Nubaroo - weight reduction

[Nubaroo]

Hi guys please can you be of assistance.

My Daewoo is making round 300KW/520NM at the wheels and the car weighs around 1350KG`s. I run consistent 12.7seconds @ 190KM/H on the 400m on semislicks at our airfiled. How will/should reducing the cars weight by round 30kg`s affect the times( I fitted lighter seats and removed the tar/underveldt from underneath the carpet.) I am sticking to subtle changes for the moment as I still use the car just about every day.

How much weight will I have to lose still to get low 12`s or high 11`s??

Maybe Precisionboost can work his magic with his calculators here???

Thanks in advance

Hannes

[daewoomofo]

well on average 100lbs lost = .10 seconds faster in the quarter. granted thats not exact, its a good rough estemate.

if you wanna loose weight ditch things you dont NEED.

heat adn or a/c
radio
powersteering system (not only weight gain but also less drag on the engine which =faster)
any power accessorys.
all the plastic and trim from the trunk.
the heat blanket on the under side of the hood.

your best bet is to be creative!

[PrecisionBoost]

well on average 100lbs lost = .10 seconds faster in the quarter. granted thats not exact, its a good rough estemate.

That's a pretty decent estimate..... I was calculating 0.11s to 0.13s for every 45Kg ( 100lbs )

Part of that calculation depends on original vehicle weight.

That is to say 100 lbs off a 2000lb car is a reduction of 5% where as 100lb off a 7500lb SUV is only 1.3%

Acceleration is linked to power to weight.... so ET's will be related to percentage of weight loss.


I had a list of all the things I took out of my Pontiac Lemans ( Astra MK2 ) as I weighed everything as I removed it.

I will try to find it... that project is in slow progress after quite a bit of work a year or so ago.

[PrecisionBoost]

Here is polar express.....

http://www.daewootech.com/forum/viewtop ... ar+express

5.75 Kg ( 12.7 lbs ) --> rear plastic panels
8.30 Kg ( 18.3 lbs ) --> interior carpet
12.25 Kg ( 27.0 lbs) --> Spare tire
9.5 Kg ( 20.9 lbs ) --> Center consol, various trim, seat belts
3 Kg ( 6.6lbs ) --> Jack and lug nut wrench
15.5 Kg ( 34.2 lbs ) --> Driver Seat
15.5 Kg ( 34.2 lbs ) --> Passenger Seat
15Kg ( 33.1 lbs ) --> Rear Seat
5 Kg ( 11.0 lbs ) --> glove box, front speakers, sun shades
3.0Kg ( 6.6 lbs )--> Instrument cluster and various trim
6.25 Kg ( 13.8 lbs )-->Sound deadening foam under feet and firewall
4 Kg ( 8.8 lbs )--> wipers, wiper motor, plastic molding
5.5 Kg ( 12.1 lbs )--> dash
5kg ( 11lbs) --> various engine bay components ( fluid resevoirs, spark plug wires, coil pack )
7kg (15.4 lbs) --> radiator and fan (no fluids)
1.25kg ( 2.8lbs) --> heater fan
16.5kg ( 36.4 lbs) --> Battery
9.25Kg ( 20.4 lbs )--> Both drive axles
12kg ( 26.5 lbs )--> torque converter
103.5kg ( 228lbs )--> Entire 1.6L SOHC engine
70kg ( 154 lbs ) --> Automatic 3spd transmission

Some of it ( like the transmission) are certainly not applicable.... but it should give you a good idea.

There were 45Kg alone in the seats.

You could race it with just a light weight driver seat ( aluminum, plastic or carbon fiber ) and then put back the other seats after the race.

Also consider an aluminum radiator with a smaller amount of fluid ( again you could just use it for racing only ) as I'm pretty sure my "drag radiator" only weighs a bit over 2kg despite being 3 times thicker and a multipass design.

Fluids weigh quite a bit.... gasoline is obviously the heaviest..... you can run it nearly empty before racing and bring along some gas cans to fill up during the race and after the race.

You could also replace the battery with a tiny light one just for racing.... use your factory battery to start the car.... then the small light one in the car to keep it running.... after racing pull out the small battery and drop in the factory battery for driving home.

Between the battery, seats and spare tire that is 75kg ( 165 lbs ) all of which can be put back in after the race.

Gasoline weighs in at 0.7276kg per liter..... so a 40L tank is about 29Kg ( 64 lbs )

Other weight reductions could come from replacing the hood with a lighter one made from carbon fiber or kevlar or fiberglass.

