Engine size = BHP

[Viv172]

Hi all,
Can some one please explain to me why bhp doesn’t always go up with engine size? It used to be the bigger the engine the faster the car…but now that we all talk in horse power I’m confused.
For example; The V6 is 3.0 and gives 230bhp, but and Evo 8FQ is a 2.0 and produces 305bhp.... Why didnt Renault just put a 300bhp 2.0 in the V6??

 

[Peter/Clio]

Isnt the Evo turbo charged??

The old Renault F1 cars had about 600-700 bhp from a 1,4 l. turbo charged engine!!

 

[RobFenn]

So many factors contribute to how good the power per litre it is, but essentially its down to how much fuel can be burnt and air can be got.

The most important thing is the inlet valve area, and the bigger the engine the bigger the valve area. Messing around with bore/stroke and the amount of cylinders also creates more power per litre.

But at the end of the day its hard to get everything reliable (engines generally with low specific output last for ages and vice versa) and it costs money to do..some companies just cant do it because of those factors and the turnaround time they have to do it in i guess. But the EVO is a cheat having a turbo.. I know thats a pretty crappy explanation but it would take me all day to even have a go, and i dont know how accurate i would be!

Im sure Ben will elaborate when hes on..

-Rob

 

[jabba]

having a turbo is NOT cheating!!!!!

 

[funkimic]

power is also related to how high u can rev and engine. small engines can rev higher, so can produce more power from there smaller size, but cant produce the same torque as a bigger engine.

thats why bikes and formula one can kick out such high power. F1 have only got 3.0litre engines but can produce 700bhp cos they rev up so high

 

[BenR]

Quote: Originally posted by funkimic on 20 August 2003


power is also related to how high u can rev and engine. small engines can rev higher, so can produce more power from there smaller size, but cant produce the same torque as a bigger engine.

thats why bikes and formula one can kick out such high power. F1 have only got 3.0litre engines but can produce 700bhp cos they rev up so high





not really, a 1000cc bike revs to about 13-14,000rpm and makes about 150bhp. An F1 engine is 3ltrs and revs to 18,000rpm, MotoGP engines are 1000cc and rev to 14,000rpm and make roughly 220bhp..........lots more to consider than pure rpm.

Turbos arent cheating, they just artificially increase efficiency.

 

[BenR]

Quote: Originally posted by VivJ on 20 August 2003

Hi all,
Can some one please explain to me why bhp doesn’t always go up with engine size? It used to be the bigger the engine the faster the car…but now that we all talk in horse power I’m confused.
For example; The V6 is 3.0 and gives 230bhp, but and Evo 8FQ is a 2.0 and produces 305bhp.... Why didnt Renault just put a 300bhp 2.0 in the V6??

To put it simply..........Air.

BHP is the work done (remember GCSE Physics) by and engine, torque being its actual power.

The more fuel you can burn the more work you can do as youll be processing more energy stored in fuel. Controlling fuel is easy, not a problem, the problem is processing air. On a NA engine max theoretical power is limited to total inlet valve area as there is only so much you can flow past a tulip valve design of x diameter at 1 atmosphere.

So, This will kinda take ages to explain and was talked about in another thread.

Put simply, BHP is related to the amount of air/fuel you can process, which is not related to engine capacity in the least........bigger capacities just make it easier to make power without stressing the engine as much and sacraficing low rpm drivability. A gain in one area always equals a loss in another on a NA engine.

Turbos, well....put simply, the more boost you can push whilst keeping control, the more power you can make. 1500cc F1 cars in the early turbo earo were psuhing 1500bhp in qualifying trim from 1500cc. Why, an engine 1/2 the size with twice the power of a 3000cc NA engine is lighter.

 

[BenR]

http://forum.cliosport.net/display_topic_threads.asp?ForumID=6&TopicID=46460&PagePosition=2http://forum.cliosport.net/display_topic_threads.asp?ForumID=6&TopicID=46460&PagePosition=2

This thread might interest you

 

[viceroy]

Torque is usually more indicative of engine size.

Power is a function of Torque and engine RPM, which is why high revving small engines can put out as much or more power than a larger engine.

Adding a turbo or supercharger will not only increase the power but also the torque of an engine because as BenR said, the more air you can get into a cylinder the more fuel you can burn and the more power and torque you can produce.

A 172 for example produces 200Nm of torque at 5500rpm which is about average for a highly tuned N/A engine. The engine also creates 124kW of power at 6250rpm which is also about average for a highly tuned 2.0 engine.

A Honda VTi on the other hand produces about 118kW from its screamer of a 1.6 engine, but it only produces about 147Nm which is about average for a 1.6 engine.

As you can see, the Honda produces 95% of the power of the 172 but only 74% of its torque because of its smaller capacity.

Were you to turbo or supercharge the Honda you would find that both the Power and Torque figures would improve for the simple reason that you are getting more air into the cylinder which means you can now burn more fuel.

 

[Tom]

My mate has bought a car thats a 1.3 and has 245bhp (no turbos)

 

[ChavyBoy]

Yerr Turbos arent cheating they are just increasing the amount of air being forced into the cylinder, whats cheating about that, someone used thier noodle to increase engine efficency.

 

[BenR]

Quote: Originally posted by Tomclio16v on 20 August 2003

My mate has bought a car thats a 1.3 and has 245bhp (no turbos)

What a wankel!

 

[Tom]

Yeah He is!

(saw what yer did there, nice)

 

[BenR]

lol.........

which one?

