G Force vs fuel distribution (another argument thread)

[wagspe208]

So, a buddy of mine and I were having a discussion over many beers. We were arguing how g forces from acceleration would affect fuel cyl to cyl distribution. In a blown piece, and N/A piece.
Then the air flow at/ past the engine.... how does this addect cyl to cyl distribution?
I think it would, but not tons. He says...tons! Like if it is tuned on a dyno, then thrown in a boat it will be totally different.
My boat acceleratees at 1g. Jets, much harder. Many boats with props... much less.
Let it fly.
Wags

[rich s]

I have had this on my mind for quite a while, since I am switching from a jet to a hydro, adding in the fact that my hat is now on backwards. I intend to let spud make the call on my deal why I get to it.........please carry-on

[gn7]

I have had this on my mind for quite a while, since I am switching from a jet to a hydro, adding in the fact that my hat is now on backwards. I intend to let spud make the call on my deal why I get to it.........please carry-on

Ask the NHRA Pro Stock guys if it has any effect. Ask anybody running a fueler. Of course it matters.

Running the hat reversed, now thats another thing. How does that effect anything?

[wagspe208]

Does it matter in our world? 1G isn't much. LOL
Fuelers....pro stock... they acccelerate just a little harder than that.
And in a fueler I'd think blower opening shape f***s up everything a ton also. So, AND IF it affects it so much how come 1 and 2 have to have more fuel? The fuel SHOULD be going that way anyway and less fuel would be required. (drag boat application... our world) On a fueler 1 and 2 generally have lower compression height. (again due to blower opening) but fuel should be there do to g forces? CONTRADICTION!
Wags

[wagspe208]

Oh, and a fueler the volume of fuel (hence weight of fuel) is 10x + what we use.
Wags

[steelcomp]

Wags...is there something that gives you the indication that you have a fuel distribution problem?

[gn7]

Oh, and a fueler the volume of fuel (hence weight of fuel) is 10x + what we use.
Wags

And some how less fuel is affect differently than lots of fuel?
The weight of the fuel remains the same regardless how much you flow. The weight of the mixed fluid stays the same regardless how much you flow. There is only so much mixture in the manifold at any one time. Only the TYPE of fuel can change the weight of the mixture.
Think there is an effect on the NASCAR boys at places like Daytona when they were running carbs? Hell for all I know, they may still issues even with the EFI.

If it has mass, its effected.

Now, like Steel asked. Are you having distribution issues? Only on the track but on the dyno its fine?

[wagspe208]

Wags...is there something that gives you the indication that you have a fuel distribution problem?

Well, NOT after torching the head gaskets and putting my tuneup back to where it was pre computer. (and now that you guys finally got me off the champion plugs and onto the NGK pieces (I can't believe I was such a hard head) there is some different stuff to look at)
This is actually where this argument started... years ago... I wanted to have my engine thrown on a dyno to balance cylinders. Of course it can be done at the track, but how much faster is it to pull, check plugs, pull, check plugs, pull, vs run, wait 3 hours for another round, run, wait 3 hours, race day we do not change port nozzles, etc.
So, I was talking to my buddy about this.. he said not only will the acceleration make it all f***ed up, but the air flowing into the hat different also will change it. I think he is crazy (for a number of reasons... but on this too)(he has a magneto)(I don't think it will make a significant change). For our application. I was just curious.
Plus, it makes for interesting discussion. I know somewhere EFI will get mentioned, Beer will show up, and all hell will break loose.
So, curiosity and amusement.
Wags

[gn7]

Well, NOT after torching the head gaskets and putting my tuneup back to where it was pre computer. (and now that you guys finally got me off the champion plugs and onto the NGK pieces (I can't believe I was such a hard head) there is some different stuff to look at)
This is actually where this argument started... years ago... I wanted to have my engine thrown on a dyno to balance cylinders. Of course it can be done at the track, but how much faster is it to pull, check plugs, pull, check plugs, pull, vs run, wait 3 hours for another round, run, wait 3 hours, race day we do not change port nozzles, etc.
So, I was talking to my buddy about this.. he said not only will the acceleration make it all f***ed up, but the air flowing into the hat different also will change it. I think he is crazy (for a number of reasons... but on this too)(he has a magneto)(I don't think it will make a significant change). For our application. I was just curious.
Plus, it makes for interesting discussion. I know somewhere EFI will get mentioned, Beer will show up, and all hell will break loose.
So, curiosity and amusement.
Wags

He is not nearly a crazy about the G forces as he bis about the hat. Thats almost comical at the speeds you guys run at. Again, N/A can be a different deal, but it shouldn't. If a foward facing scoop on a N/A deal drastically changes the distribution, then the scoop needs to rethought out. You can't control G forces so you have to deal with them. Shitty air distribution with a N/A scoop deal is a design issue, not a G force issue.

The blower discharge has a much bigger effect on how the fuel is disdributed in the manifold than the G forces at your level.

As for the hat?

