exhaust manifold?! how come?

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bmw2101
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Blev medlem: tis feb 16, 2021 9:33 pm

exhaust manifold?! how come?

Inlägg av bmw2101 »

I have the b230a, the spec is 531 head i ported this myself i think the bit i may have done wrong is port the exhaust ports to the size of the gasket? , standard valves, t5 300 deg cam, compression up around 11:1 or more. Its on the LH2.4 type injection manifold, with microsquirt. Its working well.

I had it mapped with the cast type manifold, 50mm down pipes into 63mm system, it made 166 bhp

I had it mapped again with a scandix? manifold, tubular one, that went 4-2-1, although i modified it to fit RWD car and the BMW, all the tunes i modded where the same length as it was. Now, back to the same rollers and it was 160 bhp


It had lost 6 bhp. :doh: Is it the head porting? or is it just better to have the cast? i am thinking of going back to the cast one...

thanks!
Erland Cox
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Re: exhaust manifold?! how come?

Inlägg av Erland Cox »

It seems like the cast manifold worked better.
But it can be that your engine runs to lean now too.

Erland
bmw2101
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Re: exhaust manifold?! how come?

Inlägg av bmw2101 »

yes ill have to get the old map put into it and checked.

i just presumed the manifold was really restricting it. I dont know if it will now with the lh2.4 style inlet.
Erland Cox
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Re: exhaust manifold?! how come?

Inlägg av Erland Cox »

The B230F manifold is really restrictive.
I ported a 405 head for a group A engine with stock valves and got 205 CFM:s at 12mm lift.
With the nmanifold attached flow dropped to 165 CFM.

Erland
OttoB
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Re: exhaust manifold?! how come?

Inlägg av OttoB »

So it doesn't matter what cylinder head you put on B230 engine, if you use B230F intake manifold? Or how much stock 530 and F-manifold flows together?
bmw2101
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Re: exhaust manifold?! how come?

Inlägg av bmw2101 »

is there any way to flow it better ? I either have to use 2 carbs, which i dont want to do, or use the standard injection fitted to that engine type for my rallying. The K-jet dosnt have "normal" injectors, only the F type. Im at 166 bhp, if i can get more id be happy!
Thunderbo1t
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Re: exhaust manifold?! how come?

Inlägg av Thunderbo1t »

what is the rules for intakes? Modify, fabricate, replace?
https://shop.klracing.se/sv/artiklar/vo ... jall-.html
bmw2101
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Re: exhaust manifold?! how come?

Inlägg av bmw2101 »

has to be a totally factory part! you mod it at your own risk of getting caught
Thunderbo1t
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Re: exhaust manifold?! how come?

Inlägg av Thunderbo1t »

bmw2101
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Re: exhaust manifold?! how come?

Inlägg av bmw2101 »

oh that looks really interesting!! i never heard of it before, will research that! thankyou
fulsnut
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Blev medlem: tor jan 20, 2022 2:17 pm

Re: exhaust manifold?! how come?

Inlägg av fulsnut »

We tried this for about thirty years ago , maybe its a solution.
Cheating, of course :hihi:

https://www.extrudehoneafm.com/service- ... rlotte-nc/

Gaston
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Re: exhaust manifold?! how come?

Inlägg av bmw2101 »

fulsnut skrev: fre feb 18, 2022 10:22 pm We tried this for about thirty years ago , maybe its a solution.
Cheating, of course :hihi:

https://www.extrudehoneafm.com/service- ... rlotte-nc/

Gaston


yes that is exactly what id do but no one does it over in the Uk that i know of, and also i hear it is expensive?
fulsnut
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Blev medlem: tor jan 20, 2022 2:17 pm

Re: exhaust manifold?! how come?

Inlägg av fulsnut »

The main advantage was that it took the most at the outer edge of the radius.
I don't remember if it was expensive.

(correct English)? :confused:
bmw2101
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Re: exhaust manifold?! how come?

Inlägg av bmw2101 »

what bhp did you end up with? I think my lh2.4 is really restricting my engine now.
fulsnut
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Re: exhaust manifold?! how come?

Inlägg av fulsnut »

It was in a boat with B21E and first we tried with blasting sand.

Then we tried the extruder.
Maybe it gave us a few more knots. :scratch:

Erland is the expert :)
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