Power drop off over 7K RPM
05-27-2005, 01:10 AM
#26
I tried the "heavier oil" idea by switching from 5W20 to 20W50. Although I went from 14.0's to 14.4's, the engine sounds smoother in all rpm's. I still have the power loss, obviously, but it appears the noise and power loss issues are, indeed, lubrication-related. I will next switch back to the 5W20 and try the pre-mix idea. I have some other ideas I'll run past my Mazda tech. on Friday, which include asking him to take the time to "reghost" my PCM back to the M flash. If I am lucky maybe he'll be as curious as I am and we'll compare the various flashes and their respective performances. Wouldn't it be nice if we could combine the best aspects of the M and N/P flashes?
CRH
CRH
05-28-2005, 02:46 AM
#28
According to my Mazda mechanic, if the seals are a problem there will be difficulties with idling. He kept saying that he was confident my seals are in good shape because my idle was glass-smooth.
On the other hand, the Racing Beat website suggests using their MOP mod for anything over stock power levels as the factory pump is maxxed out at redline. The funny thing is that Nemesis just mentioned that Mazda is now starting to replace the MOP's on the vehicles that show a CEL regarding the MOP issue with higher volume MOP's just like the ones that RB offers. If that is true, I guess Mazda didn't take too much time to consider that some of us would modify these cars after a while. Another way to test seal wear is to install a vacuum gauge in place of those black caps in the lower intake manifold and see if it still reads 16" of vacuum at idle. The manual suggests a rebuild if it reads below that.
I did the pre-mix in the tank that Shocar suggested and the engine sounds real smooth at 9,500 rpm's. I still have the 20W50 in the oilpan but I will switch back to 5W20 in the morning. To describe the difference between the 5W20 and 20W50 in terms of feel is to also describe the difference between the stock flywheel and the SR, ACT Prolite, or similar flywheels. Yes, the difference is that dramatic. With the 5W20 in the pan and the premix in the tank I'll do another run Saturday night and see where I am at that point. If I am lucky enough to find myself hitting those 13.7's again then we have zeroed in on my problem. I am confident that I'll at least hit a 13.9, or so. I'll also try the nitrous and see what gains I get from it.
CRH
On the other hand, the Racing Beat website suggests using their MOP mod for anything over stock power levels as the factory pump is maxxed out at redline. The funny thing is that Nemesis just mentioned that Mazda is now starting to replace the MOP's on the vehicles that show a CEL regarding the MOP issue with higher volume MOP's just like the ones that RB offers. If that is true, I guess Mazda didn't take too much time to consider that some of us would modify these cars after a while. Another way to test seal wear is to install a vacuum gauge in place of those black caps in the lower intake manifold and see if it still reads 16" of vacuum at idle. The manual suggests a rebuild if it reads below that.
I did the pre-mix in the tank that Shocar suggested and the engine sounds real smooth at 9,500 rpm's. I still have the 20W50 in the oilpan but I will switch back to 5W20 in the morning. To describe the difference between the 5W20 and 20W50 in terms of feel is to also describe the difference between the stock flywheel and the SR, ACT Prolite, or similar flywheels. Yes, the difference is that dramatic. With the 5W20 in the pan and the premix in the tank I'll do another run Saturday night and see where I am at that point. If I am lucky enough to find myself hitting those 13.7's again then we have zeroed in on my problem. I am confident that I'll at least hit a 13.9, or so. I'll also try the nitrous and see what gains I get from it.
CRH
05-30-2005, 04:45 PM
#29
Administrator
no offense meant to kevin but i wantr to see the part number for this new MOP. when someone mentioned it a couple weeks ago i could not find a part number for a new/different pump.
05-30-2005, 11:05 PM
#30
I'd also like to get to the bottom of the MOP part from Mazda. I wonder how much difficulty I would have in arguing that my seal issue, if I indeed have one, was caused by the MOP and not the nitrous. I am wondering if my trip to Atlanta for two days of HPDE track time combined with the MOP volume issue was all the stock seals could take.
CRH
CRH
05-30-2005, 11:29 PM
#31
Originally Posted by zoom44
no offense meant to kevin but i wantr to see the part number for this new MOP. when someone mentioned it a couple weeks ago i could not find a part number for a new/different pump.
I meant to go ask Friday - but got sidetracked. I'll go byl on Tuesday and get the scoop. Remind me if I forget again :o
05-31-2005, 07:00 PM
#33
OK, there have been (2) part numbers... I'll have both the code and the part numbers on Wed. He was busy. The code was thrown from carbon buildup. It first showed up on an automatic, but they have replaced one on a 6-Speed also. The MOP came up from California, and has been changed - hence the two numbers. It is to pump 1/3 quart more oil per 3000 miles than my OEM pump. I asked if this could also be the cause of power falling off from lack of oil sealing up the chambers under haevy load above 7K, and he said yes. I cannot get the MOP without the code thrown. I'll bet it is the same MOP upgrade that Racing Beat has for us. Hell, they might have engineered the part for Mazda for all I know. Someone needs to ask Racing Beat if they changed theirs also, ie the two part numbers...
06-01-2005, 03:50 PM
#36
Administrator
I asked Racing Beat about the MOP and wether it was their part or not. here is the reply
I have not heard of any higher-volume pump available from Mazda. Of course, it could be true - the modification we offer is based on a high-flow pump supplied by Mazda on a supercharged engine we ran here. The only possible reason I can think of for them to do that would be for very cold or very hot starting, where extra oil can be helpful. However, since the MOP only runs wide open at high RPM/high volumetric efficiency, it seems they could simply re-flash the ECU to provide more oil at cranking. They certainly wouldn't want a stock engine running more oil ALL THE TIME - oil consumption is already an issue.
I haven't seen any carbon build-up problem in the engines we have disassembled. The best way I know to avoid it is: Break the engine in slowly and correctly; change oil regularly; and run the engine HARD regularly.
You are welcome to share this info with anyone you wish.
Jim Mederer
I haven't seen any carbon build-up problem in the engines we have disassembled. The best way I know to avoid it is: Break the engine in slowly and correctly; change oil regularly; and run the engine HARD regularly.
You are welcome to share this info with anyone you wish.
Jim Mederer
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