So what's it really like to drive a BEC?

   Last update: 8/31/09 Return to top of home page


So far I've got over 600 miles on the car. I am still working on some details so most of my driving has been to test out the things I'm working on. But I can give you a general  idea of what it's like to drive the car.

As they say on TV, "But first.............."
First and foremost, you better have your "Miner's faster than your's" mentality under control. A BEC Locost is a seriously fast (not so much in top speed but in speed changes, cornering etc) and is truly a high performance car. It is NOT for the immature racer wannabe. Luckily I got over (well mostly) the, "Mine's faster than your's" urge to show off after owning a series of XK Jaguars and a 911 Porsche. You have to think, "I KNOW mine is faster than your's and I don't have to -prove- it!" It doesn't always work, but it helps.    ;-)

You can get in trouble very quickly if you don't watch it. Like the time I did a spectacular burn out from a stop light because my foot slipped off my throttle foot rest! Luckily I was first in line so at least I didn't ram anything. And I got proof that the LSD was working.



OK, now that the sermon is over, what IS it really like to drive a BEC?        

     FUN, FUN, FUN!
bugs in teeth

The following comments apply unless you are into some really serious racing machinery.

It's like the overpowered racing go kart you lusted for when they were running two and three engines. It corners better than anything you've ever driven. The acceleration is mind boggling and overpowers your senses while it's happening. Hearing the engine in a "car"  rev to the 12,400 RPM red line is almost unimaginable. Having YOUR engine do it is even better! The sound of unmuffled intakes howling is something that you have probably never heard before, even on a motorcycle.

cat

A Locost, like it's grandpa the Lotus 7, is a VERY basic car with few frills, somewhat hard riding, noisy, corners like a big go kart, has very direct steering, a wind in your face machine that attracts attention. It's almost a contradiction of what most people think they -need- to have in their car. You don't "get into a Locost", you strap it ON!

Once you are strapped in with a 4 or 5 point harness you will not be able to move around much at all. As a result you will have some blind spots to the rear and sides that you just can not see.  Either the headrest portion of your passenger seat is in the way or the mirrors don't cover the area. And you can NOT move your body enough to turn slightly to see them either.

This is especially bad on my car if you are sitting in the safe zone in the middle of a divided highway with the car aimed slightly in the direction you want to merge. You can just NOT see if anyone is coming in the lanes to your rear. I have resorted to leaving the shoulder straps a little loose in traffic so I can move around a bit.

Remember, the Lotus 7 started out in life as a race car.  The Lotus was based on the English Seven which had ~45 Hp.  The whole concept of the Lotus 7 was based on one overriding idea, "If it doesn't make it go faster, you don't need it." My car is rated at 165 Hp and most likely weighs less than 1000 lbs. Even at 1000 lbs that gives me a power to weight ratio of  6.06 pounds per Hp. In fact, when using a high powered motorcycle engine you have more Hp and performance than the original 7's raced with.

At a sports car race in the 1960's, I remember seeing a well tuned Lotus 7 beat -all- the 283 c.i. Corvettes and it was nipping at the slower, larger engined Corvettes. It probably had less than 120 Hp. That was impressive.

So forget a radio, you won't hear it with a "proper" muffler, cup holders will spill hot stuff in your lap, windshield wipers are nice but I suspect that more water will be coming off the rear tires and hitting the BACK of your windscreen (as my dune buggy does), pebbles and stuff from the road will end up IN the car and on you. If you wear a floppy hat with an oversize bill (as I do) to keep the sun off of you, it will flap around so much above 60 MPH that you can barely read the instruments. Big dogs can look you right in the eye when you stop. After a brisk ride you will be pleasantly numb for awhile.

You have to be aware that many people driving other cars will get in your blind spots (unless you can swivel your head 270 degrees and can see through the headrest of the passengers seat) so they can get a better look at the car. And then they start weaving around near you since they don't watch where they are driving. I have a short antenna mounted on the roll bar with a red streamer on the high end to attract the attention of other drivers. At night, headlights of cars and trucks shine right into your mirrors and blind you. I have three mirrors and the outboard ones can't be dimmed. You don't want to run through water puddles unless you like bathing while driving. And if you live in cow/horse country ............ (well let's not go there).

If you drive it like a normal car, it is very easy to control and is a real joy to drive. The steering feel is just right. My disk brake system doesn't have a booster and doesn't seem to need it. The view is excellent if you don't mind staring up the tailpipes of trucks or examining the design on other car's hub caps at stop lights. You can reach down and pick things off the roadway without even leaning over. Getting in and out of the car gives your arms a nice workout.

The GSXR-1000 engine is tractable enough that I can idle off in 2nd gear and the car pulls very steady above 3000 RPM. At first I was having a lot of trouble getting the car to drive off from a standstill. After carefully observing what I was doing (wrong) I came up with a simple solution. A small foot rest to the right of the gas pedal! This allows you to have a reference point when you apply a small amount of throttle when starting to engage the clutch.

