383 dyno success!

[JHuck]

Re: 383 dyno success!

The prop was on the boat when I bought it so I'll have to pull a number off it tonight. Thanks for the heads up on the Mirages. With little chance of testing a prop locally, I want to take my best shot on the first prop I buy.

 

[Mkos1980]

Re: 383 dyno success!

I just ordered a new 13.5 x 22P Enertia I'm hoping will work out well. I see alot of tests where the 22P keeps up with the higher RPM's as lower pitched props + giving a little more MPH. I hear good things with the X7 alloy and I also hear that these blades are super thin. Almost like a labbed prop.

 

[JHuck]

Re: 383 dyno success!

I just ordered a new 13.5 x 22P Enertia I'm hoping will work out well. I see alot of tests where the 22P keeps up with the higher RPM's as lower pitched props + giving a little more MPH. I hear good things with the X7 alloy and I also hear that these blades are super thin. Almost like a labbed prop.

How did you decide on the 22p for the Enertia vs other pitches?

 

[JHuck]

Re: 383 dyno success!

How did you decide on the 22p for the Enertia vs other pitches?

Never mind, just saw that it only goes up to a 22p. How long until you have it on your boat? Would love to see some feedback on performance.

 

[Mkos1980]

Re: 383 dyno success!

Ordered it yesterday afternoon from www.JacoMarine.com Cheapest place for mercury props. Should have results this weekend.

 

[JHuck]

Re: 383 dyno success!

I'll be very interested in the comparison vs your current set up.

I checked last night and I have a 14.25 X 21 Turbo prop.

 

[straubtech]

Re: 383 dyno success!

Jeremy,
I would contact Julie at www.throttle-up.com and see what they think you need for all around performance. Julie and Matt know there stuff.

 

[Mkos1980]

Re: 383 dyno success!

+1 for throttle up! Julie is the one who gave me the good advise about the Laser and Enertia props.

 

[JHuck]

Re: 383 dyno success!

This weekend I had the chance to play some more with my Smart Tabs and trim angle to see what kind of WOT speeds I could hit. With the tabs on the lightest setting and the family and toys in the boat it went 64 mph (gps) at 5600 rpm. A couple times during the 1 minute run power would fade for a second and then come back. It wasn't an abrupt fall off like an electrical issue or rev limiter (set at 6000 rpm) but just a slight decrease and then it would come back up.

Anyone know if the stock SB mechanical fuel pump could be the cause of this. We used the dyno fuel pump during testing and this never occurred. The ignition system is the same as it was on the dyno. If it is the issue, I wonder if I could pick up a higher flow marine pump to fix the problem.

 

[Mkos1980]

Re: 383 dyno success!

I'm running the stock pump, and so is a few others on another board, but in doing this they found a huge gain in removing the checkball in the fitting on the tank. The check ball is there for a safty feature but I'm just telling you what others are doing. They are also rerouting the fuel lines. They are going from tank to the pump, to the F/W Sep then to the motor VS tank to F/W Sep to pump then to motor. I'm going to be making these changes as well in a few weeks.

 

[JHuck]

Re: 383 dyno success!

I'm running the stock pump, and so is a few others on another board, but in doing this they found a huge gain in removing the checkball in the fitting on the tank. The check ball is there for a safty feature but I'm just telling you what others are doing. They are also rerouting the fuel lines. They are going from tank to the pump, to the F/W Sep then to the motor VS tank to F/W Sep to pump then to motor. I'm going to be making these changes as well in a few weeks.

Good to know. I think I have hard lines from the filter to the pump but I will have to check. Dang, I wish I had known about the checkball before I installed the new carpet and interior. My access cover for the tank is off slightly so I'm not sure how easy it would be to make the modification. I will take a look at that also.

Mkos-Have you had a chance to try the new prop?

 

[Mkos1980]

Re: 383 dyno success!

Good to know. I think I have hard lines from the filter to the pump but I will have to check.
Mkos-Have you had a chance to try the new prop?

You do have hardlines. You can use A1 Rubber which most use or you can bed some custom ones.

I did try out the new prop! Its on eBay right now!

LOL The prop was bad out of the hole and I had to give it alot of gas to maintain a plane. It kept the same RPM's as the 21 Laser but it was 4-5 MPH slower too.

 

[n2ostroker]

Re: 383 dyno success!

Just fyi I drilled out the check ball today. I'm glad I found out about it too. There is no way enough fuel gets throught there. Not even enough for a stock 5.7. No way.... I'll most likely switch the lines for 1/2" to the pump and 3/8" after pump soon. I think this may have been a problem before with larger props. Holeshot has never been a problem but top end has. I think it has been leaning out up top on mine.

