Custom inlet manifold.
 

Over Christmas I have quite a bit of time to myself so decided to make my own inlet manifold with the different bends and sheet ally I have. It will be purely for looks but I still want the car to run nice and (maybe better than standard if possible)- but not needed..

So my questions would be if I built some sort of trumpets into a plenum would this sound as well as run okay? Also is it worth keeping the internal volume of the plenum and throats the same as standard?

Any help would be great it's more of a project to learn than anything else but it would be a nice show piece at the same time...

runner length etc plays a big role

but spec and engine will be a good starting point

See this is why I want to lean more about this sorta stuff. Engine is pretty much standard. It's a mk1 45kmiles vtr engine with a raceland 4-2-1 manifold lightened fly balanced on the crank, lightened aux pully.

That's pretty much it.

I'm not looking for more power out of this just for the car to run nice and idle nice its more a learning experience.

I have built my own inlet manifold for a b16 Honda engine but I worked from a plan using stainless tubes and flanges made in a kit by golden eagle.

best person to ask would be sandy

or do some googling on inlet tract length etc

this is a good read

http://www.team-integra.net/forum/bl...culations.html

Spot on mate ill have a read of that.

I didn't really want to ask sandy as i think he would be in the same boat as people asking me how i get the finishes i get at work ect.

As said anything i can learn from it will be a bonus because tbh I am sick of fitting shite that people have bought on ebay thinking "well I can make that but it should be better."

i was thinking that while i was writing it tbh lol

kind of defeats the purpose of his job

but theres plenty info out there

Look through google scholar. You'll find tons of papers on inlet design. Depending on how refined you want it will depend on how dig you need to research, but the digging is endless.

I've probably got photos somewhere of the innards of a Dp inlet if that helps at all? I'll try and keep an eye on this thread if you want em.

That would be good mate I got a basic formula for what length I need. Just got my head full of it all at the mo..

Inside of the manifold I made, with internal trumpets.

Here's a photo of Deans DP inlet when he had it cut about.



And here's mine:









Hope they help :)

Inlet design really is an art... In America certain companies spend an absolute fortune designing single tb inlet manifold and some have got that good that theyre pretty much as good as ITB's. I know the design I'd go for if I had to start from scratch but is quite difficult because the way these engines are layed out.

First of all you need to decide what the engine consists of I.e charged, cams, head etc

will a C2 vts inlet fit? as that'll flow a good 180 very nicely.

As I said I'm not bothered about power figures as long as I learn something from it.

That DP manifold is a nice looking bit of kit!

It's an off the shelf solution to a problem/need. If I were starting again, I'd probably still run this inlet but with a smaller throttle body. 70mm is much too big even at high power. the fuel rail should have welded fittings not the bolt on ones they supply. The supplied throttle body is a jap/generic ebay special, and the welds on the manifold are a little cold in places but it's not too bad. Still - I'm not sure you should be able to pick faults like this in a £1000 manifold.

If there was a market for them, someone could make money designing something similar and selling at a much lower cost.

The dp exhaust manifold can suck donkey dick though. Never seen a straight one from the factory, and again, not something I want to repair before fitting...

Exactly why I'm not buying a turbo mani from em and trying my own if it warps I'm not fussed won't cost me 700 so can try a few :)

Danny made an excellent manifold himself. He might give you some guidance :) constella would also be able to make one - they made their own 205 Evo manifold.

im trying a ramhorn style one like all the civic/starlet folk seem to run