I am going to try a low speed "launch control" option with my Megasquirt ECU when I get it installed in the car. This would allow the engine to speed up to some predetermined RPM and not go any faster till the clutch is fully released (then hang on).  The throttle response is so sensitive in neutral, that the engine will over rev with even a gentle push of the gas pedal.

The way I take off normally is to rest the right side my throttle foot on the foot rest and  twist my foot slightly to give it a little gas. The car has so much acceleration that if you don't have your throttle foot heel resting on the floor that you will just as likely as not, hit a condition that as the car starts to quickly accelerate your foot moves slightly off the throttle. The car then slows down, your foot goes back on the throttle, the car speeds up etc etc. Makes you look like a first time driver.

The same thing can happen with your clutch foot. You need to rest your heel on the floor and let the ball of your foot slide on the clutch pedal as you release it. If you have your foot floating in the air the car will take off with a lurch and most of the time it will stall as your foot further releases the clutch. Once the car is rolling the rear end stays firmly planted and the tires don't spin (at least not with my LSD).

Sometimes you can feel the LSD giving you hints that it is working as the rear end yaws from side to side a few inches under hard acceleration. You really feel it if you make a tight "U" turn under some power in low gear.

One aspect of light weight, having LSD and a powerful engine is that if you take off fast from a standstill and are going around a 90 degree street corner at the same time, it is possible for the front end to get so light that you have the same affect as extreme under steer. i.e. you may not  -make- the corner if you don't let off the throttle a bit! But it is all very controllable. Normally, if you're used to an over steering car you will have fun with a Locost. I learned to drive really fast in a 1940 Ford that was an over steering fool. (Or maybe it was the driver?)  Afterwards, a 911 Porsche continued the over steering joys. So for me, Ubersteer is good.

    Under steer............. you slide off the road and hit the tree head on
    Over steer............... you slide off the road and hit the tree backwards
    Neutral steer.......... the tree cuts your car in HALF!
    Remember grass hopper, over/under steer isn't bad.  It's the TREES that get you!

Where were we........... oh yes, driving a BEC.

Like a motorcycle, if you are driving along below 5,000 RPM and you want to accelerate quickly you will probably want to down shift a gear or two. My car has a paddle shifter which I highly recommend. The main reason is, it's safer to keep both hands on the steering wheel at all times. With a paddle shifter your shifts will be extremely fast by just moving your finger tips.

For casual driving I usually shift around 5,000 RPM, which with my 3.933:1 rear end isn't all that fast in each gear. The following chart is from an Excel gear ratio vs speed spreadsheet I made. The left column shows my speed in each gear at 12,400 RPM (the red line).  The right column gives the speeds that the GSXR-1000 motorcycle can obtain at the same RPM.

Gear   3.93 rear end  at 12,400 RPM            GSXR1000 speeds at 12,400 RPM with 2.47:1 final sprocket ratio
1st       51 MPH                                               80 MPH
2nd      66                                                      111
3rd       81                                                     133
4th       94                                                     152
5th     104                                                     167
6th     113                                                     180  (governor limited, 186+ w/o governor)

Think about that for a moment. How fast can your car go in first Gear?  The motorcycle speeds in each gear are outrageous!

As you can see, right now my car has the equivalent of 6 speeds between the original motorcycle 1st and 2nd gears. No wonder it has so much acceleration and my gas mileage isn't anything to write home about.

If you take off really hard, things start happening fast. At 5,000 RPM the rear end has squatted down about 2".  At 7,000 RPM the front end comes up another 2" and the intakes start screaming. With my exhaust header lengths etc the engine "gets on the pipes" at about 7,000 RPM. From there on you basically hang on for dear life.

If you're conservative, you shift at about 10,000 RPM (taking into account that by the time you actually move your fingers to do the shift, the RPMs are going to be even higher). The revs drop to about 8,000 RPM and you are rocketed back to 10,000 RPM for the next shift.

The throttle response in neutral is very quick and it is actually hard to control since the engine has very little flywheel affect. Taking off slowly from a standstill is similar to doing the same thing with a motorcycle that weighs 1000 lbs. In other words, it takes concentration but it can be done even in 2nd. without trouble.

I recently noticed a Suzuki spec sheet that listed the motorcycle gross max. weight as ~1000 lbs. So our BECs really aren't that bad as far as overloading the engine. In affect, the mechanical parts can take the "extra" load of a Locost (if you don't try to be Don Garlits at every stoplight).

