Lets talk about cams

[Magpie]

Hardened valve seats for E85.

[madjak]

what do you need to do to get the best out of your cams or what are you willing to do and make the appropriate choice of cam.
appropriate compression
appropriate air flow intake & exhaust
Exchaust frequencys & back pressure
upgrading Valve-train, when is it required
ECU tune.
Turbo or N/A application

The 'recipe' for cams with a N/A engine is a three pager with lots of options depending on what cake you want, whilst the turbo recipe is only a few lines. Supercharger cams for BP - no-one has a recipe, only some sketchy dot points and notes.

Basically for N/A what you've written above applies to any cam install. If you want results it's not something you just drop in and expect extra power. Cams are really the last piece of the puzzle and may require several attempts to get right. Intake runner length, exhaust tuning, target powerband all come in as factors that will alter the ideal cam. Built to the extreme, a N/A BP engine can hit 220whp but to get there every single aspect of the engine has to be perfect. When the power starts getting above 170whp the engine becomes an animal that can no longer be dríven on the street... so you also need to keep in mind the end usage of the build. If it's a daily then you are certainly targeting something far more mild than the ultimate build.

For the high power build you'll need:
higher compression - with pistons / head decking
Improved valve-train to handle the larger lift and higher RPM's you are targeting
Improved head flow - which requires porting and larger valves
Improved exhaust flow - free flowing 4-1 headers into an open exhaust
Improved intake flow - Larger than stock intake runners / ITB's etc
ECU with a custom tune
E85 and other goodies like lighten flywheel, oil pump upgrades etc etc that suit a high reving engine.
$ to match all of the above...

The really big problem is that anyone who has done the hard work on getting big power out of their engine will keep their specs top secret, as most of the performance builders around have spent countless hours dynoing and trying many iterations of different specs to get their ideal build. It's generally not something anyone off the street can get right first time without a lot of luck. If you are serious and chasing big power, the best bet is to find a know performance engine builder and get them to build you an engine... it will most likely be cheaper in the long run anyway.

A turbo cam is far more simple as it needs nothing else if you already have the turbo, aftermarket ECU and an exhaust to match. Basically you just need some higher lift and slightly more duration but it only helps a bit, adding 10% at most over stock cams. Once again, it's the last upgrade to do in the list. The choice of cam can help move the turbo powerband around to suit your requirements which is probably the best use of them on a turbo build.

Supercharger cams are far more complex. You can run turbo cams or even low spec N/A cams, but ideally you need something that matches the supercharger setup that you are running. As far as I know there aren't any off-the-shelf supercharger cams for a BP engine but I'm sure a cam shop that knows what they are doing could design up a suitable profile. The idea is to retain the high lift of a N/A cam, have a longer exhaust duration but restrict the overlap by reducing the intake duration especially the closing ramp.

[NitroDann]

A turbo cam is far more simple as it needs nothing else if you already have the turbo, aftermarket ECU and an exhaust to match. Basically you just need some higher lift and slightly more duration but it only helps a bit, adding 10% at most over stock cams. Once again, it's the last upgrade to do in the list. The choice of cam can help move the turbo powerband around to suit your requirements which is probably the best use of them on a turbo build.

Just made another 70whp tonight with some on a turbo na8, on less boost.

[Dan]

The really big problem is that anyone who has done the hard work on getting big power out of their engine will keep their specs top secret, as most of the performance builders around have spent countless hours dynoing and trying many iterations of different specs to get their ideal build. It's generally not something anyone off the street can get right first time without a lot of luck. If you are serious and chasing big power, the best bet is to find a know performance engine builder and get them to build you an engine... it will most likely be cheaper in the long run anyway.

I agree with that 100%, the ideal cams specs are usually found by knowledge along with a bit of trial and error which is expensive if you only are building a car for yourself.

On my Evo I made my decision on cams based on proven performance from someone who got their head benched as well as made great gains (in the end I made 26kw and more torque everywhere on my car with those fairly 'mild' cams) and on my MX5 I've purchased a set of cams based on Deckspeed's experience but they are still sitting at their shop waiting to go in, what he uses I couldn't find discussed on any of the forums but he had proven performance as well as some experience with other off the shelf cams as a basis of comparison, if I was looking for cams myself I would of never found them so I definitely subscribe to the 'find an expert' idea to save you being the guinea pig.

To contribute something here is a good thread on the big forum for the NC crowd http://forum.miata.net/vb/showthread.php?t=600266, it also contains some info regarding regrinds and the basics of cams.

[MrsB]

I run sierra rs500 cams goes great

Owen

[madjak]

Just made another 70whp tonight with some on a turbo na8, on less boost.

What were the cam specs? 264 - 272 degree or just more lift?

[madjak]

I run sierra rs500 cams goes great

Owen

Most of the performance cams for the Ford/Toyota Dohc engines work in a developed BP. I was wondering if the 272 degree high lift cosworth turbo cams would work well with a Rotex and high flow head.

[MrsB]

they do all the way to 9000rpm

[rossint]

I put cams in my car, a fairly standard 1600 motor with 2.25 exhaust, extractors and intake. All done with little research or knowledge
The cams are Maruha bought from someone on this forum, specs I was given were:
IN : 248degree 8.5mm lift
EX: 256degree 8.5mm lift
The car made 69kw before cams and 80kw after. Power down low was the same but had gains in the mid and top end. Adding a megasquirt a couple of years later brought the power up to 90kw.
I've just gone turbo and the cams are still in the motor, whether they add anything I don't know but didn't think it was worth pulling them out.

[StanTheMan]

Just installed some cams tonight. 272/264 10/9 mm lift about 10 deg overlap on 1mm?
I'm a budget restricted kind of guy. Personally not chasing hp. More about drivability & fun factor But I've been intrigued by this for some time.
Mine is a street build it has to have free reving over 5k.
Cams have been run in. And are running fine. Idle is possible at 850 rpm on current set up. Then proceeded to go for a pro efficiency burn.


Head will come off in a few months for a shave.
I've read about thinner head gaskets to increase the pressure by another 0.2 points? Once the head Ben shaved to about 10.5:1 maybe that will get it to 10.7:1 ? No I dear how to test CR

Still thinking about a basic port.....

Eventually there will be a trip to Overlord Dan for a ECU & tune. But that's way off.

[NitroDann]

Just made another 70whp tonight with some on a turbo na8, on less boost.

What were the cam specs? 264 - 272 degree or just more lift?

High 220s @0.050, 10.x mm lift, a little overlap.

[NitroDann]

Dann

[project.r.racing]

Just made another 70whp tonight with some on a turbo na8, on less boost.

What were the cam specs? 264 - 272 degree or just more lift?

High 220s @0.050, 10.x mm lift, a little overlap.

Aiming for huge torque huh?

If it was from the car in the video, wowzers!

[StanTheMan]

I ahve to admit....I had a giggle at that on facebook. Its insane....what sort of torque are you getting in that thing?

[NitroDann]

We limit it to 300 electronically, but it can make way in excess of 400.