37 replies to this topic

[LumpyVR4]

Hey all, I have a Kinugawa turbine housing on the way and am on the hunt for info about porting. I have noted that it has a step on the outlet and was wondering if it is worth going to the trouble of porting it to a nice smooth transition all the way out? Next on the list is a GTpumps evo mani that I'm going to port match it to.

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[evo-gsr]

How much is the GTPumps manifold worth these days?

[LumpyVR4]

I'm actually planning on getting a JAWarehouse one off ebay. $210 delivered.

[evo-gsr]

Spend the extra coin and get an FP. So much better.

[evo-gsr]

http://store.forcedp...ode=DSM-Exhaust

[DOUGMO]

I had my old turbo machined out from the back of the turbine wheel so I could fit a larger dump pipe, it was only a few mm though. the step is the size of the turbine and then it expands from there

[MDK87]

I don't think smoothing the exit will net you much. Also, there's nothing wrong with GTpumps manifolds. Although the FP one does look pretty.

[evo-gsr]

Didnt say there was anything wrong with GTPumps mani...but as you said...the FP is a work of art!

[LumpyVR4]

I've looked into the FP one and they quoted me as much in shipping as the manifold itself. For that much money I'm happier to get the JAWarehouse one and attack it with the die grinder.

I found a litte more info. The entry into the turbine is where the work needs to be done. Post turbine won't do too much.

 

 

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[DOUGMO]

porting like that and radiusing the wastegate inlet will help boost control, enlarging the inlet itself wont do a lot to help as you are not able to continue that porting all of the way into the housing which will decrease the effect of the housing.
smoothing and improving the shape will help though

[CLuTZ]

Thought about an 8cm FP housing? I have been thinking about one but the postage is killer. If we got 5 at once then perhaps it might make it cheaper.

[DOUGMO]

can gtpumps still get the 8cm? I think he only had 10? not sure if he has more?

[Benzo4gT]

If you change the way the turbine housing exit is shaped you'll be wasting your time, the shape helps encourage laminar flow and should only be smoothed IF it needs it, and by that I mean if it has a pronounced lip. Be very careful NOT

 

to change the shape, but follow the same line, only remove the lip, otherwise save your flap wheel.

 

I spent a bit of time in the snail smoothing out cast lines on one of mine, took a while and it's not for the heavy handed. I used a dremel, a good Sutton ball tip (small) and some cheap small stone jobbies that come in those 3 billion

 

piece accessory kits and grease. Dip the stones in grease, gives a better finish and makes them last longer.

 

Here are some pics, take note of the lip that was on the exit of the housing I had.

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[Geo&Kez]

Go nuts I reckon. There are gains to be found.





Flow and reduction in back pressure were noticeable in this case.

[MDK87]

If you change the way the turbine housing exit is shaped you'll be wasting your time, the shape helps encourage laminar flow and should only be smoothed IF it needs it, and by that I mean if it has a pronounced lip. Be very careful NOT

 

to change the shape, but follow the same line, only remove the lip, otherwise save your flap wheel.

The gas flow in this region could not possibly be laminar?

Although I agree with leaving the outlet untouched.

 

Like dougmo said, porting the inlet to the wastegate will aid boost control but not much else.

Edited by MDK87, 15 April 2014 - 01:54 PM.

[MDK87]

Damn you LumpyVR4... I got interested in the subject and bought another engineering handbook. Lol

 

That, or I'm just finding new ways to get out of doing my assignment. :-/
 

Edited by MDK87, 15 April 2014 - 02:31 PM.

[Benzo4gT]

The gas flow in this region could not possibly be laminar?

 

 

It would be if the cone-like shape was extended, otherwise known as a diffuser. I do agree that it wouldn't be laminar just from the housing, but If you followed the shape it would be.

 

I'm sure if you measured the angle of the housing outlet from the straight part to where it expands to meet the DP flange you'd probably see an angle of 7-12º.

 

I had a really good pic of a big $ turbo system that had this shape continued till it reached 3", but for the life of me I can't find it. 

Edited by Benzo4gT, 15 April 2014 - 11:41 PM.

[MDK87]

Have a read of this Benny. http://www.ehow.com/...pipe-works.html

[Benzo4gT]

Hmmm, interesting read, sounds very similar to a 2 stoke exhaust design but 3 ft long. If we were in the states we could chrome it and stand it up like a stack!

 

I thought I understood laminar vs turbulent flow, seems I might have to do some more reading.

[BMGTZ]

porting of the turbine housing can be quite effective in raising the nose over point for a turbo....but three things are important

 

1. it has been established the housing is a restriction.....such as using a 6cm housing. Even on a 14b they are tight for flow...change that alone to a 7cm and presto better top end from that turbo. however as boost levels are increased even a 7cm is getting too small when the inlet side of the turbo is made larger..such as a 20G or even a 16G with the wick turned up.

 

2. you know what you are doing!

 

3. you arent a muppet.

 

the target is to extend the range across which boost can be held at the desired set point by smoothing the flow of gas into the area sometimes refered to as the forcing cone. That is the very bottom of the cone just before it changes direction to exit over the turbine wheel. pretty much anything that pokes out into that stream of gas will cause a change in direction and turbulance behind it....not what we want. the further you can extend the peak of the cone into the "curl section" the more effect your work will have.

 

There are do's and donts when doing it.

 

Do use common sense....if it has been indicated to you at some point this could be an area you are low on. DONT start the job.

 

do remove the metal in small lots and try the turbo out for gains...common sense

 

dont rush the job....

 

Ok so now you have done the forcing cone and have achieved a better flow out through the turbine wheel.....boost is spiking all over because more gas is hitting the wheel. You now need to open up the waste gate .....some housings have a nice 34mm flapper and a tiny exit hole. Simple make the hole bigger!....no. the path to the hole is very important, in that gas entering the waste gate doesnt cause turbulence in the gas on its way to the turbine wheel and undo your work. Shaping the path into the side of the housing is easy as there is so much "meat" in the housing. there needs to be a pretty sharp bottom section in the waste gate where it sits in the forcing cone. after that sharp edge and on the outward side there should be a small depression that causes shear in the flow of gas rather than swirl in that area. That isnt there on a stock housing

 

waste gate exit after the creation of the shear point....make it smoother. concentrate on the points where the gas has to change direction. Such as off the flapper itself. open out the area around the flapper and between the main two exit holes. this is an area that really needs to worked with care as going too thin will cause cracks so be careful.

 

suggest practice on a fucked one first ......if after it it is finished you mates that dont know you did it say it looks like a muppet did it. Dont do the real one .get another and practice...practice makes perfect