alexg

Hey guys,

I don't have a bunch of time at the moment to do exhaustive searching, so I apologize if this has been asked before. I'm going to do some track days starting on April 12th and I'm preparing what I'll need to make sure I don't blow up the car. I have some data acquisition put together, but I need to know what the safe operating temperatures are when on the track. What do you think?

• Oil: I'll probably set my warning at 225 deg-F.
• Water: Not sure, maybe 220 deg-F? I read rotaries are best at 190-200 deg-F, but I'm not sure when things start to get dangerous.
• Catalyst: No idea here, but I'm definitely afraid of cat failure leading to blown side seals, so this one is really important to me. Eventually I'll replace the OEM cat with a BHR midpipe. (Side note: is the catalyst BHR can include in their midpipe prone to failure like the OEM cat is?)
• Any others I should keep an eye on? Intake manifold? EGR? If I had a laser thermometer, I would do brake pads. What else?

Thanks in advance!
~ Alex

j9fd3s

driver: anything over 90F.... i suggest water injection, using 100% water, until after the track day is over, and then switching to a 50/50 water alcohol mix. you should do some data logging, but a good start is the driver using about 1 liter/hour of water, it can be more or less depending on outside temperature.

the cat is complex, as there are two reasons for failure. the first is temperature, anything over 650c and the cat life goes from infinite to finite.

the second reason for failure is that when the exhaust port opens the pressure waves are actually fairly abrupt, on the older peripheral exhaust port engines its actually supersonic, so its a bit like hitting the cat with a hammer at high rpm/high load.

basically if you're looking at a dead cat, and the rear brick is missing but the front is fine, it ran too hot. if the front brick is bad, you stepped on the gas too long.

MagnusRacing

iTrader: (2)

Do the midpipe before the track day

j9fd3s

cat infoz Precat Facts... - Page 2 - RX7Club.com

Black2010R3

iTrader: (1)

According to the "Renesis Engine Tutorial" dated 2 Aug 2012 for the Star Mazda Racing series, posted somewhere on this forum:

Oil: 190-230F operating range, target of 200F and a terminal temp of 250F before the coolers.They quote a 30F rise in temperature through the engine, so keep in mind where you're measuring and adjust accordingly.

Water: 180-220F operating range with a terminal temp of 240F.

As for the cat, I just bought a cheap dual resonnated mid-pipe and swap it in for track days, going back to stock after.

alexg

I'm considering it. Does the catalyst in the BHR have the same risk/reputation as the OEM cat when it comes to failures? I'd prefer to clean up the exhaust if I can, I can't stand coming to a stop and being choked out from exhaust fumes.

Good stuff, thanks guys! For anyone in the NW, I'll be at The Ridge in Shelton on the 12th

TeamRX8

iTrader: (25)

it's no April Fools joke, I am in a "be generous to noobs" mood

https://www.rx8club.com/aftermarket-...s-cats-210330/

j9fd3s

a cat is a cat, the best way to keep it nice is tucked away in the garage...

JantzenRX-8

iTrader: (9)

I'm going to post this and try not to high jack the thread. I was at the track this weekend with ambient temps around 70F. With a fair degree of regularity once i hit 210 water temps the power seemed to go a little flat. I could have just been a mis-calibrated butt dyno but i noticed it on multiple occasions so it had me scratching my head in curiosity. I never exceeded 218 for the day.

alexg

Thanks, TeamRX8, I'll check it out.

j9fd3s, I'm starting to get that impression. Especially given this line on BHR's website: "catalyst has not yet been tested in racing situations and does not come with a warranty."

Catless midpipe ordered

ShellDude

iTrader: (12)

Actually it has been tested, unofficially, and failed.

Emery_

iTrader: (8)

Ideally I wouldn't want to run my water temp hotter than 200 F. With the cobb and ATR software you can easily set your radiator fans to turn on sooner, and on average should see temps from 180-195 F.

