Hello from Australia

N

NickM

New member
Hi everyone,
Great to see the forum back up, I've been lurking ever since I found Alex's videos on youtube.
I've got a 2011 lexus is350 that i'd love to feed some boost. There is a company in the US running 6psi from a rotrex supercharger with an ecu tune and some kind of additional fuel computer so that would be the end goal.
I figure i'll start at 3 and see how it copes.
Also love to do things on the cheap which can go either way...

First step is hardware.
I'm stuck in between buying a turbo to modify or a centrifugal supercharger.
I can get a T76 chinese turbo for around $300AUD locally.
I'd need to get it to about 50,000rpm for 6PSI according to the compressor maps i can find online.
This would require a custom shaft to be machined and specialised bearings & support etc.
I'm happy to attempt this and have a lathe that should be suitable.
Borgwarner matchbot says max shaftpower would be about 20kw

Alternatively, I've found a P-2 centrifugal supercharger unit locally for around $450AUD
This takes a lot of the customisation out of the process but spares are not as available as they would be for the turbo.
I haven't found a compressor map for these yet.
Belt / gear drive does provide flexibility but I'd like to direct drive to minimise losses.

Leaning towards the turbo as the customisation interests me.

Not really looking to track the car so don't need heaps of capacity. I think 20Ah would provide enough between charges however i'd like to explore this a bit more to find a good balance bewteen boost availablilty and required charge time. I like the idea of a mario kart power-up style that could provide say 15 seconds of boost every 30 minutes or something.

Appreciate any thoughts but otherwise i'll continue to organise my thoughts here and keep you posted.

Cheers, Nick
 
Welcome! The P2 is basically a Vortech Si trim. This is the Si trim compressor map:
Si_Compressor_MapSmall.jpg

As far as spare parts go, the bearings are common, there are a number of chinese companies that make billet impellers for these (at really good prices - I really overpaid for my billet impeller). The only thing that's not easily available is the volute. But choose what you think is best. WB projects (a member on here) used a turbo as his base. But he's a machinist by trade. Definitely keep us updated!
 
Ah the man himself! thanks for the map. Looks similar to what i had for the turbo exept lower RPM which is probably easier to manage.
Do you think a direct drive has much of a benefit? How are you feeling about the belt drive from the hobbywing video as a longer term solution?
I'm not looking for 100% duty, street use would see 5-10 seconds before a decent cooldown period i'd guess.

T76 with plots.JPG
 
I had great result with the direct drive set up! The real challenge is the custom shaft. It is super hard to make it right
 
NickM said:
Hi everyone,
Great to see the forum back up, I've been lurking ever since I found Alex's videos on youtube.
I've got a 2011 lexus is350 that i'd love to feed some boost. There is a company in the US running 6psi from a rotrex supercharger with an ecu tune and some kind of additional fuel computer so that would be the end goal.
I figure i'll start at 3 and see how it copes.
Also love to do things on the cheap which can go either way...

First step is hardware.
I'm stuck in between buying a turbo to modify or a centrifugal supercharger.
I can get a T76 chinese turbo for around $300AUD locally.
I'd need to get it to about 50,000rpm for 6PSI according to the compressor maps i can find online.
This would require a custom shaft to be machined and specialised bearings & support etc.
I'm happy to attempt this and have a lathe that should be suitable.
Borgwarner matchbot says max shaftpower would be about 20kw

Alternatively, I've found a P-2 centrifugal supercharger unit locally for around $450AUD
This takes a lot of the customisation out of the process but spares are not as available as they would be for the turbo.
I haven't found a compressor map for these yet.
Belt / gear drive does provide flexibility but I'd like to direct drive to minimise losses.

Leaning towards the turbo as the customisation interests me.

Not really looking to track the car so don't need heaps of capacity. I think 20Ah would provide enough between charges however i'd like to explore this a bit more to find a good balance bewteen boost availablilty and required charge time. I like the idea of a mario kart power-up style that could provide say 15 seconds of boost every 30 minutes or something.

Appreciate any thoughts but otherwise i'll continue to organise my thoughts here and keep you posted.

Cheers, Nick
Click to expand...
would you actually fit a P-2 in your engine bay ? .. it's pretty big and modern cars dont have much wasted space
 
Hey WB, I have been thinking about how to manage that. Your solution is very tidy and having a motor with a long enough shaft to mount the impeller directly on it would be the ideal scenario. If the compressor shaft was self supporting it would take some of the tolerance requirement out of the coupling which i've been wondering about. I do have a chinese GT35 in the shed that doesn't have a home yet so could experiment with that. Have you ever thought about having an extra long shaft with a bearing to support in front of the compressor?
I always seem to get to this point then it does seem to be a lot of effort to convert the turbo into what is effectivley a supercharger.
And the flip flop continues....
One thing i am a sucker for is that T51R spool noise, does the eturbo sound like a traditional turbo when it comes on?
I recently modded the hosing on another project for this and it was 100% worth it.

Hi MkngStffAwesome,
I plan to replace the airbox with this unit so i think it would be ok. RR Racing mount the Rotrex in a large void on that same side of the engine bay so i have a few options. I don't expect it to be a show stopper but i will get some dimensions to add to the comparison. I do also want to try and isolate the motor, controller and batteries from the engine bay heat while keeping wires as short as possible so there will be a few considerations there.
 
That’s a nice idea, I never think about it!
the sound look a lot like an hair drier in the car. But sound like a turbine when you are clost to it! Go check the bench test and the short pull video you will ear both
 
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