guys,

I've got an Rx7 (obviously hah) and im planning on going single turbo on it. Im pretty clue up on turbos, how they work, wastegates bla bla, but i'm not too hot on turbos, housings, compressor wheels etc etc.

Does anyone have any information or links on turbos, what numbers mean what (eg whats an a/r?) and general part numbers/turbo selection theory?

Thanks in advance

 

http://www.gnttype.org/techarea/turbo/turboflow.html

what kinda horsepower you looking for?

 

what about the A/rs and housing numbers etC?

useful article thoguh thanks!

 

i have an 88 gtu and, does anyone know what parts that i would need to convert it to a turbo model

 

well a turbo would be a good start. Then a manifold, ECU, intercooler bla bla.

Anyone have info on compressor housings and part numbers etc? I.e whts the diference between a .80 AR and a .60 AR? what does the AR Mean?

 

Bob, the A/R is a ratio that deals with the measurements of the turbine.

put simply the higher the a/r is the more space there is to fill in the turbine houseing prior to exiting the exhaust blades. too small will choke the engine (.60) too big will make it spool (slowly1.15) this is for the turbine.

some people go with huge trim wheel Q trim for instance, and a tighter a/r. the trick is the big wheel can flow enough that a tighter a/r will work good. some go with smaller wheel trims o, p and maximise exhasut flow through better header/wastegate design with slightly larger a/r's its all really a balancing act.

Now if you are talking the compressor side of the unit, then its a different story.

my suggestion is to search, simply asking might get you the answers you are looking for, but you will be much more knowledgable if you research it a little on your own, and you will probably come to realize that what you thought might work, will not.

kenn

 

Thanks Ken, i agree with what your saying, and i have searched - problem is people tend to talk about what they are going to use and why, but they dont actually state what the physical difference is!

I.e im going to use compressor wheel x with a .70 ar so it spools faster

Thats all well and good, but i have no idea what compressor wheel X is and what a .70 is and why it will spool faster...and i like to understand what im doing, and this involves (For a start) having the terminology explained to me.

So basically, AR is the size of the "hot side" of the turbo? what does "A/r" stand for? You say its a ratio...do you mean its a ratio of the size of the exhaust wheel to its housing? or the exhaust housing to compressor housing? or compressor wheel to exhaust wheel? lol

What is a "Q trim"? Im guessing that the compressor (cold side) wheels are letter coded, so an "A" wheel is very very small, and a Z is very large? How do these letters compare to coding and/or sizing of the compressor housing? i.e do compressor housings have a specific compatible compressor wheel or can you use any wheel as long as its the same size as the turbo inlet?

I understand what you are saying about using a small exhaust wheel to speed up spool and a large compressor wheel to get the required flow, but will this not restrict exhaust flow too much? (id imagine it works almost like a bike, big driving cog driving small driven cog takes more effort to turn) or is this all part of the balancing act?

Can you mix and match different parts of different turbos to create the spool and flow that you want? (or try to) or is it just a case of getting a different turbo?

sorry for all the questions, i just want to nail the basics so i know what people are talking about when it comes to turbo selection etc and then i can start to learn from reading, at the moment i read a thread and have no idea what people are talking about!

 

lemme do the noob rundown...

a/r... the higher the number, the more power at the same boost level
--but the higher the number, the slower the spoolup

turbine trims--o,p,q, etc.. q flows more than p, which flows more than o, etc..

higher letter= more power, but slower spoolup.

if you want actual suggestions, we need to know your goals. a 60-1 compressor with a .96 a/r p-trim turbine housing should make you about 300whp at 8-10 psi and close to 400whp at around 15psi, with full boost around 3500ish rpm, depending on porting and mods.