tips for turbo manifold design

[myne]

Ok, so I picked up a t25 for 100$, and some plasticine, now I'm attempting to prototype a fairly decent 4age manifold before I get my mechanic mate make it for real.


http://www.users.on.net/~jvizard/myne/Manifold/left.jpg
http://www.users.on.net/~jvizard/myn...fold/right.jpg
http://www.users.on.net/~jvizard/myne/Manifold/side.jpg
http://www.users.on.net/~jvizard/myn.../top-ports.jpg

They say with extractors to get the runners as close to the same length as possible, and they say for 4-1 extractors to make the runners enter in the order of firing.
I've attempted to do this as much as possible.
The runners are ~32cm long, and while I havent had a chance to comapre the manifold next to the engine I think it looks promising.
I'm contemplating twisting it up more to get the turbo higher, and possibly shortening the runners.

Thoughts appreciated.

[30psi 4agte]

Nice work not sure how it will go with heat though!! plasticine might melt.

On a serious note it looks good but i think the turbo will sit too low!
If you want to keep runners same length bring the manifold up higher first the bend it down like mine on my avatar!

[LeeRoy]

+rep for innovation, thats a pretty good idea to get some sort of idea on how to knock a manifold up and get lengths and sizes right. Gumby would be proud
- LeeRoy

[roadsailing]

thats a good idea using plasticine, but will be somewhat diffiicult to transfer the angles to standard elbows.

here are some tips:

keep the pipes as short as you can without sharp bends

make sure you have good access to all bolts and studs

make sure it can be put together, i think its a good idea to start with the collector and work your way to the primarys.

have the pipes enter the turbo circularly in firing order (probably not so critical but your design does this)

make sure the turbo sits level, it looks like it has a major angle in your pics but the plasticine might have just melted.

on your design, i;d just join all the primarys where the fingernail mark on primary 1 is.

[feral4mr2]

gnarly looking manifold you have there. good stuff.

they dont 'have' to be of equal lengths. the ol log style manifold works well. IMO turbo manifold design is somewhat different to na extractors.

[c2888]

I like your cutting tool!
Good thing computer cases are so bloody sharp.

[myne]

My cut finger can attest to that.

[FATMR2]

Here is a pic of the one i made for my 4agte. I tried to keep all the runners the same length. It worked quite well so i was happy.







Oh, i just looked at the rest of those pics you have......If you sit the turbo that low you will have problems with the oil return line to the sump. The way mine sat was a little on the low side as it was but there's not much you can do in an aw11.

[roadsailing]

for all the noobs,

EDIT: this is a bigger picture of the manifold shown above - thumnail link didnt seem to work



thats a nice looking manifold fatmr2

[FATMR2]

Thats my manifold......

[oldcorollas]

it's pretty

[BigWorm]

One thing I'll mention, don't be afraid to make the runner diameters even smaller than the exhaust ports. It may look weird, but seems to work quite well in practice.

[myne]

Attempt #2
Looks neater, is about 10cm shorter per runner but I think it'll fould bigtime on the oil filter.

I'll check it out tomorrow, and most likely try again, but move it over to the right a bit more.
Also thinking of ditching the 'collector' you can see.

I was originally thinking it might work as a FWD or RWD manifold but it's apparent that it's impossible to make a decent manifold that will do either.



http://www.users.on.net/~jvizard/myn...fold/2-top.jpg
http://www.users.on.net/~jvizard/myn...old/2-left.jpg
http://www.users.on.net/~jvizard/myn...ld/2-right.jpg

[roadsailing]

turbos on backwards

[30psi 4agte]

and gasket is around wrong way!

but your getting closer!

[myne]

Turbo backwards?

It makes a difference?

Oh... It's an FWD manifold if that's what you're thinking...

3rd attempt :

http://www.users.on.net/~jvizard/myn...fold/3-top.jpg
http://www.users.on.net/~jvizard/myn...old/3-left.jpg
http://www.users.on.net/~jvizard/myn...ld/3-right.jpg

[roadsailing]

yeah, on a FWD you can put it either way. you can on RWD too, but it makes the plumbing more complex. just do it whatever way gives you the simplest pipe work and best clearance.

of a FWD one of your limiting factors is going to be radiator clearance. you could always go remote oil filter for a bit more room.

[mrshin]

Here's a tip: use playdough. At least it'll set to a nice crisy finish, and taste alright if served warm with some jam afterwards!

[Toysrme]

There are a lot of designs.
If you're a newbie, a log manifold is quicker, easier, and cheaper.
Otherwise, a Ramhorn manifold gives a quicker spool, and relatively large horsepower gains over a log manifold due to the large amount of exhaust reversion in a log manifold. (Your common t3 sized turbo on a log VS a good ramhorn on a 250bhp i4 can make a 30-50bhp peak power differance at high rpms. Rules of thumb are bad... But that wone's fairly consistant.)

From there, there are as many choices as you need, or could possibly want.
Bottom mount, top mount.
Clearance problems.
(4-1 collector is generally regarded as better, even if it means more pipes.)




Log Manifold VS 4-1 collector (ramhorn) VS a 4-2-1 merge pipes.

Log


VS
Traditional ramhorn

[Toysrme]

VS
Top Mount ramhorn








VS
4-2-1 collector


I highly suggest having a 4*6 bandsaw if you're going to tackle any sort of real manifold. Using chop saws get's old when you're cutting off only1/2 a pipe (or less) at an angle... Common "$200" bandsaw is fine. You'll want a Bi-Metal blade, and if it's not the better of the two generic Asian $200 models, you'll want to sure up the stock stand it comes on.

The largest differance is that the cheaper design has no external blade adjustments.

If you can't get what "200" bandsaw is by googling... (I'm sure yall have your $200 Chinese equivilant models).

There's the $200 harbor freight model
And the $209 harbor freight model (With aforementioned better base & externial blade adjustments) Realize that *all* $200 bandsaws from any company are one of these, or the other!

Mock-ups are great, but tack-welds are spectacular! Just a little joke.