I am kinda automotively retarded.. so I decided to learn about turbos.. I have been reading pages of info here and in other sites about how the turbos fit in our Preludes, especially the 5th gens. I hear a lot about wastegates, BOV, test pipe, down pipe.. whewww! I am exhausted..

here is a pic of what I understood..



So what the heck is that thing where I have the ? mark.. my guess is that is the downpipe.. if not, what is a downpipe/wastegate.. etc..

Well, so I see that none of the turbos have an exhaust manifold like the N/A Preludes (the famous DC header is missin!) ok.. so how do the engine's gases escape the chamber and get into the exhaust? or does the turbo create enough air pressure to keep the engine from letting out the pressure and does that cause the increase in power?

yeah.. thats a whole lotta questions.. anyone who cares to help, please do.. dont say "go NAWSS" ... i'll stick a 50 shot in your *** and set you on fire..

TIA..
:cool:

 

? = Manifold

 

try the forced induction forum bro

 

First thing I want to do is have you read this
http://auto.howstuffworks.com/turbo.htm
that should be everything that you need to know. It doesn't go into detail but it's got the basics.
The thing that you pointing at is the manifold. basically how turbo works in the simplest form is that there are 2 turbines inside the snail looking part. One is spun by the exhaust and the other pushes the air. the wastegate is what controls how much exhaust goes through the exhaust turbine. The blow off valve controls how much pressure is on the air side. Read that link I gave you and come back with questions.

 

here a lil pic to help u out

 

that was some awesome responses.. especially for the link and that picture.. thanks guys.. so two questions (just for starters!)

1. when guys say they "dial up the turbo".. what does that mean? I kinda figured if you got one kinda turbo, you ran at that kinda pressure.. how can you change the psi level?

2. Is the TT as in Supra TT or Audi TT use one small turbo and one big turbo to reduce the lag or just two turbos to max the hp?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by aries4urlife &raquo;</TD></TR><TR><TD CLASS="quote">
1. when guys say they "dial up the turbo".. what does that mean? I kinda figured if you got one kinda turbo, you ran at that kinda pressure.. how can you change the psi level?
</TD></TR></TABLE>
you can change the amount of Boost aka PSI by using a boost controller. There are 2 types (that I know of) Manual and Electronic. What the boost gage will do is control wastegate. If more exhaust is pushed through the exhaust turbine the faster it will spin. The faster that turbine spins the faster the air side will thus causing more airflow.
This article explains it somewhat http://members.aol.com/TurboHonda/info.html


Modified by Sephro at 3:12 PM 6/26/2003

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by aries4urlife &raquo;</TD></TR><TR><TD CLASS="quote">
2. Is the TT as in Supra TT or Audi TT use one small turbo and one big turbo to reduce the lag or just two turbos to max the hp?
</TD></TR></TABLE>

I know the Supra TT uses a sequential turbo setup, hence the TT, which as exactly you describe it, one smaller and the other larger so there is elimination of turbolag. However, I am unsure about the Audi TT, but I would believe it would be for the exact same concept.

 

Good post Sephro.

To answer your second question:<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by aries4urlife &raquo;</TD></TR><TR><TD CLASS="quote">2. Is the TT as in Supra TT or Audi TT use one small turbo and one big turbo to reduce the lag or just two turbos to max the hp?
</TD></TR></TABLE>

TT = Twin Turbo. The two turbos are smaller in size and have less rotating mass. The smaller mass of the turbine (thing that gets pushed by the air) allows the turbo to spool up (spin at a speed that creates power) much more quickly.
I have heard of a Sequential setup wherein there is a small turbo that spools up quickly while the larger turbo (more rotating mass = more lag) spools up then creates the top end power.
Using two big turbos would give you nasty turbo lag (really slow off the line), but you have big top end power..but keeping in mind that its driven by exhaust- a really big turbo wont necessarily give you loads of HP on a 4 cylinder. reserve those for the supras and skylines, etc.

