I'm after a slimline battery for the 940 build as I'd like to avoid the hassle of re routing the stock one to the boot. Do we have any experiences with them? Who did you use? I've seen a few other Volvo guys using Braille ones, they're not cheap though! What are the Oddysey ones like?

Thanks in advance,
Ben.

 

The prob I have with mine is the immense cranking power, you can turn over until they pass the point of accepting the normal charge. I had one on my 1.9gti and it had a clogged fuel breather so didn't want to start, once unclogged it started fine but the battery caught fire as the alternator tried to recharge it. The replacement was free but I have used it a lot and if it drops below a certain voltage you need to tease up the voltage slowly with other charges before a full charge.

They are the cheapest way to go faster though. 20kg saving in weight is better than a lot of horsepower.

 

Interesting, was that with an Odyssey?

Definitely a huge weight advantage.

 

No personal experiance, but rembered this thread from last year,

https://passionford.com/forum/ford-s...n-it-runs.html

 

I will need to check the make, I don't think it is but it is lithium ion which I think is the same. They have an upper and lower voltage, if you drop below then they can drop too far even if you try and balance charge them.

If you drop too low you need to quickly "excite" them with a normal charger and then swap back to a balance charger.

 

If you're already very lightweight, and exhausted all other areas of weight reduction...then maybe, just maybe. I'd still take power every time though...and power every time knowing I've plenty of battery power to cover all scenarios.

And it's only the biggest batteries are around 20kg. There are plenty of smaller normal batteries in the 10-12kg range for a fraction of the price of a race battery.

 

I would go for a small lead acid, good if you aren't doing regular stop / starts. I wouldn't personally use a lithium if the alternator isn't designed to charge it properly, I've seen a lithium battery catch fire and you wouldn't want to be in the vicinity of it!

 

Gtirs use quite a small battery, maybe check one out in Halfords to see how they look.

 

I am sure you know but with weight we need to consider accelerating the weight, stopping / slowing the weight and steering the weight.

A lotus Elise at 120 bhp would kill a two ton Bentley at 500 bhp over 10 laps of a circuit (that's what I am getting at)

There is nothing wrong with light batteries, it is just that they keep cranking when a normal battery would stop. This lets them drop below critical recharge voltage that can lead to fire. If you stop when a Norma battery would stop then you are fine.

 

i run this one for 2 seasons no problems

http://www.ebay.co.uk/itm/PVR-22-Clu...4AAOSwR0JUMpm8

 

cant believe how small it is! bet it costs a fortune! could use this in my vr6!

 

I run an odyssey pc680 and it's incredible. The car is a toy for the road/track so is fairly stripped ....and doesn't do short start stop journeys but never had a prob.

If in doubt phone powervamp batteries. Can't remember the chaps name but he was super helpful when I was buying.

 

As you have said most normal sized batteries will not weigh 20 kg and the problems that it seems fitting a tiny race battery can cause for the sake of quite a small weight saving would not be worth it in my opinion.
I wonder if there were 2 cars the same, both with the same power and 1 has a lighter weight battery in reality what difference it would make to performance figures?

 

In terms of what you and I might experience it may not feel too different but ask an F1 team if they would like to drop 20kg and how it might affect numbers and they would be over the moon with that sort of saving.


You could certainly measure 20kg in performance on a road car but how much is hard to say..you could run a car up the strip with both and see the difference but a good or bad launch would skew the figures.


I know my track car felt much more lively after I stripped 100kg out of the interior (you could hardly pick up the electric seats but the Recaro SPG buckets were easily picked up one handed)


If you try spinning around with a car seat in your hands and then try it with something 20kg lighter you would feel the true difference.

 

You are not dropping 20kgs, so to use that as a reference is silly.

You are not driving F1 cars..so again, silly. I'm sure the Volvo 940 in question is not 500kgs...so again this is silly.

There is no way in hell on your average weight road car you will be able to measure a 20kg weight difference in terms of real world performance.

I've raced mine with passengers and it's made zero difference....on some runs I even went quicker. And that's a 100kgs change. Obviously that wont apply to all, but it's fact for my car.

People can get carried away with the most irrelevant things. It isnt to say losing weight can help, of course it can...but be sensible and practical about it.
A decent reliable battery can be around 10-12kgs...a mega expensive race battery that may not be so reliable will be around 2-5kgs and very expensive to mega expensive.

