HPBCANADA.COM

Lesson #8 Tight nuts and rigging

One thing I learned from racing. If it can get loose it will.
First always check the bolts holding the motor onto the transom.
Check the motor mounts especially if you run an OMC 15 inch. The mids are weak near the lower mounts.
On an OMC double check the 5/8's bolt in the mid directly above the prop.
On an OMC check for movement in the bracket both in the front bolt thru the side brackets and in the side pin bolts.
A yamaharude trim system eliminates this weakness.
Check everything before you race. TWICE and better still have another person do the second check.
Make a check list so nothing is missed.

Avoid using screws if possible.
If it is a screw, a bolt, or a nut it should be stainless. The bolt should have a locking nut or use double nuts.
Always use a plate on the inside when mounting a bracket on the boat and BOLT IT!
If you use cable and pulley steering use aircraft cable not clothesline cable.
The steering cable must have a clamp, then a knot and then a second clamp where it is attached to the boat.
Don't forget to wire the connections in the steering system.
Your gas tank and battery should be very tight and not move at all.

Hey Bub, Elgin's right there with Gale, Bucaneer, McCulloch, and the Eaton's Catalogue special brand,....Viking, either a washer, dryer, or outboard...I recall the washer had a better torque curve and higher rpm than the outboard.

Lesson #9 What is the FASTEST a T boat can run?

Its the most asked question at every race. How fast is your boat?
If you tell them the truth, they don't believe you and say their friends boat is much faster.
When your running ET times practising, people wonder what your doing and the lake racers want to race you down the lake.
A big difference between a true racer be it in a car, bike, snowmobile or a boat etc. is they race at the race site with safety gear and safety people there to protect them. They know the dangers and risks of careless play.

So how fast can a T850 run set up to run the kilo. 75 to 76 mph is my guess. That would be with an SST 60 T motor and on weight at 725 lbs. I don't think any of the other motors can turn the RPM. You would need ideal conditions and a long run to get there, You also would need to be a GREAT not just GOOD but great driver to balance the boat at that speed.

When SSV started they claimed 80 mph and that was at 950 lbs. Their SST 60s are not detuned like ours, We have used a Critchfield to break in several SST 60's for our tunnel. We have some super strong SST 60 motors and never saw 80 mph on a much lighter boat to the SSV.

Why is it slow? It's boat length! You need boat length to carry the speed and match the power. At the same weight a 15 footer would run the same if not faster with a T motor and with a pure SST 60 on the 15 footer will run faster than an SSV.

The length and design of our T boats helps to control the speed. Another reason that adding extra mod power is not making much difference in the races. Now add the rough water after lap 2 and NO boat is running more than 67 and most are below 63 mph.
I keep suggesting someone run a 15R Allison. It would be slower for the first lap and faster after lap 2.

So when someone asks you how fast your T boat is...SAY 85 MPH. Then they walk away happy and it saves you a lot of meaningless conversation.

If you don't fear my Elgin I'll bring out my Ted Williams in the 20 class....you've been warned...

Lesson # 10.. T850 is a 68 MPH Class with acceleration

It is not the first time nor will it be the last time that I mention this.
As more racers gain experience this statement becomes more true to them.
The big difference in T850 compared to the old EP class is ACCELERATION!
Their top speeds are close. The T850 boats just get there faster.
Our engines provide a wider range acceleration and top end speed compared to the old EP class.

Comparison
OLD EP
In APBA all the motors were OMC 49’s.
They all had the same characteristics. Basically all the top boats were the same.
The weight was 825 lbs.
The key was the dock Lemans start. So off the docket acceleration was most important.
The zero to 65 mph time is the key. This is where compression does help.
It does help with the initial 150 feet. It helps get you off the dock.
Aside from driving the other skill was starting and off the dock acceleration to the commitment pin..
Most races were a parade after lap one. The boats really spread out.
They ran two heats per day and launched twice. Heats were a few hours apart.
You had time to make set up changes, add fuel, make repairs and REST..
Your initial dock position was drawn out of a hat and your dock start position in heat two was based on your finishing position in heat one. Fastest first. So heat two was usually a parade right from the dock.

Our T850
We have 4 different OMC power heads, a Yamaha and in the future 4 four stroke.
At least 3 are different and provide for a wide range of set ups.
We weigh 725 lbs. Much lighter.
We have a clock start, so mid-range and ET for the first straight is important.
The start is much more difficult to judge and it is a skill by itself.
We run back to back heats with approximately 5 minutes between heats.
It is much more demanding both physically and mentally.
There are no set starting positions. It is an open field run to the starting line.
There is close racing everywhere and anyone can win!

