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Topic Review (Newest First)
07-18-2004 12:56 PM
Originally Posted by mike saunders
Eric, Adrian:

Wouldn't you want a slight restriction just before the turbo for the same reason you want a slight expansion just after?
The expansion after the turbo is called a "diffuser" and is designed for the purpose of converting the velocity pressure of the gasses as they exit the compressor into static pressure.

The diffuser has a lot to do with efficiency. There have been turbos with variable vane diffusers much like the Variable Nozzle Turbine exhaust sides, it was shown to increase spool up and effciency ... but it's more complex.

Generally you want a taper of no more than 7-12 degrees before the compressor inlet, and after the turbine outlet. That's the range of angles in which the boundary layer and flow field are both stable.

ERP's tapered intake side would be even more ideal if it were open to the air. Inverse hyperbolic cones are ideal to allow air from multiple directions to enter the turbo in the most efficient manner ... but since ERP's car only takes in air from one direction (from the pipe) it's probably slightly less efficient than a properly tapered bore. (Remember around 7-12 degrees.)

ERP's is still much much better than having the hard edges though. It's not a bad setup, and probably flows fairly well.

An internally polished T7 intake pipe might flow just as well. Maaaybe. It depends on exactly how fast the gasses are flowing inside. If they are flowing slowly enough for the boundary layer to be stable it should be good for its smooth transitions. Doesn't look ideal though.

07-18-2004 07:35 AM
mike saunders Eric, Adrian:

Wouldn't you want a slight restriction just before the turbo for the same reason you want a slight expansion just after?
07-17-2004 04:33 PM
SaabTuner Keep in mind, on a Viggen spec turbo there is more restriction caused by the turbulence of the lip immediately adjacent to the compressor on the turbo inlet than there is in the small tube.

Rough edges and sharp drop-offs cause more restriction than small pipes. ERP has a good setup as he ported the turbo intake, without that, there would be few gains.

Remember that the air has to go through a very small inlet to the turbo. Making a smooth transition is critical to flow ... more so than the actual diameter of the pipe approaching the inlet. Only when intake air velocity is such that the boundary layer is unstable will flow velocity be a problem. Air is a compressable fluid and it will take much more energy to compress it to 15+ psi than it will to draw it through the smaller diameter pipe.

Still it probably is worth a few horsepower IF the turbo inlet is ported into a conical shape to mate smoothly with the intake piping.

07-17-2004 01:14 AM
Originally Posted by saab4life
.. i've been trying to make one myself but its not working at all
What part's not working?
07-17-2004 01:09 AM
Originally Posted by xaamottomaax
The turbo doesn't get too hot for the silicone connector?
No probs with the silicone hose so far. There's a lot of cold air passing where the hose is connected to the turbo.
07-16-2004 11:20 PM
bollman And get rid of the MBC! Youve already ruined one engine from what I understand, so, if you wanna have this one a litle longer, stay off the MBC. There is a very good reason why the boost pressure is to be electronically controlled by the ECU...
07-16-2004 05:29 PM
saab4life but it still needs a couple more sensors plugged in i believe.. i've been trying to make one myself but its not working at all
07-08-2004 12:24 PM
xaamottomaax Very nice looking intake setup. The turbo doesn't get too hot for the silicone connector?
07-08-2004 11:57 AM
ERP Im also using the 15T turbo and instead of the restrictive intake I ported out the compressor inlet and made my one intake pipe. Check out my pictures here to see what I did.
Check here for pics of the new intake pipes.

For a T7 9-3 the intake pipe needs to be modified a little. You will need to connect the bypass valve hose back to the intake.
07-07-2004 03:47 PM
saab4life As for that inlet pipe.. do you think it would work for the T7? wiht all the sensora and what not that need to be hooked up? Is there any way you could make me one ? I would pay for it no doubt. Does it hold up to the extreme temperatures the turbo puts out???? etc etc
07-07-2004 07:27 AM
Blaque Can't wait to experience the power AJ!!

I'll be up there again probably sometime soon.
07-07-2004 03:48 AM
Re: Ordered Maptun Stage 4

Originally Posted by saab4life
Anyone have any experience wiht this upgrade?
A few months ago I did a testdrive in a T7 Maptun stage 4 9-3 convertible. The car was very fast. Power delivery was very smooth, not the abrupt kick in the back.

Make sure you've done all the suspensionmods before unleashing so much power in a 9-3.
07-06-2004 02:16 PM
Maarten Just checked the Maptun website for the stage 4. The required hardware is more or less the same as the setup on my 900SET. The engine puts out the same hp and torquelevel as well.

When my car was tuned at the Hirsch dyno, I asked what would be the most restrictive part in the current setup. They said it would be the T7 intakepipe. A Viggen spec TD04 is fitted, so I had to use a T7 intakepipe.

I've taken pictures of the T5 and T7 intakepipes for the turbo. It shows why the latter is considered restrictive.

I tried to solve the problem by fitting a Samco hose and constructing my own intakepipe.

07-06-2004 01:47 PM
xaamottomaax You DEFINATELY want that inlet pipe as it is recommended in the Stage 3. Your turbo will be gasping for air in the upper RPM's with the stock inlet pipe. There are a few options as far as purchasing one but as long as you are installing a larger, better breathing pipe you will be fine regardless of where it comes from.
07-06-2004 01:32 PM
Ordered Maptun Stage 4

I ordered Maptun stage 4 ECU and it should be here in 2-3 wks. I have all the other mods that go with it so i dont have to get the whole stage 4 upgrade. Actually i dont have the turbo inlet pipe because it apparently doesnt exist.

Anyone have any experience wiht this upgrade. ? Or other comments?

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