Loss of Power, Possible SSV?
07-07-2013, 01:56 PM
#1
Loss of Power, Possible SSV?
My RX8 2007 231 loses power when it is hot. The weather today was 30'c and it was happening all the time. I try and accelerate hard in 2nd, 3rd, 4th,5th and the power isn't there plus sometimes there is a rattling noise like a rock in a beer can. I have been reading on some threads about the SSV valve but if this was the case with mine why does it only do it when it is very hot?
I have new coils and leads and it has had an oil change every 6 months from new which is normally around 2500 - 3000 miles.
Here is a photo of the outside of my SSV, there is a lot of rust and an indent mark, could this be flapping around smacking the stop and making the noise?
Any advice greatly received please
I have new coils and leads and it has had an oil change every 6 months from new which is normally around 2500 - 3000 miles.
Here is a photo of the outside of my SSV, there is a lot of rust and an indent mark, could this be flapping around smacking the stop and making the noise?
Any advice greatly received please
07-08-2013, 02:22 AM
#3
Do you think a blocked cat would make it knock under load? I will pull the cat later today and post the photos. I have one of the old 1970's rotary engine compression testers and I did a compression test not long ago and it was fine. I will do another one and post the results.
07-08-2013, 03:23 PM
#4
Here are the results of my tests today. Compression looks good to me, slight variation on the rear rotor but I think it is within spec. CAT is perfect!!!
I don't know where to look now......
I don't know where to look now......
07-12-2013, 03:54 PM
#5
Problem solved please see here
RX8 Owners Club • View topic - Detonation in hot weather - Anyone? AKA Marbles in a can
RX8 Owners Club • View topic - Detonation in hot weather - Anyone? AKA Marbles in a can
07-12-2013, 04:10 PM
#6
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Yeah, low octane would do it. Not something we usually jump to as a possibility though, since it's labeled for premium here in the US.
In answer to the question at the end of that thread, yes, minimum octane is a function of the engine compression. High octane is required for engines that have high compression ratios, 10:1 or higher normally. Well, that is directly related to the compression test scores. High compression means that the charge heats up more, and the engine needs more octane to prevent detonation. Conversely, a weakening engine is letting more and more of the charge escape, which lowers the amount of heat in the charge. As a result, a weakening engine can run lower octane than a good engine.
Keep in mind that the octane prevention isn't looking at the engine as a whole, or average compression. You could have 5 nearly dead rotor faces and 1 really good face, and low octane could blow the seals on that 1 face, destroying what's left of the engine.
In answer to the question at the end of that thread, yes, minimum octane is a function of the engine compression. High octane is required for engines that have high compression ratios, 10:1 or higher normally. Well, that is directly related to the compression test scores. High compression means that the charge heats up more, and the engine needs more octane to prevent detonation. Conversely, a weakening engine is letting more and more of the charge escape, which lowers the amount of heat in the charge. As a result, a weakening engine can run lower octane than a good engine.
Keep in mind that the octane prevention isn't looking at the engine as a whole, or average compression. You could have 5 nearly dead rotor faces and 1 really good face, and low octane could blow the seals on that 1 face, destroying what's left of the engine.
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