ShellDude

iTrader: (12)

keep the revs, load, and oil pressure high for a couple minutes and you'll quickly exceed 200F.

bse50

Anything under 105°c water wise and you'll be fine. I generally see temperatures of 95-100°c.
Oil pressure is more important than oil temperature, as long as you know your cooling systems and how water\oil temps relate in your case. If you're going fast you don't have time to look at gauges.
Transmission temperatures are a must, so is an electric oil pump linked to a small radiator. Same goes for the differential. 2 oil pumps are too much though. The differential can be cooled by other means, the tranny not so much.

The catalytic converter will fail. A really expensive sport cat will fail as well sooner or later. High temps + premix really take a toll on them.

bse50

Bullshit. 200°f\93°c is completely fine. Why would you run any lower, at sub-optimal temperatures?
Are you also aware of the fact that fans do nothing at high speeds except blocking airflow, thus increasing radiator temps?

If you're not sure of what you're driving please simply avoid posting. Your misinformation may cost an owner his engine, which translates to hard earned cash.

darnellm

iTrader: (1)

+1 over about 35 mph fans are a restriction.
Wake up and smell the coffee

bse50

Some people just forget that this is the "racing" subforum. I started with the rx8 as a daily driver and learnt my fair share of nothing through this forum, google and some wrenching time.
Then I started using it as a track toy and soon realised that i had to learn a whole different nothing since most previous facts didn't apply there.

j9fd3s

my brother started to build a Lemons car with his friends and the first thing they did was go to the junkyard and buy a giant set of fans, i'm not sure why, but generation Y just loves big radiator fans....

j9fd3s

i have been talking to the engineering department, and a clarification is needed.

the 50/50 ratio is by the number of drinks. by liquid volume it should be more like 8oz water to 1oz not water.

etzilon

Isn't this why we have "Fan2 VSS" in the PCM? Just saying...

skc

I have been as high as 230 with my oil temps at the track. I do not have water temp gague and the last time I was at the track the stock temp gague started moving indicating overheating coolant while the oil temp was around 220F.

When this happened the car started to hesitate and lose power, I slowed down for one lap and immediately the temps dived so I went hard again until the situation was repeated.

So it appears my tuner may have added a protection mechanism when the car overheats. this mechanism may be dumping lots of cold fuel into the combustion chamber to cool things down.

Since, this incident I added ducting shrouds around my intercooler and oil coolers and the problem did not surface at the last track day.

9krpmrx8

iTrader: (46)

Going to 240F on coolant temps more than once is asking for a blown engine.

alexg

Thanks for the replies, guys. Based on the feedback, I'm going to set the warning alarm on my gauges as follows. In the meantime, I'll read up about oil pressure in the FSM. What are your typical safe zones for that on the track?

Oil: 225 deg-F
Water: 220 deg-F
Catalyst: Ignoring it since I'm putting in the BHR catless midpipe on Monday
Transmission: Cannot measure at this time

sblethen

iTrader: (3)

A couple more things to add to the converstation...

How/where are you getting your oil temps for the data system? this can make a big difference on what to use as a warning light. someone here mentioned a 30 degree difference, I have no idea on if that is true but if it is you need to know if your measuring the high side or the low side.

Water temps in C can be taken from the ECU. I have just finished hooking up my data to read that, but I did run last year using the RB adaptor with autometer guage. found temps to be around 210 or so on teh guage with that adaptor. I don't think the temp guage on the RX8 is a "Real gauge, I think it is similar to the oil pressure guage, which is more of a "dummy light" that looks cool and measures pressure or no pressure. If your "racing" you will need the fans since you will most likely be following close behind others without much flow (I know we all want to be out front but we need to be realistic at times!) If your "lapping" I would suspect you can stay out of the drafts of others and get plenty of air through the radiator without a fan.

Transmision temps, I ran without a cooler for a 4hr long race without issues BUT the fluid was toast. installing a cooler this weekend for our upcoming 12hr race.

No-one has talked about the rear diff, that sucker gets hot! Even the stock unit gets up above 250 within 30minutes of hard racing so be prepared to change the fluids before and after to be safe depending on how long your on track. Again I went 4hrs straight last fall without any failures but the fluid was changed before and after.

Stephen

etzilon

Do you think the high temp on the stock unit is caused primarily by internal friction or radiant heat from the exhaust? I'll be putting an aluminum heat shield between the two as a preventative measure as I am not measuring diff temps.