 

[Viv172]

Thanx guys that explains alot, im just gonna read through the whole thred again S L O W L Y !!

 

[Elliot]

Saw a "Auto Mundial" on Men&Motors the other day, and it slated the RX8.

What does a car feel like when u have 245bhp, and 11nm of torque?

 

[Tom]

lol

 

[123456]

Power comes down to how big of an exlosion you can get inside the cylinders.

And on another note, A moden f1 car produces 912hp(2002 Ferrair) and they NEVER had more than 1000hp, during the turbo age it is only a myth that they had over 1000hp.

 

[BenR]

never during the race, but in qualifying trim they had closer to 1500bhp.

and AFAIK the current BMW P82 still only makes under 900bhp they havent broken the 300bhp/ltr mark yet.

 

[joe_no12]

LOL!! I read somewhere that in the turbo era BMW used to search some scrap yards as the stock blocks with a 50k on them were better (somehow) than a brand new block!!

Would that makes sense Ben? something about the change in the metal. Greener or harder.

 

[123456]

No, They NEVER had over 1000hp, not even for qualifing. Not even pro drag cars have that much power/litre ratio. IF they had 1500hp that mean that they got 1000hp per litre. A pro drag car has a 13L engine and produces 8000HP or 616hp per litre. The Max they ever had is 912hp and thats the 2002 Ferrari(in qualifing).

Get the 1500HP idea out of your head as it NEVER happened.

 

[BenR]

ok, its logical to debate over this.........BUT.

All competitive turbo engine by mid 80s were running 1000bhp from 1.5 ltrs, in 1988 the BMW 4 clylinder pushed out 1300bhp and would push 1500bhp for short periods from a paltry 1.5ltrs, it was also the same year that they intorduced a restriction on maximum boost, it was becoming a war of mechanical strenth.

There was a test engine, 1.5 V6, which DID run 1500bhp on the bench.

Top fuel dragsters run 500ci engines or roughly 8.2ltrs and 6000 odd bhp.

like i said, BMW had the most powerful engine of 2002 and 2003, with the new p84 they should do the same again, but ive still no info that they have broken the 300bhp/ltr mark, not that i look or indulge in it that much.

I have my info, you have yours..........dont be so holstile and simply explain yourself......if im wrong ill eat my humble pie with some cream, but just prove it.

 

[123456]

Where are you getting your info from?

Top fuel drag cars have 8000hp(atleast one that ran 4.5sec). And last years Ferrari engine was stronger in qualifing but slower in race.

According to my sources. the 1987 winner Williams had 800HP. and the 1986 BMW had 900hp. 87 Ferrari had 880Hp,

 

[BenR]

Wonder why our figures are so different?

Im not atop of drag racing at all, to me its one of the more pointless pinnacles of engineering, might as well strap an engine to a rack and send it off. So i wont force my info on that upon anyone. Any recent documentation i could read on that, would be interesting.

My info comes from what a read every now and then, engineering friends and F1 obcessives, other race drivers and a few mates that worked at ilmore.

Care to expand on why they produced so little power, and where this 912bhp ferrari engine is talked about?

 

[123456]

I think its becuase the teams try to keep the details of there cars a very close secret.

A 1.5L doesnt produce much exhaust fumes to power a turbo, so large amounts of boost cant be made, a modern f1 engine is very delicate(300km life) and large boost rules out many exotic materials and more extreme measure to pull performance. Thats my 2 cents.

 

[BenR]

but where did u get your info from then?

its not a matter of the pure processing power of a 1.5ltr, the actual gas volumes due to the rpm and boost (when it comes on) are more than enough. When you start making boost, you start increasing waste gas production with the mroe fuel you burn and force, in, its a snowball effect and like i said, pure mechanical strength and frictional/thermo efficiency. I more than believe that 1000-1500bhp is capable, but the higher outputs only for short periods of time.....very short.

 

[123456]

After some searching the BMW was capable of producing and did produce 1200hp but it broke after 1-2 laps with 4bar of boost but im not sure if they did that again. But in race non of the teams ran over 950hp.

You learn something new everyday.

 

[BenR]

hence the use of qualifying engines 2 laps.

 

[Frosty]

The some of the turbocharged F1 cars had a 3-stage boost controller fitted. The driver could use as much as 5kg/cm2 of boost, but had to be selective about when to use this for the reliability reasons that have been outlined already.

Im pretty sure F1 cars made under 1000bhp when racing on the lowest boost setting, but once a bit more boost was dialed in - I dont doubt for a second that they made significantly more.

An easy way to tell would be to look at an average qualifying lap time, and an average race lap time.

 

[123456]

But if qualifing is 1 hour long at it takes 1 hour to fit a new engine wont that only allow teams to make 1 run? Good if it works out very bad if it doesnt.

 

[DTWD]

Yeah but as frosty says if they use the boost settings they can crank it up if they need some extra time, if they are in pole without it then fine. But if they need it they can use it. Maybe get a couple of times under the belt and then crank it up. I dont ohnestly know, but they have until the race warmup to fit another engine after qualifying.



Paul

 

[BenR]

Quote: Originally posted by 123456 on 25 August 2003


But if qualifing is 1 hour long at it takes 1 hour to fit a new engine wont that only allow teams to make 1 run? Good if it works out very bad if it doesnt.

And how much of F1 is about taking it easy?

Its all about the best, its all engineered to last the desired time, the drivers are there for the simple fact that they are the best. If it messes up, then thats racing.

No F1 team strives to make constant 2nd places.