Which Cam ?
Turbo Mini Forums

Could anybody Advice please,

I intend to run a reconditioned 1310, 8.2:1 compression (Chamber de-beaked), 10PSI Turbo Engine, I have opened up the ports in the head and the inlets are from the N.Asp. MG Metro.

I will be changing the cam..

I have an N.Asp MG Metro Cam.

I have been advised to use Avon bar Phase 2 turbo for road use as the phase 3 is a bit lairy.

I would like to just use the MG N.Asp and keep my ?70. Unless a massive difference will be seen.
How much better will the phase 2 be than the MG N.Asp ?

or has anyone got any other thoughts as to which cam is best to use ?

Many thanks

Brocky

BTW - I took my buddy VTEC Pete out for a spin this weekend, and even though I am running her in, he gave it a name, the "Brocket"...cause I'm a brocket maaannn, nah nah nah nah nah nah nah nah nah nah nah....

Build thread - http://www.turbominis.co.uk/forums/index.php?p=vt&tid=7483

Katy Mini Owners Club Thread - http://www.turbominis.co.uk/forums/index.php?p=vt&tid=505552

Let's make sure you embarrass at least one VTEC MINI today !

https://www.facebook.com/groups/17557298589...096464253807802

I have used all the 3 mentioned cams in a turbo'd an A series. The N/A mg cam offers a very long exhaust duration with suits the turbo no end.

If money is an issue and all out power is not needed go with the Mg cam(imo) and spend the Money else where.

The phase 2 has the be the compromise between practicality and performance, the 3 is a bit wild.

I still have a 3 but saving it for a rainy day.

JF.

I'm going back to an MG cam at the next build... I think there is a little too much overlap in the ph2 for higher boost levels (which will be made even worse if a smaller exhaust housing is being used)...


ps - Hi Dave, How's trix?

Edited by TurboDave16V on 7th Mar, 2005.

How much difference is there between the N/A MG and the phase 2 cam 5 to 10 BHP ? Hard to answer I know. .. Also how much boost can you get out of a standard waste gate without using a bleed valve. I mean by just adjusting the pre load or do you run out of actuation length ?

Ps not to bad Dave, how you liking it across the pond ?

Edited by Brocky on 7th Mar, 2005.

BTW - I took my buddy VTEC Pete out for a spin this weekend, and even though I am running her in, he gave it a name, the "Brocket"...cause I'm a brocket maaannn, nah nah nah nah nah nah nah nah nah nah nah....

Build thread - http://www.turbominis.co.uk/forums/index.php?p=vt&tid=7483

Katy Mini Owners Club Thread - http://www.turbominis.co.uk/forums/index.php?p=vt&tid=505552

Let's make sure you embarrass at least one VTEC MINI today !

https://www.facebook.com/groups/17557298589...096464253807802

Like you say - hard to answer! The ph2 probably makes more power upto 12/14psi, after that, the MG would make more power I reckon, especially with a stock turbo unit with the 0.25AR turbine...
This is of course assuming the timing is set at the reccomended figures - A lot might be achieved from either cam by swinging the timing a few degrees... All very difficult to say!

Any mg turbo actuator will be at least 18 years old. They do become weak.
Personally, I'd swap it out for a new 7psi unit. This will be adjustable between 5psi (hardly any pre-load) and 12psi (a lot o pre-load). Of course you can just set it to 7/8 and use a bleed valve!
Search on ebay (including ebay USA - check they deliver to UK or have a word with a friend over there ) or shop around for deals on actuators...
I reckon you could find one for less than ?40 delivered quite easilly!

Dave, which rockers are you running with that?

With supercharger cam choice, the tradition (according to everyone unanimously) is to run a symmetrical cam. 276, 286 (for ultra performance) I would have thought that the overlap would have been a problem, but according to "someones" latest findings, you can get giant power with lots of overlap. What do you think?

I've been running an MG Cam (252/268?) and it's fine, I'm changing to a Ph2 as I reckon the inlet chokes it off a bit. I can't see how on boost the turbo or blower would be different. Allthough theory tells me a 286 is a bad idea.

What do you reckon? (Apart from "For fuck sake, just try one" )

Stu (getting there gradually)

Bugger off, I'm getting there.

For fuck sake, just try 1

(different from above!)

