Cam question (Whipple 500efi)
#12
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Joined: Jan 2006
Posts: 3,601
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From: taxachusetts
Thats all i got for that dyno sheet. Eliminated sent it to me a while back.
Those afrs are certainly showing lean. Ive had supercharged engines on dyno that started there for afrs, and never shown any signs of knock. Of course they got fattened up from there.
What do you guys typically do for your dyno pulls?
Those afrs are certainly showing lean. Ive had supercharged engines on dyno that started there for afrs, and never shown any signs of knock. Of course they got fattened up from there.
What do you guys typically do for your dyno pulls?
dyno pulls,,depends,,I'll hold an engine at 3-4000 rpm and load the bag out of it to get the fuel right.
heres a true story
38 fasttech,,vortech hp500efi's,,arnesons,,rebuilt the drop boxes,,they have the gear ratio,,go out to tune mefi4b's.4 guys on the boat that want to watch me work.strap boat to dock,,set up in/out of gear idle.few tweaks and off we idle out.
go to get on plane,nothing,floor it,cough sputter weaze,,pull back throttles,,make some tweaks,,again nothing,,guys aggrevating me,,saying tunes fcked,,so back to the dock.strap it down again,,more tweaks more timing ect...
still nothing,,hearing the same schit about tuning,,I jump up,go to the throttles and pin them,,I say,what do you want me to do,,this thing thinks its at full load all the time.
I say,,either your shaft bearings are seizing or the gears are in backward,,,turns out,,gears were in backwards,,we were trying to get on plane w/ I think a ~.75-1 ratio,,boy we did idle out quickly.motors ran for years before heads rotted
out.
new afr headed 540's I tuned in the boat from a base tune,,fastest so far,,115mph.
#13
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From: taxachusetts
#14
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Joined: Aug 2011
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From: bel air, md
Thats all i got for that dyno sheet. Eliminated sent it to me a while back.
Those afrs are certainly showing lean. Ive had supercharged engines on dyno that started there for afrs, and never shown any signs of knock. Of course they got fattened up from there.
I do believe these engines went into a 388 Hustler, and have ran great all season. The power numbers look clean , dont see anything weird going on?
I could show you my dyno pull, that started at 2900rpm to 6500rpm, at a sweep rate of 150rpm per second. Wanna talk about loading an engine down.....dyno pull was like 30 seconds long. I see some of the guys here do a 4k to 6k rpm pull at 800rpm per second and call the tune perfect. Dyno pull is over in blink of an eye.
What do you guys typically do for your dyno pulls?
Those afrs are certainly showing lean. Ive had supercharged engines on dyno that started there for afrs, and never shown any signs of knock. Of course they got fattened up from there.
I do believe these engines went into a 388 Hustler, and have ran great all season. The power numbers look clean , dont see anything weird going on?
I could show you my dyno pull, that started at 2900rpm to 6500rpm, at a sweep rate of 150rpm per second. Wanna talk about loading an engine down.....dyno pull was like 30 seconds long. I see some of the guys here do a 4k to 6k rpm pull at 800rpm per second and call the tune perfect. Dyno pull is over in blink of an eye.
What do you guys typically do for your dyno pulls?
Last edited by Black Baja; 12-11-2016 at 10:23 AM.
#15
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From: taxachusetts
#17
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From: bel air, md
If you want to run that motor close to 6,000 in a boat the power curve is all wrong. That motor is petered out at 5,000 rpm. I'll bet it pulls like a freight train up to 5,000 and hits a brick wall. If you want to spin 6,000 the curve needs to move up.
Last edited by Black Baja; 12-11-2016 at 10:51 AM.
#18
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From: US of A
It's an inland boat. Maybe 30 second WOT blasts. Goal RPM is 5600 with 3.125 pullies should be close to 7psi. He currently runs the 3.375 uppers at only 5000-5100 rpm. 5psi. That dyno sheet is also 5psi
#19
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From: US of A
Baja why would you say the duration is too low? This cam is close to same duration on exhaust as 525efi but more intake. Dustin sells the 525 cam as whipple upgrade for the 500's... He doing it all wrong you feel? Please elaborate
#20
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From: bel air, md
There's nothing to elaborate on look at the dyno sheet. The motor is out of steam at 5,000 rpm. The cam is to small. I see it all the time. I don't care if Jesus himself designed the package. If you want to run that motor in close to 6,000 rpm the cam is to small.


