7thGear

alright

i know basic engine dynamics and turbo theory, ive been reading enough i think..

anyway ive been throwing this idea around for awhile, you hardcore guru's tell me if its possible or not?

also make the simple assumption that there is enough space in the engine bay for this...

alright,

exhaust manifold ----->

first turbo, a small one, like a T25 or even smaller, set to about 5-6 psi ----->

compressor pipe goes into one end of a complex intercooler ----->

exhaust from this turbo, as well as the wastegate ( external or internal doesnt matter i think...) go into ANOTHER turbo, something bigger, like a T30 or anything that preferably fades out around 8-9K rpm. and set it to max 9-11 psi, the rest being waste gated into now the actual exhaust pipe....

then the pipe from the compressor goes into the same intercooler....

then you get a single peice from the other end of the cooler that goes into the intake manifold


so..... you have a small turbo working from 2-4k rpm... then have a bigger turbo work on a small load but pull hard all the way to redline.... running 5 and 10 will give a final 15 psi no?

this should give quick response since the small turbo will spool so easily when you let off the throttle....

this is obvioulsy for a street set up

so yeah... i'm just thinking of a set up like this, i mean... i know its PHYSICAL possible to fabricate... but will it work the way i expect it to?

please let me know if you want something clarified and dont just start flaming this this is all obsurd to you :D

i'm a little greedy, at first i wanted something to fix up my D16... a small turbo is nice to spice the car up in the city, but if i ever go head to head with cars in the 300 ++ hp range there is nothing i can do on the highway, i would go a large turbo... but i dont drag... and i dont htink i ever will and it will just eat away at the response of the car... but this way i can go all the way to the top!!

DA-MAX

why waste your time with all this when you can have a single turbo setup with less headaches and probably make more power ...find yourself a nice sized turbo to match your city/highway driving and be done with it. inginueity(sp?) and uniqueness is all well and good, but all that seems plain unecessary

7thGear

well i would do that... except such turbos dont exist

if they full spool at 3K, ( for city driving) they hardly have any breath left after 5 grand, and most well built honda engines can easily rev to 8 if not more!

put a turbo on that likes it high, and it only really starts to work after 4 grand and until then my 1.6 liter is still a 1.6 liter...

i want the best of both worlds... i'm just suprised no one has publicly done it....

like i'm all for civics and tegs that run 11 seconds or less... but... you put one of those bad boys on the street and your going to have such a horrible time driving around that you'll probably get beat by geo metro's when it comes time to change lanes.

Drum_Guru

What you are talking about is called "compound turbo charging"... although I am a neophyte in the turbo world, I believe it is only done with aircraft engines... and the boost does not quite add up, but multiply somewhat, and I dont think its quite linear either... from what I understand, this is usually done to achieve boost preassures of 40-100psi...

EDIT>>> oh.. oops, I read it wrong man... i thought you said the compressed air from the small goes into the large turbo to be further compressed... nevermind... what you described is just TT... Everything would work the way you think it would, but it would be hell to plumb and fit in the car... also, read up on turbo design and you will find out that if you get a turbo with certain specs. it will perform the same job as the two described above... to a certain extent of course... its all about compromise, but you can get damn close with a little work and research... BTW the TT thing you described is also gonna cost an alot more on top of all the other drawbacks, so IMO figure out a good compromise in a single turbo...

DA-MAX

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 7thGear &raquo;</TD></TR><TR><TD CLASS="quote">well i would do that... except such turbos dont exist

if they full spool at 3K, ( for city driving) they hardly have any breath left after 5 grand, and most well built honda engines can easily rev to 8 if not more! </TD></TR></TABLE>

heh, if you say so....there are plenty streetable quick spooling turbos out there, you obviously need to do some more research. and all this worrying about "lag" "running out of breath" comes from heresay and people not sizing the right turbo for their motor. thats where research into properly sizing your turbo comes into play. and I'm not downing your idea, but from a practicality standpoint its not nearly worth it IMO.

Drum_Guru

well said...

7thGear

well ok :D

i mean i was gonna go with a t25 typish, and i probably still will. But i just wanted to see if my idea worked

and its not exactly twin turbo, most twin turbo setups i have ever seen or heard about is where two turbos get powered at the same time from a split exhaust manifold, yet they still retain the limiting characteristics of that particular turbo....

ohh and the "compounded turbo" i think is also used in 18wheeliers or any really big machinery.

Drum_Guru

yeah... your right it is used in large diesels too...

anyways... the t3/t4e 60-1 spools at 3500rpm with a lovefab sidewinder manifold, and it wont "run out of breath" till 30+psi... (quoth Tinker... the Lovefab guy...)

boostn420

Its called "staged turbo's" they do it like that for tractor pulls. You can get super rediculous manifold pressures with that setup. both/all turbo's must have the same pressure ratio's. you'd pop your baby honda motor so fast with a setup like that, you should also dream about a very low compression number for your engine.