Cylinder airmass
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Cylinder airmass How much do you normally see at WOT? Curious because I've noticed how much the difference is between my modded camaro and my stock C5. Camaro is around .80 and the vette is around .68.
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Yeah, I was glancing through my log runs that I had on my desktop last night because I was curious. I've been tuning the vette (basically stock) and thought the cylinder airmass was low, but its pretty much dialed in right now and I'm only seeing .68. The vette seems pretty wierd, trying to dial it in. Getting some knock retard and having some other timing issues, air/fuel is pretty much on VE wise, the maf is pretty close now, but I've got to pull the plugs tomorrow and try to track down some other things.
I really don't know what to think about the vette. I bought it about 4 months ago, 85k miles, haven't really done anything to it. It pulls pretty hard now, but its frustrating trying to track down all the little problems with it (electrical).
The camaro log runs I looked at were when I was cam only (hotcam) with shorties, tuned (360rwhp). I don't have any of my more recent data for my camaro on my desktop.
Checking through all the data of different cars I've tuned, it seems most stockish or near stock f-bods see around .80g/cyl, and I'm trying to figure out why the vette is low.
I really don't know what to think about the vette. I bought it about 4 months ago, 85k miles, haven't really done anything to it. It pulls pretty hard now, but its frustrating trying to track down all the little problems with it (electrical).
The camaro log runs I looked at were when I was cam only (hotcam) with shorties, tuned (360rwhp). I don't have any of my more recent data for my camaro on my desktop.
Checking through all the data of different cars I've tuned, it seems most stockish or near stock f-bods see around .80g/cyl, and I'm trying to figure out why the vette is low.
Last edited by Bombguy99z28; Dec 25, 2005 at 02:11 PM.
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could we make a general statement that the more cylinder airmass, the better, as the cylinder gets filled with more air? what other factors could get in a way of making such a statement?
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Well yeah, I would say cylinder airmass is indicative of horsepower, as airflow=horsepower.
Basically, I have this feeling that something is wrong with the vette, but I can't really put my finger on it. It feels strong, but I'm used to fbodies, not vettes (3500lbs vs. 3150lbs). I can't run any timing at all on it (stuck around 22*) and cylinder airmass is like max .68, and I see close to .80 on near stock fbodies. Everything else in the tune seems fine. Tomorrow I'm gonna pull plugs and see if anything looks odd there.
I checked my laptop, the camaro runs in the .88 timing band at wot.
Basically, I have this feeling that something is wrong with the vette, but I can't really put my finger on it. It feels strong, but I'm used to fbodies, not vettes (3500lbs vs. 3150lbs). I can't run any timing at all on it (stuck around 22*) and cylinder airmass is like max .68, and I see close to .80 on near stock fbodies. Everything else in the tune seems fine. Tomorrow I'm gonna pull plugs and see if anything looks odd there.
I checked my laptop, the camaro runs in the .88 timing band at wot.
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True. quite possible. I'm trying to troubleshoot why I can't handle more spark. I'm gonna put it on the dyno mid next month and see what kind of power its actually making.
I hate the fact that I know nothing of the engine or how its been driven for the last 85k miles. Plus even though I did a routine check before I bought it and didn't notice anything, I started getting some electrical problems the other day so I pulled the battery and battery tray and it looks like I have some classic leaky battery corrosion down by the pcm... uggh... Had to do some impromptu wiring harness maintenance at my ex's house
Its not too bad, but bad enough I need to do some cleaning up down there.
I hate the fact that I know nothing of the engine or how its been driven for the last 85k miles. Plus even though I did a routine check before I bought it and didn't notice anything, I started getting some electrical problems the other day so I pulled the battery and battery tray and it looks like I have some classic leaky battery corrosion down by the pcm... uggh... Had to do some impromptu wiring harness maintenance at my ex's house
Its not too bad, but bad enough I need to do some cleaning up down there.
Originally Posted by WS6FirebirdTA00
poor spark could cause lower numbers.
Airmass (Dynamic Cylinder Air) is foremost, the MAP as bent by
engine VE. I see a peak slightly over 0.80 on a car with minor
mods.
Exhaust efficiency affects VE and a restrictive one, lame plumbing
or degradation (busted / clogged cat) will depress CylAir.