Keep reading up in the FI forum.

 

Isn't the TT Supra a sequentaial.

 

not all audi TT's are turbo.

TT could mean several things,
being a porsche specialist (read: fanatic) theres a couple ways to look at twin turbochargers.

a. Sequential: one in line with another, usually a smaller one for lower rpms, and a larger one for higher rpms. the 959 had this technology in the mid 80s. porsche hasn't used this at all again as far as i know, the 959 was a REALLY special case.

b. Parallel: used in cars with several banks of cylinders, the 993 and 996's have smaller turbos for each bank of three cylinders, while the earlier 911 turbos: 930,965 just had one big turbo. i'd imagine it would be hard to tune parallel twin turbos, but i guess its not since 993TT's are SICK fast and don't seem to have problems with uneven boost, i suppose you could control that with differential wastegate action.

anyway, my head hurts now, time for pizza, check the websites and everything and read up on forced induction, its a great way to make power!
-Michael

 

With dual parallel turbos the boost converges into one intake and not two so the intake sees only the combined effort of the two turbos not one for each bank.

 

and then you have the newer technology of one turbine actually being used to drive a 2nd turbine, to achive extreme boost levels w/o as much of the associated turbo lag

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RAB &raquo;</TD></TR><TR><TD CLASS="quote">Isn't the TT Supra a sequentaial.</TD></TR></TABLE>

yea it is.

Forgot to mention about the Audi TT, not all are turbo..and i think the ones that are have 1 turbo anyway..haha.

 

Audi TTs run a variation of the 1.8T found in most all VWs and Audis. They are not twin turbo charged. There is a 180 hp version and a 225 hp version that just came out both of which are 1.8Ts.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by aries4urlife &raquo;</TD></TR><TR><TD CLASS="quote"> I hear a lot about wastegates, BOV, test pipe, down pipe.. whewww! I am exhausted..

</TD></TR></TABLE>

LMAO! Good one!
gmoore

 

OT, just FYI: The 'TT' designation stands for Tourist Trophy, a race held for touring cars and motorcycles on the Isle of Man from 1905 to 1922.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Kidd_Stylez &raquo;</TD></TR><TR><TD CLASS="quote">Audi TTs run a variation of the 1.8T found in most all VWs and Audis. They are not twin turbo charged. There is a 180 hp version and a 225 hp version that just came out both of which are 1.8Ts.</TD></TR></TABLE>
Until 2005 that is, when the TT gets the new 2.0T and at least 2 (possibly 3) V6 engine choices: a 3.2 L, a 3.2 L turbo and, my favorite, possibly a 3.2 L twin turbo in the TT-R (similar to the old S4 motor).

 

my bad..thought the TT in Audi stood for twin turbo too.. haha.. I always wondered how the hell our Preludes took out Audis.. or so I have heard many kill stories.. ok.. another question..

When you say sequential turbo, someone mentioned that both the turbines work to feed a single intake. Doesnt this mean that anyway you increase the psi in the turbo, the intake can handle only so much air flowing through? Lets say that your first turbo makes 4 psi and the second is a 16 psi. I understand why you would want a smaller turbo in the lower speeds. But when the bigger one kicks in, would the smaller turbo be still working? or does it switch over? Because they are sequential, my understanding is that the first one HAS to work all the time for the second one to start functioning..

How does the turbo know about the rpms.. because it just feeds off the exhaust gases and not any speed/rpm feedback controller?

damn.. here I go into a tailspin again..

 

yea..lotsa questions. but it's a great way to learn.

About the different sized turbos, the smaller one speeds up faster and does work with not as many gases from the exhaust until the larger turbo kicks, the larger turbo outshines the smaller turbo so basically the smaller one isnt doing much work comparitively speaking.
it's basic physics i guess.. as the gases are pushed out via the exhaust stroke of the piston, it pushes high velocity air through the turbine speeding them up. theres a little more to it, and i'm sure someone can put some more meat on this bare bones explanation.