Camshaft spec database ?
Turbo Mini Forums

Anyone have any listings of cam specs that people are using with their turbo setups, and also what they think of them ?

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

The figures are definately somewhere on this forum for the (gen1) phase 2 cam from avonbar, aswell as the 'current' ph2 cam.

There is a link to a list of cams that ACDodd has personally measured up and supplied data of aswell - mostly nat-asp kit, but none the less it is usefull info.

Myself - I'm using the MG camshaft. I'm intending to stick with it for the time being.
I really like the drivability of it comapred to the ph2 that i was using.
Once the injection is up, running, and sorted - I may take advantage of the increased drivaility and revert to the ph2 for a cometitive comparison - as the theory is it should work - but I guess the extent it works also depends on the turbine backpressure one is running compared to the compressor manifold pressure...
So many variables LOL!

When I first built mine, naturally I used the std cam. As soon as I found what I trusted to be a genuine MG Metro cam, I fitted it, along with the 1.5 rockers.

That is what I managed my 1/4 with back in 94

As I mentioned in another thread, I briefly tried a Kent 286, which was absolutely horrible.
No power below 3000rpm, but it did rev strongly to 8000rpm ( which sounded mad with a 6 blade steel fan )

I dont think it made any extra power though, it just shifted the power up, and killed everything down low.
I experimented for about 4 days, after that I removed it. So that should give an indication of how much I hated it !!! removal isnt an easy job.

When I had a notion to mess with the car briefly, circa 97, I fitted a new Swiftune head, and SW5, which I feel worked very well.
No idea on cam specs or differences between the 2 though.

Car got parked up shortly thereafter, and hasnt really been driven since, and leaded fuel dissappeared too. I was silly not to get the head made for UL.

I'm not a fan of big lumpy cams, and turbo motors defo dont need them.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

I'd say that turbo minis generally could use a bit more exhaust lift/duration. I'd like to know a lot more than I do about timing for turbo engines but I think you want the exhaust valve open as early as possible without sapping power. I'm a big advocate for cams which have longer durations of the exhaust rather than lift. (Piper tend to make the latter, kent the former) BL also tended to bias towards the exhaust, IMO this is better. I've played around with all sorts of cams in my engines and reckon the MG is good, the Kent series 266/76 look good and I would have thought the Ph 2 was just what the doctor ordered. Curious to know why it wasn't so good. I'm throwing my piper 270 out and going to fit a Ph2. I can only assume that the large exhaust "area" somehow stifles it at low duty. I'm going to use a Ph 2 in my supercharged engine (12PSI) and if it isn't the best cam for the job, I'll eat my hair.

The figures for the SW5 cam are very surprising, I'm surprised it works well in anything....... Must have huge lift.

Bugger off, I'm getting there.

Ive heard brief mention that some of the turbo spec cams here have much longer exhaust duration than the inlet.

That almost conflicts a lot of what I have learnt about other engines. Obviously they have very different setups though.

Timing, LCA and duration will depend on the setup. Small turbos, short manifolds with high EGBP will favour zero overlap cams, or indeed ones with duration in between the inlet/exhaust valve opening/closing.

Possibly a good setup, with free flowing manifold and well sized turbo, would possibly work with a little overlap.

What sort of LCA are current turbo profiles ground with ?
What sort of overlap are they running ?

So many variables, and unfortunately the only way to find what works is with testing.

Edited by stevieturbo on 21st Sep, 2006.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Peter recons the Kent 274 cam for the injection would be a good bet in a forced indution aplication. Its also available in scatter pattern. Pretty standard inlet duration with more exhaust. Im running one NA at the mo, cant say much about it as ive gone to 1400 and fitted a 3.76 diff at the same time so cant tell whats doing what. It does pull hard from around 2000 in fourth.

I got a kent 276 in,won't pull at all below 2k,takes of like a rocket once 4k is passed
So bit hard to drive in traffic with 3.1diff and 185/55/13's

Metro turbo weekend driver,Mini turbo in the making again!

http://www.mlmotorsport.com/forums/viewtopic.php?t=11

Mr Dodd's timing figues for reference.

I've seen the future and tbh its Pie

Interesting....

