[Miazda318]

My friend owns a 240 and on his car you can replace the intake cam with an exhaust cam. It has given the car a deeper sound and has increased torque and topend. Has anyone tried this and is this possible on a miata?

Thanks,
Tim

 

[Bryan]

Properly known as the "Exhintake" mod. Check the following Miata.net forum search, and it should answer a lot of questions:

http://forum.miata.net/vb/search.php?searchid=894216

Long story short is that not too many have tried it, but a Protege guy tried it awhile ago and, seeing as the Miata and Prote (depending on year) share engines, figured that the mod could work on the Miata's BP.

Of course, if you are driving a 1.6L car (90-93), all bets are off. Also as yet unknown if it will work on 99+ cars, as their CAS is on the front of the valve cover, and their operation will be affected, IIRC.

 

[ultimateforce]

I am offically doing this when I rebuild my motor soon. I'll let you know if it explodes.

 

[Caldera]

197.5 is the magic number. I never did it before because I didn't want to do camgears yet.

...but i have a camgear and a cam here.... seems a quick and easy project for fun!

 

[Miazda318]

I didn't think about were the CAS is on 1.6. Well since I have a 1.6 is anybody interested in buying an intake and exhaust cam. I also have an empty head that I need to get rid of.

 

[Bryan]

Well since I have a 1.6 is anybody interested in buying an intake and exhaust cam. I also have an empty head that I need to get rid of.

Make sure you post this in the For Sale/Auction section, please.

 

[freedomgli]

Miata.net searchid's expire after your session ends so don't work for directing traffic. Protege GT aka Josh Cosford has written much about his experimentation with this mod. Works okay if you've got a BP motor and adjustable or modified oem cam gears.

Exhintake w/o adjustable cam gear

 

[Bryan]

Thanks for picking up the slack for me, Kyle...I didn't realize that they expired.

Just to try to be helpful, here is a thread Alex035 started to give his impressions of the mod. Also, in case you were going to ask "Exhintake" is a combination of "Exhaust" and "Intake". I know I had to scratch my head the first time I read it

 

[Caldera]

So, i was only half-right. I didn't have an extra cam-gear... but Bill came to the rescue. My gear goes into the machine shop tomorrow.

I'm not going home this weekend, but the weekend after, it's on like Donkey Kong.

 

[Agent935]

Awesome. I'll be at your place next weekend anyway to work on getting that exhaust hanging right. I'd love to see this exintake work.

 

[Miazda318]

since the CAS is on the the intake could i use a exhaust cam from a 1.8.

 

[Caldera]

Awesome. I'll be at your place next weekend anyway to work on getting that exhaust hanging right. I'd love to see this exintake work.

Haha! Techday!

 

[Agent935]

You have more garage than house and a lift. Evryday at your place is a techday!

 

[Caldera]

It's true... so true. We gotta work on getting the hottub on the back deck and whatnot so we can have the "entertaining good looking females-day" instead of "techday" once in a while though. lol

 

[Agent935]

It'll help when you get garage #2 up and running so you can get all the cars off your lawn. ANy woman I've ever met would run screaming as soon as they saw your driveway!

 

[Bryan]

since the CAS is on the the intake could i use a exhaust cam from a 1.8.

Nope. Cams are longer (assuming you're trying to do this on a 1.6).

ps - Could you please choose a smaller sig pic? It's ridiculously large.

 

[Caldera]

It'll help when you get garage #2 up and running so you can get all the cars off your lawn. ANy woman I've ever met would run screaming as soon as they saw your driveway!

Ain't that the truth!

So I took the gear in on lunch. They told me it'd take about an hour, and cost about 60.00.

I said "eh, that's cheaper than real cams, go for it!" So i guess i'll get it back at somepoint in the next day or 2. W00t.

 

[Caldera]

...and by the next day or 2, apparently I meant "a flippin' week later!"

Hadn't heard from the machine shop all week. Went in this AM to check and see what was going on with my gear, and there it sat on the counter, just like I left it a week earlier. I was a little peeved, but glad I went in to check on it.

They called me back at around 1pm to tell me it was done. I just went and picked it up, and hopefully all is well. I had them measure out 197.5 degrees from the mark on the outer edge, and then come in to center, and drill a hole at the same distance from center as the outside edge of the other 2 existing slots on the gear.

...I'm tempted to skip seeing Borat with friends tonight so I can go install this. I'm so excited right now.

 

[Caldera]

... apparently Nature is conspiring against me getting this done. I got home around 3am and got to work. I need to oval out the camgear's drilled hole, the pin hits ever so slightly off.

... but then I got to cleaning my parts pre-install, and looked at the cam journals on my 'spare' cam.. . 2 of them are gouged to hell and back. I don't know it this will end up being useable at all. Of course I didn't find this until AFTER i hooked up the abrasive saw and chopped an inch off of my cam :grr: