Jonesboy2398

Help! I have a 2004 rx8 and yes it's a manual. I can only run my 0-60 in 8.4 seconds as my fastest time! I just hit 100,000 miles and afraid I have compression loss or could it be something else. I'm only 16 but still know how the car works and functions but can not run anything close to 6's no matter how I launch! Please help..

RIWWP

iTrader: (2)

Possible causes for power loss:
- ignition coil failure
- spark plug failure or fouling
- spark plug wire failure
- bad grounding
- coolant temp sensor failure
- low compression
- clogged cat
- fuel trims off
- eshaft sensor profile off
- eshaft sensor fouled
- MAF failure or fouled
- MAF unplugged
- sludged transmission oil
- sludged differential oil
- clogged air filter
- fuel pressure loss
- fuel pump failure
- front O2 sensor failure
- intake valve actuation problem (any one of the 4 valves)
- poor gas quality

Possible causes for normal power resulting in slower acceleration:
- Carrying more weight
- More rolling resistance
- Uphill
- Driving skill
- Hot ambient temperatures


I may be missing some reasons...

Jonesboy2398

I believe it could also be my clutch as this was the car I used to learn to drive stick on. On highway accelerations it seems more aggressive but from a stand still when your really giving it it just doesn't preform. Or am I wrong?

RIWWP

iTrader: (2)

I'm not trying to be an *** here, and I hope I don't come across that way ... but you really haven't given us any information to work with.

How about going down the list I posted first and letting us know the age and/or condition of each of those? If you don't know one, that's ok, we just need some sort of information to help you, and nebulous "doesn't accelerate as fast" isn't helping us to help you.

And yes, launching the RX-8 is actually rather difficult to do properly. Diff bushings, clutch condition, tire compound, tire width, pavement type, ambient temperature, and pavement temperature can all lead to large swings in 0-60 times.

Jonesboy2398

My idle does tend to bounce sometimes even when warmed up but only maybe 100 rpm! And when I first got the car the car fax reported the clutch was changed at 60,00 miles, I got the car at 95,00 miles but you know me being young and not very good with a clutch at the time wanted to do some launches quite often and since then I can feel there's not as much bite when I drop the clutch even when just shifting normally. A while back I ran a 0-60 like 4 months ago and I believe it was around mid 7's. The power doesn't feel any different then before but the clutch does.

RIWWP

iTrader: (2)

Well, without any other real information, I'm going to make the possible diagnosis of clutch abuse leading to clutch disc failure. I might be wrong, but I don't really have anything else to work with.

Jonesboy2398

Everything else on the car seems to be fine we changed tranny oil and diff oil 2 months ago just replaced pads and rotors on rear end but I know it's not the brakes because it had the same problem before that. But thanks for the help anyway I don't really know what else I could tell you.

RIWWP

iTrader: (2)

I've colored red the possibilities which you haven't even made a slight reference to, and green the ones you have ruled out, blue the ones that you have made a possibility:

If you want ... you could always comment on more of the ones in red?

Jonesboy2398

Intake overall is clean and in check, my exhaust is in half right before the muffler but always has been ever since I got it! Never had any misfires or any problems with engine Last January I couldn't get my car to start one morning and I believe it may of been my coils and the cold but haven't had any problem starting since. I tend to redline it often yes at least every day and some times multiple times a day. I use 93 octane on every fill up and the gas quality seems to be normal. My power band is smooth all the way through and doesn't seem to have any hesitation. I've only had the car for around 6 months and never had any engine trouble unless it was really cold out. All my wires seem to be in good shape and connections are secure. Doing quick accelerations at stop lights has the same affect regardless to weight, uphill or temp. I am a pretty good driver and can shift quick and was shifting at 9,000 rpm.

gwilliams6

Listen to RIWWP's advice. All the issues he highlights are possible problems due to possibly poor or inconsistent maintenance, and wear and tear due to your car's mileage

RX8 Club’s recommended maintenance schedule, more comprehensive and proactive than Mazda’s schedule.
30,000 miles:
- Replace Ignition coils
- Replace Plug wires
- Replace Spark plugs
- Clean MAF (mass air flow sensor)
- Clean ESS (e-shaft sensor)
- Reset ESS profile
- Clean power steering connections
- Clean battery terminals and clamps
- Replace transmission fluid
- Replace coolant (Mazda FL-22 is highly recommended)
- Replace air filter
- Replace brake fluid (fluid in the brake lines AND the clutch line)
~$300 USD in parts if you shop smartly.


every 60,000:
...all 30,000, plus...
- Clean all chassis electrical grounding points
- Replace accessory belts
- Clean OMP lines
- Replace rear differential fluid
- Replace thermostat
- Clean / Straighten AC condenser fins
- Clean / Straighten oil cooler fins
- Inspect catalytic converter
- Clean / Inspect intake valving
- Consider / inspect all points in 90,000+ as well, many items fail early
~$130 USD in parts if you shop smartly.

90,000:
...all 30,000, plus any 60,000 not yet done, plus...
- Replace coolant bottle
- Replace radiator hoses
- Replace radiator
- Replace front O2 sensor
- Replace motor mounts
- Inspect clutch pedal assembly for flex / weld breaks
~$900 USD in parts if you shop smartly.

Legot

iTrader: (1)

What does that even mean?

If you're shifting at 9k rpm them you'll never get to 60 anywhere near that 7 second (being realistic) target. The fuel cut is at 9k with a 200 rpm hysterisis. Hitting 9000 will slow you down significantly. Shift earlier.

Colon Terminus

That's normal for RX8 exhaust, they all split that way.


You hit redline at 9,000 rpm, you hit fuel cutoff at 9,500 rpm, maximum power comes in at 8,600 rpm or so. For maximum acceleration you'll wanna shift when you see about 8,500 on the tach.


If you car is in good shape, try this for a timed 0-60 dash:
With the car in 1st gear and clutch depressed to the floor
rev the engine up to about 4500-5000 rpm and slide your
foot off the clutch and slam the accelerator to the floor
do a quick shift to 2nd at 8500 rpm.


I wouldn't recommend you do this too often.

Legot

iTrader: (1)

The in-dash tachometer is off by 2-500 rpm. Fuel cut happens at 9000.

DAT2RTR

All of the above, and get a compression test done. You might think your car "seems more agressive" on the highway or racing from a roll. But it's probably not. The butt dyno lies with this car. Constantly. Go get a compression test, and run your car on an actual dyno. Then get on a dyno. You can replace every single damn part on this motor chasing down any problem you can think of, just to find out that your motor is toast. Ask me how i know.

DAT2RTR

Also, that factory 0-60 time, is probably on a prepared track or skidpad. Not you with an I phone timer on some side road. Not trying to be a dick. Just being honest.