I've posted my car awhile back, but I have a 2005 built for Touring 3. I raced about 5 weekends last year and this year I'm working towards The Runoffs.

We had a double national this past weekend at Texas World Speedway. About the only problems I've had with my car are the standard fuel pickup on hard and long left handers. That has been solved by simply keeping the tank full. I tested the car last weekend and everything was fine for 3 sessions. For this weekends practice day Friday I only got about 4 laps in before I started getting a loss of power under heavy load. Started around 7k for 3rd gear and less RPM's for 4th and 5th gear. I wasn't imagining things as I saw my shift points extended and top speed into Turn 1 about 107 instead of 135. Things progressively got worse as I went.

Friday afternoon practice this same loss of power started on just the first lap and got worse. We inspected all wires and vacuum lines along with coils, nothing looked bad. Car wasn't throwing any permanent CEL. I made sure all fluids were at level and added 12 oz. of fuel system cleaner.

Saturday qualifying it was wet and I struggled through 4 laps when under full power. I still qualified on pole because the Hoosier Rains were hooked up, but still down about 35 mph on fast straight. We reset computer for the race. Flag went green, but I didn't go anywhere. Dropped to back of field and struggled through 4 laps and last lap was so bad I couldn't even go over 50 mph and pulled over to a corner station.

Car was behaving similar to the 12A when the fuel filter was clogged. Sunday morning we took the fuel pump out and cleaned the two pickups the best we could. We also blew air through the fuel lines. Nothing looked dirty, so we weren't very optimistic. Sunday qualifying I barely could finish 1 lap, so called it quits and went home.

This will be a tough one to find if the computer doesn't throw a specific code. We'll do compression test first to rule out engine, then inspect electricals and a fuel pressure test. If none of those tests show anything it is going to be REALLY hard to troubleshoot. We might replace every part on the car before we find it. :)

I'm not that mechanical, but starting with the basics loss of power is either fuel, air, or fire.

Fuel…

We cleaned the fuel pump and blew out the lines, that is about all you can do and everything looked perfectly clean. We can do a fuel pressure test. I guess possible the fuel pump is bad. There are two saddle tanks under the rear seats straddling the driveline. They only put the fuel pickup under the left passenger seat, which is fine for most normal driving. Under hard and long left turns all the fuel goes to the right side and no fuel is picked up. Takes about 30 seconds of running dry and coughing for fuel pump to pickup again. This is solved by running a full tank all the time, but I'm wondering if the dozen times or so I've run it dry have damaged the fuel pump?

Air…

Front radiator looked clear. Filter clear. Intake from what I can tell. We did a quick inspection of vacuum lines.

Electrical…

RX8 coils are known to fail, you see why burnt marks outside them as spark is escaping. That can cause these symptoms, but on first look the coils looked fine. If electrical it could be several things like plugs or plug wires. Remember, full power in lower gears, just happens under heavier load and when warmer although it appeared to be getting worse and worse. There could be dozens of possible sensors having the computer retard power. I would think a specific code would be thrown for this though.

Anyone ever experienced these problems or different ideas after starting with the compressions test and fuel pressure?

Thank you,
rob

I am by no means an expert but knowing that modern fuel pumps don't like to be run dry, I'd guess you burned it up.

My suggestion would be to start there first. Hope that helps!

Sounds like you know your way around the car already. However, the Georgia gang has been dynoing their cars for the past year and we all have found a huge loss of power due to coils and plugs. This power loss can be to the tune of 30 hp at 7K and above. The most extreme case was with one member whose car shut down on the dyno during his 2nd pull once he was at around 8K. The diagnosis was fried coils. He had the coils replaced along with the plugs. He later also replaced the plug wires and noticed another improvement. I think you have to remove the coils in order to see signs of problems as well.

Sounds like you know your way around the car already. However, the Georgia gang has been dynoing their cars for the past year and we all have found a huge loss of power due to coils and plugs. This power loss can be to the tune of 30 hp at 7K and above. The most extreme case was with one member whose car shut down on the dyno during his 2nd pull once he was at around 8K. The diagnosis was fried coils. He had the coils replaced along with the plugs. He later also replaced the plug wires and noticed another improvement. I think you have to remove the coils in order to see signs of problems as well.

That sounds interesting.
Do you know what they replaced the coils, plug wires and spark plugs with? Did he just go back to new OEM parts or aftermarket? Is this just do to wear and tear and higher mileage or bad parts?

Let me know, I'm really interested in this.

The problems seem to begin at the 12 - 15K mile mark. It varies of course. I bet a race car would have problems sooner than a street driven car due to the loads and extended high RPM operation. All teh guys with coil/plug problems have had them replaced by OEM parts as well. One guy got the RB wires. Another (SilverEight) is going to dyno again after installing new plug wires on his car. There is a dyno thread already going where you can see before and after graphs. Pretty remarkable stuff.

