modified 502mpi intake on 502 dyno session at my shop
02-26-2016 | 04:33 PM
#171
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From: On A Dirt Floor
That last arrestor looks schweet !
The K&N set up doesn't work well because it'single large hole has to, and does, transition abruptly to the wider spaced out throttle bore in the throttle blade. . The Hardin marine one you show that is profiled like mine on one side, does the same as the K&N. Again, just a poor choice in element assembly that you need to transition too abruptly to a different shape.
Their plates are simply adapters. Most things that 'adapt' (meaning one orifice to another) don't work so well. Adapters and spacers , even though used in the same place, are called two different things for a reason.
The K&N set up doesn't work well because it'single large hole has to, and does, transition abruptly to the wider spaced out throttle bore in the throttle blade. . The Hardin marine one you show that is profiled like mine on one side, does the same as the K&N. Again, just a poor choice in element assembly that you need to transition too abruptly to a different shape.
Their plates are simply adapters. Most things that 'adapt' (meaning one orifice to another) don't work so well. Adapters and spacers , even though used in the same place, are called two different things for a reason.
02-26-2016 | 06:26 PM
#172
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From: frankenmuth michigan
Bigger is better so it seems. "Restriction" can mean no big deal or really big deal depending on your engine. Once again Smitty has provided us with sound real world testing.
For those who don't have nor ever had a 454/502 Mag EFI/MPI here are a few pictures to illustrate what is being discussed as the restriction. The 454/502 Mag EFI/MPI's
have a two butterfly two stage throttle body as opposed to the HP525's mono blade.
Stock K & N - This is what I have on my stock 502 MPI. Note the aluminum adapter. I added this air filter/FA to keep bugs and those damn puff ball seeds(cottonwoods?) out of my engine.
My stock FA would be full after a week or two of running. During testing I lost a max of 9 RPM's using the stock K & N. I did find that when at full throttle(engine off) my two butterflies were
not parallel. The primary was past open and the secondary was not fully open. There is no way to adjust them. Smitty did you notice this and/or find a solution?
Hardin Marine SS - Note the aluminum adapter here compared to the stock K & N. Keeping the air flow separate for the two butterflies may help flow. I will leave speculation to the guys
with dyno's or Scott(CFM, SB) who marketed a similar device as to how much.
Compare HP525 to New Hardin - So if Smitty's 65mm bore throttle body works well how about 75mm bores? Heck why not make an adapter and use an HP525 style monoblade? It sure would
be nice to see a chart to know at what HP level you will need a throttle body of X size in order to have no restriction.
New Hardin HP525 - Sweet looking piece and probably flows like no other but at $599 it is not for the faint of heart.
I purchased my K & N from the old Dana Marine. They now carry a Gaffrig FA that looks really neat. There have been many aftermarket air filters/FA's sold by several companies over the
years. If you have a stock engine or a slightly modified one I would not be too concerned with the restriction problem. If your HP is over 450 then a different air filter/FA and throttle body
should be considered in your budget.
For those who don't have nor ever had a 454/502 Mag EFI/MPI here are a few pictures to illustrate what is being discussed as the restriction. The 454/502 Mag EFI/MPI's
have a two butterfly two stage throttle body as opposed to the HP525's mono blade.
Stock K & N - This is what I have on my stock 502 MPI. Note the aluminum adapter. I added this air filter/FA to keep bugs and those damn puff ball seeds(cottonwoods?) out of my engine.
My stock FA would be full after a week or two of running. During testing I lost a max of 9 RPM's using the stock K & N. I did find that when at full throttle(engine off) my two butterflies were
not parallel. The primary was past open and the secondary was not fully open. There is no way to adjust them. Smitty did you notice this and/or find a solution?
Hardin Marine SS - Note the aluminum adapter here compared to the stock K & N. Keeping the air flow separate for the two butterflies may help flow. I will leave speculation to the guys
with dyno's or Scott(CFM, SB) who marketed a similar device as to how much.
Compare HP525 to New Hardin - So if Smitty's 65mm bore throttle body works well how about 75mm bores? Heck why not make an adapter and use an HP525 style monoblade? It sure would
be nice to see a chart to know at what HP level you will need a throttle body of X size in order to have no restriction.
New Hardin HP525 - Sweet looking piece and probably flows like no other but at $599 it is not for the faint of heart.
I purchased my K & N from the old Dana Marine. They now carry a Gaffrig FA that looks really neat. There have been many aftermarket air filters/FA's sold by several companies over the
years. If you have a stock engine or a slightly modified one I would not be too concerned with the restriction problem. If your HP is over 450 then a different air filter/FA and throttle body
should be considered in your budget.
