Correctable flaw in the 20v intake design?

[Sam_Q]

thanks Grega, old school suits me just fine, I will call him

where is he based (suberb) anyway?

[oldcorollas]

so you are assuming the flow is laminar to begin with...

perhaps (packaging aside) they found that they could introduce some tumble into the flow, to get better fuel mixing etc? or they are aiming for air to go more toward to roof of the port etc?

butt dynos are notoriously poorly calibrated.. fatter torque curve can feel slower than something more peaky..

[julzy_quads]

HSD is based in Moorabin,
he has a flow bench aswell,
does alot of work for race cars and high $$$ motors

[Sam_Q]

oldcorollas: these I have definately considered however the cost of two dyno runs would be too much for me, the uncalibrated butt it is.

julzy_quads: thanks I hope he is friendly and open to some questions, depending on the cost I might do a before/after on the flowbench, but as I have said before its only part of the real picture

[Turdinator]

HSD is based in Moorabin,
he has a flow bench aswell,
does alot of work for race cars and high $$$ motors

Yeah i can also vouch for HSD. They have done work for few guys in the Vic Celica Club, myself, shelldrake, Joey and slim to name a few. They are quite knowledgable and have done a fair bit of work with the 4age and other toyota 4cyl.

[Sam_Q]

oh they are the ones that did Eddies head porting? I had a look at what was done and I was quite impressed by the quality

[Celica RA45]

sam a few people swear by it .a mate in sydney tried it on a dyno with and with out no difference ,go figure and from memory its 5mm up to 25mm from memory for the wedge plate

[jfallen]

Guess I'll add my 2cents Occupation Mine Ventilation and Methane drainage engineer.

Things to keep in mind.

1: The inlet track is very short, (True laminar flow takes ~6 x diameter of the pipe to form. So if the pipe is 45mm in diameter you'll need length of 270mm to get truly laminar flow. This is impractical.

2: You have a very large obstruction in the middle of the pipe, namely a throttle body, even WOT it's reasonably large. Hence why slide throttles / carburetors (Kehin FCR / Mikuni RS) are awesome as they completely remove any restriction. Thus the throttle body will cause turbulent flow even at WOT, more so at part throttle.

3: The flow down the inlet track is far from consistent and is in fact very violent. You've got rev changes, throttle changes, fuel being injected, pulse waves from the valves opening and closing. Basically the air stops and starts very rapidly. Not good for laminar flow.

4: Turbulence (to an extent) is good for fuel atomisation. --> better fuel burn --> more power. That's why stand off injectors (injectors outside the trumpets) are best for max power as they get the best fuel atomisation. Pitty they deliver terrible fuel economy and have a habit of catching on fire. This may have something to do with the fact Standoff injectors sit exposed in the engine bay, and at low RPM there isn't enough velocity to completely pull all the fuel in. Safety Plus Kind of the same way DCOE carburetors love to spit fuel with you snap the throttle wide open.

Basically yes, smooth straight path is best, but the 4AGE 20V quads are already 98% of what is possible. However Chasing those extra fractions will cost bulk $$ and will easily get lost in Dyno variance. cash would be better spent on big cams and high comp pistons. Like Adjustable cam gears this is something that need only be done after every other avenue has been exhausted.

Cheers
Jordan

[Sam_Q]

wow disheartening

Celica RA45: any chance you could find out off your mate exactly what he did?

jfallen: your points make a lot of sense but one thing doesnt add up for me, according to your theory porting an engine to remove burrs shouldnt work either?

[oldcorollas]

if burrs (you mean mismatched head/port?) stick out into the port, they change the flow.. ie, deflecting and causing an "effective thinning" of the port.. similar to this bend.. but with the bend.. all of the port is doing it.. or something like that.

maybe the port is big enough, even with the induced issues at the bend, for the bend to not actually be a restriction at all?

if you are thinking about the reflected sound swaves and resonance.. remember sound goes around corners really well...
(ugh, too tired: the above may not even make sense )

[Sam_Q]

ah I so confused...

[oldcorollas]

i was more meaning.. if you have a larger runner, and a smalle rport, so there is a step.. that is a MUCH larger issue (cos it turns it into a virtual funnel) than having a small bend in a port, where the air will go around the outside of the bend anyway....

what abotu just radiusing the edge of the manifold and port? opens the volume up a little, but if it stops seperation...

[Sam_Q]

I am still confused, hehehehe

the most significant part of the step is on the outer radius, does that make a difference?

