Timing Figures for MD274SP Cam
Turbo Mini Forums

As I understand it, you can use the siamese code to overcome the mixture balance across cylinders, but the time to get the fuel into the right cylinder is very small, hence why bigger than usual injector/s are used. Is it not that the scatter timing will increase the time period to actualy get the fuel into the desired cylinders?

The reason for considering this cam is just because it may increase the VE of the engine at the top end.

The increase in the injection window is insignificant.

I firmly believe in high LCAs for turbo engines. The hope was that the SP version would be a significant step up. Now I not so sure.

What I'm currently trying to fully understand is the fact that Wil H lost 500rpm plus of useable boost just by having his tappets 0.008" too tight. Is this purely due to the slight change in overlap or is the exhaust valve opening also significant????

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."

I think its due to a little of both Paul,

Suposedly If you have a BIG turbo/turbine and your TIP/Boost are getting close to Parity then a narrow LCA is the way to go. :/

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."

From what I have seen, the 8 thou that will adjusted out just affects where on the tappet ramp the valve starts moving, this 8 degree could equate to 15-20 degrees change in the seat timing, and probably 10% change in the overlap "area"

Unless Ive got it twisted in my head (after several beers...) widening the LCA will affect the overlap area loads more than changing the tappet clearance, (not that that means much...)

I've forgotton where I'm going with this now... lol

What I'm thinking is that Wills tappet adjustment actually made the exhaust valve open later which is contrary to the affects of increasing the LCA so I'm a little confused. Maybe it's more to do with the 266 cam specs.

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."

It make the exh open later, but it also shuts earlier, so its not really contarary to increasig LCA,

So, we can conclude that it is mainly about overlap above all else.

Don't stop drinking Joe, we are getting somewhere

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."

Another fact to consider here is that the Phase 2 has an LCA of 110 degrees.

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."

pmsl

You have my Phase 2 Plot to look at don't you?

there is Nic's cam to consider too I belive his may be on a wide LCA, and also the other Vmax cams that are on wide LCA's

I'll plot my RE13T on a 112LCA when it turns up.

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."

give it a wirl paul ...you will be pleasentley suprized

Paul
isn't your ngine a 998?
Then anything above 250 ° inlet will not be correct duration wise.
Then I 've mesured an mpi camshaft whish should be just in your ballpark...reliable, cheap, last grind tech..

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."

I have one throwing round if you want one to play with.

I've found the data for an MPi cam on the ACDodd Forum.

13/45 55/17 0.263/0.263 238/252

Bit too mild in my opinion. Just an extra 8 degrees inlet duration more than a standard cam. LSA/LCA as standard.

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."

Your opinion thru ...
Could you just borrow Andy's one, and see...You could be surprised

I can throw it in the back of the van if you want to use it for a while, get it of John at the RR day. That's if I can remember where I put it...

.............. choking

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."

It's in the side of the van's spare wheel well.