camshafts

[Gary Morrison]

Andy...

I had a quick look at my archives... Bill Cardell at Flyin Miata used to have
a car called Red Rat, which was a normally aspirated 1.6 and had about 135hp
at the rear wheels. He used a camshaft in that which was as mild as you could
go and still gain power. I believe that it still needed an aftermarket ECU to
work though. Their current lineup of NA cars does not seem to include anything
this powerful, Red Rat is not listed, and none list aftermarket cams.

RedRat is in the dyno section of their site with dyno graphs...

http://www.flyinmiata.com/tech/dyno.asp

(Fletch, do you know where RedRat went, did Keith Tanner aquire it?)

Follwing are email extracts I have on file from Randy Stocker regarding
aftermarket cams...

============================================================

The list of aftermarket Miata cam manufacturers is on
www.solomiata.com/cams.html.

FWIW, I use Webcam. You have to get the unground billets from MazdaComp and
they grind them. They many profiles but two seem work well in the Miata.
The 505 is a good street grind and the 515 is a more aggressive profile. I
use the 515. Be prepared to use adjustable cam sprockets with the 515 to get
the overlap tight for good idle. see www.webcaminc.com

a 270-300cc injector is good for about 200 crank NA hp at normal line
pressures. See www.solomiata.com/street.html

Randy


*FWIW, Bills cams are grind 505 from webcam. They are a middle grind with
.365" lift and 262 duration. 5-6 rwhp should be achievable with most any of
the middle ground aftermarket cams but the more duration and overlap they
have the more you will need a programmable ECU to make it drivable (large
overlap is fixable with adjustable cam sprockets). Good luck, Randy

[Fletch]

I can assure you, that, just like any other 4-stroke internal combustion
engine, camshafts with more valve-lift and/or duration will increase power
(provided you have the correct air/fuel ratio)

However, the problem is, that you said you have, and presumably want to keep,
the stock engine managment computer...

The stock computer is programmed well to cope with the air-flow provided for
by the stock cams, even when you improve the air-flow a little with bolt-on
intakes and exhausts...

But when you change cam-shafts, you signifigantly change the air-flow through
the engine, and specifically, you change the shape of the curve of air-flow vs
RPM... (volumetric efficiency)

My point is, camshafts that DO work with the stock ECU, probably arent worth
having (too little improvement for the $$). Camshafts that do provide
signifigant improvement, dont work very well with the stock ECU.

So, if you want to keep the stock RCU, then for a few hundred dollars, you can
buy a camshaft that is such a small change from stock, that it works ok, but
isnt worth having, or the same money will get you one that could work great,
if only the fuel was managed properly...

And the way to manage the fuel properly, is to buy a programmable ECU, like a
Link or Haltech, or other... which costs three to five times as much as the
cams you wanted to fit...

Fletch.

P.S. I suspect (but am not sure) that FlyinMiata's "red-rat" got
transmogrified into "track-dog", the 2-litre turbo open-track-challenge car?

[Fletch]

I can assure you, that, just like any other 4-stroke internal combustion
engine, camshafts with more valve-lift and/or duration will increase power
(provided you have the correct air/fuel ratio)

However, the problem is, that you said you have, and presumably want to keep,
the stock engine managment computer...

The stock computer is programmed well to cope with the air-flow provided for
by the stock cams, even when you improve the air-flow a little with bolt-on
intakes and exhausts...

But when you change cam-shafts, you signifigantly change the air-flow through
the engine, and specifically, you change the shape of the curve of air-flow vs
RPM... (volumetric efficiency)

My point is, camshafts that DO work with the stock ECU, probably arent worth
having (too little improvement for the $$). Camshafts that do provide
signifigant improvement, dont work very well with the stock ECU.

So, if you want to keep the stock RCU, then for a few hundred dollars, you can
buy a camshaft that is such a small change from stock, that it works ok, but
isnt worth having, or the same money will get you one that could work great,
if only the fuel was managed properly...

And the way to manage the fuel properly, is to buy a programmable ECU, like a
Link or Haltech, or other... which costs three to five times as much as the
cams you wanted to fit...

Fletch.

P.S. I suspect (but am not sure) that FlyinMiata's "red-rat" got
transmogrified into "track-dog", the 2-litre turbo open-track-challenge car?

