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 Post subject: Re: Reasons to go BEC
PostPosted: January 15, 2016, 3:48 am 
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Location: BC, Canada. eh?
My initial plans were along the BEC lines. Then, I had a ride in a brand new, BEC-engined (Hyabusa) genuine Caterham. It was exciting, terrifying, exhilarating, and frustrating, all at the same time. It used an intermediate gearbox so as to provide reverse, but it was extremely harsh and crashy. You didn't push the throttle in that car...you pulled the trigger. Huge fun on back country roads & open highways, but a nightmare in traffic. At the time, at least, there were concerns about the longevity of the factory transmission & clutch, having to propel double the mass it was designed for, and parts at the time were becoming scarce.

In the end, I went with a car engine & trans - it was simple, power units were (and remain) plentiful & relatively cheap, aftermarket support is outstanding, and the power train is ridiculously robust for this application, while remaining surprisingly light.

I liked the BEC idea, but the thought of traveling through some small town & having an engine problem with, say, a Hyabusa engine would mean staying there for the foreseeable future until someone, somewhere could get me parts. Parts & repairs for my Ford engine, on the other hand, are available virtually anywhere in North America.

I think about things like that a lot...did I mention I used to drive British cars? 8)

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 Post subject: Re: Reasons to go BEC
PostPosted: January 15, 2016, 5:35 am 
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edit:


Last edited by michael ohrstrom on April 7, 2016, 2:24 pm, edited 1 time in total.

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 Post subject: Re: Reasons to go BEC
PostPosted: March 26, 2016, 1:24 pm 
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edit;


Last edited by michael ohrstrom on April 7, 2016, 2:24 pm, edited 1 time in total.

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 Post subject: Re: Reasons to go BEC
PostPosted: March 27, 2016, 1:18 am 
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I think now that Yamaha has come out with their YXP 1000 Side By Side off road car with the separate transmission (with reverse), you will be seeing this combo in road going cars soon and probably adapted to some of their bigger engines.

https://www.youtube.com/watch?v=F8cmpkr ... 2484204069

Tom

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 Post subject: Re: Reasons to go BEC
PostPosted: March 28, 2016, 2:04 pm 
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Joined: January 31, 2012, 12:49 pm
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michael ohrstrom wrote:
They are really fun to read on Locost websites throughout the world,
everyone talks about bec. and want to build one. (snip) everything falls on a reverse box that costs less than $ 1,000 this must be a disease that has spread throughout the earth ?


Which is where my dreams ended years ago. That, and warnings from BEC owners about it not being very drivable around town 'cause you really have to keep the revs up. Great track cars tho?


michael ohrstrom wrote:
but most of them are based on a dreary car engine and a standard "h" box gearbox:
are ron chapinons book for the (Locost builder ) like the corane for a Muslim?


Not like the Koran. More like the Torah (Jewish) after which have been revisions and clarifications (ie, Mishnah and Talmud and the Christian New Testament). The Haynes Roadster book is the basic article written after Ron Champion's book to do the most common fixes with a donor that was a bit more common by that time. The Car 9 people, not to mention the LSx builds, might be considered the reformation splinter movements.

Yes, I have a seminary degree, why do you ask?

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 Post subject: Re: Reasons to go BEC
PostPosted: April 1, 2016, 3:26 pm 
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edit;


Last edited by michael ohrstrom on April 7, 2016, 2:25 pm, edited 1 time in total.

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 Post subject: Re: Reasons to go BEC
PostPosted: April 1, 2016, 4:50 pm 
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This year we thought to go from New York to West Virginia is Track Day


Lots of beautiful country on a trip like that. A few famous race courses too. Watkins Geln used to have a big endurance race in July.

We can find more ideas for you, if you're interested.

Some places in USA have so many Swedish and Scandanavian that they have their own accent. And lutefisk...

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 Post subject: Re: Reasons to go BEC
PostPosted: April 2, 2016, 3:41 am 
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 Post subject: Re: Reasons to go BEC
PostPosted: April 19, 2016, 3:40 pm 
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I would like to add something to what has been listed here, with the proper engine choice and placement, packaging.

I am 6'4" and I don't have to run a 442 chassis or a big tunnel with a bike engine. Gives me the ability to use the shorter chassis, move the firewall and pedal box forward and still fit.

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 Post subject: Re: Reasons to go BEC
PostPosted: August 25, 2022, 7:22 pm 
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Zombie thread here. I'm familiar with herky-jerky throttle action by virtue of driving a car-engined locost with megasquirt and ITBs. The owner has never gotten the occasional jerking action out of the car, which is both annoying and embarrassing. It's said above that a guibo will largely alleviate that condition, but what if you're running a chain drive in a mid-engined application. The chain is going to be short with very little potential for absorbing lash. Any feedback?


