Pro Boat Thundercat 31

[Scott351]

I started this thread hoping anyone who wants to share
any info regarding the Pro Boat Thundercat 31 will post
here... A friend of mine has one of these boats and I
think it runs pretty good for $350 RTR (includes Sullivan
Tiger Drive on the Dynamite .32 marine engine).

Out of the box, the Thundercat 31 is about 5mph(?)
faster than the Shockwave 36 (both boats have the
same Dynamite .32 engine & exhaust system).

Can anyone offer any specific tuning tips for this boat?
Specifically, is there a better prop than the stock?

Thanks,
Scott

[Ron Olson]

there sure is. Last year we did some prop testing on a friends TC 31 and found an Octura M-445/3 got the boat up to just under 40 MPH on radar. There might be better props but we used what I had in my prop box.
We also upped the nitro to 65% but that might be more than what you're comfortable iwth.
Putting a fuel tank in the rear right sponson and leaving the stock one in seemed to loosen the boat up more on the water.
You can port match the header to the engine. If you don't know what that is, i'll explain quickly.
The header flange is not matched to the exhuast port of the engine. Pull off the header and you'll see where there is spent fuel on it. You'll want to grind an angle from that stained area to the pipe but be careful that you don't go too far. This mod alone can gain you about 1,500 RPM or more.

[Scott351]

Ron Olson:
Thanks for the info... I'm a little confused about the fuel
tank suggestion, though. Are you saying to add a fuel
tank's worth of ballast to the right rear of the boat while
still using the stock fuel tank to feed the engine? I assume
that "loosening the boat up" is a good thing?


To All:
My friend recently had a problem with his like-new
Thundercat 31... The pressure fitting on the exhaust
manifold (which pressurizes the fuel tank) came out.
On the Shockwave 36, the pressure fitting is welded
into place. I don't have another Cat31 to check, so
I'm not sure if this is just a quality-control oversight or
a potential problem with all Thundercat 31 boats.


Scott

[Ron Olson]

What was done was to add another tank in the right rear sponson and use that. An 8-10 oz. tank should slide right in there. Leave the stock tank empty or remove it if you'd like. If the boat gets too loose, slide it forward.
As far as the fuel pressure fitting coming out, that is a common problem. Get some JB Weld to stick it back in place.
If you run into prop cavitation problems, lower the strut a little. From what I've seen of them still new in the box, it looks as though they kept it high to fit in the box better.

[tylernol426]

i have had 1 for a while... its a realy good boat the only problem i hav had with it is flipping it twice from 2 much speed and wind.... i wish i could take it out more at a lake instead of the sacromento river, because the river has a curent and i dont like swimming for it in the curent when it dies. which is not fun.... thats why i stick to electric.... im thinking of converting it to electric (brushless)