Brazos River Rat ( Billy's ) Update

[ChryslerJet]

Billy everyone is in the right track the more HP gets you to your max speed faster not necessarily higher.  Max torque will get you more RPMs or speed.  Torque is force and Horspower is a calculation of torque and RPM giving us a power rating.  Gearing multiplies torque.  In cars aerodyamics plays a huge role over 80mph and I can imagine water dynamics plays a huge part in boats.  Once past that RPM more torque is needed to overcome the greater resistance to speed in increasing amounts.  Think about it this way my Ninja 500 maxes out at 120 mph it wont go much faster than that due to wind resistance on the bike in fact without the fairings it tops out at 112.  I can ride with a passenger at 112 with the fairings as well with some room to go so it has enough power and torque to get there no matter the weight but the resistance is too great to overcome.  My Ninja 900 with over twice the hp of the ninja 500 maxes out at 150mph.  Yes it is a bit heavier but not much heavier than riding with a passenger on the 500.  So just realize that once you get to a certain speed you may not get much more out of it.
Now with that saying yes I think there is more in your setup but by my thoughts which isn't worth much the gearing is the next step.  Your idea of airflow might be something to look at and may help a little along with the fuel flow if it is restricting.

 

[galen]

Put camera on fuel pressure so we dont lean this thing out on the big end. Pull the flame arrestor first.  This may be why it is going rich if it indeed is.  Next set timing to 33 that is where it wants to be. Dyno headers were also 2 3/8 to 2 1/2 step into a 5 inch collector= less torque more rpm..

 

[73 Sanger Flat]

That is the plan with the camera .. I think I can get get it mounted to see the gauge  , if not I will add another fuel pressure gauge so the camera can see it . .. I have a set of zoomies I can try also after taking the flame arrestor off and adjusting timing to 33* ..

 

[galen]

Billy I dont think it will scavenge right with the zoomies.  I think your on the right track with fuel pressure, flame arrestor and timing.  My headers are 2 1/4 x28 x 4. Same as yours I believe. I think if mine dont like the 32s going to a 25 or 22 and just let her rip off the line.

 

[73 Sanger Flat]

You are probable right about the zoomies . Not sure what size my headers are ,I need to measure them again .. Your boat was a beast with the 25's in it last time .. If it pulls those 32's , It going to be scary fast on top end ..
I am hopping it the flame arrestor restricting the air flow .. Fuel pressure will be checked on the next outing .. Don't think it is fuel , it has never laid over on a run yet but we will see .. What should the fuel  pressure be on a wide open run for fuel pressure .. It is set at 7.5 at idle and I think last time I checked on a WOT pass it dropped down to like a 5 or something like that .. Not sure if it should stay at the 7.5 for the whole pass or not .. I am sure in the perfect world it would stay right at 7.5 , but as long as it still has 5 or ?? at wot , I think that would be OK ???  Has anyone recorded their fuel pressure from Idle to WOT ??  Remember this is a Mechanical pump , not electric ..

 

[73 Sanger Flat]

I been searching and what i have found is it is OK to be down to 3 lbs at WOT .. Any one else know for sure .. This is a big  pump I run and pretty sure it has enough volume and pressure .. Just double checking ..

 

[73 Sanger Flat]

Flame arrestor is gutted and back in the scoop.. Timing is set to 33-34* .. It is bouncing a little so makes it hard to get it exactly on 33 .. My eyes do not like the timing light .This engine does not idle very smooth , so the timing moves a little as the engine lopes . Going to check it one more time before I go out .. pretty sure I can mount the camera on the deck and aim it back to see the fuel gauge .. Hopefully the camera will be able to see it good enough.. Fuel pressure is set at 7.5 at idle..

So I think the boat is ready for test number two .. Not sure I am ..

