exhaust manifold?! how come?

[Erland Cox]

Before the plenum after the throttle so that the size increases from 55mm at the throttle to 85mm at the plenum.
Cone length 110mm:s.




Erland

[bmw2101]

so like this? If so it may stick out some that i cant get away with but i can maybe do something? Also my throttle is from the 850 so its 63mm i think. thankyou!

[Erland Cox]

Yes, With bigger throttle you can either use less cone or use larger end diameter.

Erland

[bmw2101]

right thanks, im 3d printing a cone now and see what i can do. be really interesting to see what results it makes. it should make a lot more power imho than the 160 bhp.

I had the cast manifold on the engine, then went to a tubular one, and it lost power, should i go back to the cast one now? Its a 531 head, i have ported it myself and done the chamber work, with a kl racing t5 300 degree cam in it. thankyou again!

[Erland Cox]

What is the difference in secondary length, diameter and the final pipes diameter.
Also the difference in length to the rirst muffler.
The runners of the intake manifold need some porting too.

Erland

[bmw2101]

thanks for the reply again!

i have the two manifolds, one is from norway i believe, its a scandix? or something like that, it goes 4-2-1, it is;

400mm of 40mm
600mm of 51mm
400mm of 63mm
start of the bullet box
the from the start of that box to the back box is 1600mm


it is this one but i had to mod it to fit RHD



i have a cast manifold too, that measures

cast maifold flange to
600 to in 50mm
then the rest is the same...

[Erland Cox]

Then I would guess that the header makes your engine run lean and that is why you loose hp.
Do you have a wideband lambda?

Erland

[bmw2101]

well the thing is, both times it was on the rolling road, so it was mapped properly.

So just by adding the tubular header it lost 6 bhp! i cant work it out. Ive put the tubular one back on it for now as there isnt much time to the next rally.

[Erland Cox]

I am doing a group A head for a C20XE and I found this picture.
This is the proper side of the plenum to put the throttle:



Erland

[Erland Cox]

Do you have a picture of your header?

Erland

[bmw2101]

thanks again for the reply. the xe is a really good engine, i wish i had put one in the bmw , but i think the volvo b230 will be better in the end. I had a c20xe in my Lada 2105 many years ago!


some pics




i had to modify it so that the manifold passed the steering arm. I moved the V for no2&3 back and in, but the pipe lengths are about the same as they where.

thats the manifold that lost me 6 bhp over this one





this is the exhaust



sorry its not a good pic !

[Schoopp]

I am doing a group A head for a C20XE and I found this picture.
This is the proper side of the plenum to put the throttle:



Erland

Like this?
http://forums.turbobricks.com/showthrea ... 2b01a7.jpg[/IMG]

[bmw2101]

i think its the shorter side of the manifold, not the back or front mate!


is there any gains from putting like a wedge in the bottom of the manifold, to split the flow from the top 2 pipes to the bottom 2 pipes? ilkl do a pic of it or 3d print

[Erland Cox]

Yes from the short side so that the flow entering the plenum sees less area.
What is the difference between the secondary pipes on your header and your cast manifold?
The steel 2 pipes from the cast versus the same pipes from the header.

Erland

[bmw2101]

Both are the same size, both are about the same length,.

On the tubular one, it goes into bigger than the 63mm to go over the 63mm pipe at the joint, the cast manifold goes into 63mm then the sleeve joint .

One thing i may have forgotten to say also, when i ported the head, i ported the exhaust port size to match the gasket size, a few people said this is wrong?

thankyou again for the replies!