Speed of 24 w/ HP500?
#31
Charter Member
Charter Member
Re: Speed of 24 w/ HP500?
I agree you are in good hands ,just giving my experiences. Be prepared to spin the engine higher with a 240 duration cam though maybe 5500 to 5800. If the CR is about 9.5 :1 it will make power with the 240 duration cam. good luck.
#32
Registered
Join Date: Dec 2004
Location: Rancho Cucamonga, Ca
Posts: 27
Likes: 0
Received 0 Likes
on
0 Posts
Re: Speed of 24 w/ HP500?
Iron man,
I am running a 454, bored out to a 468 with 9.8:1 compression, a 561 lift, 306/306 with 240 @0.050 cam with merlin rectangle port heads. What rpm range should I be pulling. Also I have stock mercruiser exhaust with IMCO long risers, will I be ok with that exhaust?
I am running a 454, bored out to a 468 with 9.8:1 compression, a 561 lift, 306/306 with 240 @0.050 cam with merlin rectangle port heads. What rpm range should I be pulling. Also I have stock mercruiser exhaust with IMCO long risers, will I be ok with that exhaust?
#33
Charter Member
Charter Member
Re: Speed of 24 w/ HP500?
Depending on the centerline of the cam you will probably be ok for reversion with the long risers. with 9.8 cr you probably will need at 93 octane and conservative timing 32 or so max with the iron heads. I would try to prop for 5400 - 5500 with a good ignition system. A friend has a similar engine with a slightly smaller cam in a 22 donzi ,same exhaust riser setup and he can turn 5800+ with a mirage 23 and no problems with reversion.
#34
Registered
Join Date: Sep 2003
Location: Newport, MI
Posts: 272
Likes: 0
Received 0 Likes
on
0 Posts
Re: Speed of 24 w/ HP500?
Jo- What about the New Black 24' SE that is coming to Michigan. What kind of speeds are you expecting it to reach with 550 - 575 HP. I was just wondering the difference in the Salt water and Fresh water. Any difference in the process in Proping the boat. I am a cigarette guy but i really like the product you guys put out. (especially your 36')
#35
Registered
Join Date: Dec 2004
Location: Rancho Cucamonga, Ca
Posts: 27
Likes: 0
Received 0 Likes
on
0 Posts
Re: Speed of 24 w/ HP500?
Ironman right now I am running 92 octane, with a 23p balistic 3 blade and the thing won't get over 5000rpm at 62 mph, I have a holley 830cfm hp on it, I'm taking the carb. to my carb guy today to go through it and see what is in it. We got the carb off of a 9 second dragster and haven't really done anything to it, other than jets, which right now it has 96's in the prim. and 98's in the secondary. Huge I know but it isn't really running rich. We are thinking carb is the problem, the ignition is the MSD pro billet distributor and the msd 6m-2 ignition box. The cam specs are as follows 306 dur. [email protected], 561 lift and.o20 clearance on a 110 lobe center
#36
Registered
Re: Speed of 24 w/ HP500?
With a real 550 HP and strong torque that 24' SE should run in the 85 MPH range on GPS.Between Salt and Fresh water there is an average of a 1-2 MPH difference.There is speed on props. A labbed prop will allow you to turn a larger pitch at the same RPM which will = more speed. In average a labbed prop is worth an extra 2 mph.The 24' with that kind of power and performance is very important to have the correct prop and the proper Hydraulic steeing .The driver is also very important.
With a 500 HP carburated big block rated by Mercruiser at 470 HP the 24' SE on GPS has run right at 82 MPH in fresh water with a stock prop to give you an idea. The torque is more important than HP.
I like the 3 blade Mirage plus prop on the 24' model more than the 4 blade in most conditions.Out in the Ocean a 4 blade Bravo 1 will work well.
Thanks for the compliments,
JO
With a 500 HP carburated big block rated by Mercruiser at 470 HP the 24' SE on GPS has run right at 82 MPH in fresh water with a stock prop to give you an idea. The torque is more important than HP.
I like the 3 blade Mirage plus prop on the 24' model more than the 4 blade in most conditions.Out in the Ocean a 4 blade Bravo 1 will work well.
Thanks for the compliments,
JO
#37
JC Performance Engines
Gold Member
Thread Starter
Re: Speed of 24 w/ HP500?
Originally Posted by JO - PANTERABOATS
I like the 3 blade Mirage plus prop on the 24' model more than the 4 blade in most conditions.Out in the Ocean a 4 blade Bravo 1 will work well.
Thanks for the compliments,
JO
Thanks for the compliments,
JO
Jo, why is that?
#38
Charter Member
Charter Member
Re: Speed of 24 w/ HP500?
riverrat i had an 800 holley on a 454 in the past and had a 6.5 power valve in the primary 79 jet and a 85 jet in the secondary with a PV. A mirage 23 will greatly reduce slippage and act like 1" pitch larger than the ballastic after you find more power through tuning. Try going down 2 jet sizes at a time and test for improvement, it is time consuming but you will be pleased with the results.
#39
Registered
Join Date: Dec 2004
Location: Rancho Cucamonga, Ca
Posts: 27
Likes: 0
Received 0 Likes
on
0 Posts
Re: Speed of 24 w/ HP500?
Iron Man,
I pulled the carb and took it to Dave Lange @ fuelcurvewest. I think most of my problems are now solved. the Air bleeds on the carb were too small, the Power valves were 2.5's not 6.5s the jets were way to fat, and the cam pumps were too small, the secondary float spring was so stiff it was just holding the float closed in the secondaries. So now we have 6.5 PV's .070 Airbleeds, 87 jets in prim. and 89's in second. So I'll be out to test the boat with the carb the 1st week of march and we'll see if I pick up any RPMS and power. As far as the prop goes, I ran the ballistic last weekend, when I put the carb on I'm gonna run a 23 mirage, and also a 25 mirage and see how it responds. Also I figured out I have a heating issue in the motor, and the intake isn't heating up, so I'm gonna run some waterflow restrictors to see if I can get the temp up, I haven't been able to get the engine temp up over 110 degrees, so we'll see how it responds at 165-175.
I pulled the carb and took it to Dave Lange @ fuelcurvewest. I think most of my problems are now solved. the Air bleeds on the carb were too small, the Power valves were 2.5's not 6.5s the jets were way to fat, and the cam pumps were too small, the secondary float spring was so stiff it was just holding the float closed in the secondaries. So now we have 6.5 PV's .070 Airbleeds, 87 jets in prim. and 89's in second. So I'll be out to test the boat with the carb the 1st week of march and we'll see if I pick up any RPMS and power. As far as the prop goes, I ran the ballistic last weekend, when I put the carb on I'm gonna run a 23 mirage, and also a 25 mirage and see how it responds. Also I figured out I have a heating issue in the motor, and the intake isn't heating up, so I'm gonna run some waterflow restrictors to see if I can get the temp up, I haven't been able to get the engine temp up over 110 degrees, so we'll see how it responds at 165-175.