 

[jimsplace]

This is what I am running 10 x 3 inch with only two rounds of the screen on it only .. It should flow pretty good with just two rounds of screen on it , but  am going to take them off and try it . I have to use the frame of the arrestor to hold the scoop on , but I can remove all the screen and do that

Billy
I would certainly think the flame arrestor would be a problem.
Without knowing what its flow rate is, I can't be sure.
I run a K&N, oval air filter that probably flows at least 5-8X what that flows and according to K&N, I'm borderline, and you've got a larger motor.
    :smile17:

 

[jimsplace]

I been searching and what i have found is it is OK to be down to 3 lbs at WOT .. Any one else know for sure .. This is a big  pump I run and pretty sure it has enough volume and pressure .. Just double checking ..

At 3 lb. fuel pressure, my engine loses power.  I would think it needs to be at least 5 or more.
Is there a reason for running 7.5 lb. of pressure.
If you are running with a regulator, around 6.5 to 6 3/4 is usually recommended.
If you are using a regulator, the more pressure you run, the less fuel that will be supplied.
    :smile17:
    :smile17:

 

[73 Sanger Flat]

Jim- I run my regulator after the Carb and then return  the excess to the fuel tank .. So I would think the more pressure I hold - 7.5 compared to 6.5 , it would have more fuel to the Carb because I am holding the pressure after the carb and not before it .  .The only problem I see is that it will try and push fuel past the needle and seat at idle with higher pressure . If the regulator was before the Carb then I would think it would decrease the fuel to the Carb like you stated  .. I may be wrong again ..
The fuel pressure  was at about 6.5 and I adjusted up to 7.5 to make sure it has enough on the top end for this next outing  . It is going to loose some pressure with the mechanical pump on higher RPM .. I hope that it will maintain 5 lbs at top end , I was just researching what was on the web and most said not to drop below 3lbs at WOT ..
The Flame arrestor  had 2 to 3 wraps of the mess screen on it .. I can't see it being very restrictive but we will see . It has no screen now , just a big wide open hole to the carb now , using the frame of the arrestor to hold the scoop down .. I loc-tighted all the screws on it also
Looks like Trey and I may go test Saturday or Sunday at Chisholm Trail or Steel Creek .. Trey will pick where  .. It will depend on how much rain he gets at his place today either we go Saturday or Sunday ..

 

[73 Sanger Flat]

Flame arrestor is gutted and back in the scoop.. Timing is set to 33-34* .. It is bouncing a little so makes it hard to get it exactly on 33 .. My eyes do not like the timing light .This engine does not idle very smooth , so the timing moves a little as the engine lopes . Going to check it one more time before I go out .. pretty sure I can mount the camera on the deck and aim it back to see the fuel gauge .. Hopefully the camera will be able to see it good enough.. Fuel pressure is set at 7.5 at idle..

So I think the boat is ready for test number two .. Not sure I am ..

I am going back to set the timing one more time and I will adjust the idle up top where the engine is smooth and no bouncing of the timing mark and set it at 33*  .. This thing wanted 32* or 34* when I was trying to adjust it .. I could not get it exactly on 33* .. I will get it before I go test .. Maybe next year a magnetic pick up is in order , pretty sure My distributor was set up for one when i bought the boat so I don't think I would have to buy another distributor ..

 

[Carnivalride]

FWIW Billy my scoop is open, no flame arrester, no filters. You need enough fuel pessure and volume to maintain a consistent fuel level in your float bowls. Not only do you have jets but emulsion holes, idle feed restrictors and power valve circuits.

IMO if the motor is running right water drag is your biggest enemy in a boat. With my old engine my boat would run within 1 mph with 12s and 18s but the acceleration difference was huge. I do agree looking at the last picture you sent that with 950hp no more than the boat was dragging you should be above 110. I'm betting on the spark arrester being the culprit.

Good luck testing and be safe.

 

[73 Sanger Flat]

FWIW Billy my scoop is open, no flame arrester, no filters. You need enough fuel pessure and volume to maintain a consistent fuel level in your float bowls. Not only do you have jets but emulsion holes, idle feed restrictors and power valve circuits.

IMO if the motor is running right water drag is your biggest enemy in a boat. With my old engine my boat would run within 1 mph with 12s and 18s but the acceleration difference was huge. I do agree looking at the last picture you sent that with 950hp no more than the boat was dragging you should be above 110. I'm betting on the spark arrester being the culprit.

Good luck testing and be safe.