The LSA's ( lobe seperation angles ) all seem very tight for a blower, ( based on recent LS1 and Subaru readings )

I know its totally different engine, but I had my LS1 ground on 115 LSA. Most FI builds would be similar, some being higher than that, some lower.

Tight LSA's seem to be reserved for racy n/a builds.

They also seem to suggest the intake side should have more duration that the exhaust on a turbo build.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

duno much about this stuffbut id have thought that NA requires more intake to get as much mixture into the cylinder as poss. Forced induction doesnt need a lot of inlet because the charge if forced in. Increasing exhaust on forced, releases the greater volume of gasses produced, more efficiently.

Thats how i understood it ( there is no icon for shrug shoulders)

A lot is down to the relationship between intake/exhaust, rather than looking at one of them.

Simply put, the longer the intake is open, the more charge you get in.
The more the exhaust is open, the more energy you can put into the turbo.....

Of course its nowhere near as simple as that though.

Are the cam profiles people are using with shorter intake timing, due to them running tighter LSA's ?? which almost encourage overlap.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

http://www.turbominis.co.uk/iain/up/cam_data001.gif


Above is an image of the data for the "MED T3" camshaft...
incidentally - exactly the same figures are used for the Avonbar Phase 2 camshaft (which i believe came out first)...

I found it by trawling through various old posts.

Wouldnt that cam have horrendous amounts of overlap ???

Are Mini engines requirements so vastly different, to normal port per cylinder engines ??

Are there any cams available, that have virtually no, or very little overlap, yet still with moderate duration ?


And what sort of EGBP are turbo Minis making ?

Edited by stevieturbo on 23rd Sep, 2006.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Here some more camshaft data: http://members.home.nl/jeroen.kuijf/techno...nokkenassen.xls

Op de bank beleef je geen avonturen

Some very useful info there...

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

I have currently a Phase 2 cam in my engine with 1,5 rockers. It pulls strong from about 1500-2000 rpm but the big difference to typical engines is the size. I have a 1380 engine which tames the cam quite a bit. The first cam that got kind of destroyed was from Stuart Gurr back in mid 90s and I dialed the profile after it was removed from the engine (there was actually one in and one ex lobe that were still looking like cam lobes). It was surprisingly similar to MD286 and ran very strong. I had to raise the boost to get anywhere close to RR figures with Ph2.

I did fit a SW10 into a friends turbo engine but it has not run in 3 years due to house renovations and various activities with females so don´t know how it works. Anyway, SW10 is an option for me once I get to rebuilding the engine. It may be too much for 1275 engine but should suit my engine.

I'll defo be going for a custom grind....either that, or just stick with the SW5 I currently have.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

I'm not sure about the longer inlet than exhaust. I suppose if you have a massive valve, massive ports and massive velocity, the ramming effect may be more important than the weeny bit of residual you have from a shorter exhaust. Bearing in mind things like the supersprint cam have huge durations anyway and so you could be looking at exhaust pressure effects (shockwaves) adding to the picture. I'd also be aware of the compressed charge having a greater density, resonant properties. Not sure about this and I had a think about it a while ago, did some calculations, not really relevant for our 5 porters but if you did want to employ resonance (take notice of it anyway) it would be at a considerably higher frequency. Again, port sizes being more important.....I'd say that the inertial ramming effect would be less as there is significantly less dP between atmospheric and valve closed rather than boost pressure vs valve closed with ramming. So, on that note, I would have thought that incresed duration may allow the lot to get up to speed but I suppose the overlap would start doing interesting things to it. Looking at the valve sizes and the ports, I'd say that boosting an engine to say 1 bar is looking like giving you a realistic exhaust flow of a 2L N/A engine. Since the ports are weeny, you're looking at getting some huge life, some huge duration on that just to make it towards the ideal. This may compromise your inlet timing by having to shuffle it a bit. I reckon it would be interesting to try a Ph2, a 274spi and a Ph2 against each other and see which is the best. All on 1.3 rockers. My money is on the Ph2, followed by the 274 and bringing up the rear the SW5.

I'd like to see some crankshaft angle versus lift graps available which would then be transposable to area for flow vs angle graps with rockers/valve sizes.

My hunches are just hunches this boring thursday night.

Stu..........

Bugger off, I'm getting there.

Updated pic of the med t3 camshaft

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