Some people go so far as to remove the trunk lid as well.... on a hatchback that can be good as you can replace the heavy glass with a lighter clear plastic.

[Nubaroo]

Thanks guys will have a look and see - Sunday is raceday so I will give feedback ASAP

[WOLFMAN AK907]

Nice write-up on trimming the fat off your car. I did this on my turbo daytona. It helps dramatically. I skinned all my doors and what-not with alluminum sheetmetal to make it pro, but it's not required.

[Nubaroo]

Wolfman - have you any pics????

[WOLFMAN AK907]

It's parked out at the farm right now, but I'll try to get some pics for you this week. Mine looks just like this except I didn't do the the center. I just peeled the carpet and everything outta the floor and spayed truck bed liner on all the floor panels in the car.

[Nubaroo]

Managed a 12.730 second 400M @ 190KM/H. Not quite what I was hoping for. The new semi`s are not as good as the Toyo`s so traction is a bit off. Lightening the car by only 35KG`s did not help much either I suppose. Next I will be looking at removing the 65L steel fuel tank (winch MUST weigh quite a bit) and replacing it with a lighter 20L alluminium one?? I thought doing this would push me out of the 4BF class into 4SF class, but I saw a few cars there today with modified fuel tanks still running in the 4BF class.

[Nubaroo]

@ Precisionboost - any idea on the weight of an average 65L steel fuel tank???

[PrecisionBoost]

They are two pieces of relatively thin sheet steel with internal baffles.... so they are not ultra heavy.... for the cost it might not do all that much.

I'd assume the main advantage is being able to more closely monitor your fuel levels in the aluminum tank and only run a few liters of fuel.

So you went with Semi slicks and had worse traction than the autcross tires?

What brand and size of semi slick?

What pressure did you run them at?

[Nubaroo]

I have stripped out the fuel tank from my "spares" Nubira - it only weighs 7KG`s with the internal fuel pump, so it would be a waste of time to go the fuel cell way for weight reduction

My best times so far was run on Toyo R888 tires(205/40/17), but they are finished now. So I bought Bridgestone Potenza Re55 tires(205/40/17) - not good traction at all as these are track tyres.

My tuner gave me some Mickey Tompson street "semi-slicks" ET Street radials (205/40/17) so the next race meet I will be using these

[PrecisionBoost]

I have stripped out the fuel tank from my "spares" Nubira - it only weighs 7KG`s with the internal fuel pump, so it would be a waste of time to go the fuel cell way for weight reduction

My best times so far was run on Toyo R888 tires(205/40/17), but they are finished now. So I bought Bridgestone Potenza Re55 tires(205/40/17) - not good traction at all as these are track tyres.

My tuner gave me some Mickey Tompson street "semi-slicks" ET Street radials (205/40/17) so the next race meet I will be using these

RE55's are another track/circuit tire not designed in any way for drag racing.... you'd probably get better times with a cheap soft radial tire than the RE55/R888.... good on circuit = horrible on drag racing.

You need a nice soft flexible sidewall and the semi slick should be run at a much lower pressure than usual... say 15psi

[Nubaroo]

Thnks guys

[Nubaroo]

Hi Precisionboost - Thanks for the advice. I know you have told me on numerous occasions that I should go for 15" rims with drag tires with soft sidewalls :oops The thing is - I will have to buy rims and tires in order to run these which is a costly exercise... Also I dont know if I will be able to run 15" rims with my brake upgrade - will have to check.

My next buy WILL be these and I am sure my times will improve.

I run my tires (17") round 0.9 bar pressure??

My Daewoo head is also still stock standard. It revs easilly to the limiter at 7000 without any issues. I am just wondering if it would be worth my while to maybe have it flowed and 3 angle valve seats fitted, as well as I am still running a stock intake manifold - people say that if I build a "intake plennum" with a bigger throttle body I should also see some nice power gains?? Then again with 300 wheel kilowatts the drivetrain (F18 with LSD and 2L sideshafts) are holding up with carefull/propper driving. Maybe more power will just push everything to breakdown limits???

My tuner also reckons that my turbo exhaust housing is restricting my car`s power. Iam using a T3 0.63 exhaust housing with a "dash 3" wheel. He says we should have the T3 housing machines to fit a T4 "dash 2 " wheel - any ideas on this??? I am thinking I will land up with TOOOOO much lag?????