Looking for advice on basic engine mods to boost performance.

[Supercharged111]

That's a fair point, but what's a "basic engine mod" that will help him out? I consider supercharging a major engine mod.

Out of curiosity, how well does E85 perform at altitude?

Meh, it's external, more like an involved bolt on. I installed my blower around 240k, I have zero qualms modding healthy high mileage motors. I'm in the upper 280k range now and kick around the idea of turbocharging and Etec heads.

 

[Schurkey]

what's a "basic engine mod" that will help him out?

For all practical purposes...NONE. Altitude is a killer of performance because it reduces the mass of air entering the cylinder, which means reduced fuel burn, which decimates cylinder pressure. Either you jack up the compression ratio, or you supercharge; and supercharging is probably more effective. It's also easier to limit if you happen to go down the mountain at some point. Once you get cylinder pressure, other mods might be useful.

Lack of cylinder pressure is why they sell 85 octane fuel at higher elevation. There's essentially no danger of detonation because it's like your engine has 6:1 compression.

14.7 psi at sea level, 59 degrees = 10.5 psi at 9000 feet, 59 degrees. You'd need ~5 psi boost just to break even.

Best case for "basic" is to assure that everything is working properly, maybe advance the timing as an experiment, and remove the heavy-ass high-inertia, high rolling-resistance tires.

 

[Erik the Awful]

Meh, it's external, more like an involved bolt on.

Yeah, but throwing boost onto stock ring gap makes me nervous enough that I wouldn't recommend someone else do it.

 

[Supercharged111]

Yeah, but throwing boost onto stock ring gap makes me nervous enough that I wouldn't recommend someone else do it.

Stock 200k+ ring gap? Most any motor ever made takes an easy 10psi, and the Whipple only manages to eek out 6-7 back in MI. Like gears, don't fear the boost.

 

[Schurkey]

throwing boost onto stock ring gap makes me nervous enough that I wouldn't recommend someone else do it.

5 psi boost at 9000 feet does nothing more than driving down the mountain to sea-level. If the engine can handle sea-level, it can handle 5 psi boost at altitude.

Ok, there's a couple of variables not accounted for: The air going through the radiator is also damned thin; and the supercharger is going to heat the air some; and draw some horsepower to do it. OTOH, both of those are also offset somewhat by the generally lower temperature at 9K altitude.

 

[0xDEADBEEF]

Stock 200k+ ring gap? Most any motor ever made takes an easy 10psi, and the Whipple only manages to eek out 6-7 back in MI. Like gears, don't fear the boost.

Does ring gap change with mileage? Doesn't seem like it would. Ring seal, sure.

 

[Supercharged111]

Does ring gap change with mileage? Doesn't seem like it would. Ring seal, sure.

Back when I checked on an older Ford 5.0 it was out of spec. Could have also been due to cylinder bore wear, but it went back together and ran like a champ.

 

[SAATR]

Does ring gap change with mileage? Doesn't seem like it would. Ring seal, sure.

Sure it does. For every .001" of bore wear you have, you're going to get around .003" of additional gap, not factoring in the wear in the ring itself.

Given that the bulk of bore wear is on the thrust sides of the piston, they don't wear as perfect circles, but any change in bore circumference will change ring circumference, and therefore gap.

 

[0xDEADBEEF]

Back when I checked on an older Ford 5.0 it was out of spec. Could have also been due to cylinder bore wear, but it went back together and ran like a champ.

Never thought about it before.

The ends don't really wear but the bore does. Makes sense.

 

[gldixon86]

A super simple effective mod is to advance the timing 5 to 6 degrees. It wakes them up quite a bit.

So on a 5.7 (350) advance the timing 5 to 6 degrees will do it better like more power??? Will it hurt it in longevity an will it run or idle different???