Duke

It's absolute so in fact only 0.6 bar boost. It moved "slightly" better when I turned it up to 1.35 bar

Thom

Still don't understand why the 4-1 merger popped out, the pics you had posted showed serious welds... and I can't believe any back pressure caused this.

Duke

A double slip fit collector is not welded to the primaries. Some info here about the benefits: http://www.burnsstainless.com/techno...boheaders.aspx

Thom

Ok... did you also weld some outer securing "sticks"?

Duke

Read the posts Thom
Now I have added tabs and bolts to hold it together.

Thom

Hard to figure without pics that the "springs" you mentioned was actually that... sorry Sir!

Duke

Sorry I've been looking at so many headers the past years that I took it for granted. Double slip fit piping is always held together by either springs or bolts. Here's an example

Thom

Well, I saw many race headers up close in the past but could never understand how mere springs could hold them together...

Could a double-slip set up require a certain EGT level to cause the inner sleeve to expand enough and tighten the outer sleeves?

Duke

It seems to be enough with normal running temps. Everything is very tight and I had to use the sledgehammer to seat it fully. I haven't seen any soot at all around it.

refresh951

As you raised the boost a bit, what kind of hp/psi were you seeing? Looks like 30 hp+/psi? I was seeing over 20 hp/psi with the 8V head. With your setup I bet it is an amazing increase for every psi.

Duke

I don't really know but the difference is huge. The 150-200 km/h sprint was cut in half (!) timewise with high boost compared to low boost as in the video. Almost got me scared

cruise98

Love the video!

A.Wayne

I would suspect wastegate ^^^ issues with such a design. The springs helps to control harmonics, less chance of breaking header ..

Dutch944

Nice video Gustaf! I'm curious to the 1.35 video.. ;-)

A.Wayne

Where's Duke., It's Monday ....