Vekta.5 engine question

cardarear

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Oakland County, MI
I'm new to the Forum, and pretty new to forums in general. I have a Vekta.5 with an OBR full mod 34 cc engine. I enjoy the Vekta (although it's down right now after a battery box thermal issue) however I would like a bit more speed. I've topped out at about 38 to 39 mph so far (near the end of my first gallon of 24:1 oil mix following Botejell breakin). I'm guessing it will not be much faster at 25:1 or 28:1. So I've started to think about an engine upgrade to OBR 40.8 that was recently announced. But I'm wondering if expensive drivetrain upgrades will be required. If I have to go down that path then it may make more sense (somehow) to go all in for a larger engine (rcmax 55 maybe).
 

Z.hb71

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Tbh is you do really want to go fast and don't mind upgrading stuff, I'd do the rcmax. The obr looks decent for a racer as it's light, but that probably won't be as powerful as a rcmax being it looks like it's still based off a goped motor (rcmax is fully custom now so they are much better), plus the obr looks very basic as it's still using a 54mm clutch, so if your going to spend some money and don't mind upgrading the tranny Id go for the rcmax. Also Not sure if you'll have to upgrade the tranny for the obr.
 

cardarear

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Oakland County, MI
Wassup. I never think about upgrading until I break something. I say get the 40 or 55, drive like you do then replace the part if it breaks. Why fix something that ain't broke?
The cost jump going from a 40 to 50 or 55 cc engine doesn't seems that great but if you have to upgrade the transmission/diffs/etc with the 50 but not the 40 then that could quickly become very significant. Ideally I would think the 40cc would be enough power but if I have to bulletproof the drivetrain to run it then I would probably pay the couple hundred more and get the bigger engine.
Tbh is you do really want to go fast and don't mind upgrading stuff, I'd do the rcmax. The obr looks decent for a racer as it's light, but that probably won't be as powerful as a rcmax being it looks like it's still based off a goped motor (rcmax is fully custom now so they are much better), plus the obr looks very basic as it's still using a 54mm clutch, so if your going to spend some money and don't mind upgrading the tranny Id go for the rcmax. Also Not sure if you'll have to upgrade the tranny for the obr.
Yeah, I am eagerly awaiting some videos of the OBR 40.8 to try to get an impression of the power vs what I've seen on videos of the RCMAX 40GT. I definitely like the price point of the OBR and I have had a good experience with my current engine and customer service to this point.
 
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Z.hb71

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The cost jump going from a 40 to 50 or 55 cc engine doesn't seems that great but if you have to upgrade the transmission/diffs/etc with the 50 but not the 40 then that could quickly become very significant. Ideally I would think the 40cc would be enough power but if I have to bulletproof the drivetrain to run it then I would probably pay the couple hundred more and get the bigger engine.
Email Detroit Performance rc, they will be able to tell you exactly what to upgrade with the 40 and 55.
 
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1,751
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Rochester,NY
Guess I'll ask the dumb quetion . Why not change your gearing . It's a lot cheaper than engine swaps. I'm assuming your running the stock gearing right now. Does the Vekta have swappable pinion and spur gears? Even with a engine swap I have a feeling what ever gearing you have is going to limit your speed. If not sorry I suggested it .
 

cardarear

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58
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Oakland County, MI
Guess I'll ask the dumb quetion . Why not change your gearing . It's a lot cheaper than engine swaps. I'm assuming your running the stock gearing right now. Does the Vekta have swappable pinion and spur gears? Even with a engine swap I have a feeling what ever gearing you have is going to limit your speed. If not sorry I suggested it .
I'm currently using the mega torque gearing (17 tooth pinion I believe) with the trepidor tires. If I go with a larger pinion I will trade acceleration for top speed. I believe the only way to preserve or increase acceleration and also increase top speed would be with a more powerful motor probably in combination with a gearing change.
I did reach out directly to Kraken. They responded that any big bore 40cc and up would most likely require some upgrades.
 

