I am looking at putting a stock renesis engine into a roadracing chassis. I'm interested in how the engine has held up in RX 8's that see a lot of track / autocross time. I am new to rotary engines so I'm interested in any info both good and bad you can give me -oil cunsumption, heat problems, seal wear etc. Even folks who push their cars continuously on the street or drag race would be good sources of info for me. Thanks.

 

I average about 8mpg and a quart of oil in a single track day. No problems at all in terms of heat so far, but we will need to give it time out in the market before we can discuss any long term wear issues. It has been holding up extremely well. Mazda uses these exact engines in their formula mazda cars.

 

Thanks Murix. Is your track day about 1 hour of track time( 4 20 minute runs)? I assume that oil usage is the apex seal lubrication that ends up getting burned as a byproduct of the combustion process. I am aware of the proMazda use of a modified REnesis but have been unable to get in tpouch with anyone who has info on engine longevity or time between refreshes. I will be drysumping in order to reduce the engines height but don't plan to make any other changes than improvements to fuel mapping via a race ECU.

 

I am getting 6 30 minute runs per track event with the group I go with so about 3 hours worth of track time. The oil usage is indeed lubrication. After this last track run I drove it home through the mountains for 4 hours to get home and had no problems.

 

How many miles do you have on the car and how many track events have you done in it. also what are you using for oil?

 

Yes. Look at the ad on the inside cover of SCCA's mag. It says thier achieving a 2.9 0-60 with what sounds like the stock 8 engine in a formula car. That's quick.

 

www.starmazda.com

 

Hopefully Mazda has learned how to make the rotary more relaible with the new scientific advantages available today. In previous rotary cars, heat, detonation, etc. were problems. These things keep rx7 owners very meticulous about our cars. maybe they got the kinks out before producing the rx8....time will tell.

 

they have

 

14,000 since November, 2003. Two full track days on this car, one cross country trip, several long but shorter trips, and lots of spirited driving in mountain backroads.

I use 5w20 Castrol

 

I assume the Castrol is organic. Does Mazda recommend against synthetic for the Renesis? I've heard that they did on the first two generations but I have no firm info.

 

do a search on synthetic oil on this forum

derive your own conclusion.

 

I have raced rotarys in SCCA ITS class for seasons without rebuilding the engine. From the 80s on NA rotarys are very reliable as competition motors. the only caution is make sure it is getting oil and cooling. I have never had a rotary blow up on me.

I have 6000 miles on my 8 with two track events at Sebring all shifts are in the redline. The car handles great but with a little push

John

 

Thanks to all who responded. all of the feedback I've had on the rotary especially the Renesis has been extremely positive. I will be pursuing building or buying a purpose built racecar with the Renesis engine with particular emphasis on excellent cooling and lubrication systems. I appreciate all of the feedback. Thanks.

 

I just got back from Nelson Ledges with my rx-8 and what a blast. A comment and a question.
I was at beaver run (PA) about 3 weeks ago and on my last lapping session my engine starting cutting out. I ended my run and then after a short while drove the 2hrs home to the Cleveland Ohio area.

As I was saying I was at Nelson Ledges this weekend and yesterday the same thing happened..... My driving instructor suggested it might be because my tank was at abou 1/4 of a tank and sure enough today, I filled up at lunch and everything was fine. my comment, the slushing around of the gasoline in the car is a problem when the tank is low- my friend with a 911 s4 has the same problem.

My question, after my hot laps and during the cool down lap my oil light comes on for about 1/3 of a lap and then goes off. Has anyone else had this problem? I'm running my last lap in 4th gear about 50 mph...

Thanks

PS The car goes fast. now i'll admit i'm a rookie (Class C out of Class A through D and my third event) but this car was faster then the 911 S4 and Corvette Z06, in fact the guy in the Z06 said he thought I was accelerating as hard as him coming out of the carosel (I know not likely but I had alot of people who were shocked by how fast this car is!)

 

As most of us here we have the daily driver/ weekend racer thing going on and most of us are having good success on and off the track. I agree that I go through about a quart of oil and get about the same MPG though its worth it. I've always taken my cars out for road race events and never had a problem. The secret is in the regular mantenance. It needs to be done more often at shorter intervals. Personally I think taking the car out to the track is just as benificial to the car as it is the driver. It breathes new life and spirit into the vehicle.

 

I have run my 8 so far at 3 NASA drivers schools. Homestead, Sebring and Homestead. Only real problem that I have encountered is brakes. I am an instructor and to put it frankly, I push the car. Put on slotted rotors and now run Hawk Blue pads with AP600 fluid. This seemed to solve any problems. I was using stock rotors and Porterfield R4 pads before (cooked the living hell out of them at Sebring).

The 8's like to push (understeer) and the Mazda Speed spoiler doesn't help. Working on a small splitter to attached to front bumper to put more downforce there. No oil light problems - that I would look into real quick. I run 20-50 Castrol in hot Florida and use approx. 1 qt during a day at the track plus I use 4 oz of Protec gas additive from Pettit Racing to a tank of gas.

We had 4 - 8's at homestead last weekend and two afterwards said that they had problems with leading coils. I think both have the Canzoomer stage 1. You can form your own option on that one. I pulled my stage 2 off after showing a loss in power.

My opinion of this motor is that Mazda has done a good job of engineering a strong motor that if maintained will give long life. ECU changes are going to be difficult as their computer fights everything that you try to do. Real power gains I am convinced with realiabe power may only come from a supercharger or turbo.

 

OK,
Sounds like you are running into 2 known problems.
1) The Oil light might be due to an issue with the oil pan sensor. There is a TSB for that . (The oil light tends to come on if yur oil level is slightly low. Do a search for oil pan.

2) The fuel cutout is a known issue if you are at 1/4 tank or less and are going through an extended turn (from what I remember). No fix that I know of other than not racing the 8 with a low gas level. Sorry.

 

Most cars have issues running around the track with 1/4 tank or
less fuel. Especially cars that actually handle well and are
driven hard enough to pull enough g's around the turns.

As far as the RX8 being faster than a Z06 or Carrera 4S,
A Z06 is way faster than an RX8. I would just say you're a
much better driver than those other guys. Your driving
skill makes a huge difference.

I have outrun 1000cc sport motorcycles in my RX8 on the track
and passed modified wrx's in my stock 93' miata. Of course,
it goes both ways. Driver is at least as important as
the car modifications.

 

Jay,

What slotted rotors are you using at the track? Is the AP600 fluid Dot3 or Dot4?

Btw, how difficulat it is to swap the track pad and rotors by yourself? I know for the pads, all you need is to unscrew the two 14mm hex bolt at the back side of the caliper for it to come lose; and then just take out the old pads and slide in the new one, right? What about the rotors then??

TIA,
Pete