The Rushmore and previous models have an oil cooler, the M8 is a bigger cooler but I think as long as there is an oil cooler the heads are benefiting from it. Either way, they are both Air Cooled as a primary means of cooling, oil is not that good at transferring heat so while there is a cooler I think it's more to keep the oil from overheating in the VTwin than to actually cool engine parts. I know that there is a direct relation but again, not really an effective way to cool an engine.

 

My 11 was much hotter than my 14 and there were fewer differences between those two motors than there is between the TC and the M8. I would imagine that all of the things working together produce a noticeable difference. But we won't know until we try for ourselves.

 

I am not done with this one yet. Honestly, if I ever sell the SG it wil be to get something more comfortable and I am not talking Ultra. Hopefully I will be on this one for 20 more years but every bad bump gets me closer to that Spyder!!

 

Just tossed on some Progressive 444s. Night and day difference from stock.

 

That is a high dollar upgrade for sure. Guess I am going to have to spring (no pun intended) for a pair.

 

Oil cooled heads on the M8 touring adds a bit more than just .5 qt.


Progessive 944s are great. Put 'em on my old Ultra and felt an immediate difference.

 

I need to sell some stock....geesh!!

 

I just rode both the 2016 and 2017 Street Glide Special's today as I'm deciding on which one to purchase in the next few days. I rented a 2016 last Saturday and rode 300 miles here in Florida during the day to see how the heat would affect me. Heat index was 105 that day. I'm not going to lie, it was hot, my legs were cooking. I was wearing jeans and I found myself spreading my legs/knees out as far as I could to get some air flow to my chest and around the back of my legs. I was doing my best not to hug the bike with my knees.

Today, on the test ride with the 2017, I noticed the heat was less, but was definitely there. My right thigh was getting hot. I was wearing the same jeans as when I rented. We were in stop and go traffic, hitting lights. I specifically asked after getting off on the highway to hit a few more lights to see how the heat was feeling as we would sit waiting for green.

This was the deal breaker for me on the 2017. We took both the 2016 and the 2017 so I could test both right away. After 100 feet I wanted off the 2017 because of the no vibration in the motor. I own a Landscape company and I immediately felt like I was on my Toro 48 inch commercial mower.

I am purchasing a 2016 for sure.

 

Likely due to increased intake air. This is true for all internal combustion engines, if you can increase intake air flow exhaust temperatures will lower and thus engine heat will lower.

 

Biggest change in the heads is there's oil externally pumped into and around the exhaust port area for the extra cooling so overall engine temps have dropped, touring models have the external oil cooler setup like and airdam on the lower frame just under the oil filter.

This vid has a good views of a cut away engine showing how all this works .