After searching for a bit, I came to the grim realization that the 20B can Pretty much outflow any single turbo.

the Y2K looks like it can keep up with the 20B.

But a Twin T04S setup would easily keep up and have better spool time. more expensive but it seems this is the best and only way to have a hardcore streetcar 20B turbo.

Cost is a concern but a turbo is the a primary componet for a rotory and should not be cheaped out on.

( Is cheaped a word?)

what do you think or what would you do?

also, Evil can you tell me about your 20B/T66 setup? I know its a 62-1 but how???

 

RETed has done a few 20Bs.

 

Uh, why do people think they can control something that can put down 600hp at half throttle?

Get the motor mounted and installed in your car then ask turbo options then.

I really like the HKS T51R Kai SPL, with power potential over 700hp easily, for single.

I actually prefer a triple design for "simplicity".
We're going to use a trio of T3's in the near future.


-Ted

 

I'm goin to need some lessons handling the power this car will make... no doubt.

But i'm asking now so I can start planning how my setup is going to be. So I wont have the Engine in my car, and be like WTF do I do know? I see that your going non-turbo for now ted. hows that working out?

 

I read a thread that the 1.32 a/r it comes with is too small for a 20B.


Triple would be nice but I doint think it would be very simple tring to hang all that on the side of the engine. Would 3 t3/t4's even fit? have you checked for clearence.

 

 

I mean the 20b will outflow it... right?

 

Not necessarily. Are you talking about RED-Rx7's thread? If so his 20b has some major porting done. His engine was ported to support over 1000 hp. His porting is the reason is out flows his turbo w/the large A/R.

 

You tell me.

Use the "2-stroke formula":
http://www.grapeaperacing.com/GrapeA...bochargers.pdf

Compressor maps here:
http://www.majesticturbo.com/compresson-maps.html

 

I guess you really have to do the math, I saw that red's 20B would outflow a huge housing but that is because of the porting he has done to the engine.

It seems that on stock ports that the T66 will be a bit big
for a 20b but could be easily streetported for optimum performance.

 

The imortant thing about those equations is to see the variables. Sizing a turbo to any engine depends on displacement, volumetric efficiency, rpm, pressure ratio, and other factors. When you see people on this forum commenting on such, you need to consider these factors, which would translate to the engine porting, operating rpm and redline, boost level, operating conditions (drag vs. road race, high/low altitude, hot/cold weather, heavy/light car, etc.), and such.

Additionally, the characteristics of the turbo make a difference. As you can see by the compressor maps, some may work better for high boost while others are better for high flow, and the physical size may not indicate these properties. It is not quite as simple as stating that a given turbo would or would not match a given engine block.

 

From what I learned on grapeapracing.com


ok a 13B n/a stock port makes 160 h.p
a 13B n/a PP makes 315-320 h.p. (example for simplicty)

So a 20B n/a stock port would have 225 h.p.
and a 20B n/a PP will have 450 h.p.

with that said using a PPort makes the engine flow 100% better then a stock port

I am hoping a Extend port 20B will flow 40-50% better then stock port.

So. using CID x RPM /1728= CFM . 168(using 150% flow) x8000 /1728 would equal 778 CFM. with 90% volumetric efficiency that would be 700 CFM (optimistic)

so @10 PSI with a density ratio of 1.37- 700 x 1.37 x 0.069 the flow rate required would be 66 lbs/min

then @16 PSI with a density ratio of 1.56- 700 x 1.56 x 0.069 the flow rate would be 76 lbs/min.

so for this application a T72 turbo that flows 80 lbs/min would be appropriate. a T72 BB would help with spool up time.

Is this correct?

use a boost controller to switch from 10-16 PSI

 

A PP engine makes its power at higher rpm's, so you cannot compare flow rates based simply on peak hp numbers.

Volumetric efficiency would be your "flow rate" increase. I'm not sure how much your extended port will increase the volumetric efficiency, though.

If you want to simplify things, you can use a fudge factor of 1 lb/min = 8-10hp on pump gas. Once you narrow down your turbo choice some, then you can get into all the gory math to choose one. However, the racing professionals simply call their turbocharger distributor for recommendations rather than trying to figure it out themselves, so that is probably a good method for newbies also.

Look at the T72 map again. It doesn't flow 80 lbs/min close to any of the efficiency islands until it gets to a pressure ratio of at least 3.0, which is approximately 29psi boost.

BTW, the new Garrett GT turbos are better than the old T-series. You can download the catalog here:
http://www.turbobygarrett.com/turbob...downloads.html

 

opps, yeah it seems the T72 would require more boost then I am willing to use with a 20B.

Thanks for all your help evil. After viewing the GT42(R) map, this turbo sould work nicely throughout the 20B's RPM band. With a ported 20B, at around 14.7-18 PSI the turbo would be very close to it's peak efficiency. Now I just need to price it. Guess i'll be going single after all.

 

the GT42R goes for $1950.