well in this case then it doesnt matter what setup 1200rc uses does it? one big turbo doing the job or two little ones doing the job. either way it seems that the job gets done. I can see the argument for a well setup sequential system though... That would make allot of sense as far as making fast and constant boost.

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Correct. But I really think 1200rc just likes the idea of saying "my datto is twin-turbo".
Its sounds much more impressive don't you think.

Yeah twin turbo does have a certian ring to it And i must say it does LOOK good under the bonnet...

Either way you go its still very very cool. Turbo Datsun is the James Dean of the car world.

lol I'd belive that. Since he like neon lights and all that other look at me stuff.

At the end of the day its cool to see something different

i dont think 2 turbos r required on any 4 banger datsuns, otherwise nissan mintsu subaru and few other would've atleast made some car among many of their great smaller displacement 4 cyl engines with 2 turbos. and their cars r plenty pwerful for street or drag in their own class.
beside i dont think that stock oil pump will b sufficient of NA engine for 2 turbos.

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good onya rallycar. Maybe its you who should try thinking about why it is that there are no production 4cyl cars with this setup...

As far as I know, the twin turbo legacy is a sequential system, meaning all four cylinders drive each turbo, at different parts of the rev/load map. Very different to what RC is doing.

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The argument does not apply to 4cyl cars. A turbo works by the turbine being driven by exhaust gasses - obviously enough. But when you halve the number of cylinders feeding each turbo, you not only halve the total flow over the turbine, you have also made it operate on the turbine for half the time. Not big problem if you started with a 6cyl, but not so good if it was a 4cyl. Ever heard a V twin bike running? Nice way to drive a gas turbine huh? Between each pulse that is working on the turbine, there are the forces of friction and load on the impellor working against it's motion with only the spinning assembly's inertia to try to keep it going. Being so small, it has bugger all inertia working for it, so the turbine slows, then another exhaust pulse hits it and has to stop the decelleration before accellerating it again. That is not only bad for performance, it also mean reduced turbo life.

To make it work acceptably at low rpm, where the exhaust flow will be at its worst, the turbos will have to be quite small, and will restrict top end power. No question about it. Then again, if the turbos are sized not to restrict top end, you won't be able to spin them up at low revs with half the amount of gas operating on them for half the time.

And then there is the extra weight to consider.

Why don't you get in touch with someone like Ray Hall turbos for some advice? What he doesn't know about any kind of turbo setup for any sort of performance application ain't worth knowing. You can find him on the web and email him.

ah, i agree there is some slight dia-advantages to the twin turbo system setup like i have, but there is also advantages, and from looking at other things on the autospeed website i know they know exactly what they are talking about, they don't recomend anything unless they have measured the advantages themselves

i don't think that the moment of inertia of the turbine fins would be directly proportional to the diametter, in that "a turbo half the size requires half the amount of gas flow to turn it" would not be an accurate statement, and therefore the advantage of a twin turbo system can be seen, as it will spool earlier due to the smaller blades requiring a much smaller gas flow than a single larger turbine, and being there is two of them thy only require an output flow of half that of a single larger one, meaning they are not working as hard and there is not the same loads on them as a larger unit, they would also be generating less boost i would think, in that if two turbos are making 10psi the end result is more likely to be something like 12psi than 10psi further downstream

the surging speed of the turbines which you were reffering to L18_B110 i have tried to improve by changing the cylinders running each turbo, i was considering a plenum type arangement in order to get all four cylinders running both turbos, but my thinking was that there would be greater losses than gains in using such a system, though i admit this is the one issue with a twin turbo system like i have designed

theres 2 reasons i dont like speaking to places like Ray Hall or whoever, 1. being they are selling products and therefore are ALWAYS biased, 2. they don't understand the word BUDGET, they think everything has to be done the best way at high cost or not at all (of course these are generalisations, but accurate ones)

you blokes keep telling me about there being no 4cyl turbo setups, but you dont agruee the original post that is from autospeed at all, do any of you doubt what they are saying?, or is your argument that you don't think it applies to 4cyl motors?, i really don't understand that argument as i dont see why a 4cyl is any diffrent to a 6cyl or 8cyl, the TT GTR sklines are setup like i have mine, what's the diffrence if it's fed by 2 or 3 cylinders each???, i mean if you scale them to the same size, the 4cyl fires more often and fires more gas every time it fires, what's wrong with that?

oh yeah, and i do like a bit of rice, and i do love saying my cars twin turbo, and even if that was the only reason i was doing it you still haven't convinced me that a single turbo is better. (forgetting weight, packaging and cost obviously)

if ya can't be bothered reading all that, just go back to the first post and read it with an OPEN MIND, when your finished tell me you didn't go "OH BUGGER ME, TWIN TURBO IS A BLOODY GOOD IDEA, its the same as having a single but it spools a hell of a lot earlier"



oh, and when im finished my setup we will see how it goes ey?, i reckon she'll pull 12s and you blokes will still be scratching ya heads

Not wanting to sound like a "wet blanket", but who is Autospeed? What makes them right? What are their qualifications?

As a Uni student, the ability to "critically" analyse fact from fiction, is what will make or break your professional career. Using one source of reference (Who's own references are obscure), is clearly not smart.

But, without risk..there is no adventure.

End of the story is this. You have the parts and the facilities to "give it a go"...so go for it. All you have to lose is your faith in Autospeed as a technical resource. It also will look and sound cool.

...so get it going!

Chris

go to www.autopseed.com, it's an online magazine, with new car reviews and stuff but more importantely a hell of a lot of good technical articles on anything u can think of, go there and have a look, imsure you'll trust anything they say also, if you cant trust them u cant trust anyone

they have solid info and theory on all sorts of stuff that i have not been able to find anywhere else, on the net or in peoples heads

i have found out all about stuff i was unsure of there,

examples:
water spray
water injection
how intercoolers work
and other diy projects like
boost control, bov setup, turbo timer etc etc

these dudes know everything and test everything in the CORRECT WAY before they will talk about it, they are an unbelievably good source os SOLID info, im sure most anyone could learn many things from there, you have to pay to get some articles (which i don't) but most stuff is a bit older (2-3 years) and therefore free, use the search function and make sure you search "all articles"