Frankenwagen build thread AKA TD Corrado

[RadoTD]

Okay, I pick you

One thing you are missing though is that on the corrado, those bolts do hold up my front subframe, it's different than the mk2 where the nuts that rusted are actually in the frame rail

[Smokey Eddy]

We can't forget to paint all of the welds.

[R.O.R-2.0]

We can't forget to paint all of the welds.

all those nice clean welds wont be so nice and clean once the car finds the salty canadian roads.

[RadoTD]

There are interesting updates to come, but I just finished working a 20hr shift at work and I'm starting another 12hr+ shift in less than 5 hours. So all a yall's gonna have to wait.

[RadoTD]

Facepalm.

Don't know exactly how I managed to miss this critical measurement, but apparently I did. Not even sure why I didn't actually put that bracket on the engine.


Step by step how-to on fixing that issue.
Step 1 - sulk for 30s calling yourself an idiot
Step 2 - stare at car for about 5min
Step 3 - cut things apart with a grinder
Step 4 - stick said stuff back together with a welder

[Thezorn]

Such an awsome compound built rado. I have one question for you. How are you going to be wastegating the turbos? Are you using external or modified internal ones? Im thinking about doing this also, but the idea of how the compound wategating works is still beyond me.

[R.O.R-2.0]

you just need one good wastegate to bypass the little turbo at high speeds. it sends the exhaust from the engine, directly to the big turbo. pretty much bypassing the small turbo.

[Thezorn]

you just need one good wastegate to bypass the little turbo at high speeds. it sends the exhaust from the engine, directly to the big turbo. pretty much bypassing the small turbo.

Okay so any good external wategate would work for this? is there a different between gasser wastegates and one that would work on a diesel.

And how do you calculate boost on compounds? Ive heard so many different ways I dont know what to believe.

[RadoTD]

Such an awsome compound built rado. I have one question for you. How are you going to be wastegating the turbos? Are you using external or modified internal ones? Im thinking about doing this also, but the idea of how the compound wategating works is still beyond me.

I'll be using the internal wastegates for now, but keeping an eye on the pressure between the two turbo's on the intake side to make sure the K14's wastegate is working well enough.

K14 wastegate will be the difference between the manifold and the charge pipe in between. K24 will be wastegated at the difference between manifold and ambient.

The K14 will be set at around 10-15psi. I'll use 15psi for the example for now. So say there is actually a 2psi vacuum between the two turbos. Theoretically the K14 will open it's wastegate at 13psi then and start dumping more into the K24. That won't ever happen because I'm sure the K24 will be pushing positive pressure by the time I'm getting over 15psi. So, assuming the K24 builds 5psi by the time my K14 builds 15, then the K14 wastegate starts opening at 20psi at the manifold.
Extrapolating that to the other end, the K24 wastegate will open at 30psi at the manifold, but the K14 is still squishing the air another 15psi extra after it goes through the K24. So, when the manifold pressure is at 30psi, the K24 is only actually pressurizing 15psi and the K14 is pressurizing 15psi. Pressure ratio's of 2.02 and 1.51, respectively.
When you throw it on a compressor map, the way I understand it is that both turbos will be doing the full flow, but at each of those pressure ratios. That setup will put my K14 on the bottom right side of the map, but my K24 right in the middle. Due to the higher pressure ratio, the K24 will actually be doing more work, so the idea was to peg it in the highest efficiency range as possible.
So I'll be keeping an eye on the pressure between my two turbo's and if manifold pressure - intermediate pressure > 15psi, then I know my K14's wastegate is insufficient and I'll add an external one on. Otherwise, if it is enough, I have nothing to worry about. The K14 won't just be coasting, the way I want mine set up, it will still be doing work and therefore will still need air running through it, not just all bypassing

[theman53]

If the CV will fit as when I asked before you could just take and weld a new engine mount. Level with the bottom of the turbo and it would work. You could even put a nice little bend in it to clear the intake if nessesary.

