What cam????????
Turbo Mini Forums

you cant, thats my point,

to my knoledge a cam grinder is essentially a pantegraph, and what your doing is reducing the cam down to achive the highest point, wheather the base circle ends up at 400 or 500 thou the lift profile ends up the same as its done from the same pattern billet or not.

Interesting stuff.

I will post up med tech data on the ht cam when they send it.

Has anyone used this cam for a turbo application?

Thanks,
David

Edited by Sprocket on 3rd Jun, 2012.

Ah!

I get what you mean now!

the smaller base circle causes a change in the relationship between the lobe and the tappet contact point,

There is deffo a difference between billet and regrind profiles, but what it actually comes down to I don't know, but as you can see in the crude schematic I drew, the difference can be easily seen between a profile that is exactly the same with the same lift, but on a smaller base circle.

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both the RE83 and RE13T cams has a greater LCA angle for turbo and S/C use, this is so you don't blow all the fuel mix out the exhaust due to too much valve overlap. This makes it feel soft without any boost, compared to the regular RE83 and RE13.
It is designed for turbo applications in mind.

Only real benefit of a new billet is on race cams as the material is harder and they have more meat to grind adventurous profiles onto.
For the road I find regrinds work fine. Particularly GR's ones- they all have a nice big radius on the peak of the lobe

As for power, it all depends on what your set up is, there are a couple of lads here running turbo'd 1152cc motors pulling 130hp+ on the rollers, both running the RE13T, yes Joe C it will go to 8k, not that you would set it up there unless you were running a t3(ish) in a race motor requiring high power at high revs...

The RE83T i have not been in a car running one so i cant comment, the 83 is probably GR's Mona Lisa though, it makes great torque from the get go and makes it up to around 6200-6500rpm, would be my choice with the motor i am starting to assemble as it will be an 1100 i wouldnt want to pull it past 7k too often (or at all), the 83 will offer great off boost torque (i run the non turbo'd version, cam kicks in at 2300) and running it in an 1100 or 1275 will mean no sluggish off boost mini etc (or so i am led to believe)

Hope this helps out a little,

Matt

“A turbo: exhaust gasses go into the turbocharger and spin it, witchcraft happens and you go faster.” - Jeremy Clarkson

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Ill bear that in mind thanks :), but from what a friend told me and your guide for 130bhp suggesting a 266 I'm pretty confident I made the right decision

Got a replay from MED on H/T cam i bought a few years ago.

here it is:

Inlet - open: 19, close: 57, valve lift: 0.357, full lift: 109

Ex: - open: 57, close: 19, valve lift: 0.355, full lift: 109

duration is 256.

anyone have an opinion on whether this will be good for turbo application?

better than the standard metro turbo cam i would recon.

Thanks,
David

Ahhh I timed it in at 106 as well well tried to atleast - will find out soon enough pahaha

:) is it as good as the avonbar ph2? Or is that not a fair comparison

Inlet is perfect, exhaust timing should have 20/30° more duration: so about 286°.

You can correct this by using a different cylinder head,with 33/31 or 36/32 (this one pricey) valves to enlarge the exhaust window.
Boost dependant go with a bit less static compression. ratio.



here it is:

Inlet - open: 19, close: 57, valve lift: 0.357, full lift: 109

Ex: - open: 57, close: 19, valve lift: 0.355, full lift: 109

duration is 256.

anyone have an opinion on whether this will be good for turbo application?

better than the standard metro turbo cam i would recon.

Thanks,
David[/quote]

Lyons are still the kings!!

They're not working in the same league.... phase 2 is above 100% VE at 4000 and still put on top of this 20 more bhp at 6500 rpm, aside of this it does improve boost treeshold by about 500 rpm. don't saying he does like BOOST.

On 6th Jun, 2012 Craigie-B said:
Ahhh I timed it in at 106 as well well tried to atleast - will find out soon enough pahaha

:) is it as good as the avonbar ph2? Or is that not a fair comparison

On 4th Jun, 2012 BENROSS said:

On 3rd Jun, 2012 Sprocket said:

On 3rd Jun, 2012 Joe C said:
so why does a billet cam give 4 to 6 hp more?

Perhaps the difference in valve ramp due to the larger base circle? but I don't see the gain being as much as that though. Maybe Steve is talking in Baldwins.

More or less Colin, Joe c also they are 100% accurate! A billet. A reprofile cam at best is only about 98%

Craig b the 266 camshaft is a belter but please time this cock on at at 106 degrees or it will feel crap!

Yes fabrice, Lyons are still kings