olddragger

iTrader: (3)

CV joints -IDK, I do know there is tremendous drag in the diff.
I wish we could use the entire Miata rear.
Our water pump for street driving could actually benefit from a 10-15% overdrive.

PhillipM

Yep, ceramic *****, CVD/PVD coated housings, chemical polishing of the runners and cages, low friction + high temperature silicone/PTFE seals/boots, low viscosity/friction lubricants...

Big issue for us racing safari cars because when the joints are often running 26-28* of angle they absorb a huge amount of power - it's not uncommon for us to come back into service with the joints still at 220-280 degrees if the event is particularly rough...
^What you should gather from that is keep the joints as straight as you can!

EricMeyer

These RX-8's are just like any other car and you only need to look at what other cars are doing to reduce friction and make power. Back to Google and a pot of coffee for a Subaru, Corvette, dragster, Miata, etc.

I think one of the things you'll find that is pretty common is to REM or WPC your trans and ring and pinion. This is pretty common place. You'll note in the trans how much more easy it is to spin the input shaft with your hands when the trans is out of the car---reduced friction/drag. The other area that is very large step is to address the wheel bearings. A few years ago the open wheel guys started looking more closely at wheel bearings. Custom wheel bearings made of ceramic is where several of these teams have headed. Same for the Rolex and GT classes of cars. One of the things that these classes have going for them is more of a standardized hub. How many hub options are their for an RX-8? Near zero as far as I can tell. For a higher power road race car there are several, the customers have budget and therefore there is a market for these bearings. Not so for the RX-8. Could you see 1 hp on the dyno? Dunno. Back to the "what % is 1 hp out of 200+?" Not a big number right? Hard to measure. We don't run these things and I have some buddies that run them in Grand-Am. The "show-off" effort in their shop has them spinning the front wheel when the wheel is off the ground and watching it spin, spin, spin. You can easily see how the thing wants to roll. Power? They couldn't measure any additional power either on the dyno. Another benefit that the RX-8 doesn't necessarily gain from is the reduction in heat. FWD race cars are burdned by having their front wheels do a ton of work: Accelerate, Turn and Brake. These hubs get hotter than the RWD cars. Most all of these guys NEED cool air brack ducts and/or cool air hub ducts. The MX-5 cup cars run the RX-8 hubs because they are a bit more robust to heat. Failure of the RX-8 hubs (with heat or wheel bearing load) can result in a nasty wheel speed failure which leads to really ugly, ugly, ugly braking dynamics. This thread with less restrictive items on the car also ties in with lighter weight wheels and rotors. You could also think about the MOI concept with these however I'm not aware of any brake rotor or wheel manufacturers that use "MOI" in their marketing material.

Denny, lots of the performance piston crowd uses surface treatments and coatings on the various rotating and reciprocating parts. There is a guy I know doing this on the Renesis and he swears by it. I've asked him how he know it works and its difficult to proove. Perhaps after 50,000 miles you could tear down the motor and inspect wear patterns. Hard to say if you get 1 or 2 hp.

PhillipM

AP tends to release MOI info for their systems too.

EricMeyer

Very cool. Thanks and love to learn!

PhillipM

^No good if your struggling with brake temperatures under small wheels though

EricMeyer

That is very interesting. Would shocks have issue based on longer and more frequent and what I'm assume to be more brutal travel?

PhillipM

^^It leads to some interesting 'transmission loss' figures if the car bounces on the straps during a dyno...

The dampers?
Yes, we run multiple dampers per corner or large diameter singles, heat control is a massive issue as oil viscosity and damper settings alter as the heat builds up, so the valving and internal mechanisms are designed to keep those as consistant as possible.

I've seen the top bearings welded to the shafts before from the heat buildup on some cars if they damage a seal.

That little rotary buggy we have, usually runs in national events where the stages are 8-15 minutes long - it only weighs in at just over 1900lbs with fluids and driver/co-driver on board, and yet even with two dampers per side on the rear, and those being 35" long and all 4 with remote canisters for cooling, they still peak around 250F on most courses.
The French events are smoother but a lot longer - about an hour between services, so we'll use smaller, shorter dampers with those but even our old 4wd car used to run 2 x Ohlins per corner.
Obviously with the impacts and high shaft speeds cavitation is an issue too, which only gets worse with heat.

longpath

iTrader: (1)

While looking at ceramic bearings and friction reducing coatings for transmission and rear end, I came across http://www.microblueracing.com/micro...-services.html and this graphic:


I'm not sure how much of what they say is hype; but the general premise seems to follow the lines of conversation. Whether what this vendor is offering is a good example or not, the concept is once I'm curious enough to try to learn about, freely admitting I'm starting at the extreme low end of the learning curve.

http://www.youtube.com/watch?v=Z_zXqulVJUo

EricMeyer

^There are 3 options in the marketplace that travel in the circles that I run in. A. REM, B, MicroBlue (REM + Coating) and C. WPC WPC is kinda the hotter ticket in the circles I run in mainly because the media shot is much smaller than the REM media. This allows you to get into smaller nooks and crannies. I could be all washed up but this is the prevolent thinking in the circles I run in.

Any of those 3 are going to rock and roll your stuff. Have done lots of REM and WPC. I would offer that WPC is slightly superior to REM. Lots of REM vendors. Only one WPC I recall and he is on the West Coast.

Either of these two options are typical offerings from performance transmission builders/suppliers.

Highway8

iTrader: (11)

They offer the WPC treatment on almost any mechanical part including those week link side seal springs.

TeamRX8

iTrader: (25)

Unfortunately that won't address the spring tension loss due to high temperature metal fatigue issue

longpath

iTrader: (1)

Would ceramic side seals? I know it's been discussed elsewhere; but until I see some results from someone running ceramic seals, it could just be a nice hypothesis.

Tampa1stRotor

iTrader: (1)

An important thing to keep in mind if you are considering ceramic bearings is bearing life. Almost all the ceramic bearings out there are hybrid bearings (stainless bearing race and ceramic *****). I'm in the Cycling industry and we typically see a 50% loss in bearing life with this style bearing. Why? Because the ceramic is so hard it smashes any small pieces of dirt into the stainless race causing rapid wear in the bearing.

The other option is a full ceramic bearing (race and *****), life span is retained here, prepare to shell out some serious cash here. Bearing bore tolerances for these have to be absolutely perfect for these or you will crack the race on installation.

olddragger

iTrader: (3)

very cool stuff here.
To add another thought? Anyone with experience with oil shedding coatings? I know in receips they have been proven to be of benefit in certain hot areas. My thought is the interior part of the rotor?
My reasoning in summary:
How much oil usually stays in the rotor and at what rpm? Centrificul force has to have an affect of the oil's ability to drain out of the rotor? If the oil cant drain adequently then it cant cool as well as it could if it did? With the renesis rotary face being thinner than all the others more heat from the combustion is penetrating at a faster rate? So oil cooling may be more important in the reneisis and more difficult to provide? Even with a coating the centrificul force may make it ineffective?
I do know that some recip guys actually just use a special high temperature gloss black paint on connecting rods etc that works for them.
I am fishing here, so slap me if I am totally off base.
But would an oil shedding coating be of any use in helping to keep the rotor cooler?