540 help
07-09-2006, 09:02 PM
#1
Registered
Thread Starter
Join Date: Jan 2002
Location: Ca.
Posts: 61
Likes: 0
Received 0 Likes
on
0 Posts
540 help
I have a 540 with 9.2.to 1, AFR 305 w/cnc chambers, Merlin marine single plane intake 4150, cam 242/248 @ 50 646/646 on 112, over lap 21.3,4150 850 BG mighty marine, MSD w/6m box.
Motor is making around 560 @ 5600. I wound love to see the 650 + hp. I need the flowing rpm / hp to run my drive.
5500 / 526
5600 / 560
5700 / 590
5800 / 620
5900 / 650
6000 / 683
Where did I go wrong?
Motor is making around 560 @ 5600. I wound love to see the 650 + hp. I need the flowing rpm / hp to run my drive.
5500 / 526
5600 / 560
5700 / 590
5800 / 620
5900 / 650
6000 / 683
Where did I go wrong?
07-09-2006, 09:30 PM
#2
Registered
Join Date: Sep 2001
Location: Houston, TX, USA
Posts: 2,287
Likes: 0
Received 0 Likes
on
0 Posts
Re: 540 help
Not quite sure what question you are asking. I am assuming the numbers you have listed are your dyno numbers. To get more RPM's you would need to run a smaller pitch prop.
We need more information.
Type of boat?
Drive ratio?
Prop you are using?
exhaust you are using?
fuel system?
Is this a new motor and old motor ran better? or?
We need more information.
Type of boat?
Drive ratio?
Prop you are using?
exhaust you are using?
fuel system?
Is this a new motor and old motor ran better? or?
07-09-2006, 11:01 PM
#4
Platinum Member
Platinum Member
Join Date: Oct 2002
Location: DFW, Texas
Posts: 1,053
Likes: 0
Received 0 Likes
on
0 Posts
Re: 540 help
If it's making the power, but 400-500 RPM higher than you wanted it to, wouldn't that be a cam selection issue? I'm not cam expert so I can't comment on the one you're running. I'll be interested to see the replies.
07-10-2006, 08:40 AM
#6
Registered
iTrader: (1)
Re: 540 help
A 540 with a 242/248 @ 50 646/646 on 112 with AFR heads will make much more than 560@5600rpm.
I can't see using a jet pump as a dyno #. A reference, yes, but actual dyno? I'm sure there are guidlines for what hp to drive at a certain rpm, but that is probably generalistic or with a perfect set up. Kind of like a drag calculator - input hp and weight and it spits out an ET and mph. Does your car do it ? Nope, the further something in set up is away from ideal the further away actual results will be.
My strong gut feeling is you either have a tune issue with fuel system, carb, ignition - motor is not as 'healthy' as you assume - or jet pump set up is off.
=================
Let's think about this.
242, 248 at .050 . 646",.646. AFR heads, 540 cubic inches at 9.2:1 . 560hp ? No way !!!! Something is wrong somewhere and I'd be seriously suprised if it's from these parts mentioned.
To put your build into perspective using a smaller motor as example, a 502 with 230 at .050", .600" lift with these heads, cam, compression,etc,etc is going to be damn near 600hp. This is proven a kazillion times.
I can't see using a jet pump as a dyno #. A reference, yes, but actual dyno? I'm sure there are guidlines for what hp to drive at a certain rpm, but that is probably generalistic or with a perfect set up. Kind of like a drag calculator - input hp and weight and it spits out an ET and mph. Does your car do it ? Nope, the further something in set up is away from ideal the further away actual results will be.
My strong gut feeling is you either have a tune issue with fuel system, carb, ignition - motor is not as 'healthy' as you assume - or jet pump set up is off.
=================
Let's think about this.
242, 248 at .050 . 646",.646. AFR heads, 540 cubic inches at 9.2:1 . 560hp ? No way !!!! Something is wrong somewhere and I'd be seriously suprised if it's from these parts mentioned.
To put your build into perspective using a smaller motor as example, a 502 with 230 at .050", .600" lift with these heads, cam, compression,etc,etc is going to be damn near 600hp. This is proven a kazillion times.
Last edited by SB; 07-10-2006 at 08:43 AM.