Why 68 mph?
On a very good day we could see a 70 mph speed for part of a lap.
Unless that is the lead boat, a lead boat at 68 mph would not be passed by the 70 mph second place boat.
Reason: it is only doing 70 mph for a few yards, a second or two maximum. Boats race in the straights for a short period of time, 12 to 18 seconds. He is not doing to pass.
Remember it is all about elapsed time [EP] It is better being QUICK instead of fast.
The best place to be quick is in , thru and out of the turns. Some boats are 5 mph faster in and out of the turn. Just like F1 car racing. Speed thru the corner.
Coming out of the turn at a higher speed reduces the time it takes for the boat to get to its top speed.
We have shown that it is very easy to get a T boat to handle well and run 63 to 65 mph. Some have won with a boat with this capability . It was all in the GOOD start. Most have never finished worse than third if they lead on lap one.
So how do you get from 65 to 68?
First is prop selection
Second is prop selection
Did you get the point?

This is a T racing encyclopedia(deftn:. n. A comprehensive reference work containing articles on a wide range of subjects or on numerous aspects of a particular field, ...).
Hdog, sincere thanks for time & passion ur putting into this, and it's future.

Lesson #11 Motors and understanding the motor rules

T850 is a World wide UIM class. The ONLY motor that has run in the class over there for the last 20 years is the Yamaha 70CES. All of the records are with that motor and their rules are based on that one motor. we had to be more flexible and allow different motors in the class. We are very luck in Canada to have access to both used and brand new parts for all of the motors racing in T. We used Jim Whittingtons 100% pure stock out of the box 70CES as the baseline for the other motors. That boat runs at speeds equal to the World Records for T850.

So lets look at the different motors.

Yamaha 70CES
Yamaha really is not interested in boat racing. Their racing is mostly in motorcyles and their dam good in building top bikes. All of the major bike manufacturers are into bikes. T850 is a STOCK class, not Super Stock. In order to have a motor in T850, it has to be a stock motor basically the same as the production model. Yamaha had copied OMC motors in the past to save development costs. Yamaha just paid the fine, The V4 Yamaha is a good example of copying. For their T850 motor they copied the OMC Formula E. The problem was and still is, their 70 hp motor was not designed to be a Sport motor. But, by the rules the T850 motor had to be based on their 70 hp production motor. So they used parts from other models and made a few special parts just for the 70CES model, They took ideas from the OMC motor which had a higher compression head 145 to 150 lbs., a short tuner, a smaller gear case taken from a lower hp motor, and a different gear ratio. The OMC made an honest 75 to 80 hp. The 70 hp yamaha had a number of issues compared to the OMC.. Yamaha 70 hp carbs were very small, the crank assemble is very heavy, the porting and ignition were designed for 5500 to 6000 rpm. Not a good platform! Their engineers did what they could with what they had. The result was a very durable, simple motor that produces 70 hp at 6400.
The kilo record in T850 has stood for many years at 67 mph with a 725 lb boat.

OMC 49 Formula E
A true Sport motor. 75 to 80 hp and a mile record of 70 mph on an 825 lb boat.

These two motors are the pure stock ones in the class. There are UIM and APBA spec sheets for them.

I suggest you don't mess with them. The designers and engineers that worked on these know far more than you and I will ever know about the motor.


Now lets talk about the 56 OMC.

There are 3 different ported blocks.
YOU CANNOT ALTER THE PORTING IN THE BLOCK YOU CHOOSE!
The SST 60 specs for porting are not for every block.
Each block's porting is on its own.
By Stock Outboard rules you can clean up the ports.
You can select stock or replacement stock parts from different years of the 70 hp model.
Examples
The larger carbs that were on the 1986 and up 70 hp. Can go on your 2000 block. Which came with smaller carbs.
The ignition and flywheel off a 1973 can be used even on a 56
You CANNOT use a Mod 50 flywheel or machine a stock flywheel to lighten it.
You can use the flywheel off a 2000 on your 1986
You can use the lighter cast crank from a mid 70's 49 in your 56.
You can run any tuner length
You can run any gear ratio so long as it is a stock part. Ever thought of a 2.33 gear and running a 26 pitch prop?

Several T racers mention that our T rules are too tight and don't allow them to play with their motors.
LOOK above what you can LEGALLY do!

Fantastic. A set of rules that's easy for everyone. Every port can be "cleaned up"?

Yes, that is legal. It is a fine line between cleaned up and blue printed. If you needed to replace a sleeve. The rule was you could match port the new sleeve to match the other ports. So it is not improper to clean up all of them.

I really like the fact we have muliple blocks to choose from. Each block offers the opportunity to make something a little unique, especially when you have a number of stock part options. T racers I think have become so focused on compression in making a difference, that I believe they have missed the true jem in the blocks.
Hint: The key to engine performance is flow, on the exhaust side the flow is always thru the middle of the port. Any blockage there will reduce the flow.

Answering some questions
Prop selection and the advantage of a higher corner exit speed. I don't get it.
I hope this answer makes sense. Say you have done your homework, testing and you think you have the perfect prop. That prop is 22 pitch and your exiting the corner at 42 mph. The prop is working perfect and your accelerating to a maximum speed 66 mph on the straight. Now after racing a few times you are a better driver and you exit that same corner at 45 mph. The added speed allows you to run a 23 pitch prop and you will accelerate at the same rate as you did with the 22 pitch except you have 68 mph at the end of the straight instead of 66 mph. YOUR ET IS FEWER SECONDS AND YOUR TOTAL LAP TIME IS FASTER!