Exhintake Cams Mod

[Jack-MX5ATLanta.com]

Has anyone done this? I found a modified exhaust cam for sale on Mturbo.net which prompted me to do some research and it really seems like an effective low price mod. Which is unusual really because I would have expected to have heard of it by now.

The basics of whats happening for those of you who like me had never heard of this; is the exhaust cam on the 1.8's is 2 degrees different (wrong terminology...I know) than the intake cam. Now putting this in place of the intake cam would allow for more flow and more power.

But the exhaust cam on the 1.8 is the one that deals with the CAS, so that part needs cutting off and then something at the other end of the cam needs doing too. A hole needs drilling in the cam gear or you run with adjustable cam gears and mix things up.

Righto, I completely butchered what I was trying to say then so I'll provide a few links too.

http://forum.miata.net/vb/showthread.php?t=210416&highlight=exhintake dyno

You would use a 94-97 cam in a 94-97 head. Unless you wanted to swap to solid lifters with the 99 cam.

I have a 95 exhaust cam that I just modified to use in my 95 head. You have to chop off the CAS end, and redrill the cam gear to 197.5 degrees clockwise from the "I".

I haven't installed mine yet, but I'm all set to do so. I'll probably install it when I do my timing belt this spring.

Hacked off end: http://i13.photobucket.com/albums/a269/lincolnwilcox/New%20Miata/IMG_0440.jpg

Re-drilled cam gear: http://i13.photobucket.com/albums/a269/lincolnwilcox/New%20Miata/IMG_0446.jpg

Total cost = $60. Not bad for a few HP.http://forum.miata.net/vb/showthread.php?t=18329&highlight=exhintake





This post is a bit messy but hopefully it's understandable.


Just found a great guide!

http://www.diymiata.com/exhintake.html

[jesseealexander]

ive heard of people doing this on m3s... seems like a good idea

[RotorNutFD3S]

I've seen a few threads scattered across mt.net and cr.net where it has been done successfully. I don't think anyone locally has done it, but I can't remember for sure.

[Jack-MX5ATLanta.com]

I think I might go ahead and do it. I've not found any reasons not to yet. A few people predict lumpy idles but the people who've actually done it don't say anything about it. I don't even think they use engine management but just adjust the cam timing.

[redrumracer]

I have an extra 99 exhaust cam laying around and I have been meaning to do this, I just dont have a torque wrench to finish the job.

[Jack-MX5ATLanta.com]

This guide is great:

http://www.diymiata.com/exhintake.html

I just put it in the first post too.

[N3v]

awesome. I'm gonna do this pretty soon.

[FlipKing]

What kind of power is it suppose to add?

[Jack-MX5ATLanta.com]

As hard as it may be to believe, 8whpish?

[FlipKing]

Dang, with that maybe I could chirp 2nd on a more regular basis,lol. I wouldnt feel comforable doing it myself though, i'd have to come to a tech meet and let yall show me how to do it,lol

[Ricardo]

Jack did you ever do it cause I have a cam laying around and I wanna do this. But would love some feed back?

[Shortround]

I bought a cam off G but haven't gotten it yet I planned on putting it in when I do my waterpump and timing belt. I need to get a new cam gear and still it out. And I know that there is one guy locally that has it Kyle seass the guy who was having the timing problems a month or so

[caseyfoster]

holy 3 year old thread bump. haha

[evilmiata]

dust it off, just did this yesterday on my 1.6 , but I also changed the exhaust cam. It definitely has longer legs up top, I'm going back to the stock exhaust cam to see the difference with just the exhintake swap.

[Dynra Rockets]

dust it off, just did this yesterday on my 1.6 , but I also changed the exhaust cam. It definitely has longer legs up top, I'm going back to the stock exhaust cam to see the difference with just the exhintake swap.

How did you do it on a 1.6 with no drive for the CAS?

[ben91]

Should probably note that it's only possible to do in a 1.6 with a crank trigger conversion.

[Jack-MX5ATLanta.com]

:lol: I used to be so much more informational.

[evilmiata]

Should probably note that it's only possible to do in a 1.6 with a crank trigger conversion.

Wow how did you guess ? Lol lol..

[oldgrayfrog]

Keith Tanner mentions this in his new book, and quotes it at 8whp.

[ben91]

8whp is the common wisdom standard for BP. It's probably different for B6.

[Shortround]

Yeah I'll get this one day :shrug: still waiting for my cam.

[NA6R]

Should probably note that it's only possible to do in a 1.6 with a crank trigger conversion.

A 95 MX3 exhaust cam has the CAS drive and is a 1.6

[ben91]

Kinda neat, but I bet the profiles are pretty different compared to a MX5 exhaust cam.