Brazos River Rat ( Billy's ) Update

[73 Sanger Flat]

they are corrected numbers I believe .. He compared them to the raw HP numbers to make sure they was calculating correctly

We threw that run out and did not print it because it was not the exact same air temp and water temp

 

[jimsplace]

Billy I was using 6800 RPM I think it will pull more but WHY, 114/ 120 on the river with no rescue, on a race course with safety ok 7200 and 125. just my .02 Looks like a grate motor. jj

In my opinion, use the dyno sheet to determine what rpm the engine is going to operate the best.  The gearing and prop are used to allow the engine to operate in the range for which it's designed.
The boat is going to run big mph regardless with a high horsepower motor.

If it's geared high to keep the rpm down, it's only going to run higher mph.
If it's geared lower to keep the mph down, it will either over-rev the motor or be hitting on the chip most of the time.  Neither is a good option.

Or, let the motor run in its best rpm range and don't run the boat for a full 1/4 mile unless its at an organized race or there is a safety crew.
Most river or lake runs are 600-800 feet.  That'll still be well over 100mph, and quick without killing the motor.
Safety equipment is always mandatory when doing this.
      :smile17:

 

[73 Sanger Flat]

I know coming from me this may sound bad but I'd say quit brow beating it and wait until spring and run it. Just be safe and keep in mind that it'll be quicker and faster than it was last time out.

My only thought is up here lake races are usually no more than 800' due to water conditions so I typically run geared for the 1000' stuff however I don't have 950hp.

Just relax its going to run great!!  :smile17:

We need something to talk about .. It is winter and we have a few months before testing .. I know it will run good and be faster than before ,, Just like to get other people opinion on what we should try ..

 

[jimsplace]

When comparing the numbers on the new engine to the old one, keep in mind the old engine was using a cam that was designed for a much lower rpm curve if I remember correctly.
This new engine has a cam that produces a higher horsepower number in the upper rpm range where it is more beneficial and needed.
      :smile17:

  Cam is 10 degrees less at .050 Jim but the heads flow 40 cfm plus more at .700 lift.  7-4 swap and a faster ramp. Light ring pack and a whole lot stiffer valve train.

Galen
Maybe I'm remembering incorrectly (old age thing), but wasn't the horsepower curve at a much lower (rpm) point on the old motor than with the new motor numbers?

 

[jimsplace]

I know coming from me this may sound bad but I'd say quit brow beating it and wait until spring and run it. Just be safe and keep in mind that it'll be quicker and faster than it was last time out.

My only thought is up here lake races are usually no more than 800' due to water conditions so I typically run geared for the 1000' stuff however I don't have 950hp.

Just relax its going to run great!!  :smile17:

We need something to talk about .. It is winter and we have a few months before testing .. I know it will run good and be faster than before ,, Just like to get other people opinion on what we should try ..

Absolutely correct.
Its cold outside and it's all about, what if right now.  We have a number of months to think and sort out the possibilities.
Actually Billy and Galen have a number of months to do the sorting.
It will be a fun ride, regardless.
    :smile17:

 

[73 Sanger Flat]

Jim. Look ay my reply #129. It has both dyno sheets attached. Old and new engine

 

[galen]

Jim the old engine fell off bad after 6800. This engine wants to keep pulling to 7300 or more. It has a very wide power band. At 7300 it has 140 hp more and 40 more ft lbs of torque than the old one. If I remember right the old engine pulled a max power and torque number at 6700. This engine drops to almost the max horsepower and torque number of the old engine at 7500. You could gear it to pull to 7300 easy but with steel rods and 4.5 stroke I would rather not. Once in a while is fine. It starts pulling at 5900 and pulls to 7600 really quick on the dyno. It saw 8000 one time and that scared me a little.  Try it with the setup you now have Billy get some numbers and then go from there. Sad part is this engine makes 100hp less than mine on pump gas for less than half the cost.

 

[jimsplace]

Jim the old engine fell off bad after 6800. This engine wants to keep pulling to 7300 or more. It has a very wide power band. At 7300 it has 140 hp more and 40 more ft lbs of torque than the old one. If I remember right the old engine pulled a max power and torque number at 6700. This engine drops to almost the max horsepower and torque number of the old engine at 7500. You could gear it to pull to 7300 easy but with steel rods and 4.5 stroke I would rather not. Once in a while is fine. It starts pulling at 5900 and pulls to 7600 really quick on the dyno. It saw 8000 one time and that scared me a little.  Try it with the setup you now have Billy get some numbers and then go from there. Sad part is this engine makes 100hp less than mine on pump gas for less than half the cost.

I understand. 
If it was me, and it is what I have done, is to pick a max rpm that I'm comfortable with how the motor is built and gear it for that number, what ever it is.  It could be 6800, 7000 or 7200 and gear it for that and put a chip in slightly above for safety of the motor.
I picked 7500 for my number and have kept it within 200 + or -, but I have a 4.25 stroke.  A 4.5 stroke should certainly be less by a sizable amount. IMO
If the motor is set up for pulling to 7000 at the flash, my guess is that it will pull back to 5500 to 5700 when it hooks up.  That's well within the good power band.
If it pulls to a little less, it isn't going to make any difference with the way we run our boats and it's easier on the motor.

