Seriously Exhausted?

[billjackson54]

My car uses a carburrated Ford DOHC 8 valve engine and is exhausted through a standard manifold and a big custom made stainless single silencer box located under the near side running board. It's now much too loud. Much noisier than when fitted, and the original fabricator has retired, so I'd be looking for someone else to repack the box, or an improved overall system. I have though of fitting a 4-2-1 manifold and a straight system with maybe two boxes exiting at the rear of the vehicle...or retaining Mr Ford's exhaust manifold and fitting as standard a Sierra system as possible....but I'm obviously interested to know what others have done to solve the problem of overall noise and ground clearance. What did Marlin do with the Hunter that used the same engine? Where have other members mounted their boxes? Where does the tail pipe run..over or under the rear cradle? Suggestions and experiences please.

[ggrum]

Re: Seriously Exhausted?

I have the Efi version of the 8V DOHC engine with what I assume to be the standard cast iron manifold with a 2 into 1 arrangement going into a single box mounted centrally under the car toward the rear. the output pipe from the box runs centrally under the diff and then bends to the offside rear corner to help alleviate the risk of fumes being drawn back into the car. I don't know the origin of the st steel box but it looks the same as the one I fitted to my old Roadster and that came from YKC. It was a two stage box with the front having baffles and wadding while the rear section was straight through. The car is reasonably quiet while cruising only getting a bit raspy when accelerating hard or climbing a hill.

[chris_cussen]

Re: Seriously Exhausted?

Ah Well yes, good question Bill.
When I had the DOHC engine in the exhaust ran under the floorpan and then there was a large twin pipe exhaust box tucked up under the fuel tank and the exhaust exited by the rear bumper. I put heat shield between the fuel tank and the exhaust.
With the Zetec engine the exhaust follows much the same route, with a CAT under the passenger's feet, then a box just before the diff, and another under the fuel tank. To be honest this system is noisier that the DOHC system and the first exhaust box has very little ground clearance and is prone to scraping the road if the rear suspension gets compressed going over some bumps. Not ideal and I have put a sacrificial bracket just ahead of the first box. I have been tempted to get a different system made from the CAT back. The noise is great for a quick blast around the countryside but is too much for long journeys.

[milliemarlin]

Re: Seriously Exhausted?

I too have a Zetec. The cat is in the engine compartment followed by a flexi joint and a 300mm aftermarket box under the passenger seat. I too have grounding problems.

The engine is too quiet! It does make a pleasant rumble when accelerating but when idling I can’t hear it. It is particularly annoying when trying to debug stalling problems.

Even though I can’t hear the engine on the motorway I still can’t hear the stereo.

I would imagine the cost of a readymade silencer (overseas labour) is less than the cost of repacking (UK labour).

All of which serves to confuse rather than enlighten. Sorry.
Paul

[Mike]

Re: Seriously Exhausted?

Hi Bill
I do not have a Ford engine but did create my own exhaust system for the straight 6 BMW engine.I’m currently on my third system iteration - the first two being too noisy.
From hard earned experience I would suggest the nearer the engine you can locate the first expansion box the quieter your system will be. I would go so far as to say size for size a front located box is 3 to 4 times more effective than a rear box.
The second reason for having to modify my system was to reduce (word chosen carefully) the exhaust fumes rolling back in to the cabin. My first layout looked like one of my favourite car exhausts - the E-type Jag - with two pipes exiting straight backwards near the centre of the boot. It looked great, but was awful to drive as the fumes rolled into the car making it very unpleasant to drive.
My third iteration has a slim central expansion box and two large self designed back boxes (you can order all the parts to have them welded up into your own configuration), with the tail pipes taken out to the widest part of the car behind the rear wheels.
The result is a very quiet cruiser, but sounds fabulous when you press the accelerator.
But, I still get a little exhaust fumes smell in the cabin.
My planned 4th iteration will include CATS in the exhaust manifold - ie the closest they can be to the exhaust ports for quietness, and importantly removing the noxious smell of fumes containing CO - one forgets with modern cars how horrid pre-CAT fumes are.
I the hope the central box can be eliminated, thus improving ground clearance where it really matters - ie mid wheel base.
The comments before my response seem to fit in line with my experience.

My car uses a carburrated Ford DOHC 8 valve engine and is exhausted through a standard manifold and a big custom made stainless single silencer box located under the near side running board. It's now much too loud. Much noisier than when fitted, and the original fabricator has retired, so I'd be looking for someone else to repack the box, or an improved overall system. I have though of fitting a 4-2-1 manifold and a straight system with maybe two boxes exiting at the rear of the vehicle...or retaining Mr Ford's exhaust manifold and fitting as standard a Sierra system as possible....but I'm obviously interested to know what others have done to solve the problem of overall noise and ground clearance. What did Marlin do with the Hunter that used the same engine? Where have other members mounted their boxes? Where does the tail pipe run..over or under the rear cradle? Suggestions and experiences please.

[danny_nelson]

Re: Seriously Exhausted?

Hi Mike, nothing to do with exhaust pipes. Will we see you and your car at Newark? Would be nice to catch up after all that has/is happening Danny

[Mike]

Re: Seriously Exhausted?

Hi Danny

Its 50:50?!

We have family home this weekend, so I’m trying to negotiate a pass😁
Also, my brake master cylinder has failed so I have to replace with a new one - and then (hopefully pick up an MOT on Friday afternoon.

So the answer is : Maybe and possibly!

Are you going both days?

ATB
Mike

PS
Sorry to bomb this thread.

Hi Mike, nothing to do with exhaust pipes. Will we see you and your car at Newark? Would be nice to catch up after all that has/is happening Danny

[danny_nelson]

Re: Seriously Exhausted?

Probably just Sunday, I do not have a caravan at present. Look forward to seeing you if you can make it. It has been a long time since we all enjoyed Newark.