Discussion
I know, lots of debate around here in various foruns but I couldn't find the answer to my doubt. I own a Seven (Locost) with a ZX9R engine, and it's quite fast, although I feel that a similar power to weight ratio CEC would be at least as fast.
My question: In a single seater race series (Formula Ford alike) where regulations stipulate power to weight ratio (220bhp/Ton) and keeping the engines/gear boxes standard, which would be faster, a 600cc (under 110bhp, very low torque, 6 speed sequential) bike engine or a similar power car engine (higher torque, 5 speed standard gear box)?
Resuming, for the same power to weight, witch is faster?
Thanks
My question: In a single seater race series (Formula Ford alike) where regulations stipulate power to weight ratio (220bhp/Ton) and keeping the engines/gear boxes standard, which would be faster, a 600cc (under 110bhp, very low torque, 6 speed sequential) bike engine or a similar power car engine (higher torque, 5 speed standard gear box)?
Resuming, for the same power to weight, witch is faster?
Thanks
madmax5 said:
I know, lots of debate around here in various foruns but I couldn't find the answer to my doubt. I own a Seven (Locost) with a ZX9R engine, and it's quite fast, although I feel that a similar power to weight ratio CEC would be at least as fast.
My question: In a single seater race series (Formula Ford alike) where regulations stipulate power to weight ratio (220bhp/Ton) and keeping the engines/gear boxes standard, which would be faster, a 600cc (under 110bhp, very low torque, 6 speed sequential) bike engine or a similar power car engine (higher torque, 5 speed standard gear box)?
Resuming, for the same power to weight, witch is faster?
Thanks
If you had to go for a 600cc BEC I'd say the car engine would be quicker because of the low torque. However if you were going for 300-350 hp/ton and could use a 1000cc I'd probably say BEC. My question: In a single seater race series (Formula Ford alike) where regulations stipulate power to weight ratio (220bhp/Ton) and keeping the engines/gear boxes standard, which would be faster, a 600cc (under 110bhp, very low torque, 6 speed sequential) bike engine or a similar power car engine (higher torque, 5 speed standard gear box)?
Resuming, for the same power to weight, witch is faster?
Thanks
madmax5 said:
Yes.
I'm planing a final weight, with me included, of 530Kg. With a standard car engine of 117bhp.
I think I'll go with this option, I just needed to ear someone else opinion, thanks... buying the donor car tomorrow.
When I had my R1 engined fisher fury It was about 520kg with me sat in it. Any more weight and it felt pointless, a passenger gave an obvious blunt to the performance. I'm planing a final weight, with me included, of 530Kg. With a standard car engine of 117bhp.
I think I'll go with this option, I just needed to ear someone else opinion, thanks... buying the donor car tomorrow.
Now if we're talking a 600 you haven't got the torque, so you'll have to be accessing the power all time, i.e revving the spuds off it. Add that to the fact the engine/box is carrying a lot more weight than ever intended, you may (probably will!) see reliability issues at some point. A 115hp zetec would be totally understressed and unlikely to give any problems, a 600 would be the total opposite. You won't get any points for a DNF!
It depends on the circuit.
There are lots of 'ifs' and 'buts', but in terms of basic principles:
Because it's lighter, the BEC would potentially brake and corner slightly better (though the unfavourable sprung:unsprung weight ratio could mean that this advantage would be eroded if the track surface was less than perfect).
Because it's got more power, the CEC would have a higher top speed and would accelerate better in the upper part of its speed range.
So if it's a 'slow' circuit with short straights and lots of tight bends, the BEC would potentially have the edge, whereas on a 'fast' circuit with long straights and more sweeping, high-speed bends, the CEC would probably be quicker.
There are lots of 'ifs' and 'buts', but in terms of basic principles:
Because it's lighter, the BEC would potentially brake and corner slightly better (though the unfavourable sprung:unsprung weight ratio could mean that this advantage would be eroded if the track surface was less than perfect).
Because it's got more power, the CEC would have a higher top speed and would accelerate better in the upper part of its speed range.
So if it's a 'slow' circuit with short straights and lots of tight bends, the BEC would potentially have the edge, whereas on a 'fast' circuit with long straights and more sweeping, high-speed bends, the CEC would probably be quicker.
May be worth a trip to a auto grass meeting to take a peep, they have a new formula, f600, I know it short ovals and not like for like circuit wise but times are on a par with and often quicker than the 2 litre tuned cars using similar chassis but obviously a little heavier.
The f600 car as to have a sealed standard engine, the 2 litre class is unlimited tuning with the exception of no forced induction.
The f600 car as to have a sealed standard engine, the 2 litre class is unlimited tuning with the exception of no forced induction.
Jon Ison said:
May be worth a trip to a auto grass meeting to take a peep, they have a new formula, f600, I know it short ovals and not like for like circuit wise but times are on a par with and often quicker than the 2 litre tuned cars using similar chassis but obviously a little heavier.
