343 rwhp, 352 rwtq.
383, 10.3:1, AFR 195 heads, Stealth Ram, 52mm throttle body, de-screened MAF, 32 lb Bosch gen III injectors, Howards Max Torque roller 234 242 .569" .585", SLP 1.75" ceramic coated headers, Magnaflow cat, Magnaflow cat-back.
Air/Fuel Ratio was 13.5:1 +/- .2 for the duration of the dyno pull.
We did one pull with the air cleaner lid removed (to rule out the air cleaner as the restriction) and it picked up nothing. I know that the single 3" exhaust is a restriction, but 40 to 60 hp? This motor should make at least 380 hp to the wheels.
It has a 700r4, Midwest 9.5" 3400 rpm stall, 4.10 gears.
Any ideas?
your not the first and your sure not likely to be the last guy to think the dyno results are less than you expected!
your results are fairly typical, on a 383 before its well sorted out.
yes you can expect a bit more from that combo, but getting the typical magazine dyno (flywheel hp numbers) or results for your real on the street, rear wheel hp numbers is not likely.
always remember FLYWHEEL HORSEPOWER that an engine dyno reports tends to be about 18% higher than rear wheel hp, after losses in the drive train at the rear wheels.
if your making 343 rear wheel hp thats about 430 flywheel hp
its the minor details and care taken during the assembly process and tuning that add up! minor tweaks may not mean much individually but the time and effort does usually result in more durability and power
in many cases you can make a few changes and get noticeable improvements, but it takes experience and testing to locate the source of your engines problem, your combos basically well thought thru, so somethings obviously not functioning to its potential,
obviously having more info, like was the cam degreed in or installed (DOT-TO-DOT),was it installed advanced? strait up? retarded? what is the lifter pre-load set at?
whats your oil pressure? having more detailed info like the intake vacuum, readings, exhaust back pressure , ignition advance curve would help as would knowing the valves were properly adjusted and your not getting into valve float or valve control issues
why not test the exhaust back pressure, to see if its over 2-3 psi at high rpms , indicating a restriction or you could temporarily disconnect the exhaust system to see if the change in exhaust restriction makes a difference in your results?
have you done a leak-down test?
have you done a compression test?
are you getting a hot blue ignition spark, what are the plugs gaped at?
whats your fuel pressure?
whats your ignition advance curve look like?
are you sure theres no vacuum leaks or injectors not working correctly?
did you port match the plenum, runners and heads?
can you post CLEAR LABELED pictures of EACH of the spark plugs?
can you post a clear copy of the DYNO SHEET?
theres always a reason and a logical, test, & verify ,step, bye, step approach rather than random parts swapping and wild guesses will locate the problem
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viewtopic.php?f=56&t=495
383, 10.3:1, AFR 195 heads, Stealth Ram, 52mm throttle body, de-screened MAF, 32 lb Bosch gen III injectors, Howards Max Torque roller 234 242 .569" .585", SLP 1.75" ceramic coated headers, Magnaflow cat, Magnaflow cat-back.
Air/Fuel Ratio was 13.5:1 +/- .2 for the duration of the dyno pull.
We did one pull with the air cleaner lid removed (to rule out the air cleaner as the restriction) and it picked up nothing. I know that the single 3" exhaust is a restriction, but 40 to 60 hp? This motor should make at least 380 hp to the wheels.
It has a 700r4, Midwest 9.5" 3400 rpm stall, 4.10 gears.
Any ideas?
your not the first and your sure not likely to be the last guy to think the dyno results are less than you expected!
your results are fairly typical, on a 383 before its well sorted out.
yes you can expect a bit more from that combo, but getting the typical magazine dyno (flywheel hp numbers) or results for your real on the street, rear wheel hp numbers is not likely.
always remember FLYWHEEL HORSEPOWER that an engine dyno reports tends to be about 18% higher than rear wheel hp, after losses in the drive train at the rear wheels.
if your making 343 rear wheel hp thats about 430 flywheel hp
its the minor details and care taken during the assembly process and tuning that add up! minor tweaks may not mean much individually but the time and effort does usually result in more durability and power
in many cases you can make a few changes and get noticeable improvements, but it takes experience and testing to locate the source of your engines problem, your combos basically well thought thru, so somethings obviously not functioning to its potential,
obviously having more info, like was the cam degreed in or installed (DOT-TO-DOT),was it installed advanced? strait up? retarded? what is the lifter pre-load set at?
whats your oil pressure? having more detailed info like the intake vacuum, readings, exhaust back pressure , ignition advance curve would help as would knowing the valves were properly adjusted and your not getting into valve float or valve control issues
why not test the exhaust back pressure, to see if its over 2-3 psi at high rpms , indicating a restriction or you could temporarily disconnect the exhaust system to see if the change in exhaust restriction makes a difference in your results?
have you done a leak-down test?
have you done a compression test?
are you getting a hot blue ignition spark, what are the plugs gaped at?
whats your fuel pressure?
whats your ignition advance curve look like?
are you sure theres no vacuum leaks or injectors not working correctly?
did you port match the plenum, runners and heads?
can you post CLEAR LABELED pictures of EACH of the spark plugs?
can you post a clear copy of the DYNO SHEET?
theres always a reason and a logical, test, & verify ,step, bye, step approach rather than random parts swapping and wild guesses will locate the problem
viewtopic.php?f=55&t=431&p=756&hilit=holley+stealth+mods#p756
viewtopic.php?f=44&t=808&p=11560&hilit=throwing#p11560
viewtopic.php?f=32&t=18
viewtopic.php?f=52&t=266&p=322&hilit=215cc+vortec#p322
viewtopic.php?f=70&t=3949
viewtopic.php?f=57&t=4974&p=15425&hilit=temp+sensors#p15425
viewtopic.php?f=32&t=596&p=14674&hilit=temp+sensors#p14674
viewtopic.php?f=80&t=728&p=9217&hilit=temp+sensors#p9217
viewtopic.php?f=52&t=5537&p=16744#p16744
viewtopic.php?f=50&t=1249&p=7598&hilit=stroker+tips#p7598
viewtopic.php?f=56&t=495
