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Zetec exhaust manifold
Posted: Sun Aug 16, 2015 1:00 pm
by Shooter63
Can any of you guys tell me where you get/ got your exhaust manifolds from? My car has got a very well made one on at the moment but the primaries are only 1.5" , with the winter power upgrades that are going to happen I think it will strangle the power.
Regards
Shooter
Re: Zetec exhaust manifold
Posted: Mon Aug 17, 2015 11:09 pm
by stylussprinter
Shooter63 wrote:Can any of you guys tell me where you get/ got your exhaust manifolds from? My car has got a very well made one on at the moment but the primaries are only 1.5" , with the winter power upgrades that are going to happen I think it will strangle the power.
Regards
Shooter
Depends where you live . Mine was made by Graham Frankland at Exhaust By Design near Buckingham. Mines a 2lt with 231bhp so was built to my own spec of 28 inch primaries of 1 & 7/8 ths diameter joining a four into one of 2 & 3/4 qtr through pipe and exit.
Primary lengths on Zetecs can be from 28 to 32 inches long but MUST be equal length . Silencer is 22 inches by 6 inches diameter but only just gets through sound tests at track events --- so 7 inch or larger diam would be better but definitely use Basalt packing.
Re: Zetec exhaust manifold
Posted: Tue Aug 18, 2015 10:24 pm
by kevp
Rob
I dont think the primaries have to be equal on a 4 into 1. The length of the primaries are used to tune the power/torque band. With slightly different lengths for each cylinder, it will provide a wider spread of power/torque (less peaky) at the expense of outright gain.
4 into 2 aids cylinder scavenging better.
I recommend "Four Stroke Performance Tuning" by A Graham Bell.
My own engine (RIP) jumped from 164 bhp at 6500rpm to 205 at 8000. Just by changing the exhaust.
Re: Zetec exhaust manifold
Posted: Wed Aug 19, 2015 10:10 pm
by Shooter63
kevp wrote:Rob
I dont think the primaries have to be equal on a 4 into 1. The length of the primaries are used to tune the power/torque band. With slightly different lengths for each cylinder, it will provide a wider spread of power/torque (less peaky) at the expense of outright gain.
4 into 2 aids cylinder scavenging better.
I recommend "Four Stroke Performance Tuning" by A Graham Bell.
My own engine (RIP) jumped from 164 bhp at 6500rpm to 205 at 8000. Just by changing the exhaust.
To show how old I am, I've had that book since it first came out and I was tuning A series engines all of 25 years ago ( I've got the 2 stroke one as well ) what I needed to know is, did any company that made the stylus ever produce exhaust manifolds ? It seems not, so the only option I have is to get one made. The most annoying thing is that I sold my TIG welder last year due to lack of use, if I still had it I would have a crack at making one, I've still got my MIG but it wouldn't be ideal.
Shooter
Re: Zetec exhaust manifold
Posted: Fri Aug 21, 2015 8:19 am
by kevp
My 1st manifold & system came form Stylus (1998).
it was no good. A very short 4 into 1. Welding had to be re done in places, before it was installed. And the rest of the system didnt line up.
Think there was a choice of 2 systems. Through side sill or under the floor.
Re: Zetec exhaust manifold
Posted: Sat Aug 22, 2015 8:02 am
by stylussprinter
Well I chose to listen to Paul Dunnell regarding Zetecs power tuning and it was he who told me I'd lose optimum power from the engine he built unless the primaries were equal and between 28 and 32 inches ---- I assumed he knew a bit more than me .
Re: Zetec exhaust manifold
Posted: Tue Aug 25, 2015 9:20 am
by spegru
May not be relevant for ultimate power but I've recently reused the manifold off a Focus 170 ST, which are cheap as chips. Had to cut off the last y piece and use one from jetex to get it into a rwd configuration (side exhaust), but was still pretty good value.
Incidentally ford made theirs a 421......