panioul

I have a chinese 41" deep vee and it has a zenoah clone in it (I think it has a mark at the rear side like "QJ" or "JQ", I am not very sure). I tried to modify this engine using some zenoah parts like coper flange to raise the compression, a lighter and modified piston (from Redline Performance Motors), a little port opening from me and a walbro 257 carb. With a Propshop 7016/3 prop I recently achieved 82km/h (~51mph). Now I ordered a bonzi bzx2 engine and I will try it with the same carb and with the same prop. What do you think the results will be? Will the bonzi worth the extra 350$ or the modified chinese clone will be better and faster?

P.S. How fast can a 41" deep vee boat can go with this kind of engines and what would be the best prop?

Doubledog

My Feedback: (48)

Bonzi is not exactly known for having fast engines.

Dockman

I modded the same motor for a friend's boat. I done some work on the intake and exhaust ports. I modded the stock piston and changed the squish. The squish was way off (.045) and I had to have the cylinder turned down about .030 in a lathe. It is in a 48'' cat and without any tuning it ran 45 mph.

mistycreekboats

My Feedback: (1)

Pricey for what you get from Bonzi ....... I wouldn't expect much increase maybe few mph ............ plenty better deals out there

Cheers ..... keep posting

Ron Olson

My Feedback: (1)

Echoing the above postings. Get yourself a stock RCMK and it'll be cheaper and faster than a Stage II from Bonzi'. Cancel your order.

panioul

If I gain a few mph will be good for me because I am also looking for reliability and I hope with the bonzi I will have it. I don't want to go for RCMK bcause I have a lot of parts for zenoah engines. Do you think that I will have any benefits if I replace the piston from the bonzi with the one I already have from Redline Performance Motors?

MKMotorsport

I'll 2nd that I've seen a stage IV Bonzi in action and it is less than impressive. Get yourself a stock Zen jug ($38), buy some tools if necessary, follow Scott Schneider's Zen mod aritcle carefully, and you'll have a motor that will beat many/most "garage" wanna-be "pro tuners" motors out there. In fact my first Scott Schneider jug had me looking at a popular sellers CNC'd jug ran back to back on the same bottom end/same boat/ same setup prop- thinking ***??? I can't believe some of the people out there selling "tuned" jugs to the masses at the extremely low performance levels they offer. But "its faster than stock", right?? [:-]

Dockman

Not sure why you insist on asking for advice when you have already made up your mind???

Doubledog

My Feedback: (48)

The only reliable thing you will get from the Bonzi is they cost more & perform less compared to what some others can do for you. If it were me, I'd close my eyes, pick any one of the responses here & go with it.

panioul

Thank you all, for your responses. Dockman first of all I am not asking to buy a bonzi or not, I am asking if this kind of engine will be faster than the previous one I already have. There are some reasons that I cannot explain in a forum why I chose bonzi. I know that there might be faster engines or that stock RCMK is faster but unfortunately I have already ordered this bonzi and also unfortunately I could not buy from other shops that you suggested. I also explained why I did not want to go to RCMK. Maybe the best solution was to order a stock zenoah and to try to modify it myself, but I thought that the bonzi zx2 was ok. So to return to my original question, do you believe that with this kind of engine I will be slower than the chinese?

Doubledog

My Feedback: (48)

I understand & most definitly not picking on you.
My only issue with Bonzi is that I've seen several of their so called modified engines and they really are just a lot of show & no-go. Their website really adds to the flavor and encourages such purchases.

panioul

Thanx Doubledog. I hope it will be at least at the same speed with the old one, and as soon as I will know that it is an original zenoah (hopping for reliability) I will try to mod it, starting from the modified piston I already have. The previous zenoah clone gave me a lot of difficult hours to spend and a lot of practice to retrieve a boat!!!!

panioul

Are you talking about the bonzi motor or for the chinese? And please explain me the term of squish (is the connection between the cylinder head and the cylinder base?). Do you know after the mod what was the speed of the cat?

Dockman

The Chinese clone. The squish is the distance between the top of the piston and the cylinder with the piston at top dead center. It needs to be .015 - .020 clearance. After the mods the cat ran 45 mph without doing any tuning to the strut, prop, carb, pipe.

panioul

So, the 51mph I got with a deep vee was very good for this kind of engine. Do you believe that you would have the same speed with a stock zenoah or it would be far less?

team esp

I have 2 of those "QJ" clones that are from Venom Racing. I get them cheap and they are a great motor. Maybe check the Venom website for parts (they are dirt cheap, pistons for $10 and such). I love these little motors and think few people have them and even fewer respect them just because they fall into the "clone" category. The stock 26cc motor pushed my KOS 50"+ hull just over 50mph with an aftermarket pipe/header/ and prop dialed in correctly. Although they fall into the "clone" category, they are a huge step up from older clones like Fuji's and others that would basically rattle apart after day one.



Not to pick on Bonzi or your choosing of one, but I have one of their mod motors (new) and was far from amazed with the performance. If you're stuck on Zen's and have plenty invested in them, then I understand where you're coming from. I'd totally echo one of the posts above though with choosing RCMK. For under $300 you basically have a motor that gives you more than most "modded" Zen's from these larger companies like Bonzi. You also benefit from having this extra power while continuing to have the stock reliability, ease of use, and rather cheap replacement parts (being that they're just stock parts and don't need to be matched to any other mods you have).

Either way, it sounds like you got a great running boat that's really tuned in with the speeds your at. Best of luck with whatever route you go.

panioul

If I will not be satisfied with the performance of bonzi (I am looking for at least the same speed), I will try to sell it and then maybe I will go for RCMK (I am very curious to try them). One more thing I was thinking is the weight, do you know if a real zenoah is lighter than QJ? If it is lighter I will have an extra benefit from this.

team esp

Just put one of each on the digital postal scale...

"QJ" stock- 3lb 7.4oz

Bonzi BZ-1 modded- 3lb 7.8oz

That was with their front mounts on (different mounts but appear close in size/weight), and the "QJ" had the throttle assembly still on it. Same 644 carb on each.

panioul

Although I have received the new original Zenoah a month ago from Bonzi I don't have tested yet because the "QJ" is running really really good now. I am posting a video from earlier today to see what I mean. I don't think it worths the time to change with the new zenoah and to wait to run-in. Maybe I should keep it in case the QJ brake down or I will try to sell it. Afterall 85km/h is not bad at all!!!!!!!!

http://www.youtube.com/watch?v=xk1jlo5ophw