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 Post subject: Re: Reasons to go BEC
PostPosted: August 26, 2022, 7:14 pm 
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Consider the design of the driven sprocket to ride in a hub that provides a gate that keeps it parallel and true, but allows it to rotate a few degrees on the hub, with compression springs or isolators to absorb the torque spikes. There is another build here with a single seat middy bec and colorado diff that has a similar setup. It is similar to the springs in a clutch hub.

I'd also work on the throttle pedal ratio so the ratio is low in the first third of travel then climbs to reach WOT at full pedal travel. Maximizing pedal travel helps too, for the throttle and clutch.

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 Post subject: Re: Reasons to go BEC
PostPosted: August 26, 2022, 9:00 pm 
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Good thoughts. Thank you


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 Post subject: Re: Reasons to go BEC
PostPosted: August 31, 2022, 7:26 am 
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ccrunner wrote:
KB58 wrote:
Based upon exactly one ride in a Caterham Hayabusa-powered Seven, I went with a car engine:

KB is right on these points, but as with most things, you can find get-arounds (or you must just learn to live with it)

1. Bike drivetrains don't have a flywheel, and the consequences are noticable when driving at a constant speed. The car gets into an odd oscillation where drivetrain backlash causes a slight but noticable back-and-forth jerking. The car speeds up a tiny bit, causing the driver's foot to lift very slightly off the gas, causing the car to slow down, which causes the driver's foot to very lightly press more on the gas, and it repeats. If the driver barely accelerates or decelerates, the problem vanishes, so to avoid it, the driver has to always be speeding up or slowing down.
This is a very real, and very annoying result of the bike transmission's straight cut gears.. I had to retrofit a giubo (rubber donut) into the driveline and the oscillation effect is virtually gone- a true night and day difference in the BEC driving experience.. Just my opinion, but all BECs would benefit from using a TRT or Giubo in the driveline

2. Gearing. 60 mph is about 6000 rpm - I kept looking for another gear.
This is 100% true and it is tiresome.. do not plan to drive your BEC cross-country.. despite the high rpms on the freeway, I still take mine out of town all the time (recently went 8 hours one way), and it was livable with noise-cancelling earbuds and music -hell, I drove it to work this morning :cheers:

3. Hair-trigger clutch. Even though the owner had the car for several years, he regularly stalled it.
Something's wrong with the pedal ratio (needs to be about 7/1, maybe more). If the owner is stalling it, it needs a rework.. Mine took some fiddling for setup, but it now acts no different than a 'normal car'.. easy-peasy to daily drive..

4. No low end. Yes, it may have 180-200 hp, but it's all up at the high end and takes time to get there.
In general this is true as most bike engines are peaky, but not all of them (mine only has 110HP).. BECs need to be wrung out a bit more than a 'regular' car (mine likes for me to shift above 8k, but don't mistake this for total lack of torque).. I can lug it around if I want to- pretty good grunt even down low-- part of it is my chosen engine, and part of it is the 1.9 bike tranny gear reduction --on paper I get to nearly double my bike's 55 ft lb rating as my 'geared torque' is closer to 100 ft lbs at the crank; FAR more than my car's OEM torque); but in general, you do in fact need the revs to get the 'big' power/torque

5. No reverse. Even though there are solutions, it gets annoying.
True is true :wink:

6. Unless the intake and exhaust perfectly copy the bike installation, power won't be as claimed.
Those engineers area a clever bunch.. as stated, be as true as possible to their design to get the power/torque

For a trackday car, absolutely. For the street, not so much. Believers can claim that the above doesn't bother them, which is fair enough, but the issues do exist.

Agreed- hard to beat a BEC for track day, and if you're willing to put up with the inherent differences that a BEC brings to the street, they can certainly be a lot of fun there too


--ccrunner[/quote

Something's wrong with the pedal ratio (needs to be about 7/1, maybe more). If the owner is stalling it, it needs a rework.. Mine took some fiddling for setup, but it now acts no different than a 'normal car'.. easy-peasy to daily drive..

7/1? is this at the pedal box, or on the motor side ? Can you provide a pic please


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 Post subject: Re: Reasons to go BEC
PostPosted: September 5, 2022, 9:50 pm 
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Ive put about 500-600 miles on mine this summer. I had awful oscillations with the original motor due to low compression. New motor went in and the issue is almost entirely eliminated.

I've got a 150hp 02 r1 engine.

kreb wrote:
Zombie thread here. I'm familiar with herky-jerky throttle action by virtue of driving a car-engined locost with megasquirt and ITBs. The owner has never gotten the occasional jerking action out of the car, which is both annoying and embarrassing. It's said above that a guibo will largely alleviate that condition, but what if you're running a chain drive in a mid-engined application. The chain is going to be short with very little potential for absorbing lash. Any feedback?


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 Post subject: Re: Reasons to go BEC
PostPosted: September 5, 2022, 11:13 pm 
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Regarding this: "...Something's wrong with the pedal ratio (needs to be about 7/1, maybe more). If the owner is stalling it, it needs a rework..."

That may be, but it was as-delivered from Caterham, so if it needs adjusting, it's another example of why we build from scratch, hah.

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