Improving knock resistance?
#1
Improving knock resistance?
I have tried searching for ideas on improving the knock resistance of our motors, but have not really found a lot. I know the simple answer is to just buy the next higher octane fuel, but some of us don't have that luxury. I put together a short list of some ideas and would like some feedback.
I’m looking for any tips and tricks that might allow me to maximize the use of the poor quality ACN91 fuel I am stuck with. Will any of the following offer any possible benefit?
HIGHER WATER TO COOLANT MIX RATIO – To improve the cooling efficiency of the head.
REDLINE WATER WETTER – Not sure about this product. Some hate it some love it. Again, to reduce head temp. Some say this is bad for aluminum, but we have an iron head and block, correct?
NGK BPR8ES COPPER PLUGS – One step colder plugs might help. Affordable, worth a try. May not help any at my mod level.
DISCONNECT COOLANT LINES TO THROTTLE BODY – Drop the reheating of the intake air. Hopefully lower air temps slightly.
UPGRADING FMIC – Not sure if a larger I/C really adds any power, but I'm sure it does reduce air temps. Saving up for this one already.
1.3 BAR RADIATOR CAP (19PSI, 130 KPA) – Supposedly will reduce potential hot spots in the head. Is this a bad idea on the stock radiator?
WIDEBAND LOGGING GEAR – Should allow for more accurate A/F adjustments. Would do this, but I'm waiting for a simple, small unit that interacts easily with EvoScan.
LOWER ENGINE TEMPERATURE THERMOSTAT – I’m data logging 180*F, so I don’t see much to be gained by a lower temp stat.
WATER INJECTION – I’m not so crazy about meth/alky, although I fully understand the potential benefits. However, I have been considering running straight water injection as a method of increasing the ACN91 knock resistance. Why don’t I see more Evom members who are shy about meth doing this?
Any other suggestions for improving knock resistance? Corrections to this list? Additions?
Thanks,
Jim
I’m looking for any tips and tricks that might allow me to maximize the use of the poor quality ACN91 fuel I am stuck with. Will any of the following offer any possible benefit?
HIGHER WATER TO COOLANT MIX RATIO – To improve the cooling efficiency of the head.
REDLINE WATER WETTER – Not sure about this product. Some hate it some love it. Again, to reduce head temp. Some say this is bad for aluminum, but we have an iron head and block, correct?
NGK BPR8ES COPPER PLUGS – One step colder plugs might help. Affordable, worth a try. May not help any at my mod level.
DISCONNECT COOLANT LINES TO THROTTLE BODY – Drop the reheating of the intake air. Hopefully lower air temps slightly.
UPGRADING FMIC – Not sure if a larger I/C really adds any power, but I'm sure it does reduce air temps. Saving up for this one already.
1.3 BAR RADIATOR CAP (19PSI, 130 KPA) – Supposedly will reduce potential hot spots in the head. Is this a bad idea on the stock radiator?
WIDEBAND LOGGING GEAR – Should allow for more accurate A/F adjustments. Would do this, but I'm waiting for a simple, small unit that interacts easily with EvoScan.
LOWER ENGINE TEMPERATURE THERMOSTAT – I’m data logging 180*F, so I don’t see much to be gained by a lower temp stat.
WATER INJECTION – I’m not so crazy about meth/alky, although I fully understand the potential benefits. However, I have been considering running straight water injection as a method of increasing the ACN91 knock resistance. Why don’t I see more Evom members who are shy about meth doing this?
Any other suggestions for improving knock resistance? Corrections to this list? Additions?
Thanks,
Jim
Last edited by Jim in Tucson; Oct 26, 2007 at 10:08 PM.
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WATER INJECTION – I’m not so crazy about meth/alky, although I fully understand the potential benefits. I have been considering running straight water injection as a method of increasing the ACN91 knock resistance only. Why don’t I see more Evom members who are shy about meth doing this?
This is your winner. If you just go with straight water at low volumes and don't try to treat it like race gas you will get great results.
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#8
nkg plugs.
a better tune
water or meth injection
those are the only options that will gain you some results.
changing the coolant or thermostat wont help with detonation.
a better tune
water or meth injection
those are the only options that will gain you some results.
changing the coolant or thermostat wont help with detonation.
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water injection could also be a risk if you tune more aggressively due to improved knock threshhold; just like a meth kit, if anything goes wrong, you're left high and dry
Conversely, if you only use water injection for added safety and don't tune more aggressively while on it; you probably won't see any added power with it... Probably only worth your time if you're road racing for prolonged periods
Conversely, if you only use water injection for added safety and don't tune more aggressively while on it; you probably won't see any added power with it... Probably only worth your time if you're road racing for prolonged periods
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Cam timing can play into the knock scenario. For example, adjustable cam gears allow you to alter intake valve closure after BDC, thus impacting upon your engine´s dynamic compression ratio and in turn, its tendency to preignite the combustion mixture.
Last edited by sparky; Oct 26, 2007 at 08:07 PM.
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HIGHER WATER TO COOLANT MIX RATIO – To improve the cooling efficiency of the head.
REDLINE WATER WETTER – Not sure about this product. Some hate it some love it. Again, to reduce head temp. Some say this is bad for aluminum, but we have an iron head and block, correct?
1.3 BAR RADIATOR CAP (19PSI, 130 KPA) – Supposedly will reduce potential hot spots in the head. Is this a bad idea on the stock radiator?
WATER INJECTION – I’m not so crazy about meth/alky, although I fully understand the potential benefits. However, I have been considering running straight water injection as a method of increasing the ACN91 knock resistance. Why don’t I see more Evom members who are shy about meth doing this?
REDLINE WATER WETTER – Not sure about this product. Some hate it some love it. Again, to reduce head temp. Some say this is bad for aluminum, but we have an iron head and block, correct?
1.3 BAR RADIATOR CAP (19PSI, 130 KPA) – Supposedly will reduce potential hot spots in the head. Is this a bad idea on the stock radiator?
WATER INJECTION – I’m not so crazy about meth/alky, although I fully understand the potential benefits. However, I have been considering running straight water injection as a method of increasing the ACN91 knock resistance. Why don’t I see more Evom members who are shy about meth doing this?
I ran water wetter in my SR20 for a good 130k miles (aluminum head and block) with no issues. I also used a 1.3 bar radiator cap on the stock radiator, so I'd imagine that the Evo radiator should be fine also; however, this technique was used primarily to prevent boiling and the resulting overheating, not necessarily reduce the coolant temps to a lower level. So I do not think the radiator cap will do much for you.
I've also considered running water injection purely as a buffer because of the crap gas we get in Cali. Get the car tuned to how you like it, and then add the water injection on top to add greater safety margin.