yessir. sorry physics is killing my brain..

 

I think it would be neat as shit if it worked, I just don't think it would. Whether you have 1 turbo for 1 cylinder x4, or 1 turbo for 4 cylinders x1, if the turbines are sized to start making boost way way down low, they will be too small to let it rev anywhere near the engine's potential. That's just the way a turbo works, there has to be a restriction to get the energy to spin the turbine, and the usable rpm range will always be held hostage to that, to some extent. And no, that rule doesn't just cease to exist just because you only want 3psi out of it.

Even assuming the 4 turbo thing worked, I still think a properly sized single would work better, be more reliable, and cost less. Don't forget to add in the cost of things like flanges, clamps, and couplers... oil lines... I suggest you lay out a realistic parts list and I think you'll be shocked at the outcome.

 

Plus the fabrication etc of fitting 4 turbo's in such a confined space..

 

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With the cost of all the turbos, plus time, plus parts and labor, I think you are working on the opposite of a budget build. Those little turbos have way too much of an operating range imo. I'd like to know a certain engine size and know what rpm it spooled at. Having a four cylinder even with 4 small turbos seems like spooling will be an issue if they are designed to work with up to .95 liters a piece

 

IDK if it would spool faster or not. I wonder what the wheel weight is of all four od those things compared to 1 57mm like Cat brought up. Inertia is a mother.

 

X2, angular momentum is proportional to the square of the turbo's diameter.

 

Parasitic drag from 8 bushings, 4 thrust surfaces, 4 turbine seals and 4 compressor seals wouldn't be insignificant, either.

 

It would work if that were a 400cid 4cyl. But chances are that its more like a 140" 4cyl. It would suck to drive with a 4 turbo set up you're proposing. Each cylinder would need to spool a turbo, and you don't have much cylinder to do it with.

If you want WOW factor, make a boosted 240 that actually makes usable power. I haven't seen one of those yet.

Or a twin turbo set up might actually work if the turbos are small enough.

 

Check how Subaru have twins on a boxer 4 cyl...

 

Sequential setup? That would be pretty baller.

 

I also dont think you will be able to find turbo's small enough, and if you do I dont think its the best way to go,

looking at compressor maps, bost small turbo's don't make much in the way of psi, i guess this is because its hard to get the compressor wheel to housing gap small enough in comparison with big turbos,

I do have a sugestion for you though....

what I have done in the search for low rpm boost is use a VNT turbo from a diesel, my engine is 1380cc (austin mini) and I am using a GT2559v turbo from a 3000cc V6 renault espace, normally a turbo of this kind of size wouldnt star making usefull boost until about 4500rm, i have seen a bar+ of boost at 2800rpm.

controlling the VNT turbo's is a bit tricky though.... in my experience if you just use a normal actuator to control the vanes you get a slow build of boost through the rev range, if you use a dawes valve inline you get a high low rpm boost that tails off at higher rpm.... plus it makes the car undrivable at cruise

my current set up is a megasquirt that bleeds pressure off from the actuator, this means I can map the boost to what I want, the only draw back with this (and all the above setups) is that the VNT vanes stay closed at part throttle, which dosen't help engine efficency at that point (like a potato in the exhaust)

my next setup will be megasquirt controlling the vanes via an RC servo (some of the newer and/or larger VNT's alresdy come with a servo) it seems that the MS can drive servos with little in the way of mods (a couple of resistors) this means that part throttle vane position can be mapped too, ie you can keep the vanes wide open til you nail the throttle...

it would be a good idea for you to have a look at some compressor maps, have a play with these links, the second one can actually deal with quad turbo's.

http://www.motorgeek.com/?fullpage=true&page=flowcalc

http://www.squirrelpf.com/turbocalc/

 

Not an expert but how did you plan to run the exhaust pressure for these 4 turbos? If you planned to feed each turbo by an individual cylinder then you are dealing with only one exhaust pulse every other rotation. If you are feeding them all from a common collector then as said previously, you are fighting all the power robbing items, more wheel to spool, more oil drag etc. But the biggest problem would be the single pulse to each turbo. I think you are actually shooting yourself in the foot either way. If you are doing it for pure show then do whatever you can to get your dream built, but I thnk the performance aspect will be out the window. You'll still get performance but not as expected. As far as an intercooler goes. You would have to have one per turbo to keep them seperate again. EXPENSIVE!! Or you could install a meth spray, seperate and jet it down injecting it seperately per cylinder. I think that would work as well as any single turbo injection. As far as needing it, it all depends on how the engine is built compression wise. If it is already at 11.0 to 1 then 8 lbs is going to need cooling or spray. Remember that boosting increases compression just as if you'd mechanically increased it. Also camming influences compression. So you have to take into consideration what octane fuel you are using and how it would act with more compression/cam specs. 8 lbs on 8.0 to 1 is nothing and would be fine on 91 or 93 octane. 9.0 to 1 would be iffy and 10 and up would be a problem. You also have to take into consideration where in the rpm scale the boost comes in. The lower the rpm the harder on the octane rating. Just some thoughts. Mark L

 

there was a guy with VW used to run at Union Grove for the VW weekends had 4 turbos and 4 carbs across the back. was neat sounding. ran high 9's i think. havent seen it a few years. But it is possible. Dont know if you get any better performance over a single or twin set up. would think Not.

 

One thing I can interject into to this is that he is either forgetting or not factored in the cost of the small things like silicone elbows, or pre-bent aluminum tubing, V'bands, etc.

I've just finished with a duel, remote turbo setup, where I already had an engine built {Ford/Dart 363}, already had the turbo's {bought here in the classifieds}, already had the CSU carb built, and intercooler.

Man, those elbows, t-bolt clamps, v'bands, 3" steel tubing, 3" aluminum tubing, wideband, wastegates, oil lines, return lines for oil, etc., ate a huge amount of $$$.

The next build will most likely be a Ford/World 427 with a single turbo.

 

My mate has turbo'd his 200c kart for racing but he hasn't finished it yet. We think the turbine housing will be too small. These turbo's may be ok for a quad turbo 4 cylinder,there a tdo2 from a lombardini. Got it from ebay.$300 new. Running the carby draw through on this.

 

Also, in response to your earlier worries about secrecy, remember forced induction has been around for a long time so the chance of you, or me comming up with something new is not impossible, but slim.

 

What Nissan S13 engine? US spec KA24? UK spec CA18, or Jap spec SR20?

Either way, at just 8psi boost, regardless of turbos used, it wont be very powerful. And a low power car with 4 turbos under the bonnet will look retarded.

And from experience, even fitting 2x turbos under the bonnet of an S13 is far from easy, 4x is stupid.

Why bike carbs too? They come with perfectly suitable fuel injection?!

 

You are on a budget but wanna to run an itb setup with a turbo for each? Huh?