P0302 Missfire and Power Low (-60BHP) - Help Please
10-25-2012, 02:21 PM
#26
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Hi BC,
It is higher power 231BHP
Compression has been checked twice and is within limits.
o Front 7.10 7.15 7.60 280 RPM
o Rear 7.40 7.80 7.30 280 RPM
Normalised to 250 RPM
Thanks
Stu
It is higher power 231BHP
Compression has been checked twice and is within limits.
o Front 7.10 7.15 7.60 280 RPM
o Rear 7.40 7.80 7.30 280 RPM
Normalised to 250 RPM
Thanks
Stu
10-25-2012, 02:28 PM
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If he actually does have a Kuro, it's a 6-port engine. He hasn't made any indication about transmission type yet.
Stu, If you have a manual transmission, then yes, you are down on power. None of those numbers are BHP however, they are WHP. If it was BHP that was actually being tested then they would have removed the engine from the car and tested it by itself. Every standard method of trying to get to BHP from measuring at the wheels will return low for the RX-8, because none of them account for enough drivetrain losses for the RX-8. We have quite a bit more drivetrain loss than most.
That being said, if you have a MT and a 9,000rpm redline, then you are down about 30-40whp, which is entirely within the range of possible power loss from something not being quite right with the engine. A back to back dyno test a couple months back showed that old coils, plugs, and wires vs brand new was a 28whp difference on a stock RX-8. The fact that it peaked at the RPM it did (assuming that is what the RPM means) then you have a big problem with power up top. Your peak power is another 1,000rpm later. Power loss that bad up high is most commonly coil failure that can't keep up with the rate of firing or a clogged cat. Other possibilities are old transmission/diff fluid that is providing too much resistance, clogged air filter, and dirty MAF.
If you have an automatic with a 7,500rpm redline, then actually yeah, you are about where you should be with power, and at the right peak.
Stu, If you have a manual transmission, then yes, you are down on power. None of those numbers are BHP however, they are WHP. If it was BHP that was actually being tested then they would have removed the engine from the car and tested it by itself. Every standard method of trying to get to BHP from measuring at the wheels will return low for the RX-8, because none of them account for enough drivetrain losses for the RX-8. We have quite a bit more drivetrain loss than most.
That being said, if you have a MT and a 9,000rpm redline, then you are down about 30-40whp, which is entirely within the range of possible power loss from something not being quite right with the engine. A back to back dyno test a couple months back showed that old coils, plugs, and wires vs brand new was a 28whp difference on a stock RX-8. The fact that it peaked at the RPM it did (assuming that is what the RPM means) then you have a big problem with power up top. Your peak power is another 1,000rpm later. Power loss that bad up high is most commonly coil failure that can't keep up with the rate of firing or a clogged cat. Other possibilities are old transmission/diff fluid that is providing too much resistance, clogged air filter, and dirty MAF.
If you have an automatic with a 7,500rpm redline, then actually yeah, you are about where you should be with power, and at the right peak.
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