Blower cams
#21
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From: chicago
Ive also seen stock 049 heads make what some would think, good power with an 871 on top. Does that mean a set of afrs or darts wont make more power and be a better setup?
Some of the top engine builders use modern software during engine development, as well as oem manufactures. By no means is it better than real world results, it might narrow down that trash barrel full of cams, to a picnic basket full of them.
Kind of hard to move forward, if we just keep copying someone else. The idea is to get a better understanding of why, something does what it does. Otherwise , your just a parts changer.
#22
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From: MI

"Some suggestions for a blower Cam.
A wide lobe separation (112*-115*) to reduce overlap and blow through.
Blower engines need less (2*-4*) advance. An early IVO is unnecessary. The intake column is pressurized and early openings increasing overlap. A 110*/112* ICL on a 114* Lobe sep would work well.
Increased exhaust volume requires blower cams to have additional ex duration to rid the cylinder of spent gasses. This is dependant upon the efficiency of your exhaust port. 8*-10* spread is a baseline reference.
Stock exhaust ports need an earlier EVO to blow down the cylinder. The negative of and early exhaust valve opening is the loss of some of the increased cylinder pressure. The negative of a late EVO is increased pumping losses. Optimizing your exhaust port will help, allowing you to delay the EVO, negating the pumping losses.
The shelf cams (marine) available today were designed around flow numbers from cylinder heads designed 25 years ago. This is particularly true of marine catalog grinds that haven’t been updated in years due to the relatively small market share they bring to the larger companies. Simply put they will not come close to optimizing the flow capabilities of today’s AFR/Canfield type cylinder heads. The durations are to long and the splits to wide given the near 80% I/E ratios that are commonplace today. Much of the potential HP/torque increases available are underutilized by improper camming of these engines. It doesn’t make sense to bolt on a set of CNC AFR’s and cam it with a piece that was designed around flow #’s that aren’t even close and send those increases “out the pipe”. Due to advanced modeling and software, custom cams (designed around your particular parameters) are now affordable and readily available option to the marine market. There is extensive development going on today in marine camshaft design especially in the 502/540+ displacement area that is making high, flat torque numbers on the dyno, easier on the valve train, with much better VE and BSFC #’s. This is all done while keeping peak torque/HP numbers right where you need them."
#23
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From: chicago

Due to advanced modeling and software, custom cams (designed around your particular parameters) are now affordable and readily available option to the marine market. There is extensive development going on today in marine camshaft design especially in the 502/540+ displacement area that is making high, flat torque numbers on the dyno, easier on the valve train, with much better VE and BSFC #’s. This is all done while keeping peak torque/HP numbers right where you need them."
Interestingly though, the 651 cam, and the cam he designed for a buddys blown engine with cnc afr heads, were very similar. Duration and timing event wise. Just a 680 lift, instead of 632. Made good power. Not sure how its holding up, as he sold boat with around 10 hours on the engines.
It be interesting to see how a blown 540 does, with a cam like the lunati supercharger cams, that only have 5 deg of split, with a 112 LSA, vs the tried and true 651 , with some cnc heads .
#24
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From: MI
I recall that post from Bob about 10 years ago. Mentioning the cams designed around heads from 25 years ago.
Interestingly though, the 651 cam, and the cam he designed for a buddys blown engine with cnc afr heads, were very similar. Duration and timing event wise. Just a 680 lift, instead of 632. Made good power. Not sure how its holding up, as he sold boat with around 10 hours on the engines.
It be interesting to see how a blown 540 does, with a cam like the lunati supercharger cams, that only have 5 deg of split, with a 112 LSA, vs the tried and true 651 , with some cnc heads .
Interestingly though, the 651 cam, and the cam he designed for a buddys blown engine with cnc afr heads, were very similar. Duration and timing event wise. Just a 680 lift, instead of 632. Made good power. Not sure how its holding up, as he sold boat with around 10 hours on the engines.
It be interesting to see how a blown 540 does, with a cam like the lunati supercharger cams, that only have 5 deg of split, with a 112 LSA, vs the tried and true 651 , with some cnc heads .
#25
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From: chicago
I believe my Lunati cam for my 575sci is 240/[email protected] .642/.642 114ls 110icl, I havnt even fired the motor yet but I wish I would have went a little bigger and did the 4/7 swap. Also not sure about the 5* split. At this point I dont think it would be worth the investment as I dont have anything to put it in. So, with AFR325 cnc chambered, stripped 871 with whipple chiller, stock 502 bore, 8.25:1 CMI ETops...what is my safe estimated HP on 93? The problem I see is supplying enough fuel with the dump truck injection system.
You sure your cam isnt a 112 LSA lunati?
#26
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From: On A Dirt Floor
#27
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From: MI
Custom grind specd out by Ron Sporl, 114 on the cam card, I believe he keeps them on the shelf.
#28
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From: MI
#29
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From: Toronto, Canada
I recall that post from Bob about 10 years ago. Mentioning the cams designed around heads from 25 years ago.
Interestingly though, the 651 cam, and the cam he designed for a buddys blown engine with cnc afr heads, were very similar. Duration and timing event wise. Just a 680 lift, instead of 632. Made good power. Not sure how its holding up, as he sold boat with around 10 hours on the engines.
It be interesting to see how a blown 540 does, with a cam like the lunati supercharger cams, that only have 5 deg of split, with a 112 LSA, vs the tried and true 651 , with some cnc heads .
Interestingly though, the 651 cam, and the cam he designed for a buddys blown engine with cnc afr heads, were very similar. Duration and timing event wise. Just a 680 lift, instead of 632. Made good power. Not sure how its holding up, as he sold boat with around 10 hours on the engines.
It be interesting to see how a blown 540 does, with a cam like the lunati supercharger cams, that only have 5 deg of split, with a 112 LSA, vs the tried and true 651 , with some cnc heads .
#30
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From: NW Michigan
I believe my Lunati cam for my 575sci is 240/[email protected] .642/.642 114ls 110icl, I havnt even fired the motor yet but I wish I would have went a little bigger and did the 4/7 swap. Also not sure about the 5* split. At this point I dont think it would be worth the investment as I dont have anything to put it in. So, with AFR325 cnc chambered, stripped 871 with whipple chiller, stock 502 bore, 8.25:1 CMI ETops...what is my safe estimated HP on 93? The problem I see is supplying enough fuel with the dump truck injection system.



will save you a trash barrel full of cams that were suppose to work on paper and in an computer syms.