Headers v/s manifold

[GeekOKent]

Hello,

Wondering if anyone has had the exhaust manifold replaced with headers, and has an opinion on the impact made?

Ideally with the 1hz.

I am considering it, and going to a 3' downstream. But looking for some opinions first.

Also, is anyone in the UK doing this sort of fab work? Or am I going to need to import it from Australia?

 

[Grimbo]

Benefit of import from Aus is it will be from a proven manufacturer with hopefully dyno results to back up their claims..... and of a proven quality, Australia is the best testing ground for decent kit

I've seen some nice looking exhaust manifolds on rally cars that when you dyno them actually have a negative affect..... more to the art of manifolds than a few bigger tubes especially on petrols

Personally I would bite the bullet and spend some time emailing the well known Aus exhaust company's .... supply and lead time likely to be your biggest issue

 

[GeekOKent]

Yeah, I have been looking at Genie and Pacemaker, both in Australia. What I am wondering is if it's worth the effort?

 

[Grimbo]

If a reputable company they should have dyno figures available......
I doubt the exhaust is that restrictive....

 

[Towpack]

Personally I doubt a low revving diesel like the 1H engines would benefit from fancy headers. On higher revving petrol engines exhaust scavenging is as important as free flow. Look at motorcycle engines which generally are in a much higher state of tune than car engines, hence they nearly all have tuned headers. I've seen tests on aftermarket bike exhausts that ruined the power delivery, even though they sounded "faster"!
There's a place in Sheffield that make bespoke exhausts for just about anything.


Exhaust fabrication

 

[Rodger]

I replaced the manifold on my 2H with a set of headers - actually they were for the petrol 60 series so we had new profiles cur for mating to the head - and then into a single box S/S system which we worked out the optimum length with a race car exhaust maker now long since retired. 2H was never great at hills and I live in the mountains but now the engine revs freer, and climbs hills in a gear higher than before. For me that was the best modification we've have made.

Regards,

Rodger

 

[stumog]

What is meant by extractors as i see that alot for the 1hz mentioned. Best off fitting a turbo Rich Sims has a kit on his 76 and that is impressive figures. Might be worth speaking to hin

 

[GeekOKent]

Turbos seem a lot more intrusive to be honest. Maybe that is something for next year!

The extractors are just pipes down from the engine into the exhaust, one per cylinder. unlike a manifold that is a single common chamber. The idea being that when exhaust gas is pushed out of one cylinder it creates no back pressure on the others, so the engine will breathe 'easier'.

 

[Gary820]

Kept the manifold on the 1fz fe and had larger downpipes fitted, i was going to go full headers but the cost wasn't worth the little extra gain. It was a noticeable difference just with downpipes, it revs smoothly all the way to the redline.
If easy to import a pre made and tested item for a reasonable price i don't see a negative.