[steelcomp]

Well, NOT after torching the head gaskets and putting my tuneup back to where it was pre computer. (and now that you guys finally got me off the champion plugs and onto the NGK pieces (I can't believe I was such a hard head) there is some different stuff to look at)
This is actually where this argument started... years ago... I wanted to have my engine thrown on a dyno to balance cylinders. Of course it can be done at the track, but how much faster is it to pull, check plugs, pull, check plugs, pull, vs run, wait 3 hours for another round, run, wait 3 hours, race day we do not change port nozzles, etc.
So, I was talking to my buddy about this.. he said not only will the acceleration make it all f***ed up, but the air flowing into the hat different also will change it. I think he is crazy (for a number of reasons... but on this too)(he has a magneto)(I don't think it will make a significant change). For our application. I was just curious.
Plus, it makes for interesting discussion. I know somewhere EFI will get mentioned, Beer will show up, and all hell will break loose.
So, curiosity and amusement.
Wags

Well for sake of conversation and as far as A/F distribution, I agree with you about your friend.
I think the first thing that can be looked at is how far the air/fuel mixture is traveling. I doubt it's being effected much inside the blower (or above the blower), so it seems the only time it really starts getting effected by something like G forces is going to be inside the intake runner or port. By the time it gets to the port, whatever "distributing" that's going to happen, has happened, so the intake runner and plenum is where it all matters. With a blower, the maniflod has a fairly large plenum but some very short runners. Not a lot of time for some relatively low G forces (1G) to effect or "change" the fuel distribution once it gets into free air and can "move about".
NASCAR definitely has had fuel distribution issues with carb'd engines, outside runners being rich, inside being lean, but those are some constant, relatively high G forces in the corners, and some long runner manifiods. EFI has/will change that.
Drag racers in the faster classes running TR's and even some of the long-runner, tall, singel plane intakes have to consider front to rear fuel distribution. I don't know if engines with MFI and port injection has as much an issue...I would imagine not. Again, though...way more than 1G there.
I guess the point is, if you're seeing front to rear fuel distribution problems, it might be something to consider...unless as you say, the front is rich. I think the best you can do for an engine is get as good a static base line fuel setting, and go from there. It may never get that perfect again at the track, but at least you know how good it can be, and always something to measure against. You might find distribution issues on the dyno that you could spend a lot of time chasing at the track and never get a handle on them.

[gn7]

Well for sake of conversation and as far as A/F distribution, I agree with you about your friend.
I think the first thing that can be looked at is how far the air/fuel mixture is traveling. I doubt it's being effected much inside the blower (or above the blower), so it seems the only time it really starts getting effected by something like G forces is going to be inside the intake runner or port. By the time it gets to the port, whatever "distributing" that's going to happen, has happened, so the intake runner and plenum is where it all matters. With a blower, the maniflod has a fairly large plenum but some very short runners. Not a lot of time for some relatively low G forces (1G) to effect or "change" the fuel distribution once it gets into free air and can "move about".
NASCAR definitely has had fuel distribution issues with carb'd engines, outside runners being rich, inside being lean, but those are some constant, relatively high G forces in the corners, and some long runner manifiods. EFI has/will change that.
Drag racers in the faster classes running TR's and even some of the long-runner, tall, singel plane intakes have to consider front to rear fuel distribution. I don't know if engines with MFI and port injection has as much an issue...I would imagine not. Again, though...way more than 1G there.
I guess the point is, if you're seeing front to rear fuel distribution problems, it might be something to consider...unless as you say, the front is rich. I think the best you can do for an engine is get as good a static base line fuel setting, and go from there. It may never get that perfect again at the track, but at least you know how good it can be, and always something to measure against. You might find distribution issues on the dyno that you could spend a lot of time chasing at the track and never get a handle on them.

without being on a dyno first, how would you even know if the problem was G forces or something physical in the manifolding.
Like I said, the blower discharge has a bigger influence on distribution than the forces at that level.

Don't let Beer snow you for a second with the EFI hog wash. NASCAR boys found a whole new set of distribution issues when they went to EFI. There is NOTHING in EFI that can cure a distribtion issue that can't be duplicated with a port MFI nozzel.

The hat? I am still laughing.

[wagspe208]

My big dumb ass helmet is in front of the hat too.... I am sure there are some air disturbance issues.

My theory on our deal is along what steel says. Nothing going on above the hat. From hat nozzle to blower rotor is very short. Through rotors. Then a sort of retro opening. Well, that does something to fuel. Can't come straight down with the opening as it is. Port nozzles (actually in the intake manifold runner) isn't going anywhere but into the cylinder (for practical purposes), so fuel from bottom of rotors to ports can do whatever it is influenced to do by air flow, g force, etc. It is not a big area. It is moving all different directions when intakee valves open and close on different cyls. Bigger than a single plane manifold, sure. But tuning from cyl to cyl is done with the port nozzles. SO, I say no big deal.
Plus, he has a mag and isn't making any power anyway.
Wags

[David 519]

A fast NA asphalt deal, maybe/probably. A blown/injected deal I'd think port nozzles at 100+ PSI fuel pressure would solve most any acceleration issues.

[David 519]

My big dumb ass helmet is in front of the hat too.... I am sure there are some air disturbance issues.

My theory on our deal is along what steel says. Nothing going on above the hat. From hat nozzle to blower rotor is very short. Through rotors. Then a sort of retro opening. Well, that does something to fuel. Can't come straight down with the opening as it is. Port nozzles (actually in the intake manifold runner) isn't going anywhere but into the cylinder (for practical purposes), so fuel from bottom of rotors to ports can do whatever it is influenced to do by air flow, g force, etc. It is not a big area. It is moving all different directions when intakee valves open and close on different cyls. Bigger than a single plane manifold, sure. But tuning from cyl to cyl is done with the port nozzles. SO, I say no big deal.
Plus, he has a mag and isn't making any power anyway.
Wags

Wags, you were doing so good right up to that last sentence!!