Does anyone have dyno curves for 350 MAG EFI motor stock and w/aftermarket manifold ?
10-19-2013 | 08:22 PM
#1
Thread Starter
Registered
Joined: Oct 2012
Posts: 7
Likes: 0
From: North East Iowa
Does anyone have dyno curves for 350 MAG EFI motor stock and w/aftermarket manifold ?
Looking for some real dyno number of HP gain going to Stainless Marine or CMI E Tops on a stock motor ?
Anyone put the 1.6 comp cam rocker on their 350 mag, these are the listed mecursier part on the 383 repower motors?
Someone has had to Dyno one of these but I have search all the forums and internet and can't find any actual dyno results.
There is a 383 dyno curve on CMI web page, I know the motor (350 MAG EFI) spec's to run at 4800-5200 rpm but where is the peak HP at ?
Looking at the CMI dyno the 383 peaks at 5600 stock, This would really help to know this for my winter project.
http://custommarine.com/headerapps/dyno_data2.php
Thanks !
Anyone put the 1.6 comp cam rocker on their 350 mag, these are the listed mecursier part on the 383 repower motors?
Someone has had to Dyno one of these but I have search all the forums and internet and can't find any actual dyno results.
There is a 383 dyno curve on CMI web page, I know the motor (350 MAG EFI) spec's to run at 4800-5200 rpm but where is the peak HP at ?
Looking at the CMI dyno the 383 peaks at 5600 stock, This would really help to know this for my winter project.
http://custommarine.com/headerapps/dyno_data2.php
Thanks !
10-19-2013 | 10:16 PM
#2
Registered
Joined: Jun 2011
Posts: 1,208
Likes: 141
I've never found any either. I would be very hesitant about dumping cash on CMIs and quite frankly SM in hopes of any measurable on the water performance gains. The 350 Mag EFI/MP I had would never spin above 4700 on its best day and it wasn't the stock exhaust holding it back. It was cam limited. I've often found when asking the same questions you just posed I get a resounding silence.
Others have spun small blocks and stroker small blocks upwards of 6000 rpm with GLM stock style manifolds. That information along with the lack of quality third party results of aftermarket exhaust performance gains leads me to believe your money would be best spent elsewhere.
Others have spun small blocks and stroker small blocks upwards of 6000 rpm with GLM stock style manifolds. That information along with the lack of quality third party results of aftermarket exhaust performance gains leads me to believe your money would be best spent elsewhere.
10-20-2013 | 10:18 AM
#3
Thread Starter
Registered
Joined: Oct 2012
Posts: 7
Likes: 0
From: North East Iowa
Thanks, The boat/motor only has 130 hours on it and runs good for what it is , Regal 2200 ( has their one step fast trak hull) 350 Mag/ Bravo drive and running Bravo 1 FS prop runs 57-58 mph on GPS @ 5050 rpm, going to have BBlades lab that this winter. Just put the prop that came with the boat, bblade just worked it to increase size Vensura 19" and that runs 55 mph but right on the limiter @ 5400 rpm. It will be good for a tow prop as it was 50 degrees here yesterday so I was running about a 100 rpms more with both props compared to summer.
Any one put 1.6 rocker on their 350 MAG, one thread says that they will hit the guides then I read that others are doing it ? The stock 383 Scorpians list the comp cam part number,. also read there is clearence problems with the valve cover but there again mercury list an aftermarket VC on there parts page.
AS with most of us I just trying to get a little more performance !
Any one put 1.6 rocker on their 350 MAG, one thread says that they will hit the guides then I read that others are doing it ? The stock 383 Scorpians list the comp cam part number,. also read there is clearence problems with the valve cover but there again mercury list an aftermarket VC on there parts page.
AS with most of us I just trying to get a little more performance !
10-20-2013 | 10:01 PM
#5
Registered
Joined: Jun 2011
Posts: 1,208
Likes: 141
350 Mag/ Bravo drive and running Bravo 1 FS prop runs 57-58 mph on GPS @ 5050 rpm
Vensura 19" and that runs 55 mph but right on the limiter @ 5400 rpm.
Any one put 1.6 rocker on their 350 MAG
Even if you added 75hp to the engine, you would be lucky to gain 5mph.
Engine mods will reduce the value of your boat.
Last edited by Trash; 10-20-2013 at 10:05 PM.
10-20-2013 | 10:21 PM
#6
Registered
Joined: May 2006
Posts: 4,224
Likes: 1
From: West Creek NJ
You will get nothing from exhaust, except maybe boat will plane quicker as the CMI's are lighter. Same would be for aluminum manifolds. I went back and forth for years about what to do with my 6.2's. In the end it was cheaper to by a boat 10mph faster than make mine 10 mph faster.
10-20-2013 | 11:49 PM
#7
Registered
Joined: Jun 2012
Posts: 275
Likes: 0
hey stspinner, just read your question , ill tell you what i have for facts tomorrow. im about to hit sack. in short, started with 2001 twin 350mag 29ft scarab ended with twin 383's putting 400hp @ 5600 / 420tq @ 4200 ,,,,,, stock boat ran 67mph on best day / ran 73 @ 5400 after ,,, same prop ,,,, i believe there is some left on table ,, just need time to prove ,,,,,,,,
10-21-2013 | 12:18 AM
#8
Registered
Joined: Oct 2009
Posts: 1,134
Likes: 160
From: central IL
Looking for some real dyno number of HP gain going to Stainless Marine or CMI E Tops on a stock motor ?
