Equal length turbo header

[sidemarkers]

There are interesting designs for the boxer subaru turbos. Has this been designed for an air cooled vw yet?

[buguy]

I wonder how important it is? But it seems like the header everyone uses for draw through appears to be pretty much equal length. The over the alternator one you always see.

[petew]

I had a long discussion with my local Turbo guru about this. He really doesn't see what all the fuss is about. I mean, check the factory systems or most of the 'log' manifolds used on inline motors and large V motors. Sure, if you want to run 80psi on a shortfuse drag motor you might. However for most of mere mortals it's a bit ridiculous...

I mean check this...



Explain to me how we'd feel the difference between that and this on the way to Crispy Creme?



If I had an inline motor, I'd weld up a log manifold in a heartbeat. Better retention of heat, more durable, cheaper, more compact, quicker spool. The "Angry octopus" seems very appealing until you own one and have to fit it under your bonnet/decklid/apron.

[sidemarkers]

Good questions, reminds me of the carburetor and efi comparisons a decade or so ago.

The top manifold seems a bit overkill but not to someone looking to achieve 400 horsepower per liter of displacement.

Bottom pic of the log manifold isn't too bad considering that the runner lengths are a few inches from being equal, not a few feet on a VW depending on the specific header designs.

My #4 header runner is by far the shortest and the only cylinder that I cracked a jug, pulled studs on and the first one to ping.

[petew]

What's your manifold look like? Got a pic?

[buguy]

My 1-2 header tubes are by far shorter than my 3-4.

[sidemarkers]

My 1-2 header tubes are by far shorter than my 3-4.

Judging from the pic it looks as though #4 is your shortest too.

[petew]

My #4 header runner is by far the shortest and the only cylinder that I cracked a jug, pulled studs on and the first one to ping.

I'm far from an expert, but I feel like the symptoms you're describing are more about mixture than exhaust primaries. Were you running EFI or Carby?

[buguy]

My #4 is shortest for sure.

[sidemarkers]

My #4 header runner is by far the shortest and the only cylinder that I cracked a jug, pulled studs on and the first one to ping.

I'm far from an expert, but I feel like the symptoms you're describing are more about mixture than exhaust primaries. Were you running EFI or Carby?

Been turbo/efi since 2001. Daily driver squareback that's been dependable minus a few mishaps here and there. When there has been a cylinder issue it's been #4.

[petew]

Have you been able to measure;
1. The heat of that particular primary relative to the others?
2. The heat of that cyl relative to others?
3. The mixture in that cyl relative to the others?

I guess, beside the issues of too much back-pressure/poor exhaust scavenging or a leaking exhaust valve, I'm struggling to see why you're having that ongoing problem.

BTW, came across this vid. Some interesting viewing re equal length runners.

https://www.youtube.com/watch?v=aSIpjNU1p4c

[Buggsy]

Swap your injectors around and see if the problems follow.

[petew]

BTW, What cooling fan system you using in your type 3?

[sidemarkers]

Swap your injectors around and see if the problems follow.

I tried this in 2005. Revamped the entire intake system and replaced the heads last summer. I might run a slightly cooler plug in the #4 cylinder in attempt to make up for the higher back pressure in the exhaust. For the most part the car is a comfortable compromise. No emissions, room for driving around with my 3 kids getting groceries, daily makes boost in the high teens.

Making an equal length header would help equalize the exhaust back pressure and allow the cylinders to have a more equal ping resistance. Maybe dual shorty headers with dual t2 turbos.

[sidemarkers]

BTW, What cooling fan system you using in your type 3?

Standard doghouse type 1 shroud. This is in conjunction with a fan cooled intercooler, water/meth injection, and an rx7 oil cooler. The head temps are usually in the mid to high 200s and the intake air temp is usually about 20 degrees above ambient. There is hella room in the engine compartment.