Boost Means Nothing!, Just read me Options

[EMC 3000gt]

my dad had a buddy that had some old muscle car i dont remember what it was but he would rev it up pretty high and hold it steady and slowly pour water in and he said it kind of steam cleaned his engine. i thought it was kind of interesting

Pour water where?

[Bohman731]

well its a carbureted engine and i dont know anything about those so its either into the carburetor or in the intake.....unless those are the same thing lol

[Zizman]

So...I feel like more and more of a bother every time I ask a question...

But what is the difference between a single turbo, sequential twin turbo, and parallel twin turbo set up?

I know that a single turbo is apparently "better" since a lot of twin turboed cars are switched to a single turbo to get high speeds (Supras and RX-7s come to mind).

[pwee05]

don't feel like a bother, that's what this thread is here for (IMG:style_emoticons/default/smile.gif)

using two turbos does work but, like everything else, it has it's downfalls. Example, using an evo III as turbo #1 and then a t67 as turbo #2. turbo #1 will spool quicker in turn spooling the larger turbo quicker. BUT, the smaller evoIII can only flow so much, period. Therefore, the larger turbo is still limited by how much the first turbo can flow and you don't get the high RPM hp that's needed for 1/4mile racing. That's why many people switch to a single turbo. Yea, it might spool slower, but when it does it's not limited by anything other than itself.

Parallell turbos are used more for V blocks (V8, V6). They could theoretically be used for H blocks (subarus) but most people don't because of their small displacement. Parallel turbos are great for V8's because you have 3 exhaust ports on each side of the engine and large displacement to spool the turbos. Using 2 turbo manifolds, 2 turbos, dual exhaust with an H or X pipe(or single exhaust), and a single intake inlet you have two sides of an engine working independently but towards a common goal (increasing intake charges and equalizing exhaust charges). It's beneficial over using 1 turbo that would have to be way downstream after both sides of the exhaust came together. Having a turbo that far downstream makes it harder to install and spools a little slower.

[Zizman]

That was phenomenally less complex than I thought it would be. LOL.

You keep mentioning "Evo III" and "T67"...I know these are the sizes, that T67 = 67 Trim and that Evo III is a company that makes turbos similar to those found in (wait for it) Evo IIIs. The latter turbos range from 14b to 18g from everything I've seen...

But how the heck does size of a turbo work? I know smaller turbos spool faster, getting more low end "boost", versus a larger turbo which gives top end speed because it takes longer to spool. But what sizes are there?

[jonbonazza]

That was phenomenally less complex than I thought it would be. LOL.

You keep mentioning "Evo III" and "T67"...I know these are the sizes, that T67 = 67 Trim and that Evo III is a company that makes turbos similar to those found in (wait for it) Evo IIIs. The latter turbos range from 14b to 18g from everything I've seen...

But how the heck does size of a turbo work? I know smaller turbos spool faster, getting more low end "boost", versus a larger turbo which gives top end speed because it takes longer to spool. But what sizes are there?

There are a million dif sizes. It would be impossible to name every one.

[pwee05]

^+1 there are hundreds of sizes, hybrids, etc

Evo III is a company that makes turbos similar to those found in (wait for it) Evo IIIs. The latter turbos range from 14b to 18g from everything I've seen...

But how the heck does size of a turbo work? I know smaller turbos spool faster, getting more low end "boost", versus a larger turbo which gives top end speed because it takes longer to spool. But what sizes are there?

Evo III has nothing to do with a company. It doesn't really even mean anything in regards to describing the turbo itself. the Evo III turbo is actually a td05 16g turbo that is larger than the big 16g which is larger than the small 16g. All are td05 16g turbos with different sizes of compressor wheels. The Evo III being the largest.

So the TRUE designation of the "Evo III" turbo is TD05 16g with the last part numbers being 01470. It's "street name" of Evo III only came about because this turbo was only found in the Mitsubishi Lancer Evolution III (if thats wrong someone please correct me) and dsm'rs wanted to identify it ouside of the rest of the 16g family.
This will give you more information on the other TD05 turbos and their part numbers: http://www.mitsubishi-forums.com/index.php...mp;#entry178788

the size of a turbo was slightly explained earlier in this thread. http://www.mitsubishi-forums.com/index.php...st&p=239307

Some important things to consider outside of the physical size of a turbo are it's wheels. Housing flow isn't as important as wheel flow. Wheel pitch, blade spacing and blade surface area are big factors to consider in the peak amount of power a turbo can make. After that you get into physics with cavitation, turbulence, etc. I only know a little bit about the physics so i'm not going to go into that stuff.

The td05 turbos are great examples of different wheel sizes in common housings. Assuming all of these turbos are using a 7cm^2 turbine housing think about the difference between the 14b and the evo III. When installed they look identical. Take them off the car and you can see the difference, not only in wheel size, but blade spacing, blade height, blade surface area.

[EclipseRS205]

It's beneficial over using 1 turbo that would have to be way downstream after both sides of the exhaust came together. Having a turbo that far downstream makes it harder to install and spools a little slower.

I have been doing some research on turboing a WS6 trans-am. So is this why when anyone puts a single turbo on a v8, the turbo is mounted in the rear of the car. So for a v8 going twin turbo is the best option? Only way to have the turbo under the hood without severe modification to the exhaust manifold?

[pwee05]

I would imagine that underhood space is an issue for the v8 cars that want to turbo. Some of them use a manifold that meets right at the back or around to one of the engine (kinda like a subaru) instead of going the whole way to the back of the car. I think most do it that way instead of twins

[JHAWK65]

+1 need to know more about the engine: compression ratio, head work, tubular or cast turbo manifold, stock intake manifold or aftermarket, size of IC piping, size of FMIC, etc

I was gonna put a turbo in my truck but.....na. don't need one.