Stu - My thinking is that SC's can tolerate more 'cam' than turbo's with fewer ill effects. Basically, the blower exhaust is (almost) unrestricted - and a little excess overlap will always empty the bore of the previous (spent)charge.
With the turbos, you have backpressure. I guarantee the exhaust pressure with a smaller turbo (say a stock 0.25AR T3) is well over the inlet pressure at anything over 14psi... Hence, when both valves are open, the exhaust will win, but then again, theoretically the bore is 'empty' so both inlet and exhaust would fill the bore until the exhaust closes, by which time the inlet will continue to fill it. Of course, swinging the cam around could also change this effect as we're all in a dynamic state!
A larger turbo will not have as much backpressure, so is a different case - this might get all up to max boost and still be less, or equal to inlet pressure.
As this is all happening dynamically though, it's pretty difficult to say exactly what happens ain't it!!!
Swinging the cam around might reveal goods, but that'd be different again from every engine build.

For a SC I'm not sure you need the wider separation of the ph2 so much - overlap will clean out the previous charge at the expense of a tiny little bit of efficiency - how much is ideal though; no idea!!!
My 'gut' feeling is that a 286MD would be a reasonable unit. I've just not got anything like enough knowledge to know what is the ideal.

Other thing you can try is to fit a big cam, and use 1.5 rockers, then adjust the 'duration' and 'overlap' with the tappet clearances! It'll sound like a tractor, but it'd give you somethign else to play with!

Edited by TurboDave16V on 9th Mar, 2005.

Very good point there about the scavenging. I'll do some proper testing when I get my proper engine built. I still go along with the 2L engines don't have 29mm exhaust valves though.

I have a 256/268 cam in there at the mo, will try the ph2 next as I reckon it should go like a 266 but with the exhaust duration to clear it properly. I'll hopefully have some curves printed out in due course. Hard evidence.

Cheers Stu (Still in the shed)

Bugger off, I'm getting there.

I use a MED/ Piper T3 Cam, which I would recomend!

Has/ Does anybody else use this cam?

Choppo

Hannibal: There are two ways we can do this: the easy way and the hard way. In a few minutes my friends and I are going to come down on you like your worst nightmare. You're gonna wish the Earth had opened up and swallowed you whole.
bad guy: What's the easy way?
Hannibal: That WAS the easy way.

Most peeps - given the figures are identical to the Avonbar ph2!

Is anyone runing a KENT KCM500 whats the thoughts?

love that straight cut scream!!!
______
/___|_____
_ (@)___(@)

think WilH is going to..

Just for the book, what are the durations of the Ph3?

Bugger off, I'm getting there.

Runnin a Kent 500 cam at the moment. Its got manners, as opposed to the Ph3 cam I tried to start with.
For road use, where you arent going in a straight line (ok i'm not a driving genius like giallofly), I like the 500/MG as you hae a bit more control as to when things open up - The Ph3 was peaky as sin, and came 'on cam' at higher revs, so a fast start almost always tried to pull the tires off the road, but the kent cam (same engine setup) was smoother, but had the balls where it needed it in the mid range, if not more than the Ph3.

Just my feeling and experience, probably not worth buttons besides this lot!
Ed

Well look above - it's a lot of theory - YOU have tried it and proven something - big duration is not neccesarilly needed on a turbo cam for power.

NextGen, I have exactly the same story to tell about the KC 500 and the Avonbar P2 cam. The problem I had was I could never get the wheels spinning so it always bogged down with the P2.

Wil

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

Well i was running a stock 1100 cam in my 998 Turbo (yep, its me guys, James_be from the now way-too political MM board....)
Was good to about 6000, then went awful flat...
Currently running a custom grind, an RE-13 by Graham Russell (I'll grab specs when i next chat to him or Kev) - its approximately 287' duration but with much less overlap.. a little grumbly down low (under 2000) but the power starts at 3500 (same as max boost pressure) and continues to about 8200... 73HP at the wheels from a 998 ... not too shabby....



Changing turbo it an RHF-5 in the next few weeks as well as some major head work and some "special tuning"..
Anyway, I'll post results as i find 'em

Edited by kazjim on 16th Mar, 2005.

Erwin, what have you been doing to that cat, poor thing looks half dead: mrs schrodinger.

Hi James!

Glad to see you're developing it!!!
How does midrange power compare (eg 4000-5500rpm)? Any noticable increase/decrease in lag in the same region?

How does the lift of the new cam compare to the old? Or is duration the only real difference?

Huge Lift... (running STOCK PRESSED rockers) the Midrange is incredible with tyre spinning from about 4500-6000 if not controlled ! (Yoki A008's 165/70/10)

yea, I'm going to beat Kev (DRMINI) if it kills me !

Boost is the limiter at the moment, just cant get it to flow more than 14Psi... thus the new turbo... lets see what this one can do !


J
PS - Dave, good to know you are still around....

Erwin, what have you been doing to that cat, poor thing looks half dead: mrs schrodinger.

Good to see your still around James, and still got your 998 !

Phil.

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