3IS does have a problem overheating on the track if pushed hard. Not saying it is good or bad, just stating the fact. I am just curious if architecture of transferring torque from engine to driveshafts is the same in 3IS 350 and RCF then why would 3IS overheat (that of course assumes that RCF doesn't overheat on the track)?

 

The RCF definitely has more beefy cooling. The fact that it has added coolers for both engine oil and transmission oil is helpful. The 3IS has a mocal sandwhich plate looking adapter on the side of the transmission that supplies coolant, yeah coolant...go figure...to help cool the tranny. I'd get a proper setrab. It would probably take more work than should be necessary though.

Mike

 

3IS cools with engine coolant so its 200-225 degF. That temperature will go up more when on the track so theres not much room for lowering temps. Now if youre on hot track day its going to have even less cooling capacity. Air cooler will be whatever ambient is and have a much better temperature differential for cooling than operating temperature coolant.

its design details like this that make me really like the RCF

 

Anyone think about retrofitting both to any IS with F Sport bumpers?

 

Go with a "square" setup, too. The IS isn't powerful-enough to need "meats" in the back. It's just a fashion statement.

 

i didnt do squared but i did 10mm wider all around 235/265, it was the same price as 225/255

 

It will overheat because its lack of ATF Cooler like the one equipped on the RCF

 

Yes - I noticed a major difference in handling going from a 2IS 350 (base) to the 3IS 350 FSport. The only drawback of the 3IS is the throttle response...if it was more like that of the 2IS the 3IS would be perfect.