Thanks Loren -- that is what I keep thinking .. let say it making 900 Hp , 50 Hp less than on the Dyno . It still should run faster .. The last picture I believe the water is hitting right about where the SDBA sticker is and that should be about 16" from the back .. I feel something is restricting this engine form pulling through the RPM and making the boat faster .. What is you say on the fuel pressure setting --6.5 is normal , but what about on a WOT pass , does yours drop and if so to what ?? I understand it not about the pressure , it more about having the volume .. Have to keep the bowls full at all times .
I am hoping for some good numbers on the next test .. 114-115 would be nice and ultimate mph is 118-120 for me . That will be fast enough for this big boy .. Hell 110 is fast enough now .. I just know the boat is capable of more with this set up . That is the only reason i am doing this .. Does not mean i will drive it that fast every time she goes out ..

 

[Carnivalride]

FWIW Billy my scoop is open, no flame arrester, no filters. You need enough fuel pessure and volume to maintain a consistent fuel level in your float bowls. Not only do you have jets but emulsion holes, idle feed restrictors and power valve circuits.

IMO if the motor is running right water drag is your biggest enemy in a boat. With my old engine my boat would run within 1 mph with 12s and 18s but the acceleration difference was huge. I do agree looking at the last picture you sent that with 950hp no more than the boat was dragging you should be above 110. I'm betting on the spark arrester being the culprit.

Good luck testing and be safe.

Thanks Loren -- that is what I keep thinking .. let say it making 900 Hp , 50 Hp less than on the Dyno . It still should run faster .. The last picture I believe the water is hitting right about where the SDBA sticker is and that should be about 16" from the back .. I feel something is restricting this engine form pulling through the RPM and making the boat faster .. What is you say on the fuel pressure setting --6.5 is normal , but what about on a WOT pass , does yours drop and if so to what ??
I am hoping for some good numbers on the next test .. 114-115 would be nice and ultimate mph is 118-120 for me . That will be fats enough for this big boy .. Hell 110 is fast enough now .. I just know the boat is capable of more with this set up . That is the only reason i am doing this .. Does not mean i will drive it that fats every time she goes out ..

My fuel pressure is from the regulater which is a dead head style. 7.5psi and if it drops it's less than 1/4psi. Remember dyno numbers are corrected and you have to allow for air density so depending on your AD there this time of year 900hp is probably a fair guess IF timing and jetting are optimized.

 

[73 Sanger Flat]

OK -- I will see what mine does on the fuel pressure .. I know it dropped the last time I had a temp gauge in front of me .. If I remember correctly it dropped to 4.5-5 psi on the WOT pass .. That is pressure after the carb and past the regulator on the return line to the tank , so they had at least 4.5-5 lb in the carb . I would think that would be enough to keep them full .. If not i guess i will be forced to go to an electric or a belt driven fuel pump .. The boat has never leaned over on top end like it is running out of fuel .. It might now with the flame arrestor off and if it pulls some more RPM's .. I hope she just runs out perfect this weekend and then I can start doing some electrical updates on the gauges and dash .. It needs to be rewired under the dash .. and new gauges ..

 

[jimsplace]

Jim- I run my regulator after the Carb and then return  the excess to the fuel tank .. So I would think the more pressure I hold - 7.5 compared to 6.5 , it would have more fuel to the Carb because I am holding the pressure after the carb and not before it .  .The only problem I see is that it will try and push fuel past the needle and seat at idle with higher pressure . If the regulator was before the Carb then I would think it would decrease the fuel to the Carb like you stated  .. I may be wrong again ..
The fuel pressure  was at about 6.5 and I adjusted up to 7.5 to make sure it has enough on the top end for this next outing  . It is going to loose some pressure with the mechanical pump on higher RPM .. I hope that it will maintain 5 lbs at top end , I was just researching what was on the web and most said not to drop below 3lbs at WOT ..
The Flame arrestor  had 2 to 3 wraps of the mess screen on it .. I can't see it being very restrictive but we will see . It has no screen now , just a big wide open hole to the carb now , using the frame of the arrestor to hold the scoop down .. I loc-tighted all the screws on it also
Looks like Trey and I may go test Saturday or Sunday at Chisholm Trail or Steel Creek .. Trey will pick where  .. It will depend on how much rain he gets at his place today either we go Saturday or Sunday ..

