SWB Quattro Project

[G60Rallye]

No I wont be running at TOTB. I will be coming over to have a watch as I do every year. Are you going over Mark?

I have no idea about max flow numbers but I am sure you could work it out with the cross sectional area.

[my2000apb]

does tial have max flow numbers for wg's?

[s4boy]

Hamish, are you running the car at TOTB at the end of this month?.............mark..

[porci82]

amazing work!!!
i like it

[BennyBoo]

christ that thing is big!

Mmmmmm, that's what she said!

[Jamo]

it's like you went into tial and asked them to super-size me, christ that thing is big!

[G60Rallye]

Took the exhaust side of the engine to bits this afternoon. The 60mm wastegate compared to the 44mm its huge!



I have worked out how its all going to work. The wastegate will sit in the same position as the 44mm, but the wastegate exit will feed back into the downpipe a lot higher up.

Hoping its back together in a couple of weeks at most.

[G60Rallye]

I didn't put the UJ in there mate. Its welded into the column half way up.

I did ask a mate of mine and he measured up a mk1 golf UJ and its splines were the same, so you could use one of those if you choose to put it there?

[terrybullwon]

Hamish,

What size UJ did you connect to the Audi fine spline steering rack?

[quattro84]

It is all about pressure differential over the WG compared to total turbine flow. If the WG entry is pointing towards gas flow it will reduce flow resistance enhanching flow capacity until it reaches it ultimate choking limit, which does not matter which way it points but relates to pressure difference between pre- and post-turbine. The turbine housing will be the primairy trigger for the WG operation to start, turbine will choke after reaching it's own max flow and asks for WG operation (venting can be started earlier if target boost is reached of course) By flowing the head the VE of the engine will increase making total engine flow increase even more. Still, running around 700hp means that there will be around 0,6kg of air passing by each second, figure out how much that is in liters at those temperatures.

Did you monitor/log exhaust manifold pressure? I'm sure it will make it clear plotting it against measured/calculated engine flow.
I did not expect this to happen as well with the 44mm TiAl, must be compressor vs turbine flow relation.

[Jeffer]

Lets not forget the positioning of the WG. Ive seen loads of EM designs with poor flow charactaristics into the wastegate. I've also seen a stock head with tubular GT35r and oem wastegate boostcreeping like mad. After fitting a 60 mm wg it was solved.

So couple of pointers wich I find usefull.

Position of the wg (in the flow)
Size of hotside (backpressure pre turbo)
Size of exhaust (backpressure post turbo)
Size of the WG
Spring pressure
Ballbearing turbo or friction bearing turbo

TBH I see no relationship in the amount of flow... Proper design and concideration of all of the above will wastegate all sorts of fast flowing gasses imho.

[s4boy]

Keep at it hamish you'll get there.......mark

[Jamo]

Europeanme your build isn't near this level of concern Thuppu, G60rallye, JP all have potential 700 bhp+ setups. I'm not near that probably 600-650 but stroker flow.

It all seems to do with the extreme head porting which again only JP, G60rallye and Jeffer have

[Thuppu]

The smaller hotside the more the WG needs to flow. I had no problems with your CT and stock WG.

[europeanme]

You're not alone with that feeling.

make that 3 concerned parties...possibly 4...

would the hotside size effect this over boosting issue or is it the head work?...