Really...is it worth it for a real world 5-6kg saving ?

 

I am sorry for being so silly.

My large car battery compared to the lithium is over 15kg to 20kg lighter.

The drag strip may be very different but I can assure you that I can do a faster lap around a circuit without a passenger and replicate that many times.

Re- read the reference to F1, my point was that 20kg change in weight there would change the outcome of the race for certain and the engineers would jump at the chance. All weight savings add up, if you can save a kilo here and there it makes a difference, if you do not accept that then power to weight ratios will not make sense either.

100kgs makes a massive difference to the handling of any car along with the longevity of many of the cars parts.

I will let the thread get back on track as this will only end in a silly internet argument.

If you want to buy a battery that is lighter then do so, if not then don't.

 

Ballistic battery was 1.8 kilos





1810 grammes





Merc battery I had in the back of my 205 pug that the one above replaced. This is a BIG battery as my yb needs a lot of cold cranking.





So, my change was 24 kgs saving for the same cranking power. Try running up the road with 24 bags of sugar and see how much harder that is.<br/><br/>Silly? Not to me for around Ł400

 

Of course 20kg on a 400kg car is a big difference.....does it apply to a Volvo 940 ??? I just cant see it. Although if he has a 4-500kg 940, I'd love to see it and how he's achieved it ! lol )

20kg from a 16-1700kg car...really, no need to get worked up about it. And as said, it wouldnt be 20kgs anyway. I have a 940 turbo myself, and whilst I havent weighed the battery in it, I'd guess its in the 17kg range as it is smaller/lighter than the one in my Granada. But it is the type intended for the Volvo.

The heaviest battery I've ever used was about 22kgs, that was a big Optima, although it died.. My current also huge battery is around 18kgs. Probably about twice the size it needs to be...but who cares ? I know i can sit with fans running, radio on etc etc and it wont let me down, likewise if I ever need to crank the engine over a lot...I know it wont let me down or go on fire.

So as said, you can get a very good powerful normal battery in the 10-12kg range very easily and cheaply, I simply chose a heavier one.

And I'd take 100hp more vs 10kgs weight reduction in almost all circumstances.

 

There is no way ever a YB should need a battery that large.

Hell even my V8 doesnt need one anywhere near that size ! Even my other 940 6cyl diesel didnt have a battery that size !

That's you choosing a very extreme battery to overcome problems elsewhere where one half its size/weight will do the same job.. A smaller battery installed correctly and all other aspects being good, would have no problems at all starting the engine

 

Your not going to notice a 20kg weight saving in a 1700kg volvo.
are they volvos rwd? If so an extra bit weight in the boot from a rerouted battery could help weigh down the back end.

 

Thanks for the replies chaps.

As Steve said, being a 1.8 ton Volvo it's not a huge issue with weight, it's the dimensions I'm after really as the original battery location has something in its place, so I'm after something smaller to tuck in behind it. I'll get some dimensions of space and see what we can come up with.

Thanks,
Ben.

 

There you go then, two sides to each opinion.

I saved 24kgs on the battery and then just over 10kgs by going from metal bonnet to carbon fibre, that cost me Ł1200 before paint. It is a road car and has 469bhp, the car all in is around 1000 kg and I hope to come in under that and the engine will end up around 530 bhp before Mark is finished. I can also save another 12 kg by swapping the boot which I will do.

What made the 205 gti handle so well and go so well was light weight, amongst other things, when my car was converted to 4wd cossie power a lot of weight was added and I don't want to dull that, some extra weight cannot be avoided but to me I want to keep as close to 1000kg as possible. So I added power, lots, but also added lightness in the spirit of the great Colin Chapman, simplify and then add lightness.

 

Totally agree

My cossie came with that battery which clearly was too big and heavy, so I looked for a smaller and lighter option. If you can see the benefit in a smaller battery then why not take the smallest option?

My car has always needed a lot of cranking from cold, it went to Mark Shead for a new loom and vipec ecu, it came back with about 300bhp more but still seems to need a long crank to get it started which explains why the previous owner went so big. I suspect being a bespoke car there is something odd happening in the fuel supply such as draining fuel back.

