SO for us 2.0 guys, any benefit from an R2 over an S2?

 

Here is another car with R2 cams, but its a 2.3 as well.
https://www.evolutionm.net/forums/ev...-e60-fuel.html

I read a post that the R2 cams would help a 2.0 a little bit if you had a bigger turbo and a ported head, but I haven't found any dyno data to back it up by comparing it with another cam like we have on this post.
-The data that I did find looks like the Evo 9 2.4 liter (without a ported head) gained 44 whp from an s2 to an r2 cam swap on a low level of boost (under 30 psi). The gains an 8 will make might be a little less.
-We can already see on the first page of this post that the s2 cams also gained 60 or so whp over stock. (with supporting mods)

I thought it would work fine with a 2.0 + big turbo and a ported head if you are focused on 4,000-8500; but after reading the previous post I might just avoid them without a stroked motor.
According to the previous post:
"Secondly, a shorter rod/stroke ratio engine like the 2.3 swings the piston faster around TDC, and therefore needs a slightly later intake LC. The R2 cam has a 2 degree later intake LC to compensate for this, as well as more effective duration than an S2, and it's ramp rates are a little quicker." So they are really geared towards the stroker.

 

Rrace002

Can you link us to the 2.4 S2 to R2 cam dyno
I doubt 44whp gain...unless higher boost/fuel change and/or other update was implemented.
But R2 seems Taylor made for stroker.

I worry about valve train stress with such high lift..

 

I appreciate the help. Would you degree the cams to the specified center line or just set them to 0 degrees at TDC and then try -1/-1, -2/-1 and other similar combinations to find the sweet spot?

I don't think I have a ported head. I bought the car, had a few issues with the build (it already had the 2.3 with R2 cams + an evo 9 turbo when I bought it). Turbo trix apparently installed R2 cams with stock springs and retainers and 2 retainers broke right in half at some point but them motor kept running. I think the metal pieces then caused my turbo to go bad.

 

Here is the link:
https://www.evolutionm.net/forums/ev...ting-data.html

 

This one has similar data, but they added a few other parts:

https://www.evolutionm.net/forums/ev...art-swaps.html

 

A few notes:

The R2 cam was designed with a stroker engine in mind, but it will work fine in a 2.0 with large turbo.

Under no circumstances should factory springs or retainers find their way into any engine with an R2.

Again, the difference a CNC ported head makes here is worth the expense, the degree of the result being amplified at higher power levels. https://www.evolutionm.net/forums/au...0whp-gain.html

The high lift and rapid valve action does present stresses to the valvetrain, which is why the correct valve gear is critical. To put this into perspective, the cams I'm using give even greater lift and faster ramp rates than the R2, but everything has been holding up just fine on this end. The rapid valve action and improved low lift flow of my CNC head makes very good low speed manners. I've advanced 1.5 degree with respect to the R2 intake timing, so that helps with spool and midrange, albeit makes for a somewhat bumpy idle.

 

I'm going to focus on this statement here for my question - I'm utilizing a S2s on my 2.2L de-stroker, since my geometry is the same as the 4G63 one could casually assume that my gains would be less than someone using a standard 2.3L setup, all things considered?

 

I'm not certain I understand exactly what you're asking, but maintaining the same rod/stroke ratio (1.7) as the factory engine simply tends to make the engine theoretically more efficient at high rpm by a slight margin as compared to the shorter ratio (1.5) of a 2.3. Otherwise, it still represents a 10% increase in displacement over the standard 2.0, which is significant.

 

Sorry, that wasn't my best capture:

The R2 is compensating for a faster moving piston with a 2.3/2.4, but in my case I have no change in peak piston speed, just the 10% increase in displacement.

I assume I've over thinking this, and should just pick up a set of R2s to test with my CBRE head this summer.

 

You'll have no change in piston speed/position around TDC as compared to a 2.0. Advancing the R2 intake cam by 1-2 degrees may be helpful for street work and spool, as it puts the intake LC into the area of the S2 and S3.

 

In this case , what would I set my intake and exhaust side timing degree to?
I have a fully built 2.4 stoker with BC valve spring and retainer with gsc lifters and aem cam gears. Also cp 9.5:1 piston and Manley 156mm I beam rods.
Just wondering what timing would be best for both intake and exhaust timing degree.

 

I would leave the exhaust alone and advance the intake cam 1-2 degrees. I would not necessarily recommend that BC spring set with the R2 cams.

 

I already set both the intake and exhaust side to 3.5 degree. Should I change the intake side to 5 degree and keep the exhaust at 3.5 degree???

Why can't I used the BC spring on these R2 cams?
What would be better?

 

I bought my evo with R2s already installed and they didn't install the right springs and retainers and 2 of my retainers busted in half (with about 4k on the engine) and put chunks of metal all throughout my engine and ruined my turbo. I am about halfway through the rebuild and nearly 5 grand into it without including labor. I am damn lucky the motor didn't completely blow up.....

I had to replace the turbo and rebuild the head and a few other things. I am not saying this will happen to you, but depending on the spring set and retainers you have, it is possible.

You have to make sure you have a high pressure spring with the right amount of lift for the high lift on the R2. I am not sure on the spec of the BC springs/ retainers you are using; but GSC does recommend their kit for the R2 cams (5040 or 5041).