If I was in the 450hp range like you guys I'd be scared of burning the motor up with the check ball still in there. It's got to be getting really lean at those power ranges and loads.

Mkos- That sucks about new prop. Never know if it'll work till you try it I guess. We put my solid hub labbed 23p Mirage plus on my buddies Checkmate Convincor 242 this weekend and only picked up about 100rpm over his stock rough looking 23p Mirage plus. I'm thinking he has a fuel problem somewhere though. We've lost a couple of hundred rpm over last yr so it might work out better once everything is tip top.

 

[JHuck]

Re: 383 dyno success!

Reading about these check valves makes me wonder how much I was leaning out my engine at WOT. Man, if I smoke a motor because of a $15 valve I will not be happy.

I'll just have to stay off the gas until I can replace that thing. I did a quick search but did not see any "high flow anti siphon valves". If I have to, I'll just drill the valve out like n2o.

Mkos, sorry to read about the prop. I was hoping you would report it was better than sliced bread and then I could buy your Laser. From what I've read, the Laser seems like my best bet. I'm going to e-mail Julie today.

 

[Mkos1980]

Re: 383 dyno success!

Good Call on the Laser. I'm sending mine out to her over the winter to get balanced and worked over a tad.

Hump, from speedwake has the same combo as me and he did away with the checkball and picked up some RPM's he noted so that kinda makes me excited to see what I can do.

 

[n2ostroker]

Re: 383 dyno success!

Here is a few picks of the check ball. There can't be much flow past it. all is does is keep fuel from running back into the tank. There is a spring on the back side to keep the ball closed when the pump isn't pulling fuel. It sits inside the fitting and is held there with another aluminum piece pressed in. Drill out the pressed in part and the ball falls out. Then pull the spring out with a pick or something.

 

[JHuck]

Re: 383 dyno success!

Ah, Murphy was sitting in my boat this morning when I went to remove the barbed fitting that contained the check ball. Seems as if the fitting was a bit tight because I snapped it off with half of it remaining in the 90 degree elbow. WOO HOO. I love it when stuff like this happens. I said a prayer hoping that I wouldn't trash the plastic tank trying to get the pick up tube out so I could come up with a new elbow. Long story short, I just got it put back together.

Initially I was upset because I did not see the ball or spring. After putting the tube back in, I noticed the spring on top of the tank. The ball must have shot out when I snapped the barb.

Now it's time to install a battery disconnect switch under the back seat. After launching the boat with a dead battery last weekend, I figured the switch will be a good investment!

I was really hoping to snag a 24P Laser II before we head to Dale Hollow next Wednesday but the boat allowance is tight for now.

 

[mylesm260]

Re: 383 dyno success!

Whenever I do a high performance build for a road vehicle, I install a wide-band O2 sensor and a meter, so I can see EXACTLY what my AFR is.

Because that isn't an option in a boat (unless you run 2010 style exhaust manifolds and o2 sensors) I often wondered if there was some alternative. I wonder if anyone makes a sensor that you could install into you're float bowl that will tell you if your fuel drops bellow a certain level.

In you're situation, it sure would be nice to have some way to verify that the float bowl is full. A buzzer and alight on the dash would work perfectly.


Another idea:

They make adjustable fuel pressure switches: If you put a T on the fuel line going to you're carb, and plumbed in a switch, you could set it to switch on at 2 PSI or so. Then if you ran the wires from the switch to a relay, and ran the relay to a light and buzzer on the dash, you could have yourself a warning system that kicks in when you're fuel pressure drops bellow 2 PSI at the carb when the ignition is on.

Here's an example of the type of switch I was thinking of. You're local performance shop should carry these.

http://www.pegasusautoracing.com/productdetails.asp?RecID=2980


That way, if you're at WOT, and your fuel pump, filter, anti-siphon valve or pickup tube starts acting up, and you drop fuel pressure, you will know right away, before you're bowl runs low and you start running lean.


With you're higher compression ratio, running really lean could lead to detonation and melting.

 

[JHuck]

Re: 383 dyno success!

Great idea. I already have the 1/8" tap in my carb fuel line so installation would be a snap.

Now that I have the ball and spring out I'm interested to see if there is a difference at WOT.

 

[mylesm260]

Re: 383 dyno success!

Yeah, and upon further inspection of the link I posted, it looks like that is exactly what the switch is for.

It appears to be OPEN above X pressure and closed bellow it. So wiring in the light/buzzer would not even need the relay.