 

Then the ballistic I showed would do the job well, it is tiny. One tip though, If you go down that route then try to get one with a low volt cut that keeps one last start in reserve as over cranking the lithium adds to hassles. Mark Shead is not a fan of race batteries.

1.8 tons down to 1.78 tons is a good step on the way to a total weight reduction programme but maybe only worth considering if you want to go further and try to hit say 1500 kg as that would make for a far better handling car.

I guess that puts it all in better perspective...if you wanted to try and hit a target weight then the battery is a very obvious starting point (get the pun) along with seats....

 

Once the pump has run for 1sec, there should be more than enough fuel to start the engine....that's why on key on, the pump always primes. There should be no way it is a fuel pump issue causing a poor start.

If the engine is spinning fast enough, and it's tuned correctly it should start promptly.

If it isnt spinning fast enough, then it is a wiring/starter issue, unless there is a mechanical problem stopping it from turning over correctly.

It'd maybe be different if it was a mega high CR n/a race engine...but any turbo engine ? They can all just start easily.

And it's already been said why the smallest option is bad. By the same argument...presumably your fuel tank is small enough to last only a lap or two of the circuit you race on ? No sense in having a larger tank, with larger reserve of fuel either ?

Cooling system ? and all other areas...minimal paint on the car etc ?

from 27:50 if the link doesnt work right

 

By all means, but also take into account the negatives of a small battery and how far do you really need to go ?

And as for weight, racing etc....at a few hillclimbs Ive ran faster in my car than several Caterham type cars....and quite a few other much lighter cars. Which is pretty shocking really ! And it's not like they're anywhere near straight lines.

 

My car was mapped by Mark Shead who has a pretty good reputation for getting the mapping right, we have agreed to do some more cold start mapping to try and solve the issue.


The fuel tank is small, yes. It is a road car but only designed to take around 30 litres and this includes the swirl pot as it is a fun car. the Tank was made out of ally and is sited right in the middle of the car for weight distribution and safety within the cage. It is not a race car, it will be used on Track, the strip but mainly the road.


The pump does indeed prime as you say. The engine, as far as we know is 100% standard 200 block and makes 469 bhp using the Borg Warner twin scroll. No lary cams or compression tweaks....we will know more when Mark rebuilds as a proper 500+ spec.

 

If the engine is 100% standard, then it should start as well and easily as a 100% standard car ( for a Ford anyway lol )
It should never have needed a huge battery

Swirl tank etc sounds like additional and unnecessary weight. Given your main tank sounds like a custom unit, design it right and there should never be a need for a swirl tank, you could easily save a few kgs there too, as well as some money if it was done in the first place. Although changing afterwards would add cost.

 

The swirl is built in to the sump of the tank, it was designed and built by allard engineering, I believe he did it that way to stop any fuel starvation, it is baffled too. (Edited to add that I just checked and it is just a sump design, no extra pump so cannot be a swirl) I was a little disappointed with the design as the tank outlet is pretty small and in hind sight I should have spent more on the ATL that tempted me.


The engine is standard but the car is a Pug 205 running YB, I am yet to find out the cause of the additional cranking need, I am sure Mark will get to the bottom of it in good time. The whole electrical system is new along with coil on plugs etc.

 

Ahh sounds good, thought you meant an external swirl setup.

A good tank with sump ( and foam or baffles inside too etc ) really is as good as any and as simple as you'll get.

What size is tank outlet ? It's surprising how far a small outlet will go. Mine's less than ideal at 5/8" BSP, internal hole is pretty small. It's something I keep meaning to change....but it hasnt presented itself as a problem so never bothered.

 

I cannot remember the size, I think the o/d may be 10mm, it just looked like a pea shooter compared to the 044 inlet size. I would have preferred bigger to know I was flooding the back of the pump as much as poss.

It obviously flowed enough to make the numbers on the dyno but I wonder if I will run in to issues later, especially as I MAY go for the long stroke option which could be as high as 580 bhp and torque to match.

