simon at nizpro has done something like this on his raceboat and its craftsmanship the way he has set it up its unbeleivable!

That rb30 i posted before went high 9's on crap all boost with a 100% stock bottom end, however it is in a rail, so doesnt weigh much.

theres afew turbo diesel BMW that have this sectup from factory

Quote: Originally Posted by HTURBO Me too, I'd like to see some evidence(video footage) of a drag between a single turbo charger setup and a compound turbo charger setup, or some figures using the same turbo charger. (ie one GT42 agaist a gt35 & gt42). both would prob run the same time, yeh the twin set up would have a larger powerband.... but when ur revvin to 6500 in every gear and the revs drop 2000rpm between gear changes in a manual setup... its not goin to make any difference on the 1/4 mile....

Quote: Originally Posted by Morgz Heres a local one using an RB30ET, and Agent86 yeah this ones running diesel, and loves detonating lol. dyno graphs anyone? would like to see a torque curve specially with a big huffer be a much more responsive engine.. you would really have to know exactly what your end result was and choose the most efficient turbo setup accordingly

a single turbo can attain boost pressures in excess of 50-60 psi. how many petrol engines ( note i did not say alcohol ) can handle this? dual stage turbocharging is mainly used to up the cylnder pressures. I know people use them on gas engines, i have watches some people develop them. The complexity, cost and resulting amount of hardware, to me is insane for the minimal benifits over a corectly setup combination. Morgz, last i spoke to the guy with that rail, it wasnt running normal fuel. He was going to build a ignition setup for my last VLT. but that car is sadly no longer with us. No, diesel isnt invincible, but when you compare a stock diesel, to a stock gas engine, they are vastly stronger. but thats fine, go build the setup, let me know how many engines you go thru trying to make it run even at 80%. Turbos work by multiplication of the inlet air pressuer, to a point. addding boost to the inlet wont double its flow output, but it will allow, allowing for inefficencies, a much higher discharge pressure. how manygas engines do any one of you guys gone that can run 70-80 psi inlet pressures? most people here struggle with detonation at 20-25 psi on pump fuel with a GT35.

i dont remember saying anything about running 70-80psi could someone explain to me tunability with a setup like this, i heard its hard but the person didnt elaborate on it, what makes these harder to tune then say a sequential turbo charging system as i assume that boost would be delivered similarly? Some original photos have not been recovered yet.

IMO a better way to tune this would be with an afm rather then a map sensor as your mesureing actual airflow and not just pressure, away to get around it with map sensor is set the smaller turbos wastegate a fair few psi lower then the larger one, ie smaller turbos wastegate at 20psi and the larger ones at 25psi(which u need to do anyway other wise big turbos wastegate will he open before it's boosting) many people on this site purely think of drag racing but this set up is more suited for circuit where u want liniar and quick throttle response whcich a gt42 would not give u by it self, teamed with a gt30 it would make one hell of a set up though,

Out of curiosity wouldnt you constantly have problems with the smaller turbo from being overpowered by a bigger unit? or would both units run identical boost, theoretically having the smaller turbo max out at say 20psi and the bigger can max out at 30psi but would you only run 20psi to keep it safe??

Once the smaller turbo hits it's full boost it's wastegate opens and feeds the larger turbo along with the outlet of the smaller turbo, and once the larger turbo becomes over 20psi of boost the smaller turbo is not providing any boost and the larger turbo is Simply blowing through My best try at explainig it I'm a rush lol

Quote: Originally Posted by ProTig Once the smaller turbo hits it's full boost it's wastegate opens and feeds the larger turbo along with the outlet of the smaller turbo, and once the larger turbo becomes over 20psi of boost the smaller turbo is not providing any boost and the larger turbo is Simply blowing through My best try at explainig it I'm a rush lol yep i think i get you, so as long as the gate stays open on the smaller turbo to feed boost into the bigger turbo then your not putting it at risk?

i can name lots of cars that run in excess of 40psi on petrol and i can tell u alot of diesel engines that have lost a head after more 10psi or more has been put through Some original photos have not been recovered yet.

Quote: Originally Posted by pro747 i can name lots of cars that run in excess of 40psi on petrol and i can tell u alot of diesel engines that have lost a head after more 10psi or more has been put through go name 5 cars that do??? Some original photos have not been recovered yet.

Found this on Youtube. 100psi compound turbo in a dodge truck. http://www.youtube.com/watch?v=OS8m-OfQTsw

Compound Turbo Charging (One turbo compressor wheel feeding the other) Compound turbocharging is not the same as twin turbo charging. A compound turbo utilizes different sized turbos feeding off one another to do the job of one turbo. Air enters the low-pressure turbo (the larger of the two) and is fed into the high-pressure turbo (the smaller of the two), then directed into the engine or intercooler. This is why this type of turbo charger arrangement is referred to as Compound Turbo System. Compound Turbo Chargers work in series. Multiple turbo chargers are also commonly referred to as twin turbo chargers; twin turbos are just that "twins". The two identical sized turbo chargers are the same in nature or identical is size and work in parallel. Typically each turbo is used to do one half of the work and is not in a compound configuration. The air that is compressed into the engine is not fed from one turbo compressor to the other; the air that goes to the engine is simply split between the two of them. The compound turbo charger set up offers all of the attributes of a small and large turbo charger with out the negative effect of ether one of them. There is a small turbo charger and a large turbo charger plumbed in series to one another. The small turbo charger is referred to as the high-pressure turbo charger and the large turbo charger is referred to as the low-pressure turbo charger or the atmosphere turbo charger. In a "Compound" turbo charger set up the small turbo is responsible for generating quick turbo response and rapid air flow right off idle. As the engine is accelerated from idle the small turbo begins to produce boost immediately wile the large turbo slowly starts to produce a positive pressure to the small turbo. The large turbo when matched properly should be supplying boost pressure to feed the small turbo shortly after the small turbo is making boost in to the engine or intercooler. If the large turbo charger is not matched properly it will cause the small turbo charger to stall and the low-end performance will suffer. Turbo charger balance is a fine art; the exact balance must be achieved to produce the desirable results or the turbo charger design will not perform efficiently. In order to design a compound turbo charger package, the exact pressure ratios must be matched between all of the stages of the turbo chargers. This balance is only achieved by sizing the turbine housings, turbine wheels, compressor wheels, diameters and an array of other calculations.

just for referrence, compound isnt about being quick, its about streetability/wider torque curve, with stupid hp to back it up. who cares what boost you run with petrol vs diesel etc, point is, on a 2jz, this setup has made 20psi @ 2800rpm, and went over 800hp from memory in the top end. theres a graph floating around somewhere too i believe

bingo!

So is the larger turbo first to get the exhaust gas or the smaller one? The info is conflicting. Air comes out of engine into large turbo, which dumps to small turbo, which produces boost into large turbos impeller and then into the cooler and engine yeah?

does it dose? :P

Quote: Originally Posted by Katsa does it dose? :P cant believe that questions hasnt been raised yet! Some original photos have not been recovered yet.