GPU with 200hp

[AirAg]

So now you guys started it, I am full of questions! If I do rebuild this 4 cylinder GPU, according to the math, I will have a displacement of 346.19in^3, and 200 hp. So, with this information, how will this engine compare to a lycoming 200 or 180, power, not weight.

Also, I have noticed that the gitso 520's are used so you can use your original intake. My intake now is ported out, and I placed a 350cfm 2 barrel Holley on it. Is this carb. and intake good, or should I go with an aircraft setup? Not sure, but the oil pan on the engine would be in the way of an updraft. Dont know for sure though.

By the way, one of these days, I am going to drag my boat boat over to Florida. Its just a long way from Texas!!

Thanks, Brent

 

[Mike Thurman]

If you are talking about a stock 4 cylinder Continental GPU it will not make near 200hp. It produces around 135 hp. It should be about 313-315 ci. Your 346ci would be correct if using 5.250 bore 520 cylinders. A GPU has a 5.000 bore. A stock 6 cylinder GPU is 470 ci. You cannot use any aircraft oil sump and carb set up on this motor. There is just nothing that will match up. We usually make our own sumps from aluminum. Mainly just for looks. But keep the carb on top. Piston choice is important for HP. Go with a higher compression 4 ring piston.

 

[AirAg]

Thanks for the reply Mike. So if I use high compression pistons, bore out the case, use dual mags, how much power are we talking about? Just trying to decide if it would be worth the money and effort to rebuild the engine. Thinking total cost around $1500. By the way, it is stock right now, other than the holley carb and ported out intake hole.

 

[mountain man]

airag

a word of advice make sure your crank has not been turned 10/10 20/10 etc. if the crak has been turned you can only stay stock

 

[bowidmann@gmail.com]

dude,a p.e 90 4 cyl. gpu has 150 h.p,putting gitso 520's with dome 4 ring piston's might get you 180+/-

 

[plumcrazy]

mine sure feels like 200 i do know its got more balls than a 200 lycombing i had 4 years ago, my compression is up there no water needed on a heavy hull two 250pounders ice chest full and 20 gal s fuel, and it dont burn much, it just feels more torky than the 200 lyco

 

[goldhunter_2]

yep I've watched plum climb the mound with that thing and didn't miss a beat :lol: