Alright, first off, can someone please explain the whole .48/.42 stuff??
Also, what's the biggest turbo a street ported 13b can support?
Look at this monster:

http://cgi.ebay.com/ebaymotors/ws/eB...tem=1876574393

Could I throw that on there?

 

The .48/.42 stuff is the A/R Ratio numbers.
The smaller the area (A) is, the faster the flow at the exhaust gases enter the turbine blades.
Smaller A/R makes turbo more easy to spool when accelerating, in other words it means less turbolag. On the other hand too small A/R ratio causes exhaust gas packpressure to rise which is fatal to the engine.
The correct A/r ratio for the motor is always a compromise between good low end throttle response and high output power. Small A/r turbines cannot handle hign flow rates like bigger ones.
Rotaries genearlly require a bit larger A/R than a piston engine of equivalent size (ie: 13B - 2.6L piston)

Yes, you COULD throw that T76 turbo on there. If it's a streetdriven car though you probably wouldn't want to. It would probably spool up at about 5500rpm leaving you a pretty small powerband. That is more of a drag suited turbo for a streetported 13b. Do some searches in the Single Turbo forum to find out info and get examples of large turbochargers which are well suited for the 13b.

 

You could probably put a t-76 on it. Im putting a hx35 (from a diesel truck) on mine, its susposed to make 5psi @ 3200rpm and be at 15psi by 4100rpm, and thats decently sized turbo..

 

Ok, so is the .42 the area measurement of the blades, like .42 sq ft or sq in or what? The fog is lifting, but it's not all clear yet. So the .96 on this thing means it's basically double the area of a .48, right?

 

A/R is a number often used to describe turbos. It is basically the area (A) of the cross section of the intake pipe divided by the radius (R) of the internal bit of the impeller wheel. A 'big' A/R turbo (say > 1.0) wil flow LOADS of air, at the expense of lots of lag.

 

Ahh. Very cool. Now, why is the a/r of the exhaust side always smaller than the intake side?

 

Actually, upon doing some digging, it seems to be the opposite. This is what I found on some current rotary setups. Just those specs. I'm still learning too and at some point I want to understand how this info. relates to divided, on-center, etc. etc.. How it all ties together. I've got to get my hands on one of those books, either the Bell or MacInnes one.

Hot - Cold
1.32 - 0.70
1.15 - 0.70
0.96 - 0.71
0.96 - 0.60
0.70 - 0.81
0.70 - 0.60

For a half-assed comparison, a stock S4 turbo has a 0.88 A/R hotside and an S5 has a 1.00. I haven't found the specs on the compressor side yet.

 

"Maximum Boost" by Corky Bell.
It's the definitive guide to turbochargers! Everyone will tell you this... I highly recommend everyone on the forum reads it (i still have yet to... my friend has a copy I've only yet been able to skim over)

 

Sweet. I emailed the guy, and he said that it would work great on a rotary, but we'll have to see.

 

He is suggesting a " .81 turbine and a .60 compressor with a 76 mm compressor wheel". He says it's capable of 35 psi, minimum. Agree, disagree? Will that lag like a ****? I still don't know exactly how to set this up.

 

You will see a fair bit of lag with that. However, you will make a bull load of power

 

DO you think a street port will be able to handle this?

 

Exactly. I'm not sure you'd want that for a street car. But hey, go for it, and tell us how it spools...

 

How much power do you wizards foresee? The guy that makes them is claiming I can run it at 14-17 all day and see 400+.

 

Take Bridgeported's advice, this turbo is too big for the street. Its gonna require some major mods to support it and should be a track only turbo. Its gonna be laggy as hell even with that small exhaust turbine the guy is recommending (.81 A/R) I would never go that small on a 13b let alone with that large of a compressor wheel. Smallest that turbine housing should go is 1.0 or 1.15 on a 13b, that will give great power on top, but a laggy bitch on the streets. I'd imagine most of the racers on this site would recommend a 1.32 A/R turbine housing with that large of a compressor. It also looks to be a Q-trim turbine wheel, great for flow, but more lagg. Tell us what power your looking for and we can recommend a good turbo size for you. Its actually BETTER to ask the knowledgable rotory guys in hear for turbo sizing questions then it is to ask "turbo experts" from turbo suppliers. They are usually used to piston engines and often give bad turbo advice for the rotary engine. You want good answers go to the single turbo section. I can get GREAT prices on turbos also.....

~Mike.......

 

I'm sure his claims are true. 400+ hp @ 14-17 psi, sure.

But where do you want to make your power, between 3500-6500 or between 5500 and 8500?

The latter is what you are going to have to expect with that thing.

For that price, you can get a T04B 60-1, which will make 350 hp and be more useable on the street.

You best bet is to link this thread into the SINGLE TURBO section. The gurus there will be able to tell you more...

Remember, to run 14- 7 psi, on a monster like that, you're gonna need more fuel, bigger injectors, etc etc etc. Big turbo = big upgrades

*edit: listen to what racerXtreme7 said.

 

Turbine A/R and compressor A/R are not entirely related....you can mix match to any liking you want for what your trying to acheive. Im just trying to say when you order a X.X A/R turbine housing, then you can get any X.X compressor housing as well, not that xx Turbine housings comes with specific XX compressor housing. Turbine A/R, the smaller the number the faster the turbo spools, but the less power you'll make on the top end do to back pressure. A Larger Turbine housing A/R will spool the turbo slower but you get more power up top. Compressor A/R however is different and does not affect performance nearly as much as Turbine a/r. A smaller compressor a/r tend to have a broader and more linear power output. A larger a/r compressor housing tend to have a peaky output, they usually develope boost later but the boost onset is usually rapid and you get a surge of power.... smaller A/R compressor housings usually can handle larger boost PSI before turbo surge happens. The smaller housing give the air more velocity in the snail shell so the surge has to fight the slightly higher inercia of the air before it reaches the compressor blades. Hope this helps...

My $.002

~Mike......

 

I have no problem with the big upgrades and all that... I know I can't just slap a giant turbo on (although that would be so much easier... sigh.)
I want 450 hp, or as close to it as possible.

Thanks for the help. I am going to link the thread over there too.

 

If possible, I want as much power as possible, but with strong response from about 4k up...