interesting engine tuning theories

[themadscientist]

I like this guy, good stuff.http://www.mototuneusa.com/break_in_sec ... k_fast.htm

[krazy skwerel]

Best part of the second articel is this:

Warning: Bread is Evil

[JESTER]

Bread is evil. It is loaded with carbohydrates. They are bad.

Anyway, two very interesting subjects. I tend to go witht he principle of break it in like you are going to drive it. But never as early as he suggested. Of course, I would actually have to buy a new vehicle for that to apply anyway. Aint gonna happen.

The port articles are interesting as that is one of the main things we are taught to always do to make more power is open the up ports.

[Mr1der]

agreed, I go with the break it in like you gonna drive it theory too.

I need a vehicle from this decade.

[crzycav86]

Second article was pretty interesting, but that principle would only go so far.

When you port the head, you usually port it so that the incoming air has the least turbulent path through the valve.

If you make the valve smaller, you're taking away some power(because the piston uses more power to suck in air), but you get more power because the air has more inertia, so it keeps filling the air even when the piston slows down and goes into the compression stroke.

I'd like to see if he tried this out on fuel injected engines because we don't suffer from that double carbueration problem like the bikers do.

And also, cam specs have a lot to do with this... but I have to go now. I think the point is that there are too many factors involved to prove or disprove this idea, but my gut feeling is saying that this isn't absolutely true.

[krazy skwerel]

agreed, I go with the break it in like you gonna drive it theory too.

I need a vehicle from this decade.

You'd be doin' good to get a vehichle from the last decade.

Also I can see the break it in hard theory. My friend just bought a new Mazda 3 and will probly break it in hard. we shall see how it turns out.

[Mr1der]

yeah, you too monkey boy...

I had a '90 model once thank you!

[SeVa-S13]

I thoroughly enjoyed the porting atricle, but I doubt the break-in one will ever apply to me.

Question: Would those same principles of porting apply to a forced-induction engine? Specifically my RB20? I too was wondering about the whole Carb vs. EFI bit and if FI adds in another variable to be considered. I was hoping one day to get a spare 20 head and do some work to it but I'd rather not have adverse effects, naturally.

[gsxtasee]

nope, the principles of porting he discusses don't apply to FI because with FI you're stuffing air in there anyway, you'd want the most efficient ports you could get to allow the FI source to most efficiently stuff air in there. making smaller ports would increasse velocity marginally and make you see more boost but you'd be getting less volume per charge. since the piston isn't "sucking in" the air but the charge is instead being forced in their, there is ample velocity already and you want a clear pathway. though you do want the intake ports a little rougher than the exhaust side to aid in keeping the fuel/air suspension at its most efficient state. general rule is port the intake and clean it up but don't "polish" it.. polishing the exhaust is koo-beans though.

[gsxtasee]

also, on turbo cars in particular, you're better off buying a better turbo and suporting it more than spending large sums of cash on head work. you'll get a better $/hp return typically. Head porting is (to some) almost a black art and is often times hit-or-miss so you could easily spend $1500+ on "NICE" headwork and have the guy screw up a little and you'd end up with marginal net gains at best.. but if you put the same cash into a proven turbo or support device(s) you're almost guaranteed a nice hp/$ return.

[Nathan]

I like that break-in article and I've read it before. While I felt a little uncertain breaking my engine in that way...its just kinda happening In under 5 miles it saw 7000rpms and a very smokey accidental burnout (more power than I expected + 6 puck racing clutch). Since then I've put around 20 more miles on it and its seen numerous pulls up through third gear, shifting at 6k, 7 lbs. of boost. I figure its not ridiculously hard on it, but its certainly not being babied. Oil's allready been changed twice anyway. Ya know what? It smoked like a mother at idle until I went out and ripped on it for 10 minutes...came back and it hasn't smoked since Rings seating is a beautiful thing!

[crzycav86]

My dad was telling me recently that when he had bought new cars in Lebanon(in the middle east), they didn't necessarily tell him to drive the car at low rpms, the just told him not to stay at one rpm for too long.... I suppose this is the same concept applied as the one in the article..