[RadoTD]

Yes, I picked up plate steel to make that new mount and drop it under my intake hose. I had to modify the mount itself and where it's bolted to the subframe to keep the engine at the same angle while lowering the mount under the intake

[R.O.R-2.0]

Such an awsome compound built rado. I have one question for you. How are you going to be wastegating the turbos? Are you using external or modified internal ones? Im thinking about doing this also, but the idea of how the compound wategating works is still beyond me.

I'll be using the internal wastegates for now, but keeping an eye on the pressure between the two turbo's on the intake side to make sure the K14's wastegate is working well enough.

K14 wastegate will be the difference between the manifold and the charge pipe in between. K24 will be wastegated at the difference between manifold and ambient.

The K14 will be set at around 10-15psi. I'll use 15psi for the example for now. So say there is actually a 2psi vacuum between the two turbos. Theoretically the K14 will open it's wastegate at 13psi then and start dumping more into the K24. That won't ever happen because I'm sure the K24 will be pushing positive pressure by the time I'm getting over 15psi. So, assuming the K24 builds 5psi by the time my K14 builds 15, then the K14 wastegate starts opening at 20psi at the manifold.
Extrapolating that to the other end, the K24 wastegate will open at 30psi at the manifold, but the K14 is still squishing the air another 15psi extra after it goes through the K24. So, when the manifold pressure is at 30psi, the K24 is only actually pressurizing 15psi and the K14 is pressurizing 15psi. Pressure ratio's of 2.02 and 1.51, respectively.
When you throw it on a compressor map, the way I understand it is that both turbos will be doing the full flow, but at each of those pressure ratios. That setup will put my K14 on the bottom right side of the map, but my K24 right in the middle. Due to the higher pressure ratio, the K24 will actually be doing more work, so the idea was to peg it in the highest efficiency range as possible.
So I'll be keeping an eye on the pressure between my two turbo's and if manifold pressure - intermediate pressure > 15psi, then I know my K14's wastegate is insufficient and I'll add an external one on. Otherwise, if it is enough, I have nothing to worry about. The K14 won't just be coasting, the way I want mine set up, it will still be doing work and therefore will still need air running through it, not just all bypassing

theres no way to keep the exhaust from going thru the turbo.. its not gonna just coast.. its still going to be working no matter what. exhaust takes the path of least resistance.. and the path of least resistance is thru both the WG and turbo..

and dont you just love it when you hang your turbos on your engine just to figure out that your rear motor mount is in the way of your turbo intake?

[RadoTD]

theres no way to keep the exhaust from going thru the turbo.. its not gonna just coast.. its still going to be working no matter what. exhaust takes the path of least resistance.. and the path of least resistance is thru both the WG and turbo..

and dont you just love it when you hang your turbos on your engine just to figure out that your rear motor mount is in the way of your turbo intake?

Yes, I realize it won't completely bypass, but with a large enough wastegate and the HP turbo wastegated between say 15psi manifold and ambient, if you're boosting 30psi, the HP turbo will actually be a restriction that the LP turbo is forcing through. The way I'm planning to wastegate it, the HP turbo is always compressing the air more. That's what I meant, maybe not the best choice of words.

And bumps along the way just make it more interesting

[Thezorn]

So I'll be keeping an eye on the pressure between my two turbo's and if manifold pressure - intermediate pressure > 15psi, then I know my K14's wastegate is insufficient and I'll add an external one on. Otherwise, if it is enough, I have nothing to worry about. The K14 won't just be coasting, the way I want mine set up, it will still be doing work and therefore will still need air running through it, not just all bypassing

So this intermediate pressure is refuring to the pressure in the pipe the outlet of the k24 and the inlet of the k14?
After reading over it about 5 times ill start to understand it more haha, thanks for the info man.

[RadoTD]

Yes, that is the pipe I'm referring to

If anything doesn't make sense, I can attempt to clarify it better. I read through it and confused myself! Then I clicked Post