Tannhauser Posted February 24, 2004 Share Posted February 24, 2004 OK, this may not be the revelation of the century for you folks, but it’s only just occurred to me and I just want someone to check my thinking. I’ve been looking at some of the weight reduction threads on supraforums and after some quick calculations, my initial reaction was ‘why bother?’ For example, let’s say you can reduce the car weight by 50kg (e.g. aftermarket seats and no spare tyre). All figures below approximate and just for the sake of argument. The weight of the supra goes down from say 1.559 tonnes to 1.509 tonnes. This means, assuming you have a stock 326bhp, that the power to weight ratio goes up from 209 bhp/tonne to 215.9 bhp/tonne. This is an increase of only 3.3%. So, you could have kept the car at full weight and increased power to only 337bhp to get the same effect!! This looks a bit lame. BUT THEN it occurred to me that the great advantage with reducing weight is that although the increase in power/weight is modest compared to other mods, you get this increase across the entire rev range. It’s there from before the turbos spool to the red line. For a contrast, if you fit - for example - some more aggressive cams, as I understand it they increase horsepower only towards the middle or upper part of the rev range, which is where the supra excels anyway. A lot of performance mods seem to similarly only benefit at the top end. As a performance modification, then, weight reduction would seem to have the potential to help produce more of one thing I really want from the supe – low end grunt. Also, presumably, it means improved fuel economy. Don’t know how far I would go in practice, ‘cos I don’t want a stripped out interior and I like my creature comforts, but is my basic thinking correct on this? Also are there any nasty side effects of reducing the car’s weight e.g. effects on handling, traction etc? Regards, Cliff Quote Link to comment Share on other sites More sharing options...
Need4Speed Posted February 24, 2004 Share Posted February 24, 2004 Reducing the weight will fundamentally make the car quicker in corners and stop quicker. Reducing the weight at the extremities would give the max benefit. If you only do drag racing, it's not a major issue, you may as well go for BHP. I would reckon to be able to reduce the weight of a Supra by at least 250kg, but it wouldn't be a lot of fun on the road. I built a Porsche for racing that was at least 300kg under the road car weight. Weight is always the enemy - there are no benefits in having it. Quote Link to comment Share on other sites More sharing options...
Terminator Posted February 24, 2004 Share Posted February 24, 2004 I guy I know who stripped out his RX7, went as far as taking all the sound deadening off all the panels. I don’t thing there was anything left to take off the car. It was one quick machine, had a go in it on semi slicks it was like a go-cart on steroids, but as John said not that comfortable or quiet on the road sitting in a metal shell and roll cage. Quote Link to comment Share on other sites More sharing options...
Tannhauser Posted February 24, 2004 Author Share Posted February 24, 2004 Interesting, John. 300kg for your Porsche seems a colossal amount of weight to lose. I bet it didn't look too pretty. I know this begs a facetious reply, but how would you 'lose weight from the extremities'? Quote Link to comment Share on other sites More sharing options...
Need4Speed Posted February 24, 2004 Share Posted February 24, 2004 Terminator - you haven't started to get weight off until you've removed the underseal:eek: Quote Link to comment Share on other sites More sharing options...
Alex Posted February 24, 2004 Share Posted February 24, 2004 Reducing weight is a very good idea...however its hard to achieve significant gains in the Supra... For instance...that big ass bonnet looks like it should be heavy...well the one I picked up the other day was equivalent to a crisp packet., and with the fire proofing removed it would have been lighter still - CF would reduce the weight but at a big cost. The seats are the easiest route to a bit or weight loss but as with everything there is a trade off...and its usually dis-comfort...remove the seats and stick in your carbon backed ones...weight saved/arse numb. Rip out the stereo weight saved/bored in traffic jam and can only hear the drone of the road due to the sound proofing being removed as well. You'll get faster acceleration, improved steering response, improved manouverability, possibly better MPG (though aero has more to do with it when cruising). But the occupants will suffer...how much you decide...but it will be less of a GT and more of a road racer. Possibly the only way to not impact on your occupants' enjoyment of the ride would be CF bodywork and lexan windows (which would need to be replaced frequetly unless you like aged yellow screens??)...but that would be hideously expensive. Unlike power hikes though - weight loss shouldn't impact on reliability which is another big +. Just my 2p - which I'm guessing no one expected me to post Quote Link to comment Share on other sites More sharing options...
Need4Speed Posted February 24, 2004 Share Posted February 24, 2004 Make the following out of Carbon-fibre: Bumpers, wings, bonnet, tailgate, doors and remove all the steel mountings and replace with aluminium. Plastic windows (not the screen though) help. etc etc. As for the Porsche, it looked quiet normal, just don't lean on the bodywork! Quote Link to comment Share on other sites More sharing options...
Paul R Posted February 24, 2004 Share Posted February 24, 2004 I thought Supe bonnets were made from C/F anyhow? Paul. Quote Link to comment Share on other sites More sharing options...
Terminator Posted February 24, 2004 Share Posted February 24, 2004 Hmmmm John I never asked if that had been removed. With all the trouble he had gone to and the noise from stones hitting the underside as they came off the sticky tyres , it may have been removed. Serious weight reduction is for track cars. Quote Link to comment Share on other sites More sharing options...
ad500 Posted February 24, 2004 Share Posted February 24, 2004 Originally posted by Paul R I thought Supe bonnets were made from C/F anyhow? Paul. I was under the impression its made from aluminium, could be wrong though Quote Link to comment Share on other sites More sharing options...
Terminator Posted February 24, 2004 Share Posted February 24, 2004 Originally posted by ad500 I was under the impression its made from aluminium, could be wrong though You are right. Quote Link to comment Share on other sites More sharing options...
