Consider the following...

 

Car Engine Engine power Mass of car Power-to-weight ratio of car

 

Tiger Super 6 Kit Car Tuned 1-litre N/A 100BHP 500kg 200

 

Tiger Super 6 Kit Car Tuned 2-litre N/A 200BHP

 

Tiger Super 6 Kit Car 3-litre Stock N/A Z engine 221BHP 1000kg 221

 

Tiger Super 6 Kit Car 3-litre Tuned N/A Z engine 300BHP 1000kg 300

 

 

Formula 1 car 3-litre N/A 800BHP 800kg 1000

 

 

Stock 300ZX TT 3-litre TT

 

280BHP 1570kg 178

 

Stock Impreza WRX 2-litre Turbo 230BHP 1250kg 184

 

 

For the the kit car, the 2-litre engine is optimal. An F1 car is 3-litre because the engine is lighter and the car needs the extra power for very high top speeds.

 

Extra power fom big-engined heavy cars with equivalent power-to-weight ratios of smaller cars, is not as easy to transfer to the car through the tyre/road interface, as greater friction is required, so this tends to give lighter cars an advantage. It is also possible to be too light.

 

For the type of car a 300ZXTT is, the 3-litre engine is probably optimal. But a lighter car is better off with a smaller, lighter engine, unless it's an F1 engine.

 

In the motorbike world, the 750cc is considered the optimal engine size in a similar way I believe.

 

Are you sure the VG30DE weighs 400kg more than the 2l lump??? I'd be surprised because this would mean the 2l engine weighed about 25kg If this is the case then you are not comparing like for like.

 

CheerZ,

 

Andy

I mean the engine and all it's subsystems.

An F1 engine is 3litre is becuase they are in the rules of F1 Maximum CC of 3000. Believe me, if they said maximum size was 4000CC they would all be 4000CC. Dont forget that F1 cars used to be 1.5litre Turbo about 13 years ago.

Again WRC engines are made to compile with WRC regulations, otherwise they wouldnt be WRC cars.

 

Now you car compairing a bike to a car. OK then a bikes optimal size for acceleration is about 600-900cc. I can tell you that a bikes engine contributes to about 1/2 or more of a bikes overall weight.

I know because there are 3 bikes being built in my garage and I carried out the chassis and every thing from the back of the car on my own and needed help with the engine.

Also a bikes Torque, the thing that actually makes a vehicle move, BHP is a by product of Torque, is very bad.

 

Also why are you now compairing kit cars. The only reason kit cars are fast are because they weigh next to nothing. Its steel tubing chasis, no glass, no roof, plastic seats makes it go fast.

Not wanting to be a pedant (yeah right!), I think you'll find there's an all together different reason why an F1 car is 3 litre engine. I'm sure they'd still be running the 3.5 litre units of six years ago if the FIA would let them! And they'd definately be running the 1.5 litre turbo units of the late eighties if they could. The later ones produced well over 1000bhp. Ask a BMW engineer how they made the blocks hard enough for this amount of boost... if folklore is to be believed, they left them outside in the rain and insisted that the workforce pi55ed on them!

Oops! Was beaten to it!

Oh yeah, and I think an F1 car's 600Kg, and that includes the driver and the plank ballast.

Also on the bike think on of the fastest bikes on the road are the Hyabusa (Spelling ) which is a 1.3 which is huge for a bike.

The VG30DE engine weighs (correct me if I am wrong) 229Kg for the manual. So your calculations are out from the looks of things.

 

CheerZ,

 

Andy

Nelson, no offence mate. I do think you were unfairly slammed on the other post and you weren't exactly presented with reasoned arguments all the time. But if I was you, I'd seriously consider leaving this one mate. It's really not worth it, whether you're right or wrong.

Nah, keep it going its fun - as long as the slagging off stays out of this one anyway The only way we will all agree on the answer is by debating it here...

 

IMO

 

CheerZ,

 

Andy

 

Manaul is heavier lmao

http://www.fia.com/

do some homework on formula one and rallying.

 

spec on cars

200sx falls under small coupe

Nissan 200SX £22,000 4/1998 197/6400 195/4800 158 6.5 142

300zx fallsunder grand touring

Nissan 300ZX '90-'94 6/2960 280/6400 275/3600 180 6 156

Subaru Impreza falls under sports saloons

Subaru Impreza WRX £21,495 4/1994 215/5600 215/3600 158 6 143

as you can see your bhp per ton figures are out the impreza wrx has 158 bhp/ton

where the 300zx has 180bhp/ton

fact is you cant really compare cars under different catagories as you might aswell then race a wrc world rally car against an f1 car.

 

 

 

[This message has been edited by 300z (edited 30-09-2002).]

I agree. Im not having a pop at anyone, just good to have a serious discussion.

Bwahahahahaha warren you dick - the Manual is HEAVIER All of 18Kg though so.... Added to the fact the autobox weighs significantly more than the Manual box anyway, the overall difference is less

 

CheerZ,

 

Andy

Ok. Here's my view. Anyone's welcome to disagree 'coz I'm usually wrong and there's nothing wrong with reasoned debate instead of a slanging match.

 

As a general rule of thumb (I know this isn't exactly right but it's a good approximation), if you double the displacement of an engine, you should be able to double the power. All things being equal, please don't come round and kill my rabbit, etc., etc.

 

I can't imagine that the increase in all the associated ancillaries, etc. will result in a doubling of the engine's weight. Fair enough, you need a bigger block and so on. But there's a lot of components, cooling and otherwise, that will not double in size.

