[Shan2nu]

I just wanted to know. Lets say i fit a TC on my Vtec to produce 120-130 bhp. By doing this, even thought the bore a stroke of the engine remain stock, the amount of air entering the cylinder is increased by a certain percent (depending on the TC).

So, isn't it similar to having a bigger engine under the hood? So by TCing my Vtec i might be able to increase the cylinders ability to take in more than 1500 cc of air/fuel mixture.

On paper it might a be a 1.5 ltr engine but in reality, the cylinders actually take in a larger capicity of air.

I've heard that 14.6 psi is equal to the atmoshperic pressure, so if a 1.5 ltr car is fitted with a 14.6 psi TC, it would actually be taking in 3000 cc of air/fuel mixture.

Shan2nu

[Rehaan]

Originally Posted by [b

Quote[/b] (Shan2nu @ Oct. 18 2004,02:52)]So by TCing my Vtec i might be able to increase the cylinders ability to take in more than 1500 cc of air/fuel mixture.

In the true sense....no.


CC is a unit of Volume.
And adding a TC is not increacing the volume/displacement.

Think about it, cc = cubic centimeters, and thats not changing.

However, adding a TC will put in more mass of fuel/air mix, and engines cant really have a definite "mass of air" rating..since it changes with stuff like atmospheric pressure, temperature, etc (hence MAF sensors in the intake etc etc.)

cheers
R

ps - just as food for thought - ACI Speedrun determined TC'd cars' equivalent displacement by multiplying by 1.7
Turbo'd_engine_CCx1.7=N/A_equivalent_CC

[Shan2nu]

That's true, but the TC'd car does use more air/fuel mixture. So it would be unfair to say that a 1.5 ltr NA engine and 1.5 ltr TC engine come in a same category.

1.5 x 1.7 = 2.55, making the engine suck in as much mass of air as that of a 2.55 ltr NA engine (technically speaking). And even that 1.7 is never constant, it' will change, depending on the TC.

Shan2nu

[Domnic]

Hi,
As rehaan put it. The CC cannot change. But yes the Amount of air in the cylinders does increase. But again if you look at it this way, 1500 cc of air is still in your engine but just that its more dense.

What autocar did was pretty strange. That 1.7 multip factor was pretty strange. Either there should set a modified category rather than jump literally indian open.

Cheers
Dom

[bhp]

well guys how much does it cost to install a turbocharger in an lancer or the honda city and how much is the hp increase in it ?? does it run on normal fuel ??

[speedsatya]

hey dom,
can the stock engine parts withstand the additional load of the turbo?
or do u have to modify them,

satya

[ajith]

Any forced aspiration would lead to higher volumetric efficiency and consequently higher compression. The amount of boost will determine the volumetric efficiency. This is also the reason people opt for low-compression pistons when going high on boost. Trying to equate this to actual engine displacement is IMHO too simplistic. And the *1.7 conversion formula sounds pretty odd? What decides this multiplier?

[Shan2nu]

Originally Posted by [b

Quote[/b] ]And the *1.7 conversion formula sounds pretty odd? What decides this multiplier?

True, coz not all TCs produce the same amount of boost. I think the multilier should be calculated keeping the boost pressure in mind.

Originally Posted by [b

Quote[/b] ]This is also the reason people opt for low-compression pistons when going high on boost

Yup, i've noticed this too. te Skoda RS runs on a comp ratio of 8.something:1, while other NA engines run on 9:1 or higher.

Shan2nu

[Domnic]

Hi,
Yes lower compression ratios are needed to support more boost. Stock parts can handle a turbo but to a certian limit. Most indian cars about 4 psi is the max on stock internals. You could however try using thicker head gaskets to reduce the compression ratio and inturn increase the boost. But it is prefered to upgrade to stronger metals for more boost.

Cheers
Dom