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MikeT
18 Posts |
 Posted - 07/09/2010 : 06:58:52
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Hi Dave,
I'm pleased to say I haven't damaged my pump so all's working ok. However, I recently aquired some methanol and at a certain mixture, got severe engine knock above a certain rpm.
Reducing the mix quietened the knock but it was still present and at all revs this time.
I've now moved the post-IC nozzle further back downstream as I was concerned it might be a distribution problem. I also weakened the mix a further 5-10% and am pleased to say the knock is no longer audible.
Your comments would be most welcome. Was I right in my assumption or do I need to increase the mix ratio again to be sure? If I can't hear the knock, is it possible it's still occuring but too quiet to be heard when driving?
Regards,
Mike |
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cmtech
USA
385 Posts |
Posted - 07/09/2010 : 17:46:39
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quote:
[i]Originally posted by MikeT[/i]
[br]Hi Dave,
I'm pleased to say I haven't damaged my pump so all's working ok. However, I recently aquired some methanol and at a certain mixture, got severe engine knock above a certain rpm.
Reducing the mix quietened the knock but it was still present and at all revs this time.
I've now moved the post-IC nozzle further back downstream as I was concerned it might be a distribution problem. I also weakened the mix a further 5-10% and am pleased to say the knock is no longer audible.
Your comments would be most welcome. Was I right in my assumption or do I need to increase the mix ratio again to be sure? If I can't hear the knock, is it possible it's still occuring but too quiet to be heard when driving?
Regards,
Mike
well more methanol does not usually mean more knock. However in diesel more methanol=more heat. It is possible that the high concentration is causing your EGT to go very high and your engine is responding to that. The only way know if your knocking is with a wideband.
CM
www.coolingmist.com
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MikeT
18 Posts |
Posted - 07/10/2010 : 11:06:58
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Ah, you might be onto something there. There is minimal ECU control and it is only for timing. It's closed loop - a lift sensor tells the ECU when the injection begins, this is compared to it's map and adjusts the diesel injection point accordingly. The ECU has no feedback about EGTs, just the engine speed, vehicle speed and coolant temp.
But something must first give the ECU reason to make changes - ie knock from the methanol. Otherwise I can't see it being ECU related and points once again to the methanol.
Someone else advised methanol can pre-ignite in a diesel. Is that true?
Regards,
Mike |
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cmtech
USA
385 Posts |
Posted - 07/10/2010 : 19:21:59
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Methanol is going to act similar to fuel in a diesel. it will burn cooler than fuel, but it will burn.
CM
www.coolingmist.com
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MikeT
18 Posts |
Posted - 07/11/2010 : 16:44:00
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I'm getting conflicting advice from other quarters about how methanol reacts in a diesel engine but whatever is going on, the knock is due to a high methanol mix in my diesel engine.
I'm testing progressively stronger mixes, starting from 20%. I'm now at 45% and I'm not impressed so far, if truth be told but there's (hopefully) room for improvement yet. It all depends how strong I can go before the knock is induced again.
Regards,
Mike |
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MikeT
18 Posts |
Posted - 07/13/2010 : 10:05:39
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I ran 50% yesterday and the knock is again audible. The gains are evident but the knock is unacceptable.
I'm running 1gph pre-turbo and 3gph post-IC. If I spray below 10-12psi (peak is 20psi) I get bogging. If I spray 50% meth I get knock. Nothing in between gives any noticeable benefit.
Any suggestions on what to try next because I'm not impressed in the least so far?
Regards,
Mike |
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cmtech
USA
385 Posts |
Posted - 07/13/2010 : 10:32:44
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What kind of diesel do you have?
Also, just FYI. We do not ever recommend running pre-turbo. You do so at your own risk. Let me know make and model of your diesel.
CM
www.coolingmist.com
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MikeT
18 Posts |
Posted - 07/13/2010 : 11:16:50
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Hi Dave,
It's a PSA (Peugeot Citroen Group) XUD9T which is an IDI type. It's fuelled by the BOSCH AS3 (semi-electronic) which is timed by the ECU in closed loop with an injector lift sensor. At high load, high rpm, the timing is pushing 13-14degrees.
It's been suggested again, methanol is pre-igniting and/or detonating when ignited.
Again, I understand the risks I'm taking pre-turbo, thanks for the warning.
Regards,
Mike |
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cmtech
USA
385 Posts |
Posted - 07/13/2010 : 11:19:08
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why dont you run more water, maybe 75%? water is best at preventing detonation.
David
www.coolingmist.com
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MikeT
18 Posts |
Posted - 07/14/2010 : 06:20:11
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Hi David,
As stated earlier, I have tested from as low as 20% meth but it's not effective (that I can discern) until 45/50% hence my frustration.
Regards,
Mike |
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cmtech
USA
385 Posts |
Posted - 07/14/2010 : 07:16:52
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you need to change the concentration until your knock goes away, if not, you need to run a larger jet. Not sure what else to say.
CM
www.coolingmist.com
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MikeT
18 Posts |
Posted - 07/14/2010 : 12:09:04
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I was hoping nozzle size would come into question. I've still got the original (is it 6gph?) nozzles I could try. Obviously, I'll begin with a weak mix and work my way up, assuming it doesn't cause bogging.
Regards,
Mike |
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MikeT
18 Posts |
Posted - 07/29/2010 : 12:10:47
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Car's been off-road but I did manage to test the 6gph nozzle with almost the same results.
Once up to 40% meth I can feel a power hike but the knock returns. No change in EGT's.
Regards,
Mike |
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cmtech
USA
385 Posts |
Posted - 08/05/2010 : 22:13:44
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I hate to say this.
More flow, more flow. Maybe you want to tee the two nozzles together and see. You had improvement in power, if your EGT are high you can use more flow.
you also have to keep in mind that you need to be realistic on EGT drop. If your EGTs are 1600, you can expect 200-250 F drop. If they are 1100, may drop a little but not significant as thats not very hot.
CM
www.coolingmist.com
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MikeT
18 Posts |
Posted - 08/06/2010 : 08:11:34
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Hi Dave, I'm not sure why you're feeling bad about giving me this advice - I welcome any and all suggestions. 
However, what do you mean more flow - larger nozzles still or a higher pump pressure or what? After my last post, I engaged the 1gph pre-turbo nozzle, giving me 7gph total and again, nothing noticeable different except it showed peak boost rising from 28psi to over 30psi.
Regards,
Mike |
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cmtech
USA
385 Posts |
Posted - 09/06/2010 : 19:19:52
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we changed servers and it required to redo our database, just got the forum back up. Let me know if you have any updates.
CM
www.coolingmist.com
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Topic |
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Diesel knock