You could be correct, I was thinking as though the regulator was before the carb.

 

[jimsplace]

Billy

One thing that I believe you said was, "It's still pulling".
The runs that I remember you making were not even close to 1/4 runs and appeared much shorter, by a lot.
Others may remember longer, but I don't.

If it's still pulling, you haven't reached the boats potential.
If your boat doesn't seem to hesitate coming out of the hole, you can pull the 32 gears, but if you want it to accelerate quicker, I believe lower gears will do that.

If you are willing to turn the motor 7300-7400 the 25's will be very close.
27's should get you around 7200.
I know you have a fairly long stroke and don't need the high rpm of a smaller motor, but V-drive's do like rpm.  So, it depends on the quality of your parts.
I think you've actually got some very good parts.
    :smile17:

 

[ChryslerJet]

Billy I think it is good your going back to reset the timing.  You always want to set the timing at 2000-2500 RPMs.  Back in the day we did this to get total advance with the weighted springs in the distributor.  I don't think your has these but that could be part of why the jumping around and why you need to do it at a higher rpm.  It could also be the lope of the idle. 
7.5 fuel pressure is fine as that is the max you want to run anything more and you will flood the carbs as the floats/needles/seats won't hald back the pressure when the bowls are full.  Holley especially performance carbs will hold 7.5 just fine.  My old Carter and the new Edelbrock carbs won't hold much over 6.5.  Everyone is right on the fuel that volume is more important than pressure as long as you are flowing enough fuel to keep up with what is draining out of the carb into the engine.  I also don't think that is your problem right now. 
I wish you luck on the next outing and hope it runs well.  You are at a performance level that every little thing can make a huge difference.

 

[Disturbed]

Billy I think it is good your going back to reset the timing.  You always want to set the timing at 2000-2500 RPMs.  Back in the day we did this to get total advance with the weighted springs in the distributor.  I don't think your has these but that could be part of why the jumping around and why you need to do it at a higher rpm.  It could also be the lope of the idle. 
7.5 fuel pressure is fine as that is the max you want to run anything more and you will flood the carbs as the floats/needles/seats won't hald back the pressure when the bowls are full.  Holley especially performance carbs will hold 7.5 just fine.  My old Carter and the new Edelbrock carbs won't hold much over 6.5.  Everyone is right on the fuel that volume is more important than pressure as long as you are flowing enough fuel to keep up with what is draining out of the carb into the engine.  I also don't think that is your problem right now. 
I wish you luck on the next outing and hope it runs well.  You are at a performance level that every little thing can make a huge difference.

 

[73 Sanger Flat]

Jim- I think the 32's are a little too high to get it to run out the top end like it should in a 1/4 or less .. I need to air it out and just see what she will do . But dam that water is going by fast even at 110 mph .. I just need me a long stretch of water so I can just stand on it for 12-15 seconds and just see what it will do .. Most likely I will step down to 27 and keep the RPM around 7200 max . That is what I wanted it to top out at on RPM .. Yes the engine can handle a lot more , but why stress it if I do not need to .. I am not a pro racer , just a weekend speed junkie..  What I am trying to do it to get the max out of this set up to see what it will do before I change gears. then i will change gears later if I am not happy .. This sucker is pulling pretty hard on all the passes just like it is , just the MPH is off some ..  --------+++++



Chris- I understand a distributor with the mechanical advance and vacuum advance and how to set one to full total advance .. Mine is locked out so i don't need to do that .. Mine is idling pretty rough with this cam and the slack in the chain is what I am seeing I am sure .. Once I get it up to where the engine is nice and smooth , the marks does not move any more .. But it will vary about 1* at 1100-1200 rpm and when 1* is worth about 12-15 HP , that 1* degree is important.. One to much it looses and 1 less it looses .. It was the happiest at 33* on the Dyno 
Thanks for the luck from both of you ..

Jim are you going out this weekend  ??