02-26-2016 | 06:31 PM
#173
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Joined: Jun 2004
Posts: 7,320
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From: frankenmuth michigan
That last arrestor looks schweet !
The K&N set up doesn't work well because it'single large hole has to, and does, transition abruptly to the wider spaced out throttle bore in the throttle blade. . The Hardin marine one you show that is profiled like mine on one side, does the same as the K&N. Again, just a poor choice in element assembly that you need to transition too abruptly to a different shape.
Their plates are simply adapters. Most things that 'adapt' (meaning one orifice to another) don't work so well. Adapters and spacers , even though used in the same place, are called two different things for a reason.
The K&N set up doesn't work well because it'single large hole has to, and does, transition abruptly to the wider spaced out throttle bore in the throttle blade. . The Hardin marine one you show that is profiled like mine on one side, does the same as the K&N. Again, just a poor choice in element assembly that you need to transition too abruptly to a different shape.
Their plates are simply adapters. Most things that 'adapt' (meaning one orifice to another) don't work so well. Adapters and spacers , even though used in the same place, are called two different things for a reason.
03-12-2016 | 09:53 PM
#174
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From: frankenmuth michigan
Update, dynos been broke for a few weeks (tach drive adapter started working intermittently), parts came from depac and we are back up and running.
Did base line (a few days ago), correction factor is the highest we have seen so far , in the 6/7 % range (dew point almost 60 degrees, humidity HIGH, air temp in the upper 70's around dyno), motor made 534 base hp corrected, adapted 500 efi kn element onto it, hp dropped by 19, tq dropped by 21 ft lbs at 4400, still made 560ft lbs but at 4000 then fell quickly so I can see a serious hp restriction on modified hp 500's running stock air cleaners! You can ignore the BSFC#'s, we are pulling fuel thru the meter and it reads high then starts reading in high .4's to low .5's after a few pulls
Did base line (a few days ago), correction factor is the highest we have seen so far , in the 6/7 % range (dew point almost 60 degrees, humidity HIGH, air temp in the upper 70's around dyno), motor made 534 base hp corrected, adapted 500 efi kn element onto it, hp dropped by 19, tq dropped by 21 ft lbs at 4400, still made 560ft lbs but at 4000 then fell quickly so I can see a serious hp restriction on modified hp 500's running stock air cleaners! You can ignore the BSFC#'s, we are pulling fuel thru the meter and it reads high then starts reading in high .4's to low .5's after a few pulls
Last edited by articfriends; 03-12-2016 at 09:57 PM.
03-12-2016 | 10:01 PM
#175
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From: frankenmuth michigan
Found a BUNCH of hp running open headers (been running 5" flex tails with semi mufflers), made a open header pull and saw the highest numbers by far! 579 Ft lbs tq and 553 hp, the tq peak REALLY fattened too all the way to 4900! Thiese best hp/tq numbers were also WITH gen 5 flame arrestor installed, had to mill the TPI throttle body for the old style studs that hold the flame arrestor on, just about finished with this so doing all pulls here on out with the flame arreestor thats going to be ran on it.
Last edited by articfriends; 03-12-2016 at 10:09 PM.
03-12-2016 | 10:39 PM
#177
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From: frankenmuth michigan
After doing the test described above I installed new o2 sensors in both the afx meter linked to depac and my handheld innovate to see how far apart they really are for reference for tuning in boat with the innovate. The AFX is installed in #8, been getting what I thought was false lean or rich readings on it intermittently, even with new sensor still getting strange readings. Pulled motor to 4500 and was showing 16-1, usually it shows mid 12's, swapped to port innovates is in on # 7, showed totally different number and innovate then showed lean, pulled plug and found whithish ground strap all the way to base (previously has been coloring good). installed another used injector in #8, numbers came back to normal. So these injectors are questionable. Pulled motor with afx in #7, showed 10-1 thru tq peak and high 14's in hp peak, #7 injector is screwed up too, who knows where the other cylinders are but the plugs have colored good previuosly.
Ordered a injector cleaning/flow machine plus ultrasonic cleaner, not making anymore pulls till i see where these injectors are, with rich then lean numbers in #7 their might be more hp on the table once I figure this out. LESSON learned-clean and verify flow on ANY injectors that are used! In past I have taken my sieman deka injectors to Tyler and had him flow them everytime I freshened my blower motor, never found a problem. These are old injectors I used to run 12 or 13 years ago so who knows where the flow is, they were also ran at as high as 75 psi back when I ran them in blown 502.
