Intake Plenum 6a13 and 6a13tt

[mpau009]

Sorry, but I think this is wrong.

The prefacelift manual VR4 has 280BHP. The prefacelift auto has 260BHP but that is due to the ECU setup and not to do with different engine components.

...actually i think you are right that its not a physical change. Carsten (Gly) has fitted the bigger throttle bodies to a few cars a while ago, and bored out the stock manifold a bit to suit. Mine is a 98 PFL, and it definately has the slightly smaller throttlebody.

[Dom B]

Steve is right about the runner diameters. I design and manufacture throttle bodies as one part of my business.

You don't necessarily restrict the total work done by an engine (to a point anyway) by fitting a smaller runners you just change the power characteristics.

A smaller runner will give higher gas speeds at the same throttle opening which will lead to better mixing higher fuel economy and an earlier boost in torque. However it will do this at the expense of top end power which you will lose.

A compromise can be made with tapered runners. Tapered runners and throttle bodies are very much the current technology with Individual throttle bodies and there would be advantages on single point throttle bodies too although not as much. Thing is you would be looking to have a custom manifold made which to be fair is not as much hassles as you may think if you have the right facilities available.

[swinks]

TAR and mpau009 basic power setup is due to stock boost level, but everything has its own reason.
According to measurement made by Kochajj and Roch_27 who took both engines (PFL and FL) apart into bits...
Just take off both plenums, throttle bodys and exhaust manifolds to turbos from PFL and FL. Then you will realise that basic flow is smoother, bigger and easier in FL due to slightly bigger intake diameter and exhast diameter.
In other words, there's mechanical difference between PFL and FL engines, and hence then raised boost in FL (also a/t versions).

[mpau009]

TAR and mpau009 basic power setup is due to stock boost level, but everything has its own reason.
According to measurement made by Kochajj and Roch_27 who took both engines (PFL and FL) apart into bits...
Just take off both plenums, throttle bodys and exhaust manifolds to turbos from PFL and FL. Then you will realise that basic flow is smoother, bigger and easier in FL due to slightly bigger intake diameter and exhast diameter.
In other words, there's mechanical difference between PFL and FL engines, and hence then raised boost in FL (also a/t versions).

I dont doubt you i have both on my floor at home, what i am saying is that doesnt account for the difference between the supposed 280hp PFL manual vr4s and the 260hp PFL autos, as mine is a PFL manual, with the smaller throttlebody setup.

I guess what i was trying to suggest was why or if there is supposed to be a power difference between a PFL manual vr4 and any facelift?

[TAR]

I dont doubt you i have both on my floor at home, what i am saying is that doesnt account for the difference between the supposed 280hp PFL manual vr4s and the 260hp PFL autos, as mine is a PFL manual, with the smaller throttlebody setup.

I guess what i was trying to suggest was why or if there is supposed to be a power difference between a PFL manual vr4 and any facelift?

why is a pfl manual vr4 280 bhp with the smaller thottlebody?

[mpau009]

why is a pfl manual vr4 280 bhp with the smaller thottlebody?

..and why isnt the manual facelift higher hp again. Or is it?

Either way, its miles away from affecting my car, but if it is a viable bolt on upgrade, it might be worth me keeping an eye out for facelift wrecks

[Turbo_Steve]

As I recall, the facelifts generally return better MPG do they not?
Something like this could easily be a candidate.

[--hoff]

maybe the restriction are on the ecu to protect the auto trans...

[swinks]

maybe the restriction are on the ecu to protect the auto trans...

.
Nope, the same trannies in FL.

[bradc]

The Facelift gearboxes are slightly updated with OWC (one way clutch) stamped into their casing. I'm not sure how much of the internals changed though.

[keithatport]

When I changed my FL gearbox to a PFL, it would not change out of first in tiptronic but was ok in all the other gears. Changed the gearbox to a PFL one and the gears all worked but the boost dropped so there is some interaction between the engine and gearbox ecu's.

[--hoff]

Finally the 6a13 plenum fitted with minor issues...

Visually , speaking of the size of the runner and the outlet, there is no difference between the na engine plenum and the turbo engine plenum.The difference only on the shape of plenum and the runner and the diameter of the TB.

Personally I prefered the na engine plenum. Cause it has the V shape runner and shorter plenum which I THINK yields faster air distribution.

Pictures:
Messed up intake plenum

NA engine plenum installed

The minor issues. The na engine has EGR and it hit the fuel rail. I am guessing by using the na engine fuel rail should solve the problem...hopefull *finger cross*

Preview of my little project =)
I already has single turbo setup. I changed the direction of the TB inlet to the opposite side and after awhile I dont really like this idea. Not the best looking and it will give you more work when u are doing the timing belt work. I am looking more OEM look for plenum. When it's done, it should look like this


PS: i have problem of uploading and showing the picture. i usually do the same thing and it works on the other forum but i dont know why its not working here =(. anybody can help......

[Turbo_Steve]

Wow! Another single turbo version: good lad!

I would be cautious about using the fuel rail: make sure you swap the reg, and make sure the fuel rail is the same internal diameter!



Generally, the facelifts are reported to give better MPG and a slightly smoother throttle response. This, I suspect, is due to the inlet manifold and throttle body moving the power up the curve a little.

[--hoff]

I found the reason why the na engine intake plenum hit the fuel rail when I installed. It's not because of the EGR but because I am using HKS injector so I put a spacer to fit in the injector. That spacer caused the fuel rail hitting the intake plenum. Still trying the best way to fit in that intake plenum. I am sure with a little tweak it will fit just fine.

Here some data the difference between the two intake plenum:
NO ITEM NA TURBO
1 Diameter Intake 68,5 60,75
2 Diameter Output Throtle 67,25 60
3 Diameter Throtle 65 60
4 Diameter Input Throtle 68,25 64,5

not much of a different but the na engine is slightly bigger than turbo.