Compressor flow comparison table

[Lithium]

Hi all, I thought I'd put one of these references in here before but it seems I haven't - not sure how many people are actually using this place still but I feel like there are guys lurking about who might find this reference useful or interesting. 

A lot of the time people don't catch key details or even fully understand how compressor maps work - or don't even look at them and just go from heresay about deciding how different turbos may compare, but I've been putting together this table over the years as a quick reference to get a gauge of how certain compressors compare to cut down the time that can be wasted looking around aimlessly.

* This relates purely to compressor flow, so won't necessarily reflect the outright capabilities of these turbos as the power potential also comes down to the turbine side.  If you understand this, you should be able to use this 😃

* The inducer and exducer size listed are the mm of just the compressor wheel

* The values under the "psi" headings are "lb/min airflow" and reflect the maximum airflow that compressor supports before it's efficiency dips under 65%, or it reaches it's maximum speed - whichever comes first.

Any questions, or requests for other turbos which the compressor map is available for then let me know 🙂

Edited 20 hours ago by Lithium
Updated compressor maps

[Lithium]

BTW, the reason I came in here to "update" this list was that the Garrett G Series II range have been released and I've updated the list with their flow details if you're curious to check how they fit with previous Garretts and other brands The G-Series II G35 990 looks like a banger...

[Butters]

I've been hunting info on the G Series II - this is best I have found so far(Link below).

Still waiting on the G35-1150 comp map, kind of very keen

 

So how do we go about getting precision on that little table of yours ?

 

https://turbosbytm.com/sites/default/files/product/technical-info/Garrett-G-Series-II-Product_Flyer 25 30 35_1.pdf

 

[Lithium]

47 minutes ago, Butters said:

I've been hunting info on the G Series II - this is best I have found so far

Still waiting on the G35-1150 comp map, kind of very keen

So how do we go about getting precision on that little table of yours ?

 

You'll find this link is probably more useful  Performance Turbochargers - Garrett - G GT GTX GTW Series Turbo TBG

G35 1150 map may not even get added to my list depending on how it looks, the G35 1050 already is a mixed bag for making the numbers you would expect from the compressor map due to mismatch - I don't know how another 10lb/min of compressor flow is going to make that any better.   I've left out others for similar reasons as it's already getting quite big.  

In terms of Precision, provide me with legit compressor maps for them and I'll do my thing   I'll add some more of the newer Xona Rotor options are they're pretty boss, I'd take a 68mm Xona over a G35 "1150" any day of the week - or Precision for that matter.

Edited Friday at 12:20 AM by Lithium

[Butters]

It's funny , you look at the 1050 and see horror and I see win, 90 @ 20psi for a 68mm wheels seems great to me. But I don't know crap about this stuff.   Happy to hear why you'd make another choice, if you can dumb it down for me

 

What I do know is my Garrett's have been insane levels of reliable whilst others have had to have precision and xona rebuilt and I use mine WAY WAY more then they do. I have a GT3582R from 2005 that is still going rock solid.  My G35 hasn't missed a beat either and I was one of the first to get one, it gets a lot of use too. 

[Lithium]

1 hour ago, Butters said:

It's funny , you look at the 1050 and see horror and I see win, 90 @ 20psi for a 68mm wheels seems great to me. But I don't know crap about this stuff.   Happy to hear why you'd make another choice, if you can dumb it down for me

 

What I do know is my Garrett's have been insane levels of reliable whilst others have had to have precision and xona rebuilt and I use mine WAY WAY more then they do. I have a GT3582R from 2005 that is still going rock solid.  My G35 hasn't missed a beat either and I was one of the first to get one, it gets a lot of use too. 

90lb/min @ 20psi is wonderful, not so much of a problem with the G35-1050's compressor efficiency (aside from how bad they roll back at higher pressure ratios).  The issue is more to do with the turbine's flow, which is why I'm not sold on going an even higher flowing compressor with the same turbine.  I'd say go back over Motive DVD's testing of the G35 1050 and Hawkins's comments regarding exhaust back pressure issues with it, I'd need to go back but I have in my head he went to the biggest hotside and ended up sacrificing a lot of spool (so it ended up behaving like a bigger turbo) and still had EMAP issues.  I've heard various other experiences along the lines of that.

At this stage at least I rate all I've seen about Xonas (for transparency I've not used one directly, but I have spoke plenty with people who have) to have low exhaust restriction for the response they offer for any given setup - basically they allow the engine to breathe, which is good for the engine and makes making power a lot easier.  You arguably don't have to even push quite the same amount of airflow through an engine to make the same power if you don't have the bum plugged up with exhaust gas struggling to escape the engine due to an underflowing turbine.  

