Hmmmm Exhaust Question - always wondered

[Hybrid_From_Hell]

OK

I am going to have to have an exhaust made up from the manifolds, found a firm, plan is in hand.

I have seen a number of shall we say Challenge" Motors esp 90s, where the rear part of the exhaust has been modified so instead of coming out say under the bottom of the rear tub or under the rear crossmember etc it has been raised - sometimes hugely so it comes out half way up - or higher up the rear tub sides.

My question is simply "Why" ?

1. What is to be gained doing this ?. Surely if the engine is running then its running and will be ok even if the exhaust pipe is under water ?

2. If you have the end up really high, ....say higher than the rear box, .......then when this goes under water its going to possibly fill up the box with mud and silt ?...

....being that the end is higher than the box getting the silt and mud etc out is going to prove to be next to impossible ?

3. If there is an advantage whats the legal / MOT / Road / VOSA issues or are there none ?

May be a daft Q - but I have always wondered what the reason is, is it just "Trendy" and "The thing to do" (in which case I can live without it ) or is there some logical sensible real benefit that eludes me (loads does )

Up till now I have lived without knowing why - now with an exhaust build coming I need to Know

Nige

[Guest diesel_jim]

I think it's posuer value! not sure where it started, maybe an orange tint?

and maybe to stop the very end of the pipe getting wedged against a deep rut, i've had standard pipes get pushed up just when doing green lanes.

although all you get is a "whoooooshtt" and a big puff of black smoke!

[western]

IIRC a vehicle exhaust should not exit at 90 degrees to the vehicles left [kerbside] basically to prevent pedestrians getting covered in fumes when a vehicle is started.

[white90]

very Scrapion then they all have to fit deflectors to them

looking like drain pipes.

I just tucked the rear pipe work out of the way and it has lasted well

a few examples before hand were either flattened when the cross member landed on a rock

or the Simex grabbed it and bent it double

[simonr]

Like Tony, my reason was to stop it getting squashed! I even made a version from 1/8" wall CDS and it still started to be squashed by repeated landings on. Move up 4" - problem solved.

I would have made it exit through the rear X member, but there was a sodding great Husky in the way.

Si

[Mark]

On the disco, I did it because I caught the rear box on a steep descent, and bent it almost flat. I just brought the exit out above the level of the rear bumper to keep it out of the way. Not exactly bling - made out of a bit of scrap pipe I blagged from kwik fit, but it works well, and I havn't caught it since:

[FridgeFreezer]

As has been said, mainly poser value / scrapiron sheep effect

Exiting above/through something else stops it getting squished, through the rear x-member is a good thing if you can make it happen - I couldn't due to the cubby box in the rear wing so went side exit.

Did similar on dad's RR by hacking the back box off and joining a spare 90 deg bend to the end, exiting just below the rear wing as the tail pipes were always being bashed on departure. I was surprised how little the rear silencer contributes to the noise.

Exiting really high up IMHO is of no great value (unless you go for the full Petal-style tractor stack), the bit about filling with water is academic as it will be expelled by the exhaust / evaporate in the heat.

[Pete Attryde]

On the disco, I did it because I caught the rear box on a steep descent, and bent it almost flat. I just brought the exit out above the level of the rear bumper to keep it out of the way. Not exactly bling - made out of a bit of scrap pipe I blagged from kwik fit, but it works well, and I havn't caught it since.

I did the same on My disco for the very same reason, and in the same way with a bit of scrap from an exhaust place. I have had no problems with the MOT man.

Pete.

[Coastcard]

Other option for ideas may be to look at boat exhaust designs. IIRC they have a water trap built in for such an eventuality. Not sure how they work, but maybe another avenue of investigation. Mind you they are probably designed more for the occasional splash/ transom wave than full submersion!!

Of course with MS you are never likely to require full belt and braces - should the thing stop under water .

[white90]

exhaust under water isn't a problem with diesels as they normally keep running

[Coastcard]

exhaust under water isn't a problem with diesels as they normally keep running

Trouble is the fish start swimming upside down and floating to the surface

[white90]

every silver lining has a cloud(normally of diesel exhaust)

[Def_90]

I'm bringing the exhaust of my Xcab 90 to roof level.

During my last challenge I went downhill into a pond ( not too deep ). The idle was rather slow and the engine stopped. At the same time the starter motor gave up as well. So when i was winched out we tried to bump start it, and what you guess. It was really my lucky day : Water entered the engine through the exhaust and ruined my 4.6

Result : I'm fitting a new engine for the moment and DO NOT want to happen this again.

[white90]

petrol issue rather than a diesel one then.

[LandyManLuke]

I'm bringing the exhaust of my Xcab 90 to roof level.

During my last challenge I went downhill into a pond ( not too deep ). The idle was rather slow and the engine stopped. At the same time the starter motor gave up as well. So when i was winched out we tried to bump start it, and what you guess. It was really my lucky day : Water entered the engine through the exhaust and ruined my 4.6

Result : I'm fitting a new engine for the moment and DO NOT want to happen this again.

Might have been worth towing it for a while with the plugs out, to clear the water.

[will_warne]

As others have said I think the main reason people do this is to stop the exhaust being squashed / caught up although a lot of the vehicles that have it done look like they've never seen anything more extreme as a supermarket car park let alone getting close enough to the rear cross member to crush the exhaust.

[SiWhite]

a lot of the vehicles that have it done look like they've never seen anything more extreme as a supermarket car park

I bet your Landy would love to make it that far......

[will_warne]

I bet your Landy would love to make it that far......

Si, how's the turbo Sorry, that was cruel.

Are you passing any time this week? Let me know if you are and pop round for a brew.

[muddy]

Mine comes out behind the passenger door for two reasons,

1) i'm lazy so there was less exhaust for me to fab up

2) as has been said it stops it being crushed

if i was going for a full systen i would have it out of the rear quarter.