The f600 car as to have a sealed standard engine, the 2 litre class is unlimited tuning with the exception of no forced induction.
Thing is with autograss, you gear the little 600 up to high heaven and it's always singing. The f600 car as to have a sealed standard engine, the 2 litre class is unlimited tuning with the exception of no forced induction.
On track you need a spread of gears, so the power isn't always there like it would be in a grasser. I'd imagine a grasser is lighter than 450kg's too?
I was comparing similar chassis though, the 2 litre class uses the same chassis.
Not saying one is better than the other just giving a bit of info where the op could see 600 bike engines in 4 wheeled competion use.
No doubt as the series develops it will soon become pretty clear which is the best route to go, personally I would try a 600 bike engine 1st, there not particulary expensive and I "feel" they would be much more responsive particulary into around and out of twisty stuff, slip stream the cec down the long straight and do him on the brakes, single seater style.
I could be way off but that would be my starting point, as the series develops everyone will be in cecs or becs, time will tell.
Not saying one is better than the other just giving a bit of info where the op could see 600 bike engines in 4 wheeled competion use.
No doubt as the series develops it will soon become pretty clear which is the best route to go, personally I would try a 600 bike engine 1st, there not particulary expensive and I "feel" they would be much more responsive particulary into around and out of twisty stuff, slip stream the cec down the long straight and do him on the brakes, single seater style.
I could be way off but that would be my starting point, as the series develops everyone will be in cecs or becs, time will tell.
The circuits are the same where you have Formula Ford, GT racing, LeMans series, etc., they are fast.
The weight will be approximate the same, BEC or CEC we need 220bhp/ton driver included. Similar to FF 1.6 Kent.
Because I'll use a boxer car engine, the gravity center will be lower in the CEC than the BEC. In case you wonder, I believe this car was not sold in GB, but was a huge success in Italy and Portugal (where I am) it's the Alfa Romeo 33 1.7 Boxer. Already has a transaxle attached and is a very reliable, yet fast, unit.
As I said before, I was almost decided already, just wanted to here others opinions.
The races start in July, and I believe there are a few fellow competitors that are going to the BEC solution, I'll tell you the result than.
Thanks
The weight will be approximate the same, BEC or CEC we need 220bhp/ton driver included. Similar to FF 1.6 Kent.
Because I'll use a boxer car engine, the gravity center will be lower in the CEC than the BEC. In case you wonder, I believe this car was not sold in GB, but was a huge success in Italy and Portugal (where I am) it's the Alfa Romeo 33 1.7 Boxer. Already has a transaxle attached and is a very reliable, yet fast, unit.
As I said before, I was almost decided already, just wanted to here others opinions.
The races start in July, and I believe there are a few fellow competitors that are going to the BEC solution, I'll tell you the result than.
Thanks
Sorry, I thought your original question was hypothetical.
In that case, the only advantages I can see for the BEC are the quicker, sequential gearchange and the ability to change final drive (which you won't have if the gearbox has to remain standard on the car engine). The latter, in particular, is quite a big advantage, though.
madmax5 said:
The weight will be approximate the same, BEC or CEC we need 220bhp/ton driver included.
That means the engine horsepower is approximately the same, too, then and that the BEC will be ballasted to make it weigh the same as the CEC?In that case, the only advantages I can see for the BEC are the quicker, sequential gearchange and the ability to change final drive (which you won't have if the gearbox has to remain standard on the car engine). The latter, in particular, is quite a big advantage, though.
Yes, the final weight will depend on the engine power. I could use a Hayabusa engine, but then the car would have to weight almost 1ton, not very good for braking and cornering.
The sequential gearbox was the main reason why I was still thinking on the BEC, but it's not enough. The original gears/differential from Alfa Romeo are well adjusted to this tracks, it will be, again, very similar to a FF in terms of top speed, with the advantage of real 5 speeds (the original car achieved top speed in 5th).
If you want I can put a link to regulations of this formula, but you'll need to read in Portuguese, or use google translate, which I doubt works on this technical stuff.
The sequential gearbox was the main reason why I was still thinking on the BEC, but it's not enough. The original gears/differential from Alfa Romeo are well adjusted to this tracks, it will be, again, very similar to a FF in terms of top speed, with the advantage of real 5 speeds (the original car achieved top speed in 5th).
If you want I can put a link to regulations of this formula, but you'll need to read in Portuguese, or use google translate, which I doubt works on this technical stuff.
If it is a pure racing car with matched power to weight ratio the I would always want the ligtest vehicle possible regardless. As Colin Chapman famously said, if you give a car more power it will go faster in a straight line, make it lighter it will go faster everywhere... The lighter chassis will be more agile, change direction better, brake better, and will be easier on it's components like tyres and brake pads. Best though to see who wins the championship each year and copy them, if it's car engined then i'd do that.
I may be wrong of course but I'd go with a light under stressed car engine. Maybe a k series would be a good bet.Furyblade_Lee said:
As Colin Chapman famously said, if you give a car more power it will go faster in a straight line, make it lighter it will go faster everywhere...
