dizwiz24

Just curious which cylinder tends to run the leanest...

Has anyone ever experimented? (ie. some bored rich guy with wide band o2 sensors in each cylinders exhaust tube)

89'Bowtie

With the fuel injection, you should really be seeing a fairly consistent ration between all cylinders. The fuelling point (inj location) is the same for all cylinders. The air path on an LT1 manifold is pretty open and unrestricted. Without seeing any real very precise data, I'd say they are all pretty close.

Any particular reason you ask the question?

93Rubie

Considering we are probably talking FUEL INJECTION, none of them.

Each cylinder will have an injector and will be rich/stiocometric/lean as conditions dictate with in operation parameters.

Now if we are talking old school carbs with dual plane/single plane intakes well that is a different situation.

cv67

Thats all in tuning.
Someone with an engine dyno will usually have a set of headers with temp probes/02 sensors in ea primary tube to help track whats going on

427c4vette

As I understand it one of the reasons GM went to sequential injection on the LT1 from batch fire on the tpi was because of the air distribution issues of the LT1 intake.

Turbo/supercharged LT1/Minirams are known to be more prone to pronounced air distribution issues.

coupeguy2001

Then those cylinders would be RICH while the others would be around 14:1

AVL94LT1383

if all cyl. are the same then why does the factory tune have a table that adjusts the ipw at idle and "off idle" for each cyl ... and ... a few have adjustments?! Stock tune = the front two cyl and the back two...tend to be lean. Table is called Individual Cylinder Fuel Trim Mutiplier and I will bet the rich one is #6.. but I agree its all in the tune... the easy way to know is to check header temp at each cyl with an IR gun.... or install o2 on each header tube (only for the development guys) or install CHT readouts for each cyl like the avaiation guys have... be careful adjusting this though!

AVL94LT1383

78pacer

Is there a way to individually 'tune' each cylinder on an LT1??
Mike

coupeguy2001

obtain gobs of money............buy heads and intake of choice...........hire a welder that can weld aluminum.........add metal to all cylinders in the intake, begin to open up the ports in the manifold until all are ported to your satisfaction and flow the same.
THEN
get your heads ported and check flow on the rented flow bench till they all flow the same and check lift at .100. .200, .300, .400, .500, .600.
Then gasket match your package.
Then bolt your intake and heads together and flow them on a flow bench without the block in the way and proof test your setup at different valve open heights and determine the numbers are the same that you saw on the heads by themselves, then tune the cylinder runners to get what you got on individual pieces.
Then you will know how much lift your heads will support, pick a cam that suits your driving style and how you use your car


or not

dizwiz24

What tuning software are you using?

Im using tunerpro for tuning my 93

Tunerprort w/ $da2 doesn't have any individual cylinder fueltrim multipliers or even between right and left bank

93Rubie

Really, 92 and 93 LT1's use batch fire. 94-96 is sequential and maybe it was a reason but it was MOSTLY for OBD-II compliance and emissions.

mseven

those tables are available in the tuner cats/CATS ee/eeb definitions software for the 94-95 ecm.

dizwiz24

Must be nice to have that kind of flexibility in your tuning!

Im stuck w atari 2600 stuff

dizwiz24

Ok. I heard somewhere that cylindr 7 (back most on the drivers side bank) can be prone to lean out since the adjacent cylinder 5 fires right before it.

Cylinder 5 can 'steal' some of cylinder 7's fuel.

But I don't see how that can apply on multiport fuel inj bc each cylinder intake has a fuel injector in it.

AVL94LT1383

Might be temp related also... heat soak.

AVL94LT1383

I think this was a near stock 1994 LT1 6spd
Ind cyl fuel trim multi...
over 1 value is adding fuel
under 1 is pulling fuel

Study it for yourself; remember you can burn a cyl
off idle at idle cyl
1.06 1.02 1
0.96 0.98 8
1.02 1.00 4
1.02 1.00 3
0.95 1.03 6
0.98 1.00 5
0.98 0.91 7
1.05 1.02 2

#6 is pulling the most fuel relative to others off idle (TPS more than 0%)
#7 is pulling the most fuel relative to others at idle (TPS = 0%)

software to see and edit this is CATS tuner.... and we have others.
ye-ha!

davenbocafl

with todays tech, the difference is so unnoticable its a mute point with either carb or injection, even edlebrock intakes are so close in cfm's per runner there almost exact

87 vette 81 big girl

If You ever read any articles and books by David Vizzard and Smokey Yunick like I have,

Correct or exact fuel distribution to each individual cylinder has always been a problem in a V-8 engine.

Wide band O2 sensors in all 8 header primary tubes are the best to date way to tune a V-8.

Some engine dyno shops I have seen have headers on hand with 8 wide band O2's.

David Vizzard uses the same tuning logic.

Gets expensive when you want exact AFR's at all loads, driving speeds, rpm's.

But the fastest runners in the world and record breaking racers use such methods.

Seen it for myself.

How much $ do you have?

Are you dedicated enough?

Who do You know?

How much do you know?

Can You actually drive among the best there is and win the race and $$.

And do it next week again....Win.

dizwiz24

with sponsors, yes I can