Zetec, exhaust modification question/proposition

[berni29]

Hi Guys

I am having one of my more creative moments and was wondering is something such as the Dunnell RMP1801 - Exhaust Flanges was bought (see link below) it might with some welding and persuasion and fettling, allow the fitting of the standard twincam exhaust on the Zetec (2.0 blacktop in this case) head?

http://www.dunnellengines.com/zetec_com ... no=RMP1801

Or am I just being silly and it is totally not worth the effort even if it is possible?

I fully recognise that buying the new Spyder or Dunnell headers would be preferable.

Thoughts please!

Berni

[prezoom]

I used the Dunnell exhaust flange for my Plus2 conversion. The flange fits perfect, and the tubing fits easily inside the flange, with some moderate persuasion, to create a good match with the port. Bargain price IMHO, when you think of the time required to make something equal.

[berni29]

Hello Rob

Thank you that is great newsI Did you grind/cut the flanges off completely, or just grind them down so that they more closely fitted the ports in the Dunnell flange. It seems logical to grind the flanges to shape I think.

Wonder if anyone else has done this? I could not find any mention of it on the internet.

I shall order a flange tomorrow.......

Tks again

Berni

[mikealdren]

Hi Berni
Is the std exhaust narrower bore and so won't you lose some power?

[prezoom]

The opening in the flange is just a little bit larger than the port. Enough so, you can fit the exhaust tube into the flange and weld the tube to the flange on the head side of the flange. It will take some bending of the metal to go from the round tube to match the shape of the flange/port. Typical fussing around, but easy to do. I went a bit overboard, in making a form tool out of some round stock to stretch the metal to fit tightly in the flange. I was looking for the smoothest transition from the head to the exhaust. As mine was a Plus2, I routed the tubing forward of the engine mount, the alternator was relocated to the carb side, this made it possible to maintain the assembly as a single piece, easily removed from from the vehicle, without the usual shifting the engine. Since I was using an annular clutch release, I removed the slave cylinder ring from the clutch housing. This allowed significant additional room to keep the exhaust much higher than the original system. The only part of the exhaust that is lower than the bottom of the chassis, is where it dips below the trans tailshaft to go down the center of the chassis. Just my way of doing things.

[berni29]

Hi Berni
Is the std exhaust narrower bore and so won't you lose some power?

Hi Mike

I was wondering about that. But for my purposes I do not think it will matter. The actual exhaust port is only marginally bigger than the twincam manifold pipe, so any losses I would expect to come only at the highest rpm. Also I am planning to use a custom plenum with a standard throttle body, MAF and Zetec 2.0 ECU, so I expect the engine to produce around the same power as standard i.e 130bhp or so, which is fine for me. It's the other qualities associated with fuel injection that I am after.

I also have some GSXR600 throttle bodies which I intend to put on my twincam engine when the time comes. I could put those on the Zetec I suppose. I have the ST170 manifold which they would attach nicely to. I would have to look into the options of either running an aftermarket ECU, or a MAF/MAP setup with a standard Ford ECU of some type. That setup on the Zetec would give a fair bit more power.

Decisions, decisions..........

Berni

[berni29]

The opening in the flange is just a little bit larger than the port. Enough so, you can fit the exhaust tube into the flange and weld the tube to the flange on the head side of the flange. It will take some bending of the metal to go from the round tube to match the shape of the flange/port. Typical fussing around, but easy to do. I went a bit overboard, in making a form tool out of some round stock to stretch the metal to fit tightly in the flange. I was looking for the smoothest transition from the head to the exhaust. As mine was a Plus2, I routed the tubing forward of the engine mount, the alternator was relocated to the carb side, this made it possible to maintain the assembly as a single piece, easily removed from from the vehicle, without the usual shifting the engine. Since I was using an annular clutch release, I removed the slave cylinder ring from the clutch housing. This allowed significant additional room to keep the exhaust much higher than the original system. The only part of the exhaust that is lower than the bottom of the chassis, is where it dips below the trans tailshaft to go down the center of the chassis. Just my way of doing things.

Hi Rob

That is very interesting, thank you! I will have to experiment and see what works best for my set up......

Tks again

Berni