Twin Turbo Kit

[buguy]

Well once you have it built, post up your results. I'd be interested to see how it comes out.

[rens040]

You also had a TSI with a compressor AND a turbocharger.

TSI is just there whole range of turbo/supercharged engines
FSI is the range of N/A
( VW names that is, AUDI calls the turbo engines TFSI )
and GTI is a model indeed, it has the 2.0 TSI

[buguy]

I disagree. The turbo i picked was perfect for the 1600. The stroker simply makes more power off boost. Much more than i expected. The turbo from the 1600 is too small for the stroker though. I don't remember exactly now, but it was making boost at something like 1700 rpm. Making it that soon will surely result in an early end to it too.
Keep in mind my 1600 was dead stock for most of its run. I did end up changing cams and that hurt performance everywhere except the tippy top end.
I would guess to say with the 2054 @ 12 psi and the 1600 @ 30 psi, the top end performance is real similar. Once the engine is broken in more, i will start cranking the boost but i know a new turbo will have to come before i throw much more boost at it. Which I'm ok with. Part of the process.

[oprn]

[buguy]

Definitely makes a difference on the size engine you have. I was shocked how much more low end my 2054 has over the 30+ psi 1600 i had. If i had known that, i probably would have bumped up the cam some more since there is power to spare down low to give more up top.

[Dauz]

I understand why people want the quick spool bottom end. Especially with road driving. But with the power to weight ratio and short gears it was never a concern for me. I prefer my boost mid to top.

[Chickensoup]

[buguy]

Lol so every TSI has more than one turbo? Every model got more than one turbo?

[Chickensoup]

[buguy]

I thought only the gti got the twin.

[Chickensoup]

TSI- turbocharged stratified injection

TDI- turbocharged direct injection

TSI is gas

TDI is diesel

The TSI has been made with both single and twin turbochargers
_________________
-'85 c10 5.3 LS, cam, heads, long tubes, x pipe, 3 inch spin tech's
-'01 e46 325ci *tree modded
-'05 B5.5 TDI Wagon 17in sport rims ;EGR + BSM + ASV Delete, Stage-2 Tune, straight pipe
'65 Tourist Delivery Build
'66 RIP

[buguy]

Isn't the TSI a single turbo?

[oprn]

It would be very interesting to find out what pressures the VW TSIs are running at and how they are plumbed and controlled. Duplicating thier set up and tweaking from there would be the obvious starting point in my mind. Why start from the ground when thier engineers have already invested the time and money learning how best to do it?

[Bschweg]

The goal of compounds doesn’t have to be mega high boost. But commonly is in that you can keep all the turbos used in a compound well with in there efficiency ranges resulting in a cooler denser charge.

Another advantage of compounds is the ability to make an engine seem bigger then it is allowing a larger turbine to be utilized flowing more CFM making more HP.

[clonebug]

Most people run too large of a turbo.....from my experience a small turbo just runs out of the ability to flow enough air and the pressure drops as the rpm/CFM demand goes beyond the P/R of the turbo. I have not seen outrageous IAT's on a small turbo due to excess demand.
Air heats up a certain amount per lb of compression. You might see a little extra heat just going through the turbo but that is mostly at cruise.
It takes a specific amount of cfm to make a desired hp. Whether that air is cold or warm affects the CFM due to the density of the air.
200 degree air holds a lot less fuel at say 12.0:1 AFR than 75 degree air.

I've posted a calculator many times that will tell you exactly how much hp you can get depending on boost, Cu. in., rpm, VE, intake temps and a couple other variables. It's been very accurate on most of my inputs.
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[buguy]

Well I'm certainly no expert on multiple turbos (or even just one for that matter!) I did a bit of research on it when i had my 12v Cummins truck. From what i could decipher from the reading is sequential and compounds do similar things but not in the same way. Compound turbos can make big boost because they can run a big ass turbo to make tons of pressure, but have the small one to pick up the low end, so there isn't much lag. Sequential typically uses the same or nearly the same size turbos. They use the first one to compress the air, then the second to compress it even more. Something they might use on an airplane engine where the lag doesn't matter.
As far as i ever knew both turbos work together in a compound set up too. Hence the name "compound".
I think you are pretty much correct on the single. If your only wanting 15-20 psi it's not super difficult. Of course it's never just easy as that. A larger more efficient turbo will make more hp at lower boost (i assume more volume with less pressure) without much lag or heat. Smaller ones come in sooner but really start to generate heat once you push them. Also it does get pretty hairy once you get above the efficiency map. You might make more psi, but it's over spinning, damaging the turbo and mostly creating heat and doing less work. So i get the draw of compounds. I mean why wouldn't you want the best of both worlds?! Some of this stuff has to be voodoo though!
Again I'm no expert and still trying to work this stuff out myself. Multiple turbos just didn't come up for me because I'm not doing it, so i really didn't care much. I can barely make one fit where i want it! That's mainly why i was attracted to a twin scroll with a quick spool valve. But then you really need equal length primaries... Blah... Blah.

[BFB]

[buguy]

I don't know why this has become so difficult. If a guy wants to make say 500 hp with a 2276. By whatever means necessary, he has to move like 700 pounds of air per minute. So your going to have to run a ton of rpm, a ton of boost, or a big ass turbo. None of those are ideal. On a race car, it's not as difficult because you can build boost on the line and hold it through the run. On the street it's a totally different story. Can't really be driving around at 8000 rpm, building boost on a big ass turbo takes forever, and a bunch of boost on a smaller turbo builds lots of heat. So that introduces compounds. You can build boost more quickly, and it still moves enough air to make the big hp. Modern turbos are more efficient, so the gap is closing, but it's not quite there yet. Obviously compounds have their own challenges too. Most of us seem to just deal with what we get and do the best we can with it. It's especially challenging on our air cooled engines because we kind of need to keep them in the sweet spot for cooling and no water cooling to help out.
If you think I'm nuts, go ahead and give it a try! It's not as easy as it would seem.
I like the idea of compounds, and using a quick spool valve with a twin scroll. Again both have their own challenges and benefits. I've even toyed with the idea of putting a little shot of nitrous on to help spool a big turbo. Not ideal for the street either.

[Chip]

[BFB]