hi guys,
just wondering about those, was gonna order the MX1 cams, then noticed these. any real benefits to these? dyno gains? and what's the difference between the 1.1mm and 1.3mm size?

http://www.cosworthusa.com/store/pc/...&idproduct=368

http://www.cosworthusa.com/store/pc/...&idproduct=367

advice?

 

The thicker gaskets are going to lower compression slightly. This allows the factory bottom end to cope with the increased cylinder pressures of a tuned 4b11. As far as gains, you'll probably loose a little on the bottom end, but you can make up for it by turning up the boost on top considering the lower compression ratio. Lower compression = less knock and more boost.

 

These motors have stupid low compression as is. This is a more efficient combustion chamber than the 4G and a better resistance to detonation. There should be no reason to want to lower compression IMO

 

drag, but as tons0torque pointed out, getting the upgraded gaskets will lower compression? doesn't sound very good if I'm gonna lose low-end power.

the 1.1mm and 1.3mm - any difference in terms of performance/gains?

 

More aggressive cams equate to more heat which will promote detonation. As the heat in your combustion chamber increases, it is always a safer option especially in our climate to opt for lower compression gaskets which will help in reducing chamber temps.

 

Aggressive cam timing has nothing to do with heat ..

overly high boost, too lean a mixture etc are usually the cause for high cylinder head temperatures ..

 

They are usually meant for you to run high boost using bigger turbos .. it's always a tradeoff ..

You have no reason to change to a thicker head gasket if you're keeping the stock turbo ..

 

Also, since we have timing chains, its a good idea to run a slightly thicker head gasket once the head and/or the block is over shaved.

 

Can anyone do this math? What does 0.2mm equate to in comp/ratio decrease? How much additional boost might that allow?

 

An HKS 1.2mm = 9.0:1 CR
HKS 1.0mm= 9.1:1CR
HKS 1.5mm = 8.8:1CR

so a 1.1mm should be 9.05:1CR?
1.3mm 8.9:1CR?

 

i think you want to have a skinnier gasket to make more compression.
As far as i know.

 

umm, evos have timing belts not chains.... unless im wrong but im 105% its a belt.

 

Evo X is a chain.

 

The only time you want MORE compression is w/ ALL MOTOR set ups.

Boost - Lower the better.

Also, like Speedclinic stated :

The evo 1-9 are timing belts - 4G63 motors
The evo x is a timing chain 4B11t

 

oh duh, im in the X sub forum

Me = pwned