Single turbo sizing for a responsive street setup
 

Hi guys!

Coming from the 6 cylinder world I know rotaries like slightly larger turbo sizes compared to piston engines.

I've got a spare Garett GTX3582R Gen2 but I'm not sure how that matches up. The engine in question is a stock port 13b REW and power goals are around 400whp.

Thanks for any advice and guidance!

It's a great turbo. Rotaries require about 133% CFM more for a given rwhp than a piston engine.

I think you'll Howard's sticky helpful; I did:
Turbo Comparison... includes new 2015 turbos. see post one - RX7Club.com - Mazda RX7 Forum

Thanks for this! That's definitely helpful.

I also run a gt3582 and its amazing! Perfect turbo in my opinon, I am only running 14psi currently, but feels great, not really any lag if you are in the correct gears. Starts making boost in the early 3000s

GT3582R were actually the go to turbo for rotaries for many years. I personally love the EFR7670 and 8374, the first one starting to spool around 2k but only pulling to the 7ks, and the latter starting to spool around mid to late 2ks and pulling to the 8ks. The 7670 is sized a little small for our engines, but the 8374 is just right. And supposedly the Turbosource variable turbine housing can combine the best of both worlds.

This part is a pipe dream. They are already too busy making the kits that are already ordered to finish this. Took 7 months for me to receive my complete kit.

That thought crossed my mind. Along with seeing how it actually performs. Makes sense that it would spool faster, but I'd like to see results first before I plunk money down. Either way, I've always wanted the faster response of the 7670 (albeit marginal) while being able to pull all the way to redline.

Given most if you guys chasing response have modern ecus, are you actually using the secondary runner throttles Mazda gave you to increase torque and flow at lower rpm? If not you are leaving response in the table anyway. It may not change flow enough/may be consistent enough in progression onto boost to not be a serious problem but ideally you want IMP:EMP tune for the quick spool too.

I have the Garrett GT3582R that was modified by Force Performance with their billet compressor that flows similar to your "X" version.
What nobody has mentioned is the turbine AR size.
I run the 1.06 because I wanted better high end flow, but this will not be ideal for you.
You need to go to the lower AR turbine for faster spoolup.

Her are two of my boost level testing runs in third gear with the 3.909 diff. RPMs and recorded boost
12 psi boost: 4000-12.3, 4500-12.7, 5000-12.6, 5500-12.6, 6000-12.4, 6500-12.5, 7000-12.6, 7500-12.6, 8000-12.5

18 psi boost: 4000-16.5, 4500-18.7, 5000-18.6, 5500-18.5, 6000-18.3, 6500-18.5, 7000-18.0, 7500-18.2,

it’d be interesting to see how it compares against the new equivalent Garrett G30-770 1.06A/R TS-T4 with the smaller impellers. Unfortunately it’s the only TS option at the moment.

still a ways out from getting mine done though, taking forever just to get a TS-T4 manifold flange with some custom machining. Was finally supposed to be coming up in their production queue yesterday …

which the linked thread above was fine in it’s day, but the newer turbos as the one noted above prove impeller diameter alone is not an accurate indicator of flow potential. What you really need to understand is the compressor vs turbine rotary flow requirement from which a fairly accurate selection can be made if the flow maps for each are available. That’s why I’m generally going to steer away from brands that don’t have those.

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