• 175cc GY6 HP?

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 #13389  by cath8r
 Sun Apr 14, 2019 10:39 am
I was wondering what the horsepower of a 175cc GY6 engine (sold here) is? Has anyone here swapped out their stock 150cc for a 175, and if so what differences really stood out? I'm asking because I have a 420 Predator engine that I built up that I was going to put in my Spider Box. If the 175 is decent, I'd buy one of those and sell my Predator, just to save me the work of modifying the rear end of my Yerf Dog.

I know the 175 isn't going to have the power the Predator has, but I would still like to get as much info on the 175 as I can. Any input on this would be appreciated!
 #13436  by TravisXBD
 Wed Apr 24, 2019 7:29 pm
Take a look at the MBX racing videos. There's a 420 Predator swapped Yerf Dog GX150 there that has a hard time keeping up with the GY6s. Race regulations limit the GY6's to 171cc. So they're not even true 175's which require machining.

I've been doing this a long time, started with the industrial-style engines and was glad to move up to the GY6 a long time ago. The Predators are good for a lot of guys because they're accessible and are familiar (everyone has a mower). Beyond that, the GY6 has it beat in most aspects of riding, performance and overall enjoyment. Including costs, compared to a bolt-in ready 175 that goes in with no extra fuss or cash outlay. Plus the free parts credit.

As for HP ratings, I have to finish the dyno. I have a big problem with builders "estimating" (BS'ing) their HP numbers, and I refuse to do it even with a reasonable number. Here's a video of one of the races so you can see yourself how it compares in a real world all-out race setting. This was one of the better races for the 420. Fast forward to timestamp 3:15:17. The 420 is the guy that gets the launch, but can't make it stick beyond even the very first turn. The GY6's pile in on him and it's over. Red helmet.

Last I heard, he got a second Yerf and is hopping up the GY6.