[tech] Has anyone installed scraper prior to engine breakin?
12-21-2009, 05:18 PM
#16
Three Wheelin'
It's undergoing "improvements". The races have built character and taught me how to coast to the side of the track gracefully. Enough about me, Brendan's about to fire up his engine!
B', the fueling really can be a concern. No matter how careful you are, initial tuning of a new ECU/engine always seems to involve massive richness. Be careful.
For some reason synthetic oils seem to turn to jelly when full of fuel. I don't think it's understood but I've seen it.
Assuming your pistons are going to be poking out of the bottom of the cylinder, put a generous edge break there and buff it by hand. When using looser piston clearances, the piston can rock and will scuff the skirt.
B', the fueling really can be a concern. No matter how careful you are, initial tuning of a new ECU/engine always seems to involve massive richness. Be careful.
For some reason synthetic oils seem to turn to jelly when full of fuel. I don't think it's understood but I've seen it.
Assuming your pistons are going to be poking out of the bottom of the cylinder, put a generous edge break there and buff it by hand. When using looser piston clearances, the piston can rock and will scuff the skirt.
12-21-2009, 06:00 PM
#18
Racer
Join Date: Jan 2009
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Brendan, which fuel do you intend running? Mixtures for E85 need only be 20% richer across the board than petrol. You will find a healthy HP improvement swapping from Petrol to E85 on a boosted engine.
Cheers Roy
Cheers Roy
12-21-2009, 07:08 PM
#19
Rennlist Member
Thread Starter
E85 here in San Diego seems be pretty much always 85% ethanol. It does not seem to change with seasons. Since... We don't have season here, really. Between 60 and 85 most of the time.
12-21-2009, 07:29 PM
#20
Rennlist Member
Thread Starter
The latent heat values of different liquids are shown here:
Gasoline 350 kJ/kg
Water 2256 kJ/kg
Ethanol 904 kJ/kg
Methanol 1109 kJ/kg
Gasoline 350 kJ/kg
Water 2256 kJ/kg
Ethanol 904 kJ/kg
Methanol 1109 kJ/kg
It is also a higher chemical octane (100-105) so you can add those two issues together and you get a super cool fuel.
But it somehow is known to create more total heat. I don't know the full science, but it seems to be that its more dense in the chamber - therefore burns LONGER - creating more torque - but also more heat?
The flame front is also more controlled.
12-21-2009, 09:40 PM
#21
Former Sponsor
Well, it depends. As most things do. It depends on how you use the Ethanol. Technically, the flame is actually hotter. *BUT* the liquid form of the fuel has a much higher latent heat of evaporation, which means that MORE BTUs are required to raise the temperature of a unit of the fluid 1 degree than say, regular fuel. Its not has high as water or methanol, but its still very, very good.
So the charge will then be cooler upon ignition, and for that single reason (there are others with ethanol) it will not detonate very easily at all.
It is also a higher chemical octane (100-105) so you can add those two issues together and you get a super cool fuel.
But it somehow is known to create more total heat. I don't know the full science, but it seems to be that its more dense in the chamber - therefore burns LONGER - creating more torque - but also more heat?
The flame front is also more controlled.
So the charge will then be cooler upon ignition, and for that single reason (there are others with ethanol) it will not detonate very easily at all.
It is also a higher chemical octane (100-105) so you can add those two issues together and you get a super cool fuel.
But it somehow is known to create more total heat. I don't know the full science, but it seems to be that its more dense in the chamber - therefore burns LONGER - creating more torque - but also more heat?
The flame front is also more controlled.
So, to review....it's super cool, but it creates more total heat....from the more controlled flame front, which creates more torque because it burns longer.
Are you sure your not doing that "anti-matter" thing like they had in the Angels and Demons movie?
12-22-2009, 12:36 AM
#22
Rennlist Member
Thread Starter
Sorry Greg. I'm not someone who can explain things simply. My wife gets on me for that. My seven year old asks a simply question and I start "Well, James" and my wife immediately rolls her eyes. Seriously, I feel like norm from "cheers"
All the internet postings say that it burns cooler. The initial combustion may be cooler because of the additional heat the additional mass took out of the charge before combustion - BUT - and I think you may agree - if there is more mass (because it has a lower BTU for power making) and there is more actual fuel burning - and it burns LONGER - it would technically make more heat go into the piston. But possibly - I suppose, if it starts lower in temp maybe it never gets hotter than a hot burning race fuel.
I don't watch scary movies - what was that one about?
All the internet postings say that it burns cooler. The initial combustion may be cooler because of the additional heat the additional mass took out of the charge before combustion - BUT - and I think you may agree - if there is more mass (because it has a lower BTU for power making) and there is more actual fuel burning - and it burns LONGER - it would technically make more heat go into the piston. But possibly - I suppose, if it starts lower in temp maybe it never gets hotter than a hot burning race fuel.
I don't watch scary movies - what was that one about?