Just because I have all these parts in my shed, I thought I'd post some stuff for people considering boosting a D series. I know there are a lot of tweakers here. The best way to get info about the types of parts you need, is to have information. A lot of this post is info about the turbo cars that you're borrowing parts from to make a DIY turbo setup, and it's intended to serve as a visual representation for why each one is good at what it does. I'm not getting into any DSM vs. Honda he-said-she-said BS. These engines are very different.

If you're trying to fab up a turbo manifold for your DIY or "junkyard" setup, and you want to use a mitsubishi turbocharger, here's a commonly used low-cost solution. Get a 92-95 CX or VX exhaust manifold. There are other models that have manifolds like this. I know. The runners are tiny, some year cars are prone to cracking under normal use, and they don't really flow worth a crap. Well, at least the runner sizes are equal to the tiny intake and exhaust ports on your D-series head. Cheap and easy fix. Ideally, exhaust should be channeled into the turbo's exhaust housing and directed towards the exhaust wheel. You're not going to get that with this manifold. But what you will get is an enormous bore for where the catalytic converter used to be, which creates a low-pressure zone good enough to spool a properly-selected turbo.






Here's a tip for the hardcore tweakers: When you find a hi-temp hardened steel bolt that fits where the o2 sensor used to be, tap it and drill it for your EGT probe. Good luck drilling through that SOB, though. It just makes for a really clean install because the factory heat shield has a hole for it. That, and you won't compromise the strength of the cast part by drilling into it. These things like to crack. If you are concerned about possible exhaust leaks, have the bolt welded into the manifold.

 

Here's the difference between a Honda 1.5L intake manifold, and a turbo 2.0L Mitsubishi manifold. All 1.6L and 2.0L engines use the same head whether they're turbo or non-turbo, so the port sizes are the same on either engine. What the Mitsubishi lacks in port velocity, it makes up for in sheer volume. Larger intake ports work much better for moving a lot of air and making power.




A D-series head is very restrictive, so you don't need to hang a T3/T4 off the front of your motor. It can probably out-flow your head by several times. If there's too much restriction, the intake charge gets overheated. Picking a turbo that flows in the neighborhood of what your head does is ideal.

 

What the hey, here's the rest of the comparison pics.

I just happen to have a complete D15 and a 2.0L 4g63 turbo head in my shed. The DSM head pictured is from a 95. The '95 heads have smaller intake ports and larger exhaust ports on the than previous years. Head ports on the 1g DSMs are really too big for their own good. The '95+ 4g63 engines are a bit higher compression (8.5:1). They still make the same amount of power as the 90-94's (7.8:1) despite the compression bump because of a smaller turbo.

I'm only posting these to point out that one engine was designed for a turbo, and one was not. It's visually apparent. That doesn't mean that a turbo won't help the one that's not built for it, but it helps you understand what limitations it may face with moving air in and out of your engine. That's what you have to do to move enough air-to burn enough fuel-to make a lot of power. Honda engines are fuel efficient because they're very restricted by design. A junkyard setup is not going to help you much with that.

It would be best to eventually replace your intake and exhaust stuff with parts that flow better.



Here are the intake sides of the heads...

 

looks great man nice diy

 

I had to fix the title. This isn't really a DIY. It's just tech info for the DIY'ers... but thanks!

It was too easy because I had to walk right by all this stuff while tearing my intercooler off the DSM today... nothing else going on, so I thought I'd share.

 

do yuo know where to get the adapter?

 

A few shops were mentioned in another thread, and I did searches for them but came up with a link about people who raced house cats around the turn of the previous century, and thoroughbred horse breeders. (Weir Racing)

I did find these guys, though... All flange adapters are about $60. They refer to the CX/DX manifold as an HF, I believe. Does anyone know if this manifold is the same as a HF? Please speak up. I'm pretty sure it is, but there are other people that know Hondas better than I do.