Anyone put the 1.6 comp cam rocker on their 350 mag, these are the listed mecursier part on the 383 repower motors?
Someone has had to Dyno one of these but I have search all the forums and internet and can't find any actual dyno results.
There is a 383 dyno curve on CMI web page, I know the motor (350 MAG EFI) spec's to run at 4800-5200 rpm but where is the peak HP at ?
Looking at the CMI dyno the 383 peaks at 5600 stock, This would really help to know this for my winter project.
http://custommarine.com/headerapps/dyno_data2.php
Thanks !
Anyone put the 1.6 comp cam rocker on their 350 mag, these are the listed mecursier part on the 383 repower motors?
Someone has had to Dyno one of these but I have search all the forums and internet and can't find any actual dyno results.
There is a 383 dyno curve on CMI web page, I know the motor (350 MAG EFI) spec's to run at 4800-5200 rpm but where is the peak HP at ?
Looking at the CMI dyno the 383 peaks at 5600 stock, This would really help to know this for my winter project.
http://custommarine.com/headerapps/dyno_data2.php
Thanks !
10-21-2013 | 08:45 AM
#9
Registered
Joined: Feb 2011
Posts: 769
Likes: 0
From: Brookfield Wi
Looked at your link. Wonder how many people looked at the fuel info provided. Apparently, they tested on a closed loop system or a "tuned application". Subsequently, if someone were to install these on a MEFI 1 or 2 engine, improvements would be minimal at best.
Generally speaking, I would agree on the mod responses. Though, in my case. Would I rebuild / freshen (completely blueprinted before and after) up a couple 580hr small blocks without improvements to the heads and and mild cam? Never. Especially since I have air / fuel gauges to prove EFI tune before and after.
Generally speaking, I would agree on the mod responses. Though, in my case. Would I rebuild / freshen (completely blueprinted before and after) up a couple 580hr small blocks without improvements to the heads and and mild cam? Never. Especially since I have air / fuel gauges to prove EFI tune before and after.
10-21-2013 | 10:08 AM
#10
Thread Starter
Registered
Joined: Oct 2012
Posts: 7
Likes: 0
From: North East Iowa
What prop pitch and drive ratio?
Vensura is 19" that BBlades added about an 1" so around 20" runs 5380 rpm on shop tach
Bravo 1 FS 22" however the FS has about 100 rpm more than a standard Bravo 1, having BBlades LAB the Bravo 1 FS this winter it runs about 5000 RPM @ WOT
Bravo 1 Drive 1.65 ratio
I thought the rev limiters were around 5150-5180? I have the 555 EFI box rev limit is 5400 rpm, going to have Whipple reprogram for 91 octance and raise the limiter to 5600 rpm
I don't think you will see any measurable performance by simply swapping out rockers. Cam, heads, compression and displacement will make the biggest gains.
THe rockers are an easy switch, Mercury list the comp cam part # they used on the 383 Scorpians motors, I am trying to find out if they clear the guide, some say to much life other say it works not something I want to find out on my own !
You could say that about any boat. Mod it and have fun.
I bought it at a good price only 40 hrs and paid about 50 Cent to the dollar as for a brand new one, One thing with the exhaust being a Bravo 1 drive it has the same Part # "Y" pipe as a 430 HP MAG BBC so if they can run 430 HP through the y pipe I can for sure add 15-30 HP with not having back pressure concerns .
Not sure that's his concern. Besides value in a boat is like virtuosity in a whore house.
Vensura is 19" that BBlades added about an 1" so around 20" runs 5380 rpm on shop tach
Bravo 1 FS 22" however the FS has about 100 rpm more than a standard Bravo 1, having BBlades LAB the Bravo 1 FS this winter it runs about 5000 RPM @ WOT
Bravo 1 Drive 1.65 ratio
I thought the rev limiters were around 5150-5180? I have the 555 EFI box rev limit is 5400 rpm, going to have Whipple reprogram for 91 octance and raise the limiter to 5600 rpm
I don't think you will see any measurable performance by simply swapping out rockers. Cam, heads, compression and displacement will make the biggest gains.
THe rockers are an easy switch, Mercury list the comp cam part # they used on the 383 Scorpians motors, I am trying to find out if they clear the guide, some say to much life other say it works not something I want to find out on my own !
You could say that about any boat. Mod it and have fun.
I bought it at a good price only 40 hrs and paid about 50 Cent to the dollar as for a brand new one, One thing with the exhaust being a Bravo 1 drive it has the same Part # "Y" pipe as a 430 HP MAG BBC so if they can run 430 HP through the y pipe I can for sure add 15-30 HP with not having back pressure concerns .
Not sure that's his concern. Besides value in a boat is like virtuosity in a whore house.
I just want to find someone that has seen gains with exhaust there alot of theries but would think someone has real data /