 

Lol as some people have said correctly, faffing with a kg here / there on a 1000kg+ car with 450bhp+ and huge torque is honestly not worth it. Same for most of our pseudo performance cars. Start talking about a bike engined kit car with naff all torque and sub 600kg or a sub 1000kg car with a revvy engine and not much torque (205 gti?!), and yes for the latter a set of poly windows carbon bonnet and tailgate etc start to build a case in truly measurable performance improvements. In the case of my kit car example, have a good dump and trimming your nails before driving can even make a difference! The heavier your car already is through inherent body and drivetrain design (your 4x4 running gear and boat anchor cast iron yb will negate any scraps of weight you can save) the more that power and torque and how the car utilises that is infinitely more important than weight. Stevies video of the gtr is a perfect example of that and actually I'm sure without looking that most of the tin top closed wheel "proper car" super cars which are in the nurburgring top 10 will weigh a lot, but have a lot of power and use it all cleverly. If I was you and i had to pursue a weight saving ambition, I'd be more interested in spending my money on an alloy block than bits and bobs here and there , knock 25kg off in one fell swoop and not stress about the inconsequential. I guarantee you'll go just as fast and not have little bits about the car that would certainly annoy me at least (I want the battery as safe and serviceable as possible... I hated the perspex windows I had in all my cars, they made fuck all difference other than to make life in the car a sweaty pain in the backside... etc).

Your Colin Chapman quotes just aren't relevant - he had to get the most out of small cheap lacklustre engines and became rather good at it what with necessity being the mother of invention etc, by starting with blank paper designs of tiny lightweight shells and running gear (go and stand next to an original elan, scary in size and build). I'm sure he would feel touched by you trying to apply his principles to your car but genuinely reckon as a very clever engineer he'd see there is better returns of modification you could do elsewhere, take you to one side and suggest a change of tack.

Ps the quickest competiton car I've ever been in is pat Dorans rs200... that seemed to do alright in actual proper motorsport, seemed to handle and stop alright (actually the best stopping car I've ever been in!), and you know what? It weighed an absolute fucking ton lol! And that was without pats massive frame in it... didn't see him going on a diet or putting the car on one ; )

 

Lol. Ally block costs how much??

Would love one for mine as I would like to change stroke and bore

 

Reducing weight is rarely cheap !

 

the easiest option is usually for the driver to step away from the pies. No point worrying about 10kg on a battery if your a 18 stone fat fucker!

 

Re: cost... And...?! Thing is, by the time people have spent money on pain in the arse lightweight batteries and getting them to work safely, flappy scratchy Lexan all round, expensive carbon bonnets and tailgates, flappy lightweight door cards, the most lightweight and ridiculously expensive bucket seats they can get hold of (FIA GRP shells are fine!) etc. etc,. they've probably spent 1/2 to 2/3 of what the block would cost anyway. Caddyshack also doesn't look short of a few quid! ; ) I love his car just how it is by the way, none of this is out to "diss", just baffles me the things people get fixated on / distracted by sometimes. All based on the experiences I've had, that's all.

Ben

 

Very true !

Part of the reason I dont care lol

 

I have spoken to Mark on and off about the Alloy blocks and 25kg saving right there is a huge benefit across the front axle. I like this option for the long stroke and Mark said he can even get me up to about 2.7l but the costs do get pretty big when you add in the crank and head work etc. Based on my engine costs so far I would be close to 20 big ones but you could argue that a good MAD engine of that spec has a good second hand value albeit in a small market should you need to sell up later. My Borg Warner would need to be dumped too on the long stroke as it runs out of puff on the bigger capacity.


The car is my hobby and I enjoy the time on it and the journey building it.


I took my 911 to RSR engineering for its track day set up, he has won the Porsche Cup with Paul Edwards a few times and also ran some cars for Le Mans for the factory team, he blue printed my engine and told me not to bother adding power for the track and stripping the car would give a far bigger impact and 100kg was a huge improvement. I made that saving free of charge too as all I did was remove stuff, the only cost was then to add some Recaro SPG. We found a Heigo cage made of Ally as that was banned from racing but did a good job stiffening up the shell.


I am happy with the route I am going down, others may sniff, doesn't really bother me much.


I only weigh 76kg by the way, I was always quick in a Kart due to being much lighter when I raced them.

 

I remember about 13-14 years ago when I had to carry out a lot of welding repairs to another Granada I had.

Before doing so, needed to remove a lot of dirt from the inner guards etc....I scraped off over 1kg of dirt from each side lol

 

I would have swapped the dirt for Carbon fibre dust.