Up and down shifts using the clutch can be difficult to do smoothly because the engine response to slow down and speed up is very quick. Up shifts can sometimes be very noisy partly because a BEC doesn't have the rubber cushions that a motorcycle usually has in the rear sprocket.  The RX-7 LSD can make some fairly loud clunks as you let off and give the car a little gas.

If you have Heim joints in the rear suspension links (as my car does) they transmit quite a bit of drive train noise into the chassis and body work. I find the smoothest up shifts are done without the clutch and barely letting up and giving the car gas again as fast as you can. When done correctly it sounds like the car has a very fast shifting automatic transmission.

To shift up a gear without the clutch, you apply pressure to the paddle shifter (most cars seem to use the right paddle for UP shifts) as you quickly let up and give the car gas to do the shift. It's the same technique as shifting a motorcycle except your foot controls the throttle. It will take a little practice to get your foot to move fast enough so the shift is done without causing the car to lurch on and off the gas.

When moving your foot off the gas you really only have to relieve the torque applied to the gears for the shift to be completed. I've found that casual shifts and maximum performance shifts are best made without using the clutch pedal.  Between those two extremes the smoothest shifts can be made by using the clutch. As I drive the car more my clutchless up shifts are getting smoother at all speeds.

When driving along and coming to a stop I usually start shifting down a gear or two below 40 or 50 MPH (using the clutch and slightly blipping the throttle) to use the engine to help with the braking. There is a surprising amount of engine braking affect.  I wait to do the rest of the down shifting into neutral until the speed is 20 MPH or slower. Basically the same thing you do with a motorcycle.

Remember there is NO "neutral" between ANY gears except between 1st and 2nd. So double clutch down shifting is not possible through the gears (except 2nd to 1st).

I have designed and was testing an ignition interrupter, which can do that lessening of the torque on the gears in about 10/1000 (ten thousandth) of a second. I was emailing a fellow BECer who races his car and his electric shift controller is set up for a 8/1000 of a second shift. Try -that- with your T-5! He mentioned that he is using a relay to interrupt the ignition so he may have a little more interrupt time due to the relay delay, Most relays that I've measured have about 5 to 10/1000 sec. delay to switch OFF.

After trying various delay times, I've found that for street driving, the ignition cutoff delay time required doesn't seem to be the same for different engine speeds, how much throttle you are applying at the time etc etc. For testing I was using my normal paddle shifter which most likely did not apply the same instantaneous timing and pressure that an air shifter does. When it works it is fantastic, but most of the time it just won't shift at all. So I've decided to shelve the ignition interrupter for now since I can shift the car using the throttle more consistently and smoother than my test electronics can. My racing pen pal has solenoids to do the shifting and interrupt the ignition at the same time, so that may be the path to follow.

Speaking of torque, I've read comments that BECs don't have much low end torque and you have to shift them a lot. Actually the max torque of the GSXR-1000 engine is ~78 ft-lbs AT THE ENGINE CRANKSHAFT. Something that has to be considered is that the GSXR has a 1.55:1 gear reduction between the engine and the input to the transmission. So to compare the GSXR torque to a  normal car engine you should multiply the torque by 1.55 (ignoring gear losses) to arrive at the equivalent torque delivered TO the transmission of ~121 ft-lbs.  So "78 ft-lbs" is really not all that bad.

The specs show that at any crank speed above 3,000 RPM the engine will put out more than 50 ft-lbs of torque. My Honda CRX HF car puts out a max 90 ft-lbs at 2000 RPM and it goes down hill from there. The GSXR has 60 ft-lbs or more (at the rear tire of the motorcycle) from 4,500 to 10,000 RPM.

What DOES matter is that the engine torque is spread out over a much wider RPM range than normal a car engine. This gives you a broad power range. Combine the torque multiplication of the transmission with the light weight of a Locost and the result is a very high performance car.

I find that the engine has more than enough torque to keep up with traffic and in fact you have to be careful to not accelerate faster than the cars around you. A lot of the time I shift up two gears at a time because it just isn't necessary to use all of them.

I have a program called "Car Test" that I found on the web many years ago, that allows you to see what various cars performance will be on drag strips and many sports car race tracks around the world. You can input your car's specifications into the program and compare it to other cars. The program indicates that my car should do 0 to 60 MPH in 4.2 seconds, 5 to 60 MPH in 4.1 seconds and 5 to 80 MPH in 6.6 seconds.  I do NOT like to brutalize a car that way from a stand still, so I'll take it's word for for the 0 to xx MPH runs. I will do the 5 to xx MPH tests later to see what it will do. This is sort of a standard test I've seen some European writers do.

Would I build the car again knowing all this? YOU BET! I've wanted a 7 ever since Lotus started importing them to the states in the 1960s (for $2900 in So. Fla.) and the Locost is every bit a Lotus 7 as you can get. I feel a BEC Locost is actually more than a Lotus 7.  But truthfully a BEC is a bit much for the street.


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