Best Exhaust Manifold?

[tom_beverley]

Its the last piece of my engine to make it complete and was wondering which makes/types you run/have ran and how you rate them. Haven't decided 4-1 or 4-2-1 yet, also would I be better getting a bigger bore middle pipe (I'm thinking straight through) and what size without affecting back pressure?

[Adam]

A 2" bore system, and a 4-1 manifold.

Should work best on a engine on T40s.

[tom_beverley]

Are more gains available from different brands e.g. Janspeed over say Sportex due to a better design?

[garyc]

BTB are meant to be the best, but they aint cheap ;-)

[Adam]

Are more gains available from different brands e.g. Janspeed over say Sportex due to a better design?
Depends if you want to pay for a stainless system/manifold, or mild steel.

Mild steel you could go for ashley,janspeed etc.

I'd avoid sportex personally.

[Ash]

wot size is the engine, i read somewhere a 4-2-1 is better for a small block (<1.6) and a 4-1 is better for big blocks.

A

[garyc]

It has nothing to do with engine size, 4-2-1 is meant to aid lowdown and mid range power. 4-1 meant to help top end power. Go for a 4-2-1 if you can find one.

[Dan]

4-1 is the ideal manifold imo. the old lower/midrange vrs top end is twaddle as it depends on how the rest of the engine is set up.

i personally run the 4-1 and i set my engine up for low/midrange power which is what i have.

best advice is dont believe the hype

[Stuart]

^^ ditto. the whole 4-2-1/4-1 argument is really for uber high spec engines running silly power/torque etc and thats where you would notice. whereas on yer reasonably tuned 1.6 you wont really notice the difference tbh

[tom_beverley]

Thanks for the info, I'll go for the 4-1 manifold now, since my setup is already geared for low and mid range power with the cam on song at 3k and T40's and B+ head.

Can anyone recommend a good producer of 4-1 manifolds, I've read mags and had a look on the internet but I'm having difficulty finding any stainless ones!

Do you think it would be possible to get a limited run of manifolds made if I can get enough buyers together?

[Geth]

If you could get some stainless ones made up I'd be interested. I'm running a mild steel janspeed at the moment. It does the job and well happy with the high end flow, but the stainless steel looks really shabby now.

If you can't find a stainless one and have to go for mild steel I would recomend removing any paint that they have sprayed on and then spraying some VHT paint on. For some reason Janspeed use normal paint which flakes off within seconds of turning the engine on. I don't know if other manufacturers do the same.

[garyc]

BTB exhausts do stainless. Much better design than the flat 4-1 Ashley type. Unfortunately they're not cheap. If I get some spare time over the w/e I may post up how they look.

[tom_beverley]

That would be useful gary :thumb:

I've been in contact with BTB Exhausts and they do make a special order stainless manifold with expected delivery around 5-6 weeks. They did not mention a price and I am replying to find this out and if there would any chance of getting a run made with a discounted price.

They gave me prices for mild steel manifold which go for ?213+VAT both of these have the Lambda sensor though which I don't need as I don't need a cat.

[Adam]

Have one with the lambda sensor, you can always just blank it off.
And then when you come to sell it, it will be useful for quite a few engines :thumb:

[SRlew]

yer iv got an ashley 4-1, carnt say anything bad about it apart from the paint, as already said, id take the factory paint off and do it yourself.

[garyc]

http://www2.novaload.net/files/dan/manifold.jpg

[Dan]

Ok, now i have edited gary's pic which was the size of belguim (pls dont do it again)

here is a picture of my old and new manifold before i wrapped it, old one didnt have lambda pic up new one does but not an issue either way (i got a new one due to 9 yrs of abuse being enough for the old one lol)

http://www2.novaload.net/files/dan/2006/oldandnew.jpg

http://www2.novaload.net/files/dan/2006/exfin2.jpg

[uvcorsa]

i have a c12nz engine in my corsa, what manifolds fit these, am i right in believing most nova/corsa 8v engines share the same size exhaust manifolds, so which one is best to get, cheapest, and if ne1 has one they are selling. I know people will say whats the point tuning a 1.2, but i cant afford an engine change and the insurance so gotta make do with what i got

[Adam]

Corsa has a different downpipe to a nova, so a 4branch manifold to a nova wont fit a corsa.