Weighed the Megabusa

[Hank]

Wow, what a fat pig.

 

Without me in it. Full tank of gas (~12 gallons). 15" rims and Falken Azenis RT-615 street tires. Removed fire extinguisher.

 

267         279
347         291

Total Wt. 1184

Front Bias 46.1%
Rear Bias  53.9%
Left Bias  51.9%
Right Bias 48.1%

 

Same as above but with me in it. Shirt, pants, and shoes. No helmet.

 

305          284
442          341

Total Wt. 1372

Front Bias 42.9%
Rear Bias  57.1%
Left Bias  54.4%
Right Bias 45.6%

 

Plans to ditch weight:

1) Install 13" wheels and bias ply slicks = drop 80 lb (1104 lb)

2) Drain to 1/4 tank for autox = drop 48 lb (1056 lb)

3) Not a chance in hell of me doing this, but if I removed the roll cage/bolts = drop 60 lb (996 lb)

4) Trim bolts

5) Remove the passenger seat, harnesses = drop 20 lb? (race only)

6) Remove the headlights = drop 5 lb? (race only)

7) Remove the front fenders/brackets = drop 10 lb? (race only)

8) Hack up the rotors (front/rear) = drop 20 lb?

9) Work out more to go down to 175 lb

10) Turbocharge the engine to 300 HP and forget about everything else. YES! :devil:

 

So, the Westfield Megabusa flyer indicates the weight as (around 940 lb). I didn't install the rear fiberglass trunk (6.2 lb). I removed the reverse box (35 lb). I used 4 piston front brakes, secondary master cylinder.

 

Thoughts? Ideas? :ack:

[slngsht]

very nice!

[Nordschleife]

Hi Hank,

 

Great data! That corner weight information is critical for directing efforts to improve the car's performance.

 

What strikes me is the rearward weight bias. Simply removing weight is good for all the obvious reasons, but removing weight in places that better balances your car is best, of course.

 

If there is any way to move some of the weight in the left rear quadrant -- namely the driver's area and behind it in your Megabusa Seven? That would be the way to go. And the second focus would be to generally shift the weight balance from the rear towards the front. With you in the car, you're looking at a 43/57% front-to-rear balance now. That rearward bias implies oversteer as a general condition.

 

There may be nothing in the back of your car you can shift forwards easily. In that case, I thought your ideas of the 13" wheels and running with less fuel for Auto-X events were particularly good ones that will improve your times. Gas is about 6.2 lbs/gal so with a 12 gallon tank you could shed some serious rearward weight by running with 2 gallons or so in the tank for Auto-X.

 

Best Regards,

Andy

Edited February 21, 2010 by Nordschleife

[Hank]

Maybe I need to convert her to RHD? Guess it wouldn't have hurt to get in the passenger seat just to see. Can't believe I didn't think of that.

[MichaelD]

The stock tank can be removed and replaced with the 2 gal tank mounted in the right rear. You may also consider moving the battery down and forward on the right frame.

 

GT40s had fuel tank on the right and left side. Has anyone ever moved the fuel cell to the passanger side? What extra safety precautions would have to be made?

[Guest speedcraft]

Paul and I were down to the local SCCA races recently and had a chance to get his SV's and my S3's [zetec and Fireblade] on their scales...interesting results.

 

The FB weighs in at 900# when you discount fuel off the weight but does include the heaviest wheel/tire combination i have [std caterham minilites with R888's]. this also includes the FIA rollbar, passenger seat with 4way belts, lights/signals etc, and the reverser box which is a big lump of solid aluminum and steel [had to replace the chain on it so had it out and it weighs a ton]. i usually run Keizer's with magnesium centers so typically 20# lighter but had the spare set of minilites on at the time.

 

with the slicks and race wheels [keizers] its down to 850#. also i just switched out the adjustable steel seat rails for the fixed place aluminum tillet ones that match the kevlar seats which is 6# less just for rails. the seat is only 5# and since its a popular ride for others on track days, i'll keep it in.

 

you're biggest bang for loosing weight is wheel/tire combinations. the cr500's are very light compared to the r888's or r6/a6's, and they are very very sticky and have a nice feel to them, i havent found a lighter wheel @ 7# each...if there is, let me know !

