200 bhp Zetec 4-2-1 header’s primary and secondary and exit tube sizes and lenghts ?

[hawk1903]

As the title suggests, I am looking for the tube sizes and lengths of a typical 4-2-1 headers for up to 200 bhp n/a Zetec engine.

I am aware that there are few good suppliers of Zetec headers such as TLE, Simpson, Ashley, Retroford etc but these companies seemed not to quote the sizes in their manifolds on their websites. If I am not wrong, one of these company’s headers have 1,75” primaries which is approx. 44.5 mm OD, means probably 41 mm ID of the primaries. This mayyy be the manifold for 220 bhp + engine but probably not for the 150-200 bhp engine. It would be probably kill the torque if 1,75” primary headers used in a mild spec Zetec.

It seems that in today’s market, lots of manifolds has much larger primaries than needed and probably leaving lots of mid range torque on the table. But they certainly do look sexy. However, in the contrary longer primaries in 4-2-1 with the correct OD sizes probably working good.

I would be grateful if you could share your opinions as well as your mild tuned Zetec’s headers specs.

[katana]

Check out Graham's Video's on the 'Dyno Dog' manifold test - yes its a Pinto but the science will be the same for most engines - quite surprising outcomes! I believe there is a lot to be gained with longer (than usual) primaries and shorter secondaries if torque and mid range is the goal whilst not totally killing the top end IMHO.

[hawk1903]

Check out Graham's Video's on the 'Dyno Dog' manifold test - yes its a Pinto but the science will be the same for most engines - quite surprising outcomes! I believe there is a lot to be gained with longer (than usual) primaries and shorter secondaries if torque and mid range is the goal whilst not totally killing the top end IMHO.

Hi Katana,
Fully agree, long primaries will definitely be beneficial but having the correct IDs for primaries and secondaries also important.
I have watched and read Graham’s experiences. Very helpful for sure.
And btw I am quite surprised how come the most used Ashley rally spec 3 piece manifold does not have the long primaries.

[Graham]

And btw I am quite surprised how come the most used Ashley rally spec 3 piece manifold does not have the long primaries.

Because it was never developed as such, they just made a big version of an existing manifold, the n/a yb version of that manifold is the same just different flanges.

part of the problem is everyone thinks bigger is better, some people will buy anything if they think its uprated/better

[Graham]

Check out Graham's Video's on the 'Dyno Dog' manifold test - yes its a Pinto but the science will be the same for most engines - quite surprising outcomes! I believe there is a lot to be gained with longer (than usual) primaries and shorter secondaries if torque and mid range is the goal whilst not totally killing the top end IMHO.

i cant share it yet, but the 4 into 1 manifold test was a real eye opener

[hawk1903]

Hi Graham,
FULLY AGREE !!!
In my opinion, many big names doesn’t get the tube IDs quite right. Including the BD series engines. However, larger than needed primary IDs combined with long primaries may be saving the design.
Probably, they have their marketing strategy based on customer’s bigger is better point of view otherwise they really would know what is working better.
Instead, they may better look into stepped primaries etc

[hawk1903]

i cant share it yet, but the 4 into 1 manifold test was a real eye opener

Look forward to the article and the video. When is it going to be on-air and also published ?

[Graham]

Look forward to the article and the video. When is it going to be on-air and also published ?

article should be in next issue of classic ford magazine. i can release video 3 months after mag is published.

[hawk1903]

article should be in next issue of classic ford magazine. i can release video 3 months after mag is published.

Thank you very much Graham.

Was there a 3 pcs Ashley on the 200+ Bhp 2.2 RL31 engine ?

[Graham]

Thank you very much Graham.

Was there a 3 pcs Ashley on the 200+ Bhp 2.2 RL31 engine ?

no that had a small bore 105E 4 into 1 manifold and 2 inch system, although i think the 4 into 1 produced a dip in the middle of torque curve, which mirrors what ive seen on every single engine fitted with a 4 into 1

[hawk1903]

no that had a small bore 105E 4 into 1 manifold and 2 inch system, although i think the 4 into 1 produced a dip in the middle of torque curve, which mirrors what ive seen on every single engine fitted with a 4 into 1

Thank you very much Graham.