Cost of CAMs

[bootz]

Thanks guys, your experience is invaluable.

[gslender]

I got an email from Colt Cams in Canada.

Thank-you, for contacting us.
We do offer a tri-flow grind for the Miata
Pim INT: 278° .340L
Sec INT: 262° .335L
EX: 278° .333 L
It will give you approximately 12 – 15 H.P. gains on N.A.

They do something called a tri-flow cam whereby they delay the opening on the lobes between each intake valve.
Check out their website http://www.coltcams.com/html/tri_flow_technology/index.cfm

Thoughts?

G

[evil_weevil]

So to the guru's here...

in regards to an NA8 1.8 with hydraulic lifters, if you were to get a later model head with solid lifters (whats that..98 onwards?) and simply do a head swap so now the cams and lifters are all solid in the NA8 - is that going to see you get any sort of power increase?
with and without a stock ECU?
any benefit?

thoughts?
Cheers - Chris teh n00b !!

[NitroDann]

Yes because the late model heads flow much better.

Dann

[evil_weevil]

ok cool - is it an easy change over?

i.e. unbolting head, putting new head on plus gasket kit and...?

now where do I find one of these? hehe

[NitroDann]

On the forum or a wrecker, then sell your old head to recouperate the losses.

Then buy some cams etc.

As for the swap yeah its a straight swap, but obviously swap your sensors over so the ecu is happy.

Dann

[evil_weevil]

Nice one,
sounds easy enough !

jsut say you keep the standard cams which go with the solid lifters, and standard ECO - what you get, maybe 5-10hp?

also - what are stock NA8 cam specs compared to NB solids?

sorry for all the questions here!
i'll stop being a n00b soon...promise!

[NitroDann]

I really couldnt tell you the specs of the expected power increase sorry. But 5-10hp sounds reasonable.

Dann

[93_Clubman]

in regards to an NA8 1.8 with hydraulic lifters, if you were to get a later model head with solid lifters (whats that..98 onwards?) and simply do a head swap so now the cams and lifters are all solid in the NA8 - is that going to see you get any sort of power increase?
with and without a stock ECU?
any benefit?
thoughts?

ok cool - is it an easy change over?

i.e. unbolting head, putting new head on plus gasket kit and...?

now where do I find one of these? hehe

sounds easy enough !

just say you keep the standard cams which go with the solid lifters, and standard ECU - what you get, maybe 5-10hp?

also - what are stock NA8 cam specs compared to NB solids?

Chris, you need a BP4W head (cast on rear of head as opposed to BP05 cast on the rear of an NA8 head) from an 1998-2000 NB8A. Used to be scarce & accordingly expensive.

For the easiest change over, purchase an NB8A head complete with intake manifold, throttle body & fuel rail. Don't worry if the fuel rail doesn't come with the red fuel injectors as they are best replaced by the purple ones from the NB8B onwards. Initially you might find it easier to use your NA8 throttle body, but it is possible to use the NB8A one. In terms of the intake manifold, the NA8 intake manifold will not fit on an NB8A head without welding & drilling additional metal to the bottom manifold to head mounts. Finally, you'll need to wire in an RPM switch to kick in at about 5700RPM to make use of the NB8A head VICS.

Mazda power spec for 1993-1995 NA8 was 128hp & 140hp for NB8A - of course you may not realise the full 12hp difference.

Btw, see Manga Blue's 3 posts in following where he talks about testing BP05 heads for metal hardness: viewtopic.php?f=29&t=38310

May not be an issue for the BP4W head, but worth keeping in mind if a BP4W head is going to cost you big money. GL!

[gslender]

They do something called a tri-flow cam whereby they delay the opening on the lobes between each intake valve.
Check out their website http://www.coltcams.com/html/tri_flow_technology/index.cfm

Bump. Nobody heard of these tri-flow cams? Any thoughts on if this is snake oil or not?

[charlie_91]

stick to tried and tested. dont go regrinds. get brand new cams if u want to go that way.

all this about trying to get 10 extra hp or whatever is bullshit.

[manga_blue]

There's roughly a 12bhp difference in peak power between NA8 and NB8A engines. That extra 12 comes from 3 main factors:
1. Better cam profiles in the NB8A (partly bigger timing and partly increased rise rate permitted by using solid lifters)
2. Much better fuel and ignition maps in the stock NB8A ECU
3. Better gas flow in the inlet ports.

I think the third point, better ports, is less significant than the first two.

Race engine builders usually prefer to work on the NA8 head cos they can get that head and manifold to flow better than the NB.

For a road car the NB8A has a better spread of power, a result of the VICS fattening the curve up a bit at lower revs.

[gslender]

stick to tried and tested. dont go regrinds. get brand new cams if u want to go that way.

all this about trying to get 10 extra hp or whatever is bullshit.

Ok, so I guess that means "no I've not heard or looked into these tri-flow cam designs, but I think it might be snake oil".
Thanks

[rob323]

Ok, so I guess that means "no I've not heard or looked into these tri-flow cam designs, but I think it might be snake oil".
Thanks

I've heard of these cams. By opening one of the intake valves prior to the other, they help retain some vacuum at idle and idle smoother than "big" cams normally would. All in theory of course, I don't have any first hand experience with them.

[evil_weevil]

all this about trying to get 10 extra hp or whatever is bullshit.

really?
I need all the horsepower I can get