Northern Auto Tech - ECU and Blue & Me Repairs

Styling New Exhaust Fitted

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Styling New Exhaust Fitted

Punto.Jack said:
Ive just realised what youve said here, you cant have velocity without backpressure. but thats not right because turbo cars dont need backpressure because it restricts it from getting away the exhaust gases.
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You cant compare exhaust systems on an NA car to a turbo car.
Turbos dont need it because the turbo is forcing the gas out giving it the velocity it needs hence why a bigger exhaust is better as you dont need any backpressure on it as you are just slowing it down.

Anyhow its not any where near as simple as we are attempting to make it sound regardless of if the car is forced induction or not. Exhaust tuning plays a massive part in the power output of the engine which is why its so important.
 
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Punto.Jack said:
Ive just realised what youve said here, you cant have velocity without backpressure. but thats not right because turbo cars dont need backpressure because it restricts it from getting away the exhaust gases.
Click to expand...

He is right. The nature of a turbo is that it passes the exhaust gas through a turbine, increasing speed. Anything that gets in the way of the escaping gas slows it down and therefore creates a power loss.

With an N/A engine, there is nothing to increase the speed, and therefore the backpressure is needed to create a vacuum to pull the gas out of the cylinder faster. Thats my understanding of it anyway ;)
 
punto_matt said:
You cant compare exhaust systems on an NA car to a turbo car.
Turbos dont need it because the turbo is forcing the gas out giving it the velocity it needs hence why a bigger exhaust is better as you dont need any backpressure on it as you are just slowing it down.

Anyhow its not any where near as simple as we are attempting to make it sound regardless of if the car is forced induction or not. Exhaust tuning plays a massive part in the power output of the engine which is why its so important.
Click to expand...

I thought you were talking in general, yeah it definatly is alot more to it, we could argue for hours about this but theres loads of setups of exhaust systems you can get its just the one that suits the car.
 
adamcot said:
With an N/A engine, there is nothing to increase the speed, and therefore the backpressure is needed to create a vacuum to pull the gas out of the cylinder faster. Thats my understanding of it anyway ;)
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I cant really be bothered, but Backpressure doesnt create a vacuum pull it through, it builds up exhaust gases until they push throught causing a better flow.
 
James1989 said:
i heard it was ninja squirells kicking the gases out :rolleyes:
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Haha, that explains alot, no wonder exhaust create holes, they chew through em :bang:

And I think I will just have a backbox now the difference in spending another £130 for a through pipe to the cat only a 1/4 inch difference in size I cant justify, i doubt it gives any better power either.
 
GP MATT said:
How does an exhaust pop? The 1.4 8v has no mid silencer box, so would a straight through cat back 2.5" bore make this popping sound?
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if you want poping on a 1.4 8v tel the exhaust place you are useing and they will making it happen(y) its all down the the back box they use:)

it will not be the same as it is on big turbo cars tho! as they get the really big pops and bangs by droping the clutch and flooding the exhaust with unburn petrol (i think)
 
Jambo24 said:
My point is the chap was asking about advice for a backbox for his 1.4 8v:shakehead:
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GP MATT said:
Bit harsh

Thanks Jambo I have looked at Abarth backboxes to.
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Sorry, I thought you were looking for a full system mate and I would look into an backbox abit more suitable for the car as the abarth is for a turbo engine.
 
tim1989 said:
if you want poping on a 1.4 8v tel the exhaust place you are useing and they will making it happen(y) its all down the the back box they use:)

it will not be the same as it is on big turbo cars tho! as they get the really big pops and bangs by droping the clutch and flooding the exhaust with unburn petrol (i think)
Click to expand...

Thats how you get them on any car. But yeah on turbo cars they are bigger because you can get more unburnt fuel into the exhaust to explode than on an NA.
 
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