exhintake questions

[FE3-323]

boosting the NA exhintake system poorves over doubling the effective valve overlap, which will hurt your performance. giving you less of a complete burn & combustion cycle... It runs Im unable to dyno the differences @ the given moment within 2 months i'll have the dyno differences tho.

[Turpro]

Aight cool. I'll scratch that idea off the drwing board then

[photoeye0]

Me Too

[projectmx]

not sure i understand your post ryan.... the NA exhintake has the exact same spec as the gtx exhintake just the time is off a few degrees.. this can be fixed with an adjustable cam gear (i think the timing is exactly 1 tooth different)

[therieldeal]

the stock intake cams are identical aside from the timing.

the stock exhaust cams are very close, there is a slight change in duration, and also timing.

-jon

[FE3-323]

alter it more teeth as you see fit & test it...

[1967cutlass]

so in this thread people discussed 5' retarded and 5' advanced... I'm assuming this is +or- from the 180' flip and the 3 teeth as a starting point? If this is the case wouldn't leaving the timing set as is be the best balance and thus the most midrange power?

[1967cutlass]

Thanks for posting the chart Ryan

So 127whp/116ftlbs with the following, correct?? (anything I'm missing?):

Exhintake cam
Cam settings of EXHINT +5 EXH -1
17 degrees advanced timing (92 octane I assume???)
Cut intake manifold
RX7 meter
Cone filter
(Manifold back??) 2.5" exhaust w 3" cat
OEM 4-1 tubular manifold?

and Josh got 125whp/115ftlbs with the following:

Exhintake cam
Cam settings of EXHINT -6 EXH 0
18 degrees advanced timing (92? octane)
Tuned RX7 meter
Cone filter
Manifold back 2.5" exhaust
OEM 4-2-1 cast manifold

That's very nice numbers for not having dropped any $$$$ on a rebuild......

A few differences to especially note between my ~10:1 rebuild with the exhintake cam (currently 133whp/118ftlbs) is my stock ecu controlled timing of only ~8 degrees advance, and I've got a 2" exhaust..........

I don't understand why this is...

[FE3-323]

josh had very different results & what not on his dyno-graph, altho i think we had similar settings in the end i'll have to check one of these days what they were exactly. maybe i'll do that tommorow mike.

[1967cutlass]

josh had very different results & what not on his dyno-graph, altho i think we had similar settings in the end i'll have to check one of these days what they were exactly. maybe i'll do that tommorow mike.

Thanks for putting up with all of my questions

[FE3-323]

HAHA, thx for the keychain

[LRCboi]

ok so would i be right in saying that i need to cut the exhaust cam b4 the CAS and put it in at 180 and 3 teeth clockwise ?

what happens after this? i will be getting new adjustable cam gears 2

[MadMax]

This link goes into modding the stock cam gear for the exintake cam modification. http://forum.miata.net/vb/showthread.php?t=192522

On Club Protege it has been said many times that at least one adjustable cam gear is required to do this mod. I know someone mentioned modding the stock gear here but this link goes into it more. I read most of the many posts in the above link and it looks like good mod to me. Be sure to read the posts near the end because it seems like they were confused and messed up at first. There even is a photo of a modded gear that I think turned out to be slightly wrong. But still, once I looked at the photo I thought, this doesn't look that hard to do.

So if you have an extra exhaust cam in good condition, have the tools and the skills needed, it looks like to me this is a free or almost free mod that gains noticeable power. Even if you don't have the above things you still might go to the junk yard get both parts, and take them to a shop to get moddified.

[MadMax]

This is one of the posts from the above link that I liked

>>Alex, I used two degree wheels. 1 Larger than the sprocket (Crane Cams) and actually a smaller Hi Resolution photo copy laid inside and on top of the front face of the sprocket. Then I used a good steel ruler to make sure all the marks agreed. Checked more than twice. When I was comfortable with what I saw I used a razor blade with the steel rule to mark a fine line across that soft iron sprocket. Then used a drill press. Engine started right up, thanks to your pioneering. I did most of this during my planning period, I teach an Automotive Technology class in a Public High School. Since yesterday was the end of the grading period I had 1/2 dozen students do most of the work - Except for the layout. They loved it!<<

[FE3-323]

you can do it that way, problem with that method is it does not allow tuning to each engine as adjustable gears would. which can lead to less than optimal results, its much simler to just do it right from the start.