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Old 12th November 2009, 18:28   #121
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Originally Posted by MileCruncher View Post
Is Forced Induction similar to Ram - Air intake?
turbo charging, super charging NOS etc fall under FI.


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Old 12th November 2009, 18:41   #122
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Originally Posted by MileCruncher View Post
Is Forced Induction similar to Ram - Air intake?
Naturally aspirated is when air is sucked into the IC engine by the partial vacuum formed inside the combustion chamber. The driving force here is the atmospheric pressure. Forced induction is when air is forced into the engine under pressure, like turbocharged or supercharged engines. This pressure is more than the atmospheric pressure.

Forced induction leads to more oxygen being available for combustion, and hence more power output and better fuel efficiency.

More information here -

Forced induction - Wikipedia, the free encyclopedia
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Old 12th November 2009, 19:42   #123
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I meant to say that if the engine revves faster it makes more power, either if it is a NA or FI engine, the power output of all engines depends on what speed they are running, isn't?

Even in FI cars engines the power output is relative to rpm, what I am trying to say is a FI engine (example evo X's 290Hp @ 6800rpm) running at 6000rpm will be delivering more power when compared to the same engine running at 2000rpm, You see the rpm controls the power here too (Atleast upto its peak output, later it may fall slightly)
What you're talking about here is "Power Curve".

But from your post it looked like you were talking about specific output since there was mention of 300bhp/ltr for the F1 engine.

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Do you know anything about this engine?
4A-GE (20-valve) Fourth Generation "Silver-Top"

The fourth-generation 4A-GE engine was produced from 1991 to 1995.
It is a 1.6L NA engine and this engine produces 158 hp (118 kW) at 7400 rpm with 162 Nm (119 ftlbf) at 5200 rpm of torque.

It is a NA engine of early 90's technology..
But whats so interesting in this engine? Its only doing 98bhp/ltr@7400rpm. The 1.6 NA B16A does 106bhp/ltr@7800. So its right there in the NA ballpark.

Quote:
(Veyron is powerful because it has got a bigger engine)
I wasn't talking about power (bhp) i was talking about "Specific output" (bhp/ltr).

Shan2nu

Last edited by Shan2nu : 12th November 2009 at 19:50.
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Old 13th November 2009, 10:08   #124
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Quote:
Originally Posted by watashi75 View Post
Forced induction leads to more oxygen being available for combustion, and hence more power output and better fuel efficiency.
More information here -

Forced induction - Wikipedia, the free encyclopedia
Can we agree here that Forced Induction will lead to better fueal efficiency. Think that this will increase the amount of oxygen avialable per cycle, so more fuel can be pumped leading to increased power per cycle. But this should call for some trade off on efficiency.
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Old 13th November 2009, 11:14   #125
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Originally Posted by taurian2804 View Post
Can we agree here that Forced Induction will lead to better fueal efficiency. Think that this will increase the amount of oxygen avialable per cycle, so more fuel can be pumped leading to increased power per cycle. But this should call for some trade off on efficiency.
I think you are talking about fuel economy. There is a difference between fuel economy and fuel efficiency. See this thread for clarification -

http://www.team-bhp.com/forum/techni...ml#post1184383 (Do you lug your engine?)
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Old 13th November 2009, 12:13   #126
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Originally Posted by watashi75 View Post
I think you are talking about fuel economy. There is a difference between fuel economy and fuel efficiency. See this thread for clarification -

http://www.team-bhp.com/forum/techni...ml#post1184383 (Do you lug your engine?)
Even though there is a difference between fuel economy and fuel efficiency, both will increase in case of Forced Induction.
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Old 13th November 2009, 12:47   #127
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Originally Posted by MileCruncher View Post
Even though there is a difference between fuel economy and fuel efficiency, both will increase in case of Forced Induction.
As per my understanding, fuel efficiency will increase as fuel will burn completely with increased Oxygen supply. But can't get how fuel economy will increase with Forced Induction ?
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Old 13th November 2009, 14:22   #128
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Smile 150 bhp/litre NA engine

Quote:
Originally Posted by Shan2nu View Post

But whats so interesting in this engine? Its only doing 98bhp/ltr@7400rpm. The 1.6 NA B16A does 106bhp/ltr@7800. So its right there in the NA ballpark.

I wasn't talking about power (bhp) i was talking about "Specific output" (bhp/ltr).

Shan2nu
There was a mistake in my post ,

what I am talking about is..

There's a highly-tuned, normally-aspirated 4A-GE variant used in the Toyota Formula Atlantic Series. The displacement is still at 1.6L, but they fitted it with a fuel-injection/ignition system by TRD. In full-race trim, you can expect to get 240 beat-you-till-you're-senseless horsepower!

and that 240 hp comes @7400 rpm only Specific output 150bhp/ltr



and please have a look at this link,
4A-GE Info
Now what do you have to say about this NA engine?