In terms of reliability, to be fair I've had great luck with Garrett turbos as well - my GT3076R lasted forever, then I sold it and the next owner had no issues, then that car got sold and it was still going strong last I ever heard about it.  The trick is with the old GT-series turbos the compressors etc were no way near as efficient as what we have these days, it was almost hard to push them into severe overspeed situations without having a boost leak or something - and that is what often starts the failure situation.   

In terms of your G35 I'm pretty sure you're running yours within sensible limits, something people with Xonas and Precision turbos aren't often so inclined to do.  The "compressor maps" are "Joe blogs ran 45psi through his 6466 so I can do the same" and built their setup to send it to the moon.  I've seen EMAP and compressor speed data where people have actually set that stuff up on Precisions and Xonas which have been run hard and the comp speed numbers are very very exciting at times - like I've seen 76mm Precisions run at rpm that you ideally shouldn't run a G35 1050 lol.   I know people who have run G-series Garretts hard and hard a failure, then replaced them with Pulsar turbos as a cheap "get it going" stop gap with the intent of doing a proper upgrade when THAT fails... and are still running the same thing.   Like anything, ymmv and it's not always to do with the quality or trustworthiness of said product.

I've been provided with a bunch of compressor maps for Turbosmart turbos and will update my list based off that, they could prove to interesting reading and an interesting alternative as well.

[Butters]

Keen to see the turbosmart data, to date I've only seen negative things in terms of response for them. Very small sample size though.  

 

Hawkins is a big advocate in his videos of the larger rear housings. I managed to make similar power with a lower spec motor on the smaller .8 rear, keeping decentish spool.  The people he works with now are big power cars compared to mine though, mine really is setup to drive around and enjoy.  I don't have any back pressure monitoring though, so couldn't say if its good or bad on my car, just that it does what I want it to do.   Future I want a higher compression more cubes motor to give a bit more bottom end and hopefully the new g35-1150 gets me to the 850 rear comfortably.  But maybe I won't due to exhaust back pressure.

[Komdotkom]

19 hours ago, Lithium said:

 I'd take a 68mm Xona over a G35 "1150" any day of the week - or Precision for that matter.

Me too, I wish they did v band reverse rotation - I'd order one straight away.

Did you listen to the HPA interview with one of the Xona guys, quite interesting.

[Lithium]

3 minutes ago, Komdotkom said:

Me too, I wish they did v band reverse rotation - I'd order one straight away.

Did you listen to the HPA interview with one of the Xona guys, quite interesting.

Yeah I did, was a good one Also pretty sure Xona do mirror options 

[MBS206]

This comparison table needs more MaxSpeedingRods turbos added for those off us who like the LOLs 😛

[Komdotkom]

3 hours ago, Lithium said:

Yeah I did, was a good one Also pretty sure Xona do mirror options 

I might have to shoot them an email. Pity the exchange rate is so bad at the moment.

BTW, thanks for posting that table makes interesting reading. 

[Lithium]

I've edited the original post to include include Turbosmart turbos - the first list is "entry level", or up to 68mm.  The second is "for those who like to party" and starts at 62mm.

 

Edited 20 hours ago by Lithium

[Lithium]

Updated with the latest <68mm Xona Rotor turbos.  The two XRA options are on paper some of the compressor performance I've seen 

[Lithium]

On 08/03/2025 at 1:12 PM, Komdotkom said:

I might have to shoot them an email. Pity the exchange rate is so bad at the moment.

BTW, thanks for posting that table makes interesting reading. 

No worries.

They have a section on their website with some RR options listed, no doubt you can find out more by EMailing as well tho
Reverse Rotation Motorsport Turbochargers – Xona Rotor

[CefiroA31]

My take on gg2 48mm, 54mm, 58mm, and 62mm compressor map for same size compressor vs gg1 :

All gg2 only outflow gg1 above 20 psi.

As all g gen 2 surge line at lower left of comp map move to the right, all gg2 sacrifice spool vs same size gg1, surge line move to the right worst for 54mm gg2.

So for same size compressor if you want best response, use gg1, if you want max hp at >20psi use gg2 but you will be laggier vs same size gg1.

Max compressor efficiency drops to max 75% on all gg2 vs max 76%-80% of same size gg1. Iirc lower efficiency means hotter iat less dense air so lower hp at same operating point of comp map.

Also curious why gg2 is mapped to lower max rpm vs same size gg1 (only 48mm size both gg1 gg2 mapped to same rpm) :

54mm gg1 165,000 rpm  vs  gg2 160,000 rpm.

58mm gg1 150,000 rpm vs gg2 140,000rpm.

62mm gg1 145,000 rpm vs gg2 140,000 rpm.

If gg2 can safely spin to gg1 rpm then they can flow a bit more than as mapped.

Good thing that all gg 2 interchange compressor and turbine housings with same size gg 1. So gg1 owners can buy gg2 chra only if planning to boost >20psi.

Edited 3 hours ago by CefiroA31
Typo