It's a slick quote, but unfortunately it's only true up to a point. Top speed and top-end acceleration are a function of aerodynamics and power. The bottom line is that when all the available power has been absorbed by aerodynamic drag, the car stops accelerating.The shape, frontal area and aerodynamics are not significantly different fro a BEC and a CEC, so that means that whichever car has the most power will keep on accelerating longest.
It's then a balancing act between the handling and braking advantages of low weight versus the advantage of straight line speed and acceleration... and the balance will change from circuit to circuit.
You also run into the law of diminishing returns, particularly with non-aero cars, due to less favourable sprung:unsprung weight ratios eroding the grip advantage from light weight unless you have fantastically good damping.
The OP states a 600cc engine of "under 110bhp" (which could be 109..) and a car engine of 117bhp. So we are only talking potentially an 8bhp difference!
Granted then the actual vehicle weights should be similar of each car.
You are right top speed is a product of power and aero, acceleration is a product of weight and torque. A brick-shaped 7 needs massive power to go deep over 100mph, 117bhp won't get it far. Although the bike engine will have relatively low torque low down, both engines will have a "power band" and as long as you stay in that powerband then you are
getting all the beans. The bikes 6-speed sequential will allow you ( gearing dependent, could be a BIG issue in this 600cc case and is vital to check before committing to mating it to a car diff ) to stay in the engines
powerband. On the road it could be unpleasant but flat out 10/10ths on a race track you should not ever fall out of the powerband if you know how to drive.
Assuming the cars will end up weighing within 10% of each other, I would like to see specific power and torque curves of the 2 actual engines in question, then a fearing calculator. I think Sam your argument would be correct if the power levels took both cars 130+mph, but that relative low power in a 7 will get nowhere near that so it is largely irrelevant. What's more important is getting to 100mph as quick as possible , and the 6-speed sequential may well help that, and the 10% weight saving should improve handling and braking.
The OP may be better too running an enclosed body car like a Fury or Phoenix as the aero advantage could make a big difference in lap times with that low power.
Granted then the actual vehicle weights should be similar of each car.
You are right top speed is a product of power and aero, acceleration is a product of weight and torque. A brick-shaped 7 needs massive power to go deep over 100mph, 117bhp won't get it far. Although the bike engine will have relatively low torque low down, both engines will have a "power band" and as long as you stay in that powerband then you are
getting all the beans. The bikes 6-speed sequential will allow you ( gearing dependent, could be a BIG issue in this 600cc case and is vital to check before committing to mating it to a car diff ) to stay in the engines
powerband. On the road it could be unpleasant but flat out 10/10ths on a race track you should not ever fall out of the powerband if you know how to drive.
Assuming the cars will end up weighing within 10% of each other, I would like to see specific power and torque curves of the 2 actual engines in question, then a fearing calculator. I think Sam your argument would be correct if the power levels took both cars 130+mph, but that relative low power in a 7 will get nowhere near that so it is largely irrelevant. What's more important is getting to 100mph as quick as possible , and the 6-speed sequential may well help that, and the 10% weight saving should improve handling and braking.
The OP may be better too running an enclosed body car like a Fury or Phoenix as the aero advantage could make a big difference in lap times with that low power.
All of you are right, thanks.
Just a short explanation of rules.
Identical to FF 1.6 Kent with except:
Tyres: Toyo Proxes R888 under 205 - 15"
Weight: free as long as the power to weight ratio is 220bhp/T
Engine, free as long as: capacity under 2.0, NA (carburetors), standard (the official manufacturer data will give the power to calculate the power/weight ratio)
The first idea is to go with BEC, but when you see the power and how much the car will weight, the only possible engines are very small, and with +10 years, because of carburetors rule.
When I published this topic, was to see if you could make me change my mind to go BEC again, but, by what you post here, we agree in everything and the sensible way is, from my interpretation, to go with a car engine.
The only advantage of the byke engine is the 6 speed sequential, and the sound, of course. I believe the torque of the car will remove the 6 speed advantage, and a Boxer Alfa Romeo doesn't sound that bad either
Cheers
Just a short explanation of rules.
Identical to FF 1.6 Kent with except:
Tyres: Toyo Proxes R888 under 205 - 15"
Weight: free as long as the power to weight ratio is 220bhp/T
Engine, free as long as: capacity under 2.0, NA (carburetors), standard (the official manufacturer data will give the power to calculate the power/weight ratio)
The first idea is to go with BEC, but when you see the power and how much the car will weight, the only possible engines are very small, and with +10 years, because of carburetors rule.
When I published this topic, was to see if you could make me change my mind to go BEC again, but, by what you post here, we agree in everything and the sensible way is, from my interpretation, to go with a car engine.
The only advantage of the byke engine is the 6 speed sequential, and the sound, of course. I believe the torque of the car will remove the 6 speed advantage, and a Boxer Alfa Romeo doesn't sound that bad either
Cheers
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