Drivability of a boosted DC2

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ive got 660cc injectors so my car is quite inefficient when it comes to fuel consumption...
it roughly goes through 300km per tank

Larger injectors doesn't mean you sacrifice fuel consumption (to a certain extent.. also to which 660cc is not an exception)...

It means either you fang your car a lot and use heaps of fuel that way, or you are tuned too rich part throttle.

[Q_ball]

Larger injectors doesn't mean you sacrifice fuel consumption (to a certain extent.. also to which 660cc is not an exception)...

It means either you fang your car a lot and use heaps of fuel that way, or you are tuned too rich part throttle.

thats tru...i do believe that i am tuned too rich atm...
but i was only mentioning the 660cc injectors as an example of something that would decrease fuel.
as for the thangin part...well, no...cruising round and i still get roughly 300-320 so its not that bigger increase overall.

[aaronng]

Larger injectors are less efficient at spraying small amounts. So if you were driving with very small throttle, the fuel atomisation is not as good as with small injectors. So yeah, you would get a more incomplete burn. And your exhaust will look like it was running rich.

[string]

Larger injectors are less efficient at spraying small amounts. So if you were driving with very small throttle, the fuel atomisation is not as good as with small injectors. So yeah, you would get a more incomplete burn. And your exhaust will look like it was running rich.

Please give me a link to some evidence that a 660cc injector isn't very "efficient" at spraying small ammounts.

Enough to cut your fuel economy near in half with only 660cc? I don't think so.

Take Weq for example. He was still getting 300km out of 20L on 750cc injectors.

[aaronng]

You can't compare different cars. You have to take the same car, and put the two different injector sizes from the same injector manufacturer and design. There is a minimum duty cycle for injectors too. Not only a maximum that everyone cares about.

If you want evidence, there are various sites on sizing injectors that tell you not to use too high a flowrate. Just do a search. They say to use 40% minimum and 80% maximum duty cycle when sizing injectors and if you use too large an injector, you get "poor engine performance, surging and stumbling". Another site says that injectors running at below the minimum duty cycle are a "controlled leak"

[string]

You can't compare different cars. You have to take the same car, and put the two different injector sizes from the same injector manufacturer and design. There is a minimum duty cycle for injectors too. Not only a maximum that everyone cares about.

If you want evidence, there are various sites on sizing injectors that tell you not to use too high a flowrate. Just do a search. They say to use 40% minimum and 80% maximum duty cycle when sizing injectors and if you use too large an injector, you get "poor engine performance, surging and stumbling". Another site says that injectors running at below the minimum duty cycle are a "controlled leak"

Sure I can compare them. I was comparing relative fuel consumption. Weq lost only a tiny ammount of fuel economy, due to the fact he now has a turbo in the way of his exhaust.

Blaming a fuel efficiency loss of almost 50% on a set of relatively small (660cc is small) injectors is incredibly stupid.

People have issues with larger injectors because the pintle can't open and close fast enough, so they over-fuel on idle. 660cc is NOT a large injector. Unless he has Joe's Homemade Injectors, it is not the injectors fault he is running excessively rich on part throttle.

Please, give me a link to this website telling me to run injectors at a minimum 40% duty cycle. What a crock of shit.

[Q_ball]

Sure I can compare them. I was comparing relative fuel consumption. Weq lost only a tiny ammount of fuel economy, due to the fact he now has a turbo in the way of his exhaust.

Im pretty sure its not a fair comparison cause fuel consumption depends on a number of factors, car type included.
Say you were to compare Weq's car to mine, his car is a civic, b16a if im not mistaken, mines an integra b18b.
Just looking at those 2 cars stock is enough to say that the fuel consumption for both are different on many levels, and shouldnt be compared for accuracy purposes.
The turbo setup for each car is different too.
Now explain to me this, how can you compare two cars to get an "accurate" comparison of fuel consumption, if both cars are so different?

[Weq]

ur running a microtech arnt u Qball. thats ur answer right there :P
im running hondata, idles perfect, 720cc injectors, tuned by dynodave. i get around 8l/100km general driving, 10l/100km when boosting hard and 7l/100km on the highway.

[string]

Im pretty sure its not a fair comparison cause fuel consumption depends on a number of factors, car type included.
Say you were to compare Weq's car to mine, his car is a civic, b16a if im not mistaken, mines an integra b18b.
Just looking at those 2 cars stock is enough to say that the fuel consumption for both are different on many levels, and shouldnt be compared for accuracy purposes.
The turbo setup for each car is different too.
Now explain to me this, how can you compare two cars to get an "accurate" comparison of fuel consumption, if both cars are so different?

I'm NOT comparing fuel consumption. I'm comparing each car's individual fuel consumption relative to stock sized injectors.

A stardard GSI will get around 9L/100km. You are getting what, 14L/100?
I'm comparing what Weq got before to what he gets now. It is very similar.

The turbo setup is different yes. Different enough to cause such a huge difference in fuel economy, again, not a chance. Your issue is the tuning, not the injectors.

[aaronng]

Sure I can compare them. I was comparing relative fuel consumption. Weq lost only a tiny ammount of fuel economy, due to the fact he now has a turbo in the way of his exhaust.

Blaming a fuel efficiency loss of almost 50% on a set of relatively small (660cc is small) injectors is incredibly stupid.

People have issues with larger injectors because the pintle can't open and close fast enough, so they over-fuel on idle. 660cc is NOT a large injector. Unless he has Joe's Homemade Injectors, it is not the injectors fault he is running excessively rich on part throttle.

Please, give me a link to this website telling me to run injectors at a minimum 40% duty cycle. What a crock of shit.

I was not talking about fuel economy loss of 50% on 660cc injectors. I was talking about larger injectors being less efficient when you use it to deliver small amounts of fuel.

Looks like we are talking about different things. Oh well. Here's the link that you wanted anyway: http://www.ttmtechnical.com/fueldelivery.htm
Just search for the quote: "A duty cycle of 40-50% at full power is too low and means that your injectors are too big for your engine."

[string]

I was not talking about fuel economy loss of 50% on 660cc injectors. I was talking about larger injectors being less efficient when you use it to deliver small amounts of fuel.

Looks like we are talking about different things. Oh well. Here's the link that you wanted anyway: http://www.ttmtechnical.com/fueldelivery.htm
Just search for the quote: "A duty cycle of 40-50% at full power is too low and means that your injectors are too big for your engine."

Well that doesnt answer my question. Thats telling me that by running them at 40-50% duty cycle at max, that they are too big. Not what you said originally, which was that there was a minimum duty cycle, to which your 40% number came out.

Yes, larger injectors may become less "efficient", I havnt argued that. Now i'm saying that a 660cc injector is not large enough to have issues delivering a small enough ammount of fuel for a 1.8L engine's idle, let alone part throttle.

[StrawberryFace]

You wan't better drivability, simple, reduce the size of the snail.

Another option would be to go the supercharger route. They are often over looked in terms of forced induction and are even better in some areas then a Turbocharger. A more linear power curve etc etc.