dyno question ....

so when you guys dyno an engine, can you tell anything by exhaust header temps ? should there be any deviation from side to side ?

bruno wrote:so when you guys dyno an engine, can you tell anything by exhaust header temps ? should there be any deviation from side to side ?

Exhaust gas temperatures at the exhaust port exit can tell someone about the fuel distribution within the intake manifold; IF all the other parameters are equal from bank to bank.
Is the compression ratio from bank to bank .2 different...? Are the combustion chambers aligned with the cylinder exactly the same way from bank to bank...? Is the valve train geometry exactly the same from bank to bank...? Are the cylinders in the exact proximity to the crankshaft throws from bank to bank which could make for a degree different ignition timing on each side...?
Everything within 50 degrees difference is usually a sign that everything will be OK.

Yes their will typicaly be a difference on regular performance motors, now extream stuff like NASCAR, Prostock, Indy, Formula, ect I'd think you'd see alot tighter numbers.

so can you say there is a problem with an engine if the opposing banks were 80-100 degree diff , but within the 30-50 degree on each side

bruno wrote:so can you say there is a problem with an engine if the opposing banks were 80-100 degree diff , but within the 30-50 degree on each side

NOT necessarily a problem with that temperature differential however, it is certainly not optimum.
300 degrees would probably indicate a problem.

cyl temps are usually the lowest on the longest runners ( front 2 and back 2 cyl ) from my findings and 80 to 100 is ok Intake manifold runner length and equal flow between runners is usually the biggest problem when you see alot of variance between cylinders

rmcomprandy wrote:

bruno wrote:so can you say there is a problem with an engine if the opposing banks were 80-100 degree diff , but within the 30-50 degree on each side

NOT necessarily a problem with that temperature differential however, it is certainly not optimum.
300 degrees would probably indicate a problem.

When we see over 150* we start looking, sometimes play with staggering jets just to see if we can close the gap to make sure it's just a distribution issue.

G