Last edited by r@CYR@y : 13th November 2009 at 14:23. Reason: Forgot to add a referred link before posting
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Old 13th November 2009, 18:04   #129
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Now what do you have to say about this NA engine?
I dont have anything to say about this NA engine bcoz its not what you made it to be.

Carefully read the specs for the Formula Atlantic engine again and see at what rpm those 240 horses are being produced.

Dude, dont bother wasting your time with this. If high specific output was achievable at low revs from NA engines, F1 engineers wouldn't have even bothered spending millions to get the engine to produce 300bhp/ltr@18000rpm, they would have produced it as lower down the rev band as possible.

Shan2nu

Last edited by Shan2nu : 13th November 2009 at 18:18.
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Old 13th November 2009, 18:32   #130
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Originally Posted by taurian2804 View Post
As per my understanding, fuel efficiency will increase as fuel will burn completely with increased Oxygen supply. But can't get how fuel economy will increase with Forced Induction ?
Fuel economy will increase because you will get the amount of power reuired by burning less amount of fuel. So the same amount of fuel will burn more for increased fuel economy.
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Old 13th November 2009, 21:55   #131
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Originally Posted by Shan2nu View Post
Dude, dont bother wasting your time with this.
Shan2nu


I am not wasting anyone's time, Just wanted to see whether what I knew was correct or wrong, Well anyways this thread has given me lot of knowledge in a very short time..

It is worth remembering, I thank all those who have replied to the posts and the one who started it..

Keep revving..
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Old 25th February 2010, 16:52   #132
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Question What is the difference in the terms PS@rpm and Nm@rpm?

Ok...This might be a dumb question to all the intelligent folks out there, but still taking the courage to ask.

With so many new launches happening and everyone showing off different specs of engines, I am majorly confused with the the terms BHP and torque - PS and NM respectively.
  1. In some cars the bhp is lower, but have a higher torque (mostly diesels I guess) and the other way around. Why is it so?
  2. If a car has higher bhp, does it necessarily mean more power to the wheels?
  3. How does each of these - BHP and TORQUE, affect my driving in the city (low to mid range pulling) and the highways (top end pull)
Coming to the cylinder terminologies - Is a 4 cylinder necessarily better than a 3? Will a modern 3 cylinder (POLO / K-Series...) have the same sweet exhaust note and be more smooth than a 4 cylinder?

Thanks!
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Old 25th February 2010, 17:24   #133
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PS is a term used for power and Nm is a term term used for torque.

For details on the relationship between Power and Torque please go through this thread: http://www.team-bhp.com/forum/techni...ue-vs-bhp.html (Torque vs BHP?)
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Old 25th February 2010, 19:46   #134
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Originally Posted by ukamath View Post
Ok...This might be a dumb question to all the intelligent folks out there, but still taking the courage to ask...
Of course, you can ask all these questions, and more, but am not sure if these questions warrant a separate thread, since it would have been discussed already in some other thread


Quote:
Originally Posted by ukamath View Post
....
  1. In some cars the bhp is lower, but have a higher torque (mostly diesels I guess) and the other way around. Why is it so?
  2. If a car has higher bhp, does it necessarily mean more power to the wheels?
  3. How does each of these - BHP and TORQUE, affect my driving in the city (low to mid range pulling) and the highways (top end pull)
For simplicity sake, I am referring only to non-CRDE diesel engines and carb petrol engines in the below replies :

1. Usually , diesels have better low-end torque compared to petrol engines. Power and torque should always be used in reference to the engine rpm. The power is usually mentioned at a specific RPM (the rated RPM), while the torque may be in reference to an RPM range.

2. Assuming that this is not a trick question, the simple answer is "YES, more engine BHP means more power to the wheels".

3. Better low-end torque (and good torque spread) is good for city driving. The higher BHP will be useful in high-speed highway crusing , but even in the highway driving, the torque will have a say, when you want to quickly overtake those 38kmph / 40kmph lorries (trucks) which are overtaking each other.

For any IC engine, the peak torque always occurs at an RPM which is lower than the RPM at which the max. power is delivered.

As an eg., in a 1300cc petrol engine, peak power could be 80 BHP at 4500rpm, while the max torque could be 10kgm at 3000-3500 rpm.

Hope this helps.

Last edited by Blue Thunder : 25th February 2010 at 19:49.
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Old 25th February 2010, 22:34   #135
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Further to what Blue Thunder has said, please also note Power @ any RPM = 2*Pi*N*T/60 wherein N= RPM and T= Torque at that given RPM.

Also Torque is the primary measure whereas Power is a derived measure.
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