Also, check for a clogged catylitic converter. I've had 3 replaced on my car so far. This will also cause a loss of power. If so, also look for oil to be blown back into the intake. MAF will have to be cleaned/replaced and airfilter replaced.

The problems seem to begin at the 12 - 15K mile mark. It varies of course. I bet a race car would have problems sooner than a street driven car due to the loads and extended high RPM operation. All teh guys with coil/plug problems have had them replaced by OEM parts as well. One guy got the RB wires. Another (SilverEight) is going to dyno again after installing new plug wires on his car. There is a dyno thread already going where you can see before and after graphs. Pretty remarkable stuff.

This is good to know.
I guess that i might buy some Racing beat wires to replace the OEMs. I hope that they will last longer. Anyone have any recomendation on aftermarket spark plugs (are there any) or should I stick with the OEMs?

I'd recommend calling Sylvain at SpeedSource too, he has a ton of racing experience with these cars and may have some mods to assist you as well. He's a very nice guy and won't mind discussing your situation with you:

http://speedsourceinc.com/index.cfm?template=contactinfo

interesting--all good advice here. Check your codes if it is a cat with that much power lost a code should show
. TA is right on about the ignition things we Ga boys have been dealing with but i dont know of anyone that has had the extreme lack of power you are saying you have. But I do know the computer has a fail safe mode of some kind. I saw the car that shut down at 8k on the dyno--no warning--it was not hot--it was not skipping--just shut down! Smoked like hell on the restart but ran ok. Blew a LOT of oil into the intake but hasnt blown anymore since(by report). Also since new plugs ,coils and RB wires by report the car is running very strong. So we figue no side seal damage. No one here has ever seen an 8 do that before.
Good luck and let us know what you find.
olddragger

Also, check for a clogged catylitic converter. I've had 3 replaced on my car so far. This will also cause a loss of power. If so, also look for oil to be blown back into the intake. MAF will have to be cleaned/replaced and airfilter replaced.

You can't just clean out the cat? Less expensive and also more flow?

Right now a clogged cat is the likely suspect. Instead of using 2 cycle oil, I use Benol, which was great in the 12A, but supposedly it burns up RX8 cats. :(

forgive me for not knowing the rules for SCCA T3, but can you not run without a CAT?

forgive me for not knowing the rules for SCCA T3, but can you not run without a CAT?

We should, but can't run without them. They're nothing but an expensive fire hazard.

A theory right now is my use of synthetic oil causes the cat to clog because synthetic oil doesn't burn.

Others with clogging cats use synthetic oil?

Like I posted, my car has had 3 cat replacements. All with standard dino oil. First one went within a month of having the car. Second one went at about the 4 month mark. 3rd one went recently 19K mi. / 20 months.
You can't just clean out the cat? Less expensive and also more flow? I think they meltdown and clog the output. Not much to clean up.

oil will typically foul a cat and cause it to not be emissions compliant, but not clog it, if it was severe enough to cause clogging it would be all over the inside of the pipe, you would have gotten a cat deficiency CEL early on if that was the case

the cat may have overheated and deformed internally enough to clog, this is typically caused by raw fuel getting into the cat and combusting with the O2 conversion gases (basically creating a blow torch effect) not running lean like most people think, the easiest way to test this is to have a catless testpipe to throw in there and see if that resolves the problem, too bad I just sold the one listed in the FS area.

Did you ever flood it?

A theory right now is my use of synthetic oil causes the cat to clog because synthetic oil doesn't burn.

Others with clogging cats use synthetic oil?
nonsense

Its never really been flooded. Maybe once I've had to do the gas down key turn.

Alnielsen, did you ever figure out a cause why your cat was clogging? Seems like you had the problem more than most. Using any gas additives?

We run 2 cycle oil about 1 oz. to Gallon. I actually run Benol, which is a natural caster type oil. Keeps the engine healthy with our rev bouncing extreme use. Not sure if that contributed.

nonsense

I don't know, I'm considering everything right now. This came from one of the first "15 Master Mazda Techs" in the world. He was assigned to the DFW area when Mazda service shops had a problem they couldn't fix he was called in. 30 years rotary and racing experience with them. He worked with Mazda engineers when they required all 12A's to run natural oil, he isn't sure why the new rotaries aren't the same. He's retired now. I'm sure there is a good reason, so maybe "nonsense" for the RX8, but there was a reason for the 12A.