 

talking with james whitting who designed the car for caterham...there's still more to loose. my FB has the heavy 4 Pot caterham/AP brakes and vented discs...theres a 2 pot aluminum alcon set up with solid discs that drop some weight [apparently the 4 pots dont work as well as the 2 pot despite being a 'higher' spec], remove the heavy caterham rubber mats, trunk floor, and remove a few other things [ie reverser box]...and a lighter exhaust i can probably shave off 30#+ but not sure how much more there is that can be thrown off. there's alot of little bits that keep the weight off already so there isnt say 100# or 200# to loose here.

 

probably by nature the BEC's are rear weighted - the FB has the same issue and is pitched forward a little to try to get more weight up front [it is RHD to try to better balance it L/R].

 

the S3/zetec car i have weighs in at 1150# [without fuel] and with the keizer's/R888's. surprisingly its pretty close on the corner balance despite being LHD with the exhaust and all also on the left. i've been able to loose a few pounds off this but minor.

 

the zetec is the heavy bit here...the duratec i would imagine is a big weight savings. i was surprised about how heavy some things actually are...the starter weighs a ton as does the alternator.

 

to put it all in perspective though, as crazy as we 7 people can get about the weight of things, the FB weighs as much as my toolbox WITHOUT tools in it, and the entire zetec/S3 car is the same weight as just the engine in my truck [cummins 5.9L].

 

i agree with others though, dialing in the set up [balancing, alignment etc] will pay off more than removing a few pounds here or a few pounds there.

[Guest speedcraft]

...so who was the closest guess from the other thread...?

[slomove]

GT40s had fuel tank on the right and left side. Has anyone ever moved the fuel cell to the passanger side? What extra safety precautions would have to be made?

 

I believe the Team Birkinsport guys had a huge 30+ gallon fuel cell on the right hand side for the NASA California endurance races in 2004. They could run the 3-hour race without tank stop.

 

I suppose that was accepted by the NASA folks but obviously they had serious fire suppression systems.

 

 

http://www.teambirkinsport.com/gallery/album14/DCP_3528?full=1

[andrew7]

I wasn't far off, 10 gallons less gas would be about 1125#.

 

Kodiak Racing wheels will make an aluminum forge wheel in 13",any bolt pattern/offset its around 7-8# but their not very pretty. Avon ACB10 tires are around 10# in 13".

 

I haven't cycled the starter longer than a second, I'm going to replace my battery later with a small 4 or 5amp/hr one. They only weight a few pounds. Think 100cc minibike. I have to check and see if a RC high drain 12v custom pack will work, they weigh grams.

 

Those are my early morning suggestions.

 

The Hayabusa is about 50# heavier than an R1 engine, I think you could rip it down to a race weight of sub 1000# but I don't think it will be street worthy. Its a cool ride don't sweat the numbers.

[Nordschleife]

Auto-X may be different -- I just don't know. With one car on the course at a time the risk of accident is greatly reduced, and the speeds are lower of course.

 

For road racing and vintage events I believe there are condition-based provisions for mounting a fuel cell in the cockpit area, but only if the fuel cell is contained within a metal enclosure, which is itself further separated away from the driver with another metal bulkhead that totally separates the cockpit from the container carrying the fuel cell. The floor under the fuel cell must be designed in such a way as to ensure spilled fuel does not accumulate (for obvious reasons), and any fuel lines running through the cockpit must be covered and designed to deflect fuel spray should one of them burst.

 

This assumes a proper FIA FT-3 spec fuel cell, such as those from Fuel Safe/ATL. In European FIA Appendix K historic events they still allow you to run with foam-filled aluminum tanks last time I checked, but here in the USA a proper fuel cell is required by almost all race sanctioning bodies. And if you're using a fuel cell then you would want a fire suppression system to cover the cockpit and engine bay.

 

All in all, cockpit-mounted fuel cells are a lousy idea. Keep the fuel as far away from the driver as possible. The risk to driver safety greatly exceeds the improvement in performance. My 2 cents...

 

Best Regards,

Andy

Edited February 21, 2010 by Nordschleife

[Hank]

Both Spaz and speedcraft guessed 1150 so they were the closest to the as-found weight I believe.

[Spaz]

Both Spaz and speedcraft guessed 1150 so they were the closest to the as-found weight I believe.

 

Nice! What can I say, I am good