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Welds look ok to me. As good as mine anyway!

buguy wrote:Welds look ok to me. As good as mine anyway!

Thanks!

I’m having fun so that’s half the battle.

Heck yeah. I really enjoyed building my header. I had the car on a lift right next to a band saw and it went pretty well. That helps a lot.

Got the 9b turbo swapped on yesterday!

Looking to get some spool information before I add more parts to the mix. Some of the items like silicone couplers fit strange but I don’t want to make anything permanent.

Looking at oil lines I need to find a place that can make me some before my next phases of this go any further. I have a pretty big write up started once I get down that path. Stay tuned.

I see 900 rpm boost in your future!

It’s not that small!

Do you still have your spreadsheet for turbo sizing. There is a map here for the 9b. You could plug the numbers in and see where it lands.
https://forums.nasioc.com/forums/showth ... p?t=789643

I do but flow wise I’m more worried about matching this for quick spool not max power at all. I’m hoping 6-8psi by 2500 or so.

I’ll drop my write up this weekend that I’m working on. It’ll explain some of my ideas and the why behind them.

Also I want to run the car and see what rpm I get boost to get a base line for future changes.

If / when I build bigger I can swap the 13t back on almost all my set up is built with modularity in mind.

Sure man. I'm all about trying new stuff!

Schweg wrote: ↑Thu Feb 18, 2021 4:22 pm It’s not that small!

We all know it's how you use it

What kinda EGTs you getting with that though?

No clue! Also I don’t have an Egt probe.

It’s been rainy and colder here so I had a nice day and got it swapped. I’ll drive it this weekend.

Looks Like u have the fuel pump block off? I grabbed a drain from JayCee that bolts up there,in a 10 a/n worx great

madmike wrote:Looks Like u have the fuel pump block off? I grabbed a drain from JayCee that bolts up there,in a 10 a/n worx great

I just need to order a weld on bung I just haven’t yet. That was my plan though


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All right, I am at the point that I have all the items I need to try out a compound turbo set up. I am going to run over the basics of this set up so I can one make sure that I am not doing the wrong things. There are failings in this system and my design so be kind and realize I am building this on a slim budget with parts I have laying around or I have gotten relatively cheap.

Let me clarify what a compound set up is, it involves a high pressure turbo (small) and a low pressure turbo (big). The exhaust flows first through the small turbo then into the big turbo. The intake air follows the exact opposite path it flows through the big turbine into the small. This is not a twin turbo set up or sequential but a compound. The science behind this allows for both turbos to work better in the efficiency range allowing for quick spool and high boost. The best up side to this should also be a larger torque curve and should make it a heck of a street engine.

First off let me lay out some of my thoughts and goals with this adventure.

1- I am looking to capitalize street/driving efficiency and power under the curve. Really I want quick spool and higher boost then I can obtain with a single turbo.
2- This is a quest to see what I can do with a stock-ish VW engine. In line with the 1600 Challenge I am sucked into the mouse motor challenge and want to throw this in the running. (if it works)
3- I am also interested in this set up as drag guys use them to great success and site that the cars are more drivable and they are able to “pedal” the car mid track and get it under control and finish un like falling off of boost on a large turbo and never getting back to it.
4- Last is my own sheer morbid curiosity to see what a VW engine will take. I think we are all impressed with guys in Washington and Sweden results with stockish parts and small CC ranges.
5- Try and get to around 35-40 psi of boost. Not a must but compound systems shine best with higher pressure ratios.

With all that out of the way lets start talking about some specifics and some shortfalls I am going to see.

I have a Td04-13t on the car currently, that said I may go back to this for a high pressure turbo.

The setup that I plan to use is a Td04-9b high pressure turbo and a WH1C Holset turbo as the low pressure turbo. Some of the math is not perfect but here we go:

CFM to Lbs./Min conversion of CFM*.069= Lbs./Min.

Why is Lbs./Min important you may ask? Well at 1lb/min we see approximatly10 wheel horse power. If the science holds it should be pretty awesome. If you look at the numbers below.

- Td04-9b Flows 275 CFM flows 18.9lbs/min so 189hp
- Td04-13t Flows 381 CFM max flows 26lbs/min so 260hp
- Wh1c/HX35 Flows 574 CFM / 39.6lbs/min so 390hp

All of the research I have done says to match the compound set up with desired flow then half it for the small I ended up lucking out in having a Holset I got on a deal and finding a 9b. I know that both of these turbos are old. I am aware that I can most likely get the same performance overall from new technology but I like to learn the hard way.

I'm excited to see how it works out!