One point, I know its well known the RX8's meter oil, but does everyone realize how MUCH under our race conditions? We go through over a quart in 30 minutes (about 45 miles). Our engines are 100% stock and this is common among all T3 RX8's. Haven't done it yet, but we'll actually program the computer to meter even more. :)

Are you the Rob Lay from FerrariChat?

Your symptoms are classic plugged cat, and your oil use is the direct cause.

If it was fuel or spark related (filter, coils, pumps etc.) you would be getting misfires, not steady power losses.

If you are really using 10 ounces of Castor Oil per tank, you will ABSOLUTELY plug the catalyst!

Anyone who thinks synthetic doesn't burn is just wrong, it burns very cleanly if you get ISO EGD quality - but castor oil truly is the worst "old-school" crap!

The old two strokes would gum up inside, it would cause carbon build-up and bad exhaust port deposits, eventually plugging off the whole silencer!....and that is an open exhaust with NO cat - I can't imagine what the "twentieth-of-an-inch" holes on your cat look like :nono:

Break the header/midpipe joint and take a look. :Eyecrazy:

S

he said 1 ounce per gallon which is a bit high if the metering pump is operating, typically I wouldn't use more than 1/2 ounce/gallon

12A motor is a different animal, 25 years of design improvements makes a difference

if you're in the DFW area I may be able to assist you, but we'll have to move fast

PM me

Are you the Rob Lay from FerrariChat?

Not too many Rob Lay's in the world. ;) What's your username there?

StealthTL, thank you for the info. My "guy" is VERY old school. Was trained on the RX8's, but retired soon after. His expertise were mainly through the 12A.

So 2 cycle synthetic oil better… 1/2 oz. a gallon?

Looks like we found the root cause. Been running the Benol through last year, I guess it just couldn't take anymore.

Still curious why street cars not running additives would clog their cats too.

Its never really been flooded. Maybe once I've had to do the gas down key turn.

Alnielsen, did you ever figure out a cause why your cat was clogging? Seems like you had the problem more than most. Using any gas additives?

We run 2 cycle oil about 1 oz. to Gallon. I actually run Benol, which is a natural caster type oil. Keeps the engine healthy with our rev bouncing extreme use. Not sure if that contributed.
I've never flooded the engine. I also don't run any additives, 2 stroke or otherwise. I believe that, for some reason, it is running rich. I am one of the people with poor gas milage. With the last cat problem, the MAF was changed and that didn't seem to make any change to that.

I use Amsoil 2 stroke, no issue yet

this is highly regarded too

http://www.idemitsu-usa.com/page_214.htm

1/2 oz/gal = 1:256 ratio

I've never flooded the engine. I also don't run any additives, 2 stroke or otherwise. I believe that, for some reason, it is running rich. I am one of the people with poor gas milage. With the last cat problem, the MAF was changed and that didn't seem to make any change to that.

Hmm, that's interesting too, I ran car 1,000 miles on street before building out. Gas mileage was terrible! 13-15 MPG, but I thought that was normal for the city. Maybe mine was running rich too?

Absoulutely correct---no castor. I'm friends with an owner and professional dirt biker/four wheeler idiot and he turned me on to the full synthetic Yamaha pre mix. He alsao castor well eventually give you problems. I run premix on the track only and only add 5 oz's per tank(almost a 1/3oz per gal) I know that is light but it does make a differance even at that low concentration. I only use maybe 1/2 quart oil for a track day Apprx 175miles. I get good gas milage on the street and have 30thou on the car.
I suggest pre mix for everyone that does anytype of high performance driving. Autocross, dragging or track
olddragger

Mine turned out to be a fried cat. We think the direct root cause is adding 2 cycle oil to the gas. That helps protect the engine more, but kills the cat whether you use castor or synthetic oil.

Through this experience I've learned a bunch and loss of power can be so many things… fuel, air, and spark.

We are harder and wear things out quicker racing, but maybe some of our experience will help those on the street too…

Fuel…

No external fuel filters, it is all built into the fuel pump below the rear driver side seat. I haven't heard of an RX8 with fuel problems yet, but lack of fuel flow (filter or bad pump) would cause the symptoms of power loss under load.

Air…

As others have mentioned, make sure your air paths are clear.

Spark…

Coils go bad, white marks around outside of coils indicate spark being lost.

Plug wires can go bad.

We are changing spark plugs every 3rd race weekend.

Good luck with your problems.

As for plug wires, Jim Langer at Racing Beat said his Ultra wires are good for 50K of rotary use.

Old school Castor is very slippery, and OK, short term, in a racing motor.

The old 12A engines differed significantly, peri-port exhausts obviously, but more importantly - they used a thermal reactor system and NO cat. Nothing to plug up, no fine mesh to foul.

S