Quote:
Originally Posted by KingLT1
Not meth injection...Ethanol. Meth injection cools the intake charge, but that temp drop is miniscule once we start talking about Cylinder temps and EGT's. Big difference between injecting meth through a fertilizer pump vs Ethanol through 8 injectors at 2000+ psi. The Ethanol literally pulls a ton of heat out of the cylinder by hundreds of degrees. Cooling the intake charge 50 degrees might keep the ECU happy so you get all of your timing but that 50 degrees in the cylinder isn't nothing when the flash point of Meth creates a lot more heat vs E85. Keeping the heat out of the cylinder keeps the piston rings from expanding.
Don't get me wrong meth works. It's proven on the ZL1 but it is 1.5 point lower compression with properly gapped piston rings. The meth will act as high octane race fuel but it's something you have to understand because it will allow a lot more timing without KR. On a forged piston with proper ring gaps, it's a non-issue. On a stock piston LT1 with 10-12 thou ring gap it's no bueno. Hence why 90% of the SBE LT1 boost failures always are pump gas and/or meth. E85 also allows a lot more timing but it starches the heat from the timing increase, so the engine is making more power with lower cylinder temps and egt's.
Now if you used water injection as cooling then it would help a ton with cylinder cooling, but you don't get the power gain. Everybody wants to inject 100% meth for max power gains and that is where the trouble starts on the stock piston stuff. Then you have the distribution issues and there is already very little room for error on a stock LT1 as is.
Mike Sitar aka ToohighPSI has explained this in much better detail in the past and if you wish to know more contact him.
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Thanks KingLT1 for that explanation. The best pump fuel we can get anywhere in my geographic area is 91 octane Shell. And the pump labels say that the gas "may contain up to 10% Ethanol". I find that rather a useless a label, since (a) it does not specify which of the 3 available grades of fuel from the pump have the Ethanoi, and (b) what the specific Ethanol content is in the 91 octane, and (c) does the percent Ethanol change from one fuel truckload delivery to the next?
I don't want to mix fuel in my garage or driveway.
Even if I did, I would not want to create a problem for myself when going on a long road trip where the availability of specific types of fuel is unknown.
So, I am kind of stuck. Shell Canada has said that they are rolling out 93 octane gas across the province where I live, but so far it is only available in an area at least 175 km away from where I live.
I'm not worried about it though. The car runs fine with my very limited usage - street only, no track or drag strip, with the longest sustained time at WOT being maybe 8 seconds at a time.
Our climate also helps. It is very rarely above 30C = 86F even on the hottest summer days.
For the short term, I have no plans to alter the engine physically or to alter the Magnuson tune. In the future, I may consider doing things like the fuel system upgrades, and forged pistons with lower CR, but I have no idea what that would cost, all labour included as I am not set up with either skills or equipment to do them. Also, since I have OEM LT1 width wheels, I would have to change all 4 wheels and tires (I would not tolerate different rear wheels versus front wheels).And I would have to ask myself if doing all that would actually make any sense at all, given my modest usage (the local law enforcement punishments for going more than 20 mph over the speed limit are pretty draconian).
The car as it sits now with the unaltered Magnuson kit is a LOT of fun.
Jim G