I finally made the jump from S2's to R2's. This is for my 2L drop-in build with a mildly ported head and cleaned up bowls. Had the cam install done at English Racing as usual for anything I don't do myself. I don't have any dyno comparison numbers yet because English installed a new clutch at the same time, and it needs a bit of break-in before it will hold full power. For now, I can say though that off-boost performance is the same or nearly the same as my S2's. Idle is completely unaffected, but the R2's are perhaps slightly softer than the S2's for offboost below 2500 rpm. I'm not 100% sure yet though. That's how small of a difference there is if there is one at all.

I'll post up S2 vs R2 road dyno plots in a few weeks.

 

Awesome. I've been waiting to see this comparison.

 

Aaron says that S2 -> R2 will be a different story on a non-MIVEC motor. In his experience, boost threshold will shift to the right by 200-300 rpm. We didn't discuss any other aspect though.

 

here is a preliminary comparison of r2 vs s2 on an evo 9. r2 is the darker lines. the only difference is the cams. road dyno conditions are identical including segment of road used and air temperature. overall, they are very similar for my setup. the r2's moved the boost threshold just slightly to the right, but interestingly, that liitle gap where the r2's reach peak torque a little earlier is real and consistent across many s2 and r2 runs on that road. the little bump in the s2 torque curve is somewhat anamolous though. as for peak power, they are essentially identical, but note that, for whatever reason, boost was 1-2 psi lower above 4500 rpm for the r2's. i might attempt to do some boost matching on friday to see if the r2's will make more power.

r2 is darker lines.

 

Less boost due the cams flowing more air. Should pick up some power with turning up the boost, if the turbo can do it. Hopefully it can, you're running about the same amount of boost I am with my Red at peak (32-33). Your car looks like it tapesr a bit less, holding 30 where my car drops to about 28.

 

The R2 cams are very nice. Its basically a middle option between a S2 and S3.

They are starting to become very popular now on setups.

Yes if you match the boost curve for both cams, the R2 is going to make more power because they are more efficient and flow more air.

 

BUMP

MrFred - did you end up increasing the boost back to it's original value?
I'm running a 2.3L with S2's, wondering if it's worth upgrading...

 

I switched from S2's to R2's in my 2.3L just because they are more setup for a stroker app, where you aren't wanting to rev as high. I dont really want to rev my car past 7800 so these should bring the power band more to the left. Once I get the my BB black and Haltech on the car, I'm going to take it to Boostin to get it tuned.

So far, I did have to add a little fuel to the original map with the S2's because it was quite a bit leaner after the R2's, so thats a good sign.

 

RSMike, Are you maxing out the turbocharger? May be easier to add a few lbs of boost or better fuel to pickup power vs the cost/time of changing cams. What power level and setup do you have.

I think the S2's work well and may be easier on the valvetrain then R2. They also do well on the bottom end of things.

This isn't a mivec car but a good back to back test of alot of cams on a 4g63. Engine was a 2.0

https://dsportmag.com/the-tech/showc...final-results/

 

RSMike I also run a 2.3L and was running S3 cams, just switched to R2 cams, didn’t lose any power in fact picked up some and definitely spools faster. I know I wasn’t running S2’s but the R2’s were designed to run with strokers. New #s mustang dyno 4th gear pull , 30 psi 93 pump/ meth 488/408.