Superchargiing the P engine?

[quentin.vds]

G'day blokes,

Acquired a 1976 G60H MWB and in the process of a complete refurbishment. But to make it an even more unique specimen I'm wondering on the plausibility of supercharging the weapon. Based on looks the factory pistons don't seem super strong, and I wonder what other bottle necks might exist.
I know there is a fella in Oz who turbo charged and EFI converted his P engine but that was quite involved (rb30 pistons and custom con rods etc).
Any ideas/opinions are appreciated.
No engine swap suggestions please.

Cheers,

Quentin

[Esteban]

We would love to follow the transformation!

Without knowing anything about supercharging, my only concern is that the P engine is probably the most undersquare engine out there with a bore of 85.7 mm and stroke of 114.3 mm (3-3/8"x4-1/2") and with a very low compression ratio of 7.6:1. Sort of the opposite of a typical supercharged engine.

What will happen with the added power of the supercharger on components like the connecting rods or even the crankshaft, is difficult to assert without being completely immersed in that field. The other issue is the intake and exhaust capability of an engine like this once supercharged. You have tiny valves and that will be difficult to overcome.

[r1lark]

The low compression ratio is actually a positive thing for supercharging, and supercharging is one way of overcoming smaller valves and restrictive intakes. But as Esteban points out, with its long stroke the engine is rpm limited. You would have to get the pulley ratio right to get decent boost at the low rpms that these run at. There was probably a reason that the guy in Oz replace the pistons and rods. Also, doubt there are any 'performance' cams for this engine readily available (someone will prove me wrong now!), but cams can always be reground to a different profile.

Increasing performance is always a slippery slope -- you find more and more that has to be upgraded/changed as you start making more horsepower.

Definitely, if you do this please please post your modifications and results here!!

[quentin.vds]

I figured the low rpm of the engine would make it more suited to supercharging over turbo charging. I'm not quite sure yet if it has had new valve seats put in for unleaded fuel, so there is potential for larger valves to be put in at the same time (no clue if thats possible with this engine). Its a fun idea to play with anyway.

Cheers guys.

[L60Boerne]

Quentin,

I'm surely the last person to understand this subject but it is my understanding is that a supercharger is best suited for high rpm applications while the turbo can be better suited for lower rpm applications. My early experiences off road left me wanting instantaneous power because I was occasionally in very slick mud. I solved that problem with my first off road vehicle, a K5 Blazer with highly modified motor by a mud racing team mechanic. Then I found it was quite easy to twist the axles out of it, which I did twice. Plus the extra power tends to spin the wheels way too much when I was in the rocks. Tire spin sliced banana length slices in the tire sidewalls almost every time. 36" tiresome expensive and they never could be patched, that was why I traded that one off. Added power caused me more problems than it solved.

Now older..... I fully respect vehicles as designed. I wanted more power out of my first Patrol, then this forum talked sense into me and have since focused on the best carburetor I can find for the P. With a good carb these tractors will crawl up any reasonable rock trail without breaking anything. Hopefully my buddy will send me the video he took of me climbing out of a canyon up a rock slide type trail last weekend in my red 65 with NAPA clone Rochester carb. We will see if he sends it and I can figure out how to upload it.

However, if you really want to address your need I suggest nitrous oxide (NOS). It the easiest to add, fits in an open space available near the carb and is easy to install. if you can find or make a proper injector for the intake. Still, I see this as a fast step towards self and vehicle destruction as tractor motors just aren't designed for high RPMs. But my applications now are hill climbs, not mud. The stock P Motor delivers enough torque for most applications of mine up to 13,000 feet.

As I was taught, unless you want a mud racer, drive your Patrol first and see if it doesn't fit your needs as is.

Rollling and Patrolling,
L60Boerne

[quentin.vds]

L60Boerne,

Thanks for your reply.
I reckon you have a good point about waiting and seeing. Nitrous would be quite funny in such an old rig but ill keep it in the back of my mind.
I've since talked to Michael Trinidad who previously raced a g60 in mud runs and he kindly sent me his cylinder head and carbouretor setup (3mm off the head, and a 350 holley economaster).
Hopefully with these additions itll spin the earth backwards will all its torque.
Apparently the economasters unique jet design keeps fuel velocity high when at low RPMs and should mean even more torque at low speeds. Ill post something about the performance when I finish the rig.

Cheers