Andrew's '93 NA6 - KL V6 swap

Postby **NitroDann** » Fri Feb 03, 2012 3:09 pm

And L-C-D screeenz in yo wheels dawg!

Dann

Beelzeboss · Postby **Beelzeboss** » Fri Feb 03, 2012 4:45 pm

I like this Lexan cover idea :lol:

I just finished making and polishing the trumpets. It seems a shame to cover them up under some aluminium.

6 stacks are cut to length

Then the ends are machined down to 1.2mm thickness to make the spinning process easier

Then the trumpets are formed on the lathe. I hit them with some 240 and 400 grit to smooth them out. The spinning left them a bit rough.

On the engine

Bruce, I took a pic with a ruler showing the room between the manifold and the firewall. There's enough to put a 90 degree fitting, about 160mm.

That lexan top really wouldn't be very difficult to do... Damn you guys! Making more work for me :lol:

Sealing the cover against the bonnet would be awesome but the bonnet on my car isn't very straight. The car has been in a light front end accident before I bought it so it's not 100%. I plan to fix it some time in the future and I wouldn't want to have to redo the manifold.

bruce · Postby **bruce** » Sat Feb 04, 2012 12:13 pm

Hmmmmm.....
Going through the firewall is a pain as it has to go up through your brake lines. It also has to be a flexible connector to allow for engine movement.
How are you going to fit filters? Individual onto the trumpets? Seal the box and filter it through the connector?

Beelzeboss · Postby **Beelzeboss** » Sat Feb 04, 2012 12:30 pm

It's not going through the firewall. I meant there's room for a 90 degree connector to put the intake out from behind the engine to where the stock mx-5 airbox was. There's going to be a throttle body on the back of the manifold then piping to the stock mx-6 airbox. I'll use the standard filter in the airbox.

bruce · Postby **bruce** » Sat Feb 04, 2012 2:57 pm

Gotcha. I forgot about the throttle body. I keep thinking about individual throttles under each trumpet.
Anodised red or blue trumpets under a clear lexan cover then!

Beelzeboss · Postby **Beelzeboss** » Sun Feb 05, 2012 1:22 pm

Gotcha. I forgot about the throttle body. I keep thinking about individual throttles under each trumpet.
Anodised red or blue trumpets under a clear lexan cover then!

That would be pretty awesome but I have to weld the trumpets in so unfortunately no anodizing

.

I've pretty much got the manifold finished except for the welding (so it's about 10% done :roll:

). I sat a piece of glass on the top just to see what it would look like and I was sold. It's going to be lexan

I'm going to weld these 6mmx15mm strips onto the top edge of the manifold. They'll have a M6 threaded holes about every 50mm to hold the lexan and I'll also use some sort of clear sealant.

I also did some practice welds. The TIG rods I have are very old and dirty and it takes FOREVER to clean them properly. If they're not 100% clean then you get that roughness which you can see on some of the welds. I'll have to buy some new ones tomorrow, along with the lexan.

How thick a piece of lexan do you think I'll need? I was thinking 6 or 8mm but I don't really know how strong/stiff lexan is.

bruce · Postby **bruce** » Mon Feb 06, 2012 3:11 pm

Keep in mind you need to drill the lexan, so not too thick to avoid cracking.

Postby **NitroDann** » Mon Feb 06, 2012 4:38 pm

8mm. It is flexible and there will be a mighty vacuum there.

Dann

Jace · Postby **Jace** » Mon Feb 06, 2012 4:51 pm

8mm... but the thicker it is, the more refraction and the weirder the fish will look.

Beelzeboss · Postby **Beelzeboss** » Mon Feb 06, 2012 5:06 pm

Cheers guys, I wish I'd read this before I headed out shopping. The place I went to only had up to 6mm so I grabbed some of that. I also have a decent size offcut of it if I need to make a central support to stop flexing.

I also bought two 2 1/2" stainless bullet mufflers to make the exhaust a bit quieter. Here's the link:
http://www.ebay.com.au/itm/BULLET-304-S ... 3a6d30fdb3
they look very high quality for such a cheap unit. My mandrel bends also arrived in the main today. Now I have all the parts required to make my exhaust, though it would be a lot easier if I could find another MX-6 front manifold. The rear manifold points straight at the steering universal joint.

Jace · Postby **Jace** » Mon Feb 06, 2012 5:20 pm

There's a ford probe dumped outside my house... you want the exhaust manifold? haha

Beelzeboss · Postby **Beelzeboss** » Mon Feb 06, 2012 9:23 pm

Lol Jace, that would be fantastic if you could grab the front manifold from it! Happy to pay postage and a bit of $ for your trouble :lol:

Here's a few pics of the cheapie mufflers and bends.

The mufflers look pretty good for $39 a piece

Can anyone comment on how loud the exhaust will be? Factory manifolds to 2.5" 200cpsi metal cat, 2 2.5" bullet mufflers, dog leg over the subframe brace then a straight through oval twin tip muffler... Any chance it will be under the legal limit?

bruce · Postby **bruce** » Tue Feb 07, 2012 1:17 pm

I think it will be loud. In my experience bullet mufflers do nothing. What usually kills the sound is a great long hotdog in the centre section.

sailaholic · Postby **sailaholic** » Tue Feb 07, 2012 2:05 pm

I knew i had read more about the K series somewhere, stumbled across it here: http://www.solomiata.com/Mx5Engine.html

The 'K' engines are not designed for RWD and not only do the manifolds and plumbing not line up correctly for RWD but it will have oil starvation problems if used as such. MCA tried a swap of it back in 93 but was stillborn. The Susuki variant of the engine as used in the Vitara has real possibilities though! This swap has been talked about at length in the Miatapower list list and 'ask Bob' at Miata.net.

Obviously your sump is a "little different" but thought you might like the heads up.