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The mkiv Supra Owners Club

Knock/Detonation with 95 Octane Fuel


Samurai 20V

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Hi Guys..

 

My TT6 is BPU, I have been fiddling with my HKS EVC to get the boost up at 1.2bar consistently.

 

South Africa only has 95 octane, so I have been running water injection to compensate..

 

At a full 1.2 bar, there does not seem to be any knock based on the post by Ryan G below in 2007 from this post..

 

http://mkivsupra.net/vbb/showthread.php?119115-Knock-Frequency/page2&highlight=knock

 

I do intend to get the car mapped soon, mainly to pull some fuel out of it (running very rich, around 8.5:1), in the interim is my car safe or am I risking it?

 

 

Just so you guys know the standard knock sensor system on the supra are superb. When i have mapped powerfc's on supra's they always picks up det on the datalogging when ever i hear it through the det cans. And the ability to flash the warning triangle in the middle of the dash lets drivers know if they are ever getting any slight knock if crap fuel or high air temps cause it.
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8.5 AFR is very rich and not at all ideal, presumably that's at WOT? Pretty sure that I have run 95 octane with no problems, also running WI, but I will say that I did not rely on the std knock sensors, I have KS-3 fitted, I have read that all std knock sensors do degrade over time and become less sensitive.

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8.5 AFR is very rich and not at all ideal, presumably that's at WOT? Pretty sure that I have run 95 octane with no problems, also running WI, but I will say that I did not rely on the std knock sensors, I have KS-3 fitted, I have read that all std knock sensors do degrade over time and become less sensitive.

 

Yes, that is at WOT... I have no idea why it turned out that rich, its been like that ever since I went BPU, even when the car was in Japan. I do have a HKS Knock Amp fitted, but its a bit hit and miss with the setup, so I'm not sure if its working properly..

 

Do you have an aftermarket/standalone ecu? or knock pickup device as thats what ryan was referring to, it may be worth investing in though given your rubbish fuel over there, saying that, water injection will help reduce det.

 

HKS knock amp fitted, but I am unsure if its setup correctly..

 

I don't have an aftermarket ECU fitted, car is using the stock ECU. I am considering fitting a piggy chip to sort the fueling out..

 

I think best is to hook up the det cans before I increase the boost..

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The std ECU run injectors at 100% DC when it sees over the std boost, that's why it can be that rich, a piggyback or stand alone would be the best bet, I would be surprised if you any knock at WOT and with WI, but you may be getting close to or have a little knock at peak load areas.

Also worth remembering that adding too much water will limit power and mess with AFRs.

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The std ECU run injectors at 100% DC when it sees over the std boost, that's why it can be that rich, a piggyback or stand alone would be the best bet, I would be surprised if you any knock at WOT and with WI, but you may be getting close to or have a little knock at peak load areas.

Also worth remembering that adding too much water will limit power and mess with AFRs.

 

 

Thanks, going to contact the tuner soon..

 

Also going to try some methanol in the water injection for some extra safety..

 

I did have too much flow of water at first, it was misfiring & holding back at high rpms, I adjusted it to pull out some water..

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