camshaft LCAs
Turbo Mini Forums

so what kind of LCAs do turbo cams have .

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I assume you are talking about the angle between the lobe peaks in real cam degrees, sometimes also called the Lobe Separation Angle.

Most of the available A series cams have 107.5 degrees same as standard.

However, I believe this is because the profiles are ground from a stock cam and no one would pay for a proper billet.

I'm after a 260 degree cam with a 110 plus degree LCA but it will cost mega bucks.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Didnt Mini1071 say he could get cams ground for sensible money in the US ???

Mini cams seem to run much much tighter LSA's then conventional engines.

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

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

my billet crossdrilled were £320 the pair from piper , and turned around in 6 days from receiving my master. a top service at reasonable money when you consider what i had first time round,


carl

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I've done a bit more searching and it would appear that the Avonbar Phase 2 has an LSA of 110 degrees and this is reckoned to be the best cam available for a 1275 turbo.

However, it has durations of 262/294 with 58 degrees of overlap, much too much for my 998.

At least it confirms that high LSAs do work well on the turbo A series.

So would Piper grind me a 252/268 with 40 degrees overlap and 110 degree LSA?

Lift say 0.38"

Anyone else interested in a group buy?

Edited by Paul S on 25th Oct, 2006.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

this is a bit too technical for me, are you basically trying to design a turbo cam for a 998?
or a cam that will work well in all motors, including a small bore motor?

pending price, and testing, id be up for one.

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"

snap

I'm thinking the above spec would be good for both 1275 and 998.

Not as radical as the PH2 for the 1275.

Need a concensus of opinions though.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Just found that the Piper BP270i has virtually the above spec, so scrap the idea of a group buy.

However, is 110 degree LSA enough?

There is a lot of web based discussion on this subject in the states and naturally based around the small block V8s. It would be easy to dismiss this as irrelevant to the A series, but guess what, the stroke and con rod length of a small block chevy are very similar to the A sereies.

1275 has 3.2 inch stroke and 5.75inch rod length.
327 cu in Chevy has 3.25 inch stroke and 5.7 inch rod length

998 has 3.0 inch stroke and 5.75 inch rod length.
302 cu in Chevy has 3.0 inch stroke and 5.7 inch rod length

Hence the relationship of cylinder volume and crank position are very similar.

My thinking is that what works in LSA terms for a small block chevy should be good for the A series. I'm not looking at durations as the sbc uses hydraulic tappets and durations are much longer as a result.

Anyway, what i'm getting at is that LSAs of 120 degrees are not uncommon in factory cams. Stevieturbo is using 115 in his LS-1 V8 Turbo to good effect.

Is this an area worth exploring?

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."