[lou Girardin]

Hi Fletch, I think that they do not promote cam changes so much in the States
because it doesn't give many HP per dollar. Especially when you can buy a
basic Greddy kit for US$1500. Granted there is nothing like the feel of a well
set-up NA motor, although the BR coldside sounds the closest yet. All I need
now is to hide NZ$2500 from my accountant (wife)!
Lou

[lou Girardin]

Hi Fletch, I think that they do not promote cam changes so much in the States
because it doesn't give many HP per dollar. Especially when you can buy a
basic Greddy kit for US$1500. Granted there is nothing like the feel of a well
set-up NA motor, although the BR coldside sounds the closest yet. All I need
now is to hide NZ$2500 from my accountant (wife)!
Lou

[shaznandy lockyer]

Thanx guys...
I had a look at the "...Rat" before making further enquiries and realise a Link ECU is gonna have to happen...Looks like I'll just keep on saving and get the comp., cams and pulleys all at once:(
Or Sharon( My accountant) will snatch the cash for our March wedding...
Or I could buy a nice new, shiny exhaust system right now...
Cheers, Andy
Gary Morrison wrote:Andy... I had a quick look at my archives... Bill Cardell at Flyin Miata used to have a car called Red Rat, which was a normally aspirated 1.6 and had about 135hp at the rear wheels. He used a camshaft in that which was as mild as you could go and still gain power. I believe that it still needed an aftermarket ECU to work though. Their current lineup of NA cars does not seem to include anything this powerful, Red Rat is not listed, and none list aftermarket cams. RedRat is in the dyno section of their site with dyno graphs... http://www.flyinmiata.com/tech/dyno.asp (Fletch, do you know where RedRat went, did Keith Tanner aquire it?) Follwing are email extracts I have on file from Randy Stocker regarding aftermarket cams... ============================================================ The list of aftermarket Miata cam manufacturers is on
www.solomiata.com/cams.html.

FWIW, I use Webcam. You have to get the unground billets from MazdaComp and
they grind them. They many profiles but two seem work well in the Miata.
The 505 is a good street grind and the 515 is a more aggressive profile. I
use the 515. Be prepared to use adjustable cam sprockets with the 515 to get
the overlap tight for good idle. see www.webcaminc.com

a 270-300cc injector is good for about 200 crank NA hp at normal line
pressures. See www.solomiata.com/street.html

Randy

*FWIW, Bills cams are grind 505 from webcam. They are a middle grind with
.365" lift and 262 duration. 5-6 rwhp should be achievable with most any of
the middle ground aftermarket cams but the more duration and overlap they
have the more you will need a programmable ECU to make it drivable (large
overlap is fixable with adjustable cam sprockets). Good luck, Randy

[shaznandy lockyer]

Thanx guys...
I had a look at the "...Rat" before making further enquiries and realise a Link ECU is gonna have to happen...Looks like I'll just keep on saving and get the comp., cams and pulleys all at once:(
Or Sharon( My accountant) will snatch the cash for our March wedding...
Or I could buy a nice new, shiny exhaust system right now...
Cheers, Andy
Gary Morrison wrote:Andy... I had a quick look at my archives... Bill Cardell at Flyin Miata used to have a car called Red Rat, which was a normally aspirated 1.6 and had about 135hp at the rear wheels. He used a camshaft in that which was as mild as you could go and still gain power. I believe that it still needed an aftermarket ECU to work though. Their current lineup of NA cars does not seem to include anything this powerful, Red Rat is not listed, and none list aftermarket cams. RedRat is in the dyno section of their site with dyno graphs... http://www.flyinmiata.com/tech/dyno.asp (Fletch, do you know where RedRat went, did Keith Tanner aquire it?) Follwing are email extracts I have on file from Randy Stocker regarding aftermarket cams... ============================================================ The list of aftermarket Miata cam manufacturers is on
www.solomiata.com/cams.html.

FWIW, I use Webcam. You have to get the unground billets from MazdaComp and
they grind them. They many profiles but two seem work well in the Miata.
The 505 is a good street grind and the 515 is a more aggressive profile. I
use the 515. Be prepared to use adjustable cam sprockets with the 515 to get
the overlap tight for good idle. see www.webcaminc.com

a 270-300cc injector is good for about 200 crank NA hp at normal line
pressures. See www.solomiata.com/street.html

Randy

*FWIW, Bills cams are grind 505 from webcam. They are a middle grind with
.365" lift and 262 duration. 5-6 rwhp should be achievable with most any of
the middle ground aftermarket cams but the more duration and overlap they
have the more you will need a programmable ECU to make it drivable (large
overlap is fixable with adjustable cam sprockets). Good luck, Randy

[zorruno]

the red rat has been reborn as 'Track Dog'
http://www.flyinmiata.com/projects/dog.asp

[...]

[zorruno]

the red rat has been reborn as 'Track Dog'
http://www.flyinmiata.com/projects/dog.asp

[...]