the driver's seat and a rear silencer just behind the back bumper, but I'll take a look and see!

Current thought it keep the box under the driver's seat and straight pipe from there with just one smooth bend to exit in front of the rear wheel...

 

[Towpack]

The squashed bit is the culprit. It really is the main restriction. I have done a couple of these home made jobs and not found the boxes particularly restrictive. On the silver one, I took them all out. On this one I have just removed the middle and small rear can. I made the new side exhaust mostly from the bits I cut out, but I did need a section from Jetex. 2.5 tube. Just to fill in where the centre (heavy) box sat. Without the squashed bit the engine breathes so much better. it's an immediate improvement. I'd like a nice stainless custom system, but truly I doubt that it would actually add much more over the chop job. This isn't a Lambo, it's just a big truck engine. Maybe if you had the header redesigned and everything smoothed out and done in 3" you might technically add a bit, but just chopping bits out probably makes the same difference near as dammit. It's a cheap way to see if you like it before committing the cash.

I originally wanted a rear exit exhaust but the guy at the exhaust fabricators took one look at the OE system and the squashed bit over the rear axle and said no chance, so side exit it was. Ideally with a 3" bore system you need a bigger 3" dump pipe/exit elbow on the turbo which would give a little extra oomph but given the cost of the part and fitting, maybe not worth it. JMO

 

[Chris]

We had a look at the dump pipe recently and it would take some work to get that to 3". Machining it out isn't the issue, there just isn't enough meat on the casting to do it. No point doing a 3" system without that. You may as well just stick to the original 2.25

 

[Towpack]

You'd need something like this. Not found any available off the shelf over here although I dare say you could have one made up for extra cost.
http://www.ebay.ca/itm/Toyota-Landc...H_DefaultDomain_15&hash=item19fc74dd47&_uhb=1

 

[Dave]

I have a side exit, with just the front/first little box. Can't say I noticed a jot of difference in performance, none if this 'feel the turbo spool up faster' rubbish, just a bunch more noise and a black sooty oily back wheel.

 

[Towpack]

The pump needs tweaking to get the pump to spool up faster, at least on the 1HD-FT which was set quite lean low down from the factory apparently. Made a noticeable difference to mine.