[jfallen]

porting an engine to remove burrs shouldn't work either?

Porting an old 2V engine like 3K, L18, 202 or 308 boat anchore, can result in serious gains as the factory ports are in retrospect poorly designed and often very small. Take a long hard look at the factory ports on any modern (especially hi-power) multi valve engine. We'll take the 20V-4AGE for arguments sake. The port is huge for a 1600cc (compared to say a 2T-C, L16) and the casting is of a very high quality. One can easily see that time and effort has been spent designing this port for maximum performance. Which when you see 165/170PS from a factory 1600 is easy to understand.

This next paragraph does not follow on form the one above:
What I was eluding to in my previous post regarding turbulence being a positive, is an effect commonly known as swirl. Now I'm not talking about the crappy Swirl ports and combustion chambers of various 2T-G. Good Swirl in the inlet port is important to get fuel evenly distributed in the air being ingested (The CA18DET does this poorly as it's 8 port head only has an injector in every second port!!!) If this is done poorly (mixing of fuel and air) you suffer a loss of power, possible knock, poor fuel economy...

Like I said you're chasing that 2% which is like chasing god. You might find it one day many years form now, and if and when you do you'll be drastically underwhelmed. Realising that time, money and effort could have been better spent elsewhere in your quest for power.

Cheers
Jordan

[allencr]

Guess I'll add my 2cents Occupation Mine Ventilation and Methane drainage engineer.

Things to keep in mind.

1: The inlet track is very short, (True laminar flow takes ~6 x diameter of the pipe to form. So if the pipe is 45mm in diameter you'll need length of 270mm to get truly laminar flow. This is impractical.

2: You have a very large obstruction in the middle of the pipe, namely a throttle body, even WOT it's reasonably large. Hence why slide throttles / carburetors (Kehin FCR / Mikuni RS) are awesome as they completely remove any restriction. Thus the throttle body will cause turbulent flow even at WOT, more so at part throttle.

3: The flow down the inlet track is far from consistent and is in fact very violent. You've got rev changes, throttle changes, fuel being injected, pulse waves from the valves opening and closing. Basically the air stops and starts very rapidly. Not good for laminar flow.

4: Turbulence (to an extent) is good for fuel atomisation. --> better fuel burn --> more power. That's why stand off injectors (injectors outside the trumpets) are best for max power as they get the best fuel atomisation. Pitty they deliver terrible fuel economy and have a habit of catching on fire. This may have something to do with the fact Standoff injectors sit exposed in the engine bay, and at low RPM there isn't enough velocity to completely pull all the fuel in. Safety Plus Kind of the same way DCOE carburetors love to spit fuel with you snap the throttle wide open.

Basically yes, smooth straight path is best, but the 4AGE 20V quads are already 98% of what is possible. However Chasing those extra fractions will cost bulk $$ and will easily get lost in Dyno variance. cash would be better spent on big cams and high comp pistons. Like Adjustable cam gears this is something that need only be done after every other avenue has been exhausted.

Cheers
Jordan

*********************
*********************
Porting an old 2V engine like 3K, L18, 202 or 308 boat anchore, can result in serious gains as the factory ports are in retrospect poorly designed and often very small. Take a long hard look at the factory ports on any modern (especially hi-power) multi valve engine. We'll take the 20V-4AGE for arguments sake. The port is huge for a 1600cc (compared to say a 2T-C, L16) and the casting is of a very high quality. One can easily see that time and effort has been spent designing this port for maximum performance. Which when you see 165/170PS from a factory 1600 is easy to understand.

This next paragraph does not follow on form the one above:
What I was eluding to in my previous post regarding turbulence being a positive, is an effect commonly known as swirl. Now I'm not talking about the crappy Swirl ports and combustion chambers of various 2T-G. Good Swirl in the inlet port is important to get fuel evenly distributed in the air being ingested (The CA18DET does this poorly as it's 8 port head only has an injector in every second port!!!) If this is done poorly (mixing of fuel and air) you suffer a loss of power, possible knock, poor fuel economy...

Like I said you're chasing that 2% which is like chasing god. You might find it one day many years form now, and if and when you do you'll be drastically underwhelmed. Realising that time, money and effort could have been better spent elsewhere in your quest for power.

Cheers
Jordan
Today 06:55 AM

Thank you very much! Good job!
If the rep rating points meant much, I'd recommend removing Thousands from most of these replies to transfer to you.
'Chasing his tail' & 'chasing god' is a perfect description.