Z.hb71

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I'm currently using the mega torque gearing (17 tooth pinion I believe) with the trepidor tires. If I go with a larger pinion I will trade acceleration for top speed. I believe the only way to preserve or increase acceleration and also increase top speed would be with a more powerful motor probably in combination with a gearing change.
I did reach out directly to Kraken. They responded that any big bore 40cc and up would most likely require some upgrades.
Did you ask what upgrades are required? Because maybe they are not that expensive
 

Seandonato73

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New pinion cant cast as much as a bigger engine. That one should have plenty of snot to pull a taller set of gears imo. I'd try that first. Even if you do get a bigger engine you'll want to regear it anyway. And my vote for now would be the rcmax. I love OBR but you gotta give new engines a bit of time for bugs to get worked out.
 

cardarear

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Oakland County, MI
Did you ask what upgrades are required? Because maybe they are not that expensive
My question to Kracken specifically mentioned the transmission and differentials but they did not get into specifics on upgrades required in their response. The Vertigo transmission upgrade that I am aware of looks to be about $340 and there is a RCMAX front differential case upgrade for about RCMAX $190. Although It appears that the Vertigo part can be ordered in combination with a RCMAX engine at a discounted price.
+1 try the gearing first👍
There seems to be quite a bit to think about. I think I will take your advice and start with a gearing change before jumping off the deep end. I appreciate all of the feedback. Thanks
 
Messages
1,751
Location
Rochester,NY
I'm currently using the mega torque gearing (17 tooth pinion I believe) with the trepidor tires. If I go with a larger pinion I will trade acceleration for top speed. I believe the only way to preserve or increase acceleration and also increase top speed would be with a more powerful motor probably in combination with a gearing change.
I did reach out directly to Kraken. They responded that any big bore 40cc and up would most likely require some upgrades.
There is always a trade off . It's up to you as to what you want, acceleration or top speed. You can put a bigger engine in but your still going to be limited by the gears. As the other guys mentioned you're still going to need to change the gearing. The bigger the engine the more uncontrollable the car is going to become also.
 
Messages
1,751
Location
Rochester,NY
They make specific gearing for the big bores ya know
Which means you have to change the gearing no mater what. Kind of proved my point. :LOL: thanks.

He has a 8 HP engine in his car. That cost him I'd guess 600 . For another lets say 80 he can change his gearing and get closer to what he wants in speed and acceleration.
Or as you and Mark are tryinging to talk him into doing ,get a bigger engine that will cost any where form 1000 to 2000 dollars US and that doesn't include a beefed up drive train and new gearing or the 350 dollar header because the one he has now won't fit the big bore engine that he will have to have .

Z you and the rest of us have been joking for months as to how long the diff and trans in your 5b will last with the 70cc in it. and you guys are trying to talk him into this with out giving him any Idea what the true cost of an upgrade like that would cost or what he would need .
 
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Z.hb71

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Which means you have to change the gearing no mater what. Kind of proved my point. :LOL: thanks.

He has a 8 HP engine in his car. That cost him I'd guess 600 . For another lets say 80 he can change his gearing and get closer to what he wants in speed and acceleration.
Or as you and Mark are tryinging to talk him into doing ,get a bigger engine that will cost any where form 1000 to 2000 dollars US and that doesn't include a beefed up drive train and new gearing or the 350 dollar header because the one he has now won't fit the big bore engine that he will have to have .

Z you and the rest of us have been joking for months as to how long the diff and trans in your 5b will last with the 70cc in it. and you guys are trying to talk him into this with out giving him any Idea what the true cost of an upgrade like that would cost or what he would need .
First I'm not trying to talk him into anything, maybe mark but not me lol, just suggesting, second the big bores come with exhuasts, you don't buy them extra. Also, when I said the big bores require gearing, I thought you were saying that the big bores don't have their specific gearing and is a waste of money because of that, I miss understood what u were inquiring.
 
Messages
1,751
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Rochester,NY
First I'm not trying to talk him into anything, maybe mark but not me lol, just suggesting, second the big bores come with exhuasts, you don't buy them extra. Also, when I said the big bores require gearing, I thought you were saying that the big bores don't have their specific gearing and is a waste of money because of that, I miss understood what u were inquiring.
Never said it was a waste of money . Just that they are a very expensive en devour . It was just fun to watch he suggested getting a bigger engine and you boys were all in as the saying goes . Send It ! :ROFLMAO::ROFLMAO::ROFLMAO:
 

Z.hb71

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Never said it was a waste of money . Just that they are a very expensive en devour . It was just fun to watch he suggested getting a bigger engine and you boys were all in as the saying goes . Send It ! :ROFLMAO::ROFLMAO::ROFLMAO:
Yeah man, SEND IT! 😆😆 In my world, bigger engine the better (as long as u have the money for stuff to break)
 
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