CylAir (and dynamic airflow) are products of a chain of calculation
that starts with MAF and/or speed density data. So if you've been
a-messin', it may be a ways off from the truth, what you get back.
A ported or K&N-oil-crusted MAF will read low on CylAir, make you
leaner than proper, jack your spark up and bring the ping.
A misfiring cylinder will not scavenge well and cause a lower air
value. Since you're chasing ping I'd have a look at current misfire
1-8 on the road and see if anybody has a special problem.
engine VE. I see a peak slightly over 0.80 on a car with minor
mods.
Exhaust efficiency affects VE and a restrictive one, lame plumbing
or degradation (busted / clogged cat) will depress CylAir.
CylAir (and dynamic airflow) are products of a chain of calculation
that starts with MAF and/or speed density data. So if you've been
a-messin', it may be a ways off from the truth, what you get back.
A ported or K&N-oil-crusted MAF will read low on CylAir, make you
leaner than proper, jack your spark up and bring the ping.
A misfiring cylinder will not scavenge well and cause a lower air
value. Since you're chasing ping I'd have a look at current misfire
1-8 on the road and see if anybody has a special problem.
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VE is dialed in, MAF is dialed in, amost every cell is at 0 (logging maf hertz vs ltfts in histogram), a couple bounce from -1 to pos 1, but its pretty darn close. Pulled the plugs, valve covers, rocker arms, everything looks fine. Put some copper plugs in it today, just to see if it didn't like the plats that it came with. Narrowbands show .890-.910 how its tuned, still getting knock retard even if I richen it up to .940-.950 (I spiked the PE up to see if it was a lean problem). No misfire problems.
Checked the MAF, clean, running that foam vararam filter, installed about 3 months ago. No valvetrain noise. I'm going to toss half a tank of VP unleaded in it and see if it still knocks. I'm really starting to not care, its not like I ever plan to race the vette or drive it that hard anyway. Probably pull the motor sometime in 06, so I guess it really doesn't matter.
I was wrong, its seeing .73g/cyl max, not .68. I really wish I had a wideband. Tuning with narrowbands is starting to feel like running a marathon with one leg.
Oh well.
Checked the MAF, clean, running that foam vararam filter, installed about 3 months ago. No valvetrain noise. I'm going to toss half a tank of VP unleaded in it and see if it still knocks. I'm really starting to not care, its not like I ever plan to race the vette or drive it that hard anyway. Probably pull the motor sometime in 06, so I guess it really doesn't matter.
I was wrong, its seeing .73g/cyl max, not .68. I really wish I had a wideband. Tuning with narrowbands is starting to feel like running a marathon with one leg.
Oh well.
Originally Posted by Bombguy99z28
How much do you normally see at WOT? Curious because I've noticed how much the difference is between my modded camaro and my stock C5. Camaro is around .80 and the vette is around .68.
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I been getting some knock retard too, its been like it for over a year now, tried super unleaded fuel, race fuel about 107 octain, people saying it cant ping on that stuff, well I was seeing knock on the scanner. I am thinking its false knock, my cluch it on its way out, been rumbling for a couple of years, been told its the thrist bearing, got a new clutch to slip in, just need to find someone to do it. Also my engine mounts are warn, waiting for some new ones to be delivered. I am thinking that vibration from the engine clutch and gear box is causing false knock, so i will change the lot and see if the knock goes, then I get do some proper tuning.
Perhaps your knock retard if false too? Can engine mounts cause false knock??
Perhaps your knock retard if false too? Can engine mounts cause false knock??
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worn out stock motormounts can cause some problems, I had to put poly ones on my camaro after I put the kooks on, they were worn out to the point the headers wouldn't clear right. The polymounts fixed it. If your stuff is worn out to the point it is rubbing and vibrating, it is possible that they may be causing some problems.
I quite chasing the kr, it runs well now, just only with 22* of timing. I'll dyno it on the 14th hopefully and get an idea of how accurate my AFR is.
narrowband tuning sucks monkey *****.
I quite chasing the kr, it runs well now, just only with 22* of timing. I'll dyno it on the 14th hopefully and get an idea of how accurate my AFR is.
narrowband tuning sucks monkey *****.
