how to mount a Xonarotor turbo

Talk and Tech about turbocharged 924/944/968 cars
User avatar
chris white
Posts: 434
Joined: Wed Aug 11, 2021 11:40 am
Been thanked: 175 times
Bergerac wrote: Thu Feb 13, 2025 8:03 am Put me down for one of these if you decide to produce it. Any recommendations for a 16V 3.0? I'm not expert at reading compressor maps but I feel like we sit in a weird pressure ratio/flow zone that never matches the peak efficiency part of the map.
Reading Compressor maps are like reading tea leaves for your future!
I have a custom turbo from Xona Rotor for 16v 3.0, actually two different models depending on use – daily driver or higher HP. Very tight fit and will require machining the turbo mounting arm.
Give me an email if you are interested, I am a ‘shop’ for them. [email protected]

#11

User avatar
Thom
The First Carpoke!
Posts: 570
Joined: Sat Jun 26, 2021 2:31 am
Has thanked: 138 times
Been thanked: 153 times
Bergerac wrote: Thu Feb 13, 2025 8:03 amI'm not expert at reading compressor maps but I feel like we sit in a weird pressure ratio/flow zone that never matches the peak efficiency part of the map.
Agreed, and that seems to be the case for any of the mid frame compressors they have on offer. The various compressor maps suggest these turbos will give their best with pretty high pressure ratios, as running less than 30 psi of boost will make these compressors work most inefficiently. With a low-ish static compression ratio and monster cam(s) why not, but I see a lot of trial and error before pinning down a "reasonably compromised" spec.
Last edited by Thom on Thu Mar 06, 2025 12:23 am, edited 1 time in total.
'90 944 turbo

#12

User avatar
chris white
Posts: 434
Joined: Wed Aug 11, 2021 11:40 am
Been thanked: 175 times
Thom wrote: Fri Feb 21, 2025 2:25 am
Bergerac wrote: Thu Feb 13, 2025 8:03 amI'm not expert at reading compressor maps but I feel like we sit in a weird pressure ratio/flow zone that never matches the peak efficiency part of the map.
Agreed, and that seems to be the case for any of the mid frame compressors they have on offer. The various compressor maps suggest these turbos will give their best with pretty high pressure ratios, as running less than 30 psi of boost will make these compressors work most inefficiently. With a low-ish static compression ratio monster cam(s) why not, but I see a lot of trial and error before pinning down a "reasonably compromised" spec.
The design I am using is not one of their ‘stock’ pieces. The compressor map is efficient at 1bar and then has a ton of headroom above that. In theory it would still be in the good part of the island at 2 bar.

#13

Bergerac
Posts: 329
Joined: Mon Apr 03, 2023 3:00 pm
Has thanked: 20 times
Been thanked: 125 times
Thanks Chris, my next few months is dedicated to getting the car started. Big promises were made about the turbo I have but Im skeptical, I will get in touch if it doesn't meet expectations. Im interested to see how your turbo compares to the Garrett offerings that most people have run with

#14

User avatar
Darwin
Posts: 317
Joined: Fri Jul 02, 2021 4:17 am
Location: Lompoc, CA
Has thanked: 116 times
Been thanked: 74 times
chris white wrote: Fri Feb 21, 2025 6:48 am
Thom wrote: Fri Feb 21, 2025 2:25 am
Bergerac wrote: Thu Feb 13, 2025 8:03 amI'm not expert at reading compressor maps but I feel like we sit in a weird pressure ratio/flow zone that never matches the peak efficiency part of the map.
Agreed, and that seems to be the case for any of the mid frame compressors they have on offer. The various compressor maps suggest these turbos will give their best with pretty high pressure ratios, as running less than 30 psi of boost will make these compressors work most inefficiently. With a low-ish static compression ratio monster cam(s) why not, but I see a lot of trial and error before pinning down a "reasonably compromised" spec.
The design I am using is not one of their ‘stock’ pieces. The compressor map is efficient at 1bar and then has a ton of headroom above that. In theory it would still be in the good part of the island at 2 bar.
What are we talking price point wise for a 3.1L car? You know what I have (Vitesse Racing hybrid 4/5) and you know my engine (LOL) but have been wanting to upgrade for a while now. Downpipe/crossover conversion would be a pain but I'd still like to modernize my car in that regard.

Would these suffer from the same lack of vacuum/oil consumption as I am trying to deal with now? I'd love to install an ISV finally...
1984 VW Rabbit Pick-up - Not stock
1988 944 Turbo S - Really not stock (Chris White special)
2012 VW Tiguan - Kinda stock
2013 Cayenne Base - 6 Speed! Tastefully modified, mostly stock

#15

User avatar
chris white
Posts: 434
Joined: Wed Aug 11, 2021 11:40 am
Been thanked: 175 times
I keep pressing my F9 key but nothing happens....
still figuring out the final pricing. I have to modify and reweld the turbo mounting arm and figure out any plumbing changes. redoing the crossover and down pipe is not too bad, just adding V band flanges.

#16

AZMI951
Posts: 25
Joined: Mon Apr 03, 2023 9:08 pm
Has thanked: 1 time
Been thanked: 7 times
Hey Darwin, Come spend a week at my place and build your pipes on that mount of yours I have bolted to a motor for fab and mock up.

#17

BasHenneman
Posts: 48
Joined: Sun Mar 17, 2024 11:53 pm
Has thanked: 14 times
Been thanked: 15 times
chris white wrote: Sat Mar 22, 2025 2:12 pm I keep pressing my F9 key but nothing happens....
still figuring out the final pricing. I have to modify and reweld the turbo mounting arm and figure out any plumbing changes. redoing the crossover and down pipe is not too bad, just adding V band flanges.
Joe pointed this topic out to me!
I’m also looking at a new turbo for my 968, but as I’m based in Europe I would better use a local dealer..
The mount is a different story, if you are able to send me the design or sell me the plate, I’m happy to take it!

#18

Post Reply