year: 87
model: Turbo II

what are the specs of the factory turbo? im thinking eventually mine will need a rebuild but im considering a turbo that either has a bigger wastegate or some other means of controlling boost.

 

I'm sure the stock turbo specs are in threads on this Forum but I just wanted to add that If you intend on upgrading the Stock turbo,the s4 has a Proprietary flange that is not common with other turbos.The S5 also is slightly different,so in essence you can either make the stock turbo(s4 or s5) a hybrid and use that turbo's manifold or go to a t3 or t4,BUT you would need another manifold for that new turbo.
Look at BNR turbos if you want a hybrid.

 

If you are looking for a compressor map for an HT-18, you will not find one. The general consensus is that it is most comparable to a Garrett T04B S-trim compressor. Personally, I don't see the point of knowing any statistics when there are several packages available from professional turbo shops that have already figured out what works well.

Here is the link to the BNR turbo options mentioned in the previous post:
BNR Supercars - Bryan Nickell's Rotary Supercars - Mazda RX-7 2nd Generation (1987-1991)

 

You should also consider checking out the Hybrid thread for info on what will work. I have my build towards the end of the thread.

https://www.rx7club.com/2nd-generati...-parts-921510/

 

speaking of which, get that thing on the dyno yet? pm results if you do not wish to share...

also to add, I agree with above posts. Look into hybrids or a t3/4

 

I haven't actually, still putting th ecar together.