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Romans 2005 Toyota Echo - Exhaust in progress / new big block setup


Roman

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1 hour ago, kpr said:

9.thumb.jpg.b1d0281cf3f3a8772c6908ad7cf87bb1.jpg

 

 

So does it just get run open from the back of this or is Roman going to need to tie it into a resonator/muffler/ further exhaust? @Roman are you going to run this daily or only for the drags/track, do you need a cat for Wof purposes?

Wondering how loud its going to be lol

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You know that a good straight through muffler makes more power than a straight bit of pipe? 

Because the perforated inside has less surface area than a straight bit of pipe, so theres less drag on the gas.

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Yeah, flows more.   but kinda means your exhaust is too small if makes more power.   

After the end of that pipe, idea is to simulate no exhaust.  biggest straight through glass pack can fit straight after it.  the rest of exhaust just needs to make it quieter,  while adding little exhaust pressure as possible
So yeah echo with 3" exhaust

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14 hours ago, RUNAMUCK said:

You know that a good straight through muffler makes more power than a straight bit of pipe? 

Because the perforated inside has less surface area than a straight bit of pipe, so theres less drag on the gas.

 

So really we should be running one 3" hotdog all the way from the manifold? 

 

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Bigger isnt always better.

If you read the exhaust thread, (If you can find it) a poster there said they found through extensive dyno testing to make more power with a slightly smaller diameter pipe. (Speeno decried it as BS because it contradicted his beliefs, but the same dyno should provide accurate data on the same vehicle)  too big a diameter pipe, and the gas cools down/loses its velocity.

On a turbo engine, the dump pipe off the turbo cant be too big. The bigger the pressure drop off the back of the turbo the better. As everyone knows, turbos aren't spoiled by gas flow, but by the residual thermal expansion of the gas. So having a gigantic pressure drop straight off the turbine wheel allows the gas to expand, and transfer that energy into rotational energy in the turbo shaft. 

A 3" pipe on say an SR20det, or a 4g63t makes sense. I'd honestly expect diminishing returns on an NA 1500cc engine. 

I'm happy to be proven wrong. 

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47 minutes ago, RUNAMUCK said:

Bigger isnt always better.

If you read the exhaust thread, (If you can find it) a poster there said they found through extensive dyno testing to make more power with a slightly smaller diameter pipe. (Speeno decried it as BS because it contradicted his beliefs, but the same dyno should provide accurate data on the same vehicle)  too big a diameter pipe, and the gas cools down/loses its velocity.

KPRs dyno testing shows exact opposite of all this on a variety of 4AGE combinations.

3" pipe gains power everywhere, over a smaller pipe. And actually surprisingly picks up the most gains in midrange. 
Then headers only makes slightly more power than that. 

About the gas losing its velocity, I've heard that mentioned a lot but I dont think this makes sense.
Because if you double the rpm, you double the velocity of the gas in the pipe. 
So if this held true you'd expect a 3" pipe to gain top end when the airspeed is higher again, and lose midrange.
But it doesnt happen, the opposite does.




 

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50 minutes ago, Roman said:

KPRs dyno testing shows exact opposite of all this on a variety of 4AGE combinations.

3" pipe gains power everywhere, over a smaller pipe. And actually surprisingly picks up the most gains in midrange. 
Then headers only makes slightly more power than that. 

About the gas losing its velocity, I've heard that mentioned a lot but I dont think this makes sense.
Because if you double the rpm, you double the velocity of the gas in the pipe. 
So if this held true you'd expect a 3" pipe to gain top end when the airspeed is higher again, and lose midrange.
But it doesnt happen, the opposite does.
 

Fucks sake, where is the graph?

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On 08/07/2022 at 10:31, Roman said:

Haha yeah, I guess that's also assuming you could get that 18psi to ambient air temp. 

My solution to the problem, and possibly all problems, is simply to keep revving it higher. 

Lets just disregard that this is also the cause of all my problems 


Larry from Endyn who builds the crazy Honda motors says that RPM stands for Ruins Peoples Motors

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It  depends what you are calling the "exhaust"     There is plenty to be gained getting the sizing right after the merge.
Lots of people hit me with "such and such motorbike  or race car doesn't run an exhaust that big"     In a motorbikes case, just happens the length of bike is about the right place to end exhaust.   same deal with race car.  either the car ends or not a full length system.   

Banging a 3" pipe on right where all 4 pipes join together will probably loose power yes.   but going big at the right place onward,  is the way to go.

I'll place money that most of the gains roman will see, is in the midrange along with a bit of peak power

 

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On 05/07/2022 at 09:25, xsspeed said:

seems too much of a coincidence, is that the 3pot HRE was building?

Jack Hawkswood maybe ? , as he seemed a bit unimpressed with his new car, which is sister-car to McKenzies, i believe

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