I don't think the steel rods will make any difference in how the motor lasts.  I have long rods in mine and haven't had any negative problems. (knock on wood)
  :smile17:

 

[Carnivalride]

Billy since you have me covered by over 200hp I think you should run something in the 1.60 gear range and then we could race for 800' or so.

Jim I'll make you the same deal since I know you love the short tracks. lol  :smile26:

 

[galen]

After setting on the couch nursing the flu. Going over what we saw each time we ran it. Looking at the dyno sheets. Making sure the fever I am running did not cloud my decision. Set the rev limiter at 7400-7500 and let it see where it wants to go.

 

[jimsplace]

Billy since you have me covered by over 200hp I think you should run something in the 1.60 gear range and then we could race for 800' or so.

Jim I'll make you the same deal since I know you love the short tracks. lol  :smile26:

We'd love to take you up on that, but we still have the water jackets in our V-Drive and 60's won't fit, sorry.
I guess we'd have run as we are.

Besides that, you have way more experience in real racing than either Billy or I have which gives you a big advantage.
At least you didn't try to make it 300 feet like the jet boy are trying to get down to.
  :smile17:

 

[jimsplace]

After setting on the couch nursing the flu. Going over what we saw each time we ran it. Looking at the dyno sheets. Making sure the fever I am running did not cloud my decision. Set the rev limiter at 7400-7500 and let it see where it wants to go.

With the 32's, I think that would be a good place to start.
Until it's in the water, who knows.

You're running a stroke similar to that aren't you?  You think that Hemi is more durable than the Chevy?
  :smile23:

 

[Carnivalride]

Billy since you have me covered by over 200hp I think you should run something in the 1.60 gear range and then we could race for 800' or so.

Jim I'll make you the same deal since I know you love the short tracks. lol  :smile26:

We'd love to take you up on that, but we still have the water jackets in our V-Drive and 60's won't fit, sorry.
I guess we'd have run as we are.

Besides that, you have way more experience in real racing than either Billy or I have which gives you a big advantage.
At least you didn't try to make it 300 feet like the jet boy are trying to get down to.
  :smile17:

C'mon Jim "real racing" experience?  crazy.gif

I went to one sanctioned race so I have more experience? lol

300'?!?!?!?!?! is that a burnout?  crazy.gif

 

[jimsplace]

Galen
Are you putting a governor on that monster motor? Do you remember when Billy last took you for a ride in your boat?
 

 

[jimsplace]

Billy since you have me covered by over 200hp I think you should run something in the 1.60 gear range and then we could race for 800' or so.

Jim I'll make you the same deal since I know you love the short tracks. lol  :smile26:

We'd love to take you up on that, but we still have the water jackets in our V-Drive and 60's won't fit, sorry.
I guess we'd have run as we are.

Besides that, you have way more experience in real racing than either Billy or I have which gives you a big advantage.
At least you didn't try to make it 300 feet like the jet boy are trying to get down to.
  :smile17:

C'mon Jim "real racing" experience?  crazy.gif

I went to one sanctioned race so I have more experience? lol

300'?!?!?!?!?! is that a burnout?  crazy.gif

Bill and I only have real lake boats and no real race experience.
So, YES AND YES

One race or ten is still way more than I have. I'm just a wannabe inexperienced amateur.

 

[Carnivalride]

Billy since you have me covered by over 200hp I think you should run something in the 1.60 gear range and then we could race for 800' or so.

Jim I'll make you the same deal since I know you love the short tracks. lol  :smile26:

We'd love to take you up on that, but we still have the water jackets in our V-Drive and 60's won't fit, sorry.
I guess we'd have run as we are.

Besides that, you have way more experience in real racing than either Billy or I have which gives you a big advantage.
At least you didn't try to make it 300 feet like the jet boy are trying to get down to.
  :smile17:

C'mon Jim "real racing" experience?  crazy.gif

I went to one sanctioned race so I have more experience? lol

300'?!?!?!?!?! is that a burnout?  crazy.gif

Bill and I only have real lake boats and no real race experience.
So, YES AND YES

One race or ten is still way more than I have. I'm just a wannabe inexperienced amateur.

I'm just as much or more of a lake boat than you. Dual saddle tanks, a bench seat, ski tow and real pump gas.

 

[galen]

Galen
Are you putting a governor on that monster motor? Do you remember when Billy last took you for a ride in your boat?
 

    No governor Jim. With the valve springs in Billy's I would like to see it actually stay below 7500, it has good parts in it. I am running 4 5/8 stroke in mine but a 7 inch rod.  9/16 .185 pushrods and 1025 open spring pressure. I am going to limit mine to 7500 also. I am just nervous, I dont want him to have any issues.

 

[73 Sanger Flat]

I don't know why we are even talking RPM's on here , Everyone knows that my boat is just a trailer Queen and it never gets in the water and if it does , it never get ran hard ..  crazy.gif
I need to see what chips I have  that I can stick in the MSD .. I will find something around 7200-7400

 

[Patchman]

I don't know why we are even talking RPM's on here , Everyone knows that my boat is just a trailer Queen and it never gets in the water and if it does , it never get ran hard ..  crazy.gif
I need to see what chips I have  that I can stick in the MSD .. I will find something around 7200-7400

When I saw it on the water, it was running in circle eights. I didn't know it could go straight! crazy.gif

 

[Knotty Girl]

y'all sure are making me want summer.  think.gif