Paul R Posted February 24, 2004 Share Posted February 24, 2004 Originally posted by ad500 I was under the impression its made from aluminium, could be wrong though You right. I knew it was something like that!! I'll get my coat! Paul. Quote Link to comment Share on other sites More sharing options...
Tannhauser Posted February 24, 2004 Author Share Posted February 24, 2004 Hi Alex, I agree with the huge downsides you mention. I guess it's just the attraction of improved off-the-line acceleration. I've never been in an after-market seat and it hadn't occurred to me they would be that unpleasant. Presumably they are a harsher ride too? Anyone - just how much would you have to lose before there was a noticeable difference, do you think? The car 'feels' a fair bit faster just without my 125lb girlfriend in (about 3% of the car's mass) , but I've got no reliable way of quantifying that feeling. Quote Link to comment Share on other sites More sharing options...
eyefi Posted February 24, 2004 Share Posted February 24, 2004 weight reduction has an effect on cornering performance as well. it does matter where the weight is taken from. remove or add anything and yr altering the left right or front back balance, which defeats the handling performance benefits. u can also move weight around, battery relocation to over the rear axel is useful for traction esp if u remove the easy weights, which r all in the boot/back. corner weighing on adjustable coilovers can reset the balance. getting good rubber and decent suspension will make massive differences to the handling and acceleration, weight reduction is more fine tuning, especially in something like the supra. mines an rz and i ran around for a while with:- lightflywheel no cats lighter exhaust cusco coilovers stock wheels (s03's could b lighter) no rear seat at all nothing in the boot no passenger seat no airbags no front spoiler cloth drivers seat (much better seat imo) no ice no cruise no trac the car felt different, quite considerably different. with it professionally setup (battery in boot and balanced on softish poly bushes) it would b alot better than stock. but then again im prepared to give up the luxury feel. now, rip out all the glass, elec windows, all the interior, air con, superlight wheels, tyres and brakes and it'd b a right laugh. also only carry mp3's instead of audio files Quote Link to comment Share on other sites More sharing options...
Sharpie Posted February 24, 2004 Share Posted February 24, 2004 Long time no see Alex, good to see you still around Paul, I'm sure the supra bonnet is made of Ali to reduce weight anyway. - Doh! Too late Quote Link to comment Share on other sites More sharing options...
Need4Speed Posted February 24, 2004 Share Posted February 24, 2004 A decent aftermarket seat will feel good, be comfortable and make your car look like a Corsa! When I built the race car I spent ages trying out seats and ended up with a Momo Carbon/Kevlar one. It did the job when I cartwheeled the car! Corner-weighting won't balance a car with an uneven weight distribution. All you can do is balance left to right at the front and the back will do whatever it likes according to what is where in the car. Quote Link to comment Share on other sites More sharing options...
eyefi Posted February 25, 2004 Share Posted February 25, 2004 yeah, i never meant to imply it could correct a 80/20 split to 50/50. lifting the front and dropping the rear will shift the balance backwards. Quote Link to comment Share on other sites More sharing options...
Guest Terry S Posted February 25, 2004 Share Posted February 25, 2004 Reducing the unsprung weight will have the greatest effect,wheels, tyres suspension, brakes. TBH, Toyota did a pretty good job on most things. Alex, good to hear from you buddy. Quote Link to comment Share on other sites More sharing options...
Nick Posted February 25, 2004 Share Posted February 25, 2004 The Brembo's I've fitted weigh quite a bit less than the Jap brakes and I've replaced the spare wheel with a can of tyre weld. But then again I've fitted a large FMIC and 18" wheels so I'm probably square again. I'd like to replace the front seats, mainly because the existing ones aren't very supportive. I was going to have a stereo fitted a couple of years ago until I felt the weight of the sub box, christ it was heavy!! I've still got the factory stero now. Nothing more I can do really as I want some comfort on the road... Quote Link to comment Share on other sites More sharing options...
Guest Terry S Posted February 25, 2004 Share Posted February 25, 2004 Nick, the single kit saves a fair bit:thumbs: You need to be careful not to make the rear too light. Stick the Battery in the boot tyre well. Quote Link to comment Share on other sites More sharing options...
lust2luv Posted February 25, 2004 Share Posted February 25, 2004 Originally posted by Tannhauser Anyone - just how much would you have to lose before there was a noticeable difference, do you think? The car 'feels' a fair bit faster just without my 125lb girlfriend in (about 3% of the car's mass) , but I've got no reliable way of quantifying that feeling. That's because there's no-one nagging you to slow down. Quote Link to comment Share on other sites More sharing options...
Nick Posted February 25, 2004 Share Posted February 25, 2004 Very true Terry. Just waiting to see how Wez gets on with his... Quote Link to comment Share on other sites More sharing options...
Need4Speed Posted February 25, 2004 Share Posted February 25, 2004 eyefi - the point about corner weights is to balance left to right not front to back. You can move stuff about to change the balance of a car, but by corner-weight alone you can't make the front left weigh the same as the front right AND rear left weigh the same as the rear right. To do that you will nee to think carefully about weight distribution. One big problem with a road car is thet the corner weights will change according to the weight and number of people in the car. This is all fairly acedemic on a road car such as the Supra. Quote Link to comment Share on other sites More sharing options...
dude Posted February 25, 2004 Share Posted February 25, 2004 Also fill the tyres with Helium !!!! Dude Quote Link to comment Share on other sites More sharing options...
Tannhauser Posted February 25, 2004 Author Share Posted February 25, 2004 Originally posted by lust2luv That's because there's no-one nagging you to slow down. Funnily enough, nothing could be further from the truth. Thanks for the replies; interesting stuff. Quote Link to comment Share on other sites More sharing options...
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