 

For a bigger engine to produce a worse power to weight ratio, it would have to add more to the weight than it proportionally added to the power. This is just for cars that have no other components such as seats, bodywork, etc. When you take into account the rest of the weight of the car, the weight increase of substituting a bigger engine gets proportionally less the heavier the car.

 

Please no one have a go at me for talking crap. It makes me cry on my keyboard and I'm already on my fifth one this week after reading that other thread!

 

Love

 

Mike

Originally posted by andyduff:

The VG30DE engine weighs (correct me if I am wrong) 229Kg for the manual. So your calculations are out from the looks of things.

 

CheerZ,

 

Andy

 

 

You mean for a stripped engine block ?

 

I mean for engine/turbos/intercooler/gearbox/crank shaft/brakes/suspension/radiator/fan/injection system/fuel pump etc. etc.

 

A bigger engine needs bigger most everything else to cope with the higher power and extra heat generated. this is why bigger engines are less effcicient like for like.

 

About engine rules in racing -why are particular engine sizes chosen - is it not because they have been found to be the best for their application ? I know a level playing field is needed to assess the skills of different engine manufacturers/race teams, but the chosen engine sizes are surely out of fit-for-purpose.

 

Note the old F1 car when allowed to be turbocharged were only 1.5 litre. This is because the extra power form charging meant a larger, heavier engine was not an advantage, as the car would have excess power AND be heavier, which would not help.

 

[Whoops! Double post!]

 

[This message has been edited by Mike Duffy (edited 30-09-2002).]

Sorry mate. FIA responsible for the F1 engine sizes again. They ruled that you could have a 3.5 litre N/A or a 1.5 litre turbo. The turbos were still stupidly powerful at that size so they eventually got banned totally.

 

F1 cars use the biggest engine they are allowed. As they squeeze the most out of it they can, the FIA gradually reduce the size allowed. They are currently talking about limiting the size to 2.5 litre V8s in the next ten years.

Erm no you're wrong again The choice was (again correct me if I'm wrong) either a 1.5l turbo lump OR a 3.5 N/A lump - they had a choice

 

Also, you quoted figures for an NA, as did I - so you can't start adding the weights of turbos if you are quoting NA power

 

A bigger engine needs bigger everything else - YES TRUE BUT - as mike said - the increase in power is not in proportion to the weight. If you double the power, you'll probably see a weight increase of around 10% if any at all - most stronger parts use alloys instead of steel so strengthening an engine actually makes it lighter

 

CheerZ,

 

Andy

Originally posted by Nelson MainFella:

 

About engine rules in racing -why are particular engine sizes chosen - is it not because they have been found to be the best for their application ? I know a level playing field is needed to assess the skills of different engine manufacturers/race teams, but the chosen engine sizes are surely out of fit-for-purpose.

seriously they change the rules to keep the speed in check, read the FIA website , and they have the reasons/rules ect.

Note the old F1 car when allowed to be turbocharged were only 1.5 litre. This is because the extra power form charging meant a larger, heavier engine was not an advantage, as the car would have excess power AND be heavier, which would not help.

again they were 1.5 litre because of the rule book, they then made them 3.5 litres , as soon as laptimes get to a point it is considered dangerous they implemented a new rule to decrease engine size, just as they are to in the next seven years make them 2.5 litre.

 

 

 

Shitt - I may be partly wrong.

I am prepared to admit it, but need to think more about this.

 

It takes a better man to admit he's wrong. Think you got unfairly slated on that other post Nelson. When people post more reasoned replies you get a more reasoned result.

 

Moral: Don't ask complicated questions late at night, you get answered by bottles of Stella!

But why are all supercars with massive engines all so heavy (except McClaren F1 which is a freak!!)?? To cope with high speeds ?

 

Why does a 300ZX weigh so much if the engine is only 2-300 kg ?? What's the other 12-13,00kg ?! - that's a lot of weight !

 

 

I admire Nelson's persistance on this. Its 1 against 100 at the moment but hes still staying in there.

 

I think F1 thing was 1.5 Turbo upto about 1989, then it was 3.5NA 3.0NA

Originally posted by Nelson MainFella:

But why are all supercars with massive engines all so heavy (except McClaren F1 which is a freak!!)?? To cope with high speeds ?

 

Why does a 300ZX weigh so much if the engine is only 2-300 kg ?? What's the other 12-13,00kg ?! - that's a lot of weight !

 

its a very hi spec car plus it has a steel chassis which weighs alot.

things have moved on since then, but bear in mind driver seat weighs near 40 kilos or something, add eletric aeriel, windows, hicas, ect ect and you get a fairly heavy car, although 1560 kgs is about the norm for a grand touring car, and of course it was designed for a certain market and weight target they get given.

 

Anyone know for sure the current record holder for 0-60 mph ? [cluthing at straws?!]

 

Also- I know the engine sizes for races are stipulated, BUT why don't they stipulate 6-litre engines or 1-litre engines - purely for safety (bigger only) ? Surely it is based on what tends to be best.

 

Also -isn't a 300ZXTT engine more than 50% heavier than a 200SX engine ? I still think a larger engine of the same design has to be proportionately heavier (but am prepeared to be persuaded otherwise by good argument!) - modding an existing engine is different.

the surface area of a larger engine is smaller when compared to it's size, so need greater cooling, no ? But, I suppose there is less metal in it compared to the greater displacement ?

 

 

I've got too much testosterone, I know !