sweanders

I wonder if this actually would work well..

Ian Carr

I saw a drag race celica set up like that... it seemed to work pretty well

MM951

Thats something I'd like to find more info on. Do you have any additional info? Do you know why they would design that vs. one bigger turbo? Intresting..

MarkRobinson

Hmm, being that at 3000rpm, each turbo is only getting exhaust from 25 ignitions/second...each turbo is getting 1/4 the exhaust a normal 4cyl turbo would be getting (100 ignitions/second is normal @ 3k)...so my guess is that it would be laggy as hell. Being how tiny those turbos are, I'd bet the entire motor wouldn't produce over 500hp in that configuration as they're probalby only good for 125hp each.

(it is cool looking though eh??)

MM951

Mark-- in really basic terms is that why its common for cars like the 300zx tt or supra tt going to a single turbo ?

Willard Bridgham 3

I would worry about the operation of 4 compressors in parallel.

If any cylinder put out any less exhaust volume than any other cylinder for any reason, ie, worn rings, valve differential, bad injector (assume that the turbines are perfect), it is possible, not likely, but possible that one backward inclined compressor would attempt to stall or reduce the performance of another compressor depending upon compressor inlet conditions.

Inlet conditions appear identical from the photos, but may not be. If there is a difference in inlet air rotation, for instance, this effect would be magnified.

Under the worst conditions, the pressure in the plenum would oscillate trying to reach stable operation.

I assume that all compressors share a common plenum (intake rail) from looking at the photograph.

Compressors (fans) in parallel are known for unstable operation and could cause one or more compressor to surge given the very narrow operating range of most compressors.

PCinDC

If that is truly the biggest problem with this setup (aside from packaging), would 4 compressors pressurizing discrete intake tracts with individual throttle bodies resolve it? Would be an even bigger packaging nightmare for sure, and would also suffer from a lack of exhaust energy driving the turbine. Any systems like this out there? Not on a 951, obviously. Would there be any benefit, assuming you could get it to fit, aside from ultimate per-cylinder tunability?

Lance J

Mark what i tell you about hanging out on the 951 board. there more vid's to be be made and posted of your turbo 928.

Lance J

J Chen

The thought of excess weight defeats
any added benefits. Not to mention
complication & reliabilty issues.

Laust Pedersen

It certainly looks interesting. Assuming there is no exhaust pressure equalization before the turbines maybe part of the advantage is in the inertia of the turbine wheel, which may help scavenging the exhaust gasses after getting the “kick” of the peak (pulsating) exhaust pressures.
The same concerns regarding complexity and reliability could be raised on a V8 vs. an I4 engine.

Chas

if each compressor outlet goes to the same cylinder that drives that turbo, I wouldn't think it would be a problem

Duke

That would make for a fuel injection nightmare.

95Juan

since mark hasnt responded, i'll take it, since i was a JDM fan-boy before i was turned to the dark side.

most 300ZX owners stay TT, since the V6 configuration is easier to keep TT than it is to convert to single turbo........from what i've seen.

TT was something of a "fad" in those cars (RX7, Supra, Z32 TT, etc). because it was thought that a smaller turbo and a bigger turbo would give the car ultimate flexibility. small turbo for low-rpm, big turbo for high-rpm. soon after these cars were released, turbos leapt forward in efficiency, and it was possible to create the flexibility of a TT setup with a single turbo.

hence, you see most of the big-power makers with single turbo setups (as far as Rx7 and supra). you might see a TT setup on a drag car, but there's a whole lot of work that goes into that.




edit- what kind of motor is that in the picture?

Duke

It looks like a Toyota cambelt cover but I might be mistaken.