hey guy im looking to buy a turbo buy im not sure which one to buy.im just looking for which one is best T66 or T70 turbo.can you guys give im your info.

 

There's no such thing as a "best". It comes down to what you expect of it. Power goals, intended use, engine/porting???

 

Look at the compressor maps which can be googled and look at what trim size and your expected horsepower. .80 hotside A/R is probably around where you want to be at considering the stock hot side is a .60 hotside A/R on the s4 and s5 turbos and in which case you should just get a BNR stage 4. Anyway the map will tell you horse power and maximum boost efficiency for that turbo and trim size best tool for selecting turbos.

 

wrong, the stock FC hitachi turbo has an A/R of 1.00, both s4 and s5. but, a 1.00 A/R on the stock turbine wheel/flange is much smaller than a 1.00 A/R on a p-trim T4 flange. A/R is only a Ratio, not a physical size.

I personally would not suggest going smaller than a 0.84 A/R on a T3 or T4 turbo, as it still gives great response, especially with a divided entry. As for T66 vs T70, if the exhaust side is identical on both, it depends on your power goals. The T66 will spool quicker than the T70 (maybe only marginally, but it will)

The T66 will make 72 lbs/min max, or nearly 550 whp on a rotary.
http://www.rbracing-rsr.com/turbo/TurboMaps/t66.gif

The T70 will make 84 lbs/min max, or nearly 650 whp on a rotary.
http://www.rbracing-rsr.com/turbo/TurboMaps/t70.gif

Do yourself a favour and read these articles to better understand compressors and maps and make your own decision:

https://www.rx7club.com/single-turbo-rx-7s-23/how-size-matters-compressor-map-illiterate-zero-r-472529/

http://www.turbobygarrett.com/turbob...ch_center.html


If you would use the search button, you would find all the info you need and more, I suggest you do so.