GURUS/TECHS/ENGINEERS: Why do turbos charge the opposite side of the engine?

[NolimitZ32]

My question is simply why to the turbos on the vg30dett charge the opposite side of the engine (driver's side turbo provides air for pass. side TB, Pas side turbo routes to driver's side TB) I am going to be designing a custom turbo kit+custom intercooler/piping and am really missing this here. I remember reading a blip about this somewhere but do not remember what it said, and cannot find it now.

ThanksAnton.

[AZhitman]

My guess is simply packaging - trying to route tubing that tightly would hamper flow?

But I honestly don't know if there's a more "technical" reason than that.

[NolimitZ32]

I was hoping exaclty that, I got a buddy thats a carrier welder and he does nothing but Aluminum all day, I'm designing (i got engineering background) he's bending and welding. I'm hoping to cut out about 5'-6' of piping per turbo.

[evildky]

because they don't, the stock TT passanger side turbo feeds the passanger side of the engine, and the drivers side turbo feeds the drivers side fo the engine, and there is a ballance tube on the intake to smoothe out any difference and there is an H in the exhaust to smoothe out any differences there

a lot of swaps use goofy crossflow intercoolers taht are less efficient than stock and route the piping across otherwise it should be same side routing, as for engineering it's all about airflow , the shortest smoothest passage wins, vertical flows are generally more efficient than crossflow, ricers don't get that

[NolimitZ32]

sir you are absolutely right I was picturing the system with my old FMIC, I'm an idiot. K thanks gentlemen!

god i feel stupid

[AZhitman]

Nicely done, Dave. Thanks for the education.

[AZ-ZBum]

because they don't, the stock TT passanger side turbo feeds the passanger side of the engine, and the drivers side turbo feeds the drivers side fo the engine, and there is a ballance tube on the intake to smoothe out any difference and there is an H in the exhaust to smoothe out any differences there

a lot of swaps use goofy crossflow intercoolers taht are less efficient than stock and route the piping across otherwise it should be same side routing, as for engineering it's all about airflow , the shortest smoothest passage wins, vertical flows are generally more efficient than crossflow, ricers don't get that

Ummm... Go back and look at your car again. Yes they do. the stock passenger turbo feeds the passenger side throttle body. But the passenger side throttle body feeds cylinders 2, 4, and 6. Cylinders 2,4, and 6 are the driver side cylinders. Vice-versa for the driver side turbo.

I do believe the literature of the time said it was to help equalize any potential differences in turbos and better balance the engine power. So that if one turbo was boosting slightly more than the other, that extra boost would be supplied to the weaker turbo and balance the power distribution across the cylinders. Naturally, the balance tube is supposed to help equalize it, but if there is a significant difference (like a wastegate failure or something), that little tube could not handle a 14psi difference.

[evildky]

lol, I didn't think about the intake runners, doah, you are of course correct, now go back to the Z31 section

[evildky]

with a bit of further thought the crossover does make sence, a turbo fed by 1,3 and 5 feeding 2,4 and 6 will further ballance the 2 sides, I just didn't think aobut the intake runners crossing over, I instantly got the vision of the crappy aftermarket crossover intercooelrs

[NolimitZ32]

Damnit you gentlement are right and I feel even dumber, thanks

[AZhitman]

Every time Paul is right, I kill a kitten.

[raremotive]

I do believe the literature of the time said it was to help equalize any potential differences in turbos and better balance the engine power. So that if one turbo was boosting slightly more than the other, that extra boost would be supplied to the weaker turbo and balance the power distribution across the cylinders. Naturally, the balance tube is supposed to help equalize it, but if there is a significant difference (like a wastegate failure or something), that little tube could not handle a 14psi difference.

My guess is simply packaging.

I would agree with both. Balancing the boost and tighter packaging.

[AZ-ZBum]

Every time Paul is right, I kill a kitten.

That's a lot of dead p****.

now go back to the Z31 section

Sorry. Just a little bored and seeing how many other Z31 threads might have been moved to this section.

[pintovit]

Hi gentlemen,

just re-typing what I read somewhere...

It's all about the lenght of the inlet pipes...

On development initial stages, the turbos were feeding the cylinders on the same side. But they needed longer inlet pipes. Instead of making longer tubing connected to the same bank, they just crossed them achieving a compact package and the desired inlet lenght. This change alone gave them 16 extra hp according to what I read.

Crazy engineers!

Hope this helps!

[labcoatmonkey]

On that note, how can I figure out which FMIC are crossover and whichones mimic TICs? I looked some up online and it looks like some have angled outlets that make it seem like a loop not a straight-thru... but thats just my guess...

[NolimitZ32]

Crossover FMIC is essentially any intercooler that takes the boost from the Pass. side turbo and feeds the driver's side bank or vise versa.

[labcoatmonkey]

that much is obvious, but how can I find out which front mounted ones do not crossover? I was thinking about getting two twin ICs and placing them instead of the one FMIC i have on right now, unless there is another way...

[NolimitZ32]

there are two options, one is what you suggested, which works just fine and actually the godspeed SMICs as far as I have heard can handle up to 500 or 600 whp. Also there are FMICs that are verticle flow (this sin;t the right name) its basically two verticle cores welded together and the piping runs to and from the same side as if you have 2 big SMICs welded together upfront, I belive HKS used to make a kit like this (not sure if they still do)