Ordered a injector cleaning/flow machine plus ultrasonic cleaner, not making anymore pulls till i see where these injectors are, with rich then lean numbers in #7 their might be more hp on the table once I figure this out. LESSON learned-clean and verify flow on ANY injectors that are used! In past I have taken my sieman deka injectors to Tyler and had him flow them everytime I freshened my blower motor, never found a problem. These are old injectors I used to run 12 or 13 years ago so who knows where the flow is, they were also ran at as high as 75 psi back when I ran them in blown 502.
Last edited by articfriends; 03-12-2016 at 10:43 PM.
03-13-2016 | 09:48 AM
#178
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From: taxachusetts
very good find there.
we know its a pita,but every spring we pull injectors and pressure them w/ fuel and check for any leaks then hit the pulse button and watch the flow pattern.saves me alot of before the season starts.over the course of 10yrs,I've found a handfull(really 7) bad injectors.got winterization down really good now.haven't lost any in 4yrs.
In the next couple weeks,I have to totally retune a old whipple efi top mount on a 502.has always loaded up at idle.so first I'll check injectors then blow the tune out and load a base tune and have a nice day on the water.boats a 28' powerplay.
we know its a pita,but every spring we pull injectors and pressure them w/ fuel and check for any leaks then hit the pulse button and watch the flow pattern.saves me alot of before the season starts.over the course of 10yrs,I've found a handfull(really 7) bad injectors.got winterization down really good now.haven't lost any in 4yrs.
In the next couple weeks,I have to totally retune a old whipple efi top mount on a 502.has always loaded up at idle.so first I'll check injectors then blow the tune out and load a base tune and have a nice day on the water.boats a 28' powerplay.
Last edited by sutphen 30; 03-13-2016 at 09:52 AM.
03-25-2016 | 06:57 AM
#179
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Posts: 52
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From: Jacksonville, FL
Great read really has me interested with whats going on with my motors....
Currently deployed but felt like my boat was really under performing for what it has.
Twin 454 Mags MEFI 3
stock rotating assembly
Elderbrock RPM Marine Heads
Crane Cams (HP500 specs) LS firing order
Told Manifold was port matched
Stock Throttle bodys
29 Outlaw with boxes, would barely do 70 (did 74 on imco shorites which were stolen)
what kinda power should this set up make? What exactly did you do to your stock intakes? I am looking to have motors pulled and dyno and this thread really peaked my interest on easy mods as throttle body upgrades and having some manifold mods done while motors are out. Thanks.
Josh Broome
Currently deployed but felt like my boat was really under performing for what it has.
Twin 454 Mags MEFI 3
stock rotating assembly
Elderbrock RPM Marine Heads
Crane Cams (HP500 specs) LS firing order
Told Manifold was port matched
Stock Throttle bodys
29 Outlaw with boxes, would barely do 70 (did 74 on imco shorites which were stolen)
what kinda power should this set up make? What exactly did you do to your stock intakes? I am looking to have motors pulled and dyno and this thread really peaked my interest on easy mods as throttle body upgrades and having some manifold mods done while motors are out. Thanks.
Josh Broome
Last edited by navy252; 03-25-2016 at 08:44 AM.
04-25-2016 | 04:41 PM
#180
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Joined: Jun 2004
Posts: 7,320
Likes: 1,039
From: frankenmuth michigan
Great read really has me interested with whats going on with my motors....
Currently deployed but felt like my boat was really under performing for what it has.
Twin 454 Mags MEFI 3
stock rotating assembly
Elderbrock RPM Marine Heads
Crane Cams (HP500 specs) LS firing order
Told Manifold was port matched
Stock Throttle bodys
29 Outlaw with boxes, would barely do 70 (did 74 on imco shorites which were stolen)
what kinda power should this set up make? What exactly did you do to your stock intakes? I am looking to have motors pulled and dyno and this thread really peaked my interest on easy mods as throttle body upgrades and having some manifold mods done while motors are out. Thanks.
Josh Broome
Currently deployed but felt like my boat was really under performing for what it has.
Twin 454 Mags MEFI 3
stock rotating assembly
Elderbrock RPM Marine Heads
Crane Cams (HP500 specs) LS firing order
Told Manifold was port matched
Stock Throttle bodys
29 Outlaw with boxes, would barely do 70 (did 74 on imco shorites which were stolen)
what kinda power should this set up make? What exactly did you do to your stock intakes? I am looking to have motors pulled and dyno and this thread really peaked my interest on easy mods as throttle body upgrades and having some manifold mods done while motors are out. Thanks.
Josh Broome
