Borg Warner S360SX vs S362SX-E testing on a drunk RB30DET

[Lithium]

On 26/04/2022 at 1:21 AM, GTSBoy said:

The key difference here is that the smaller engine will require a higher pressure ratio (more boost) to flow the same amount of air through the engine - hence Lithium's point about there possibly being a need for a different size turbo if that higher boost would put you up against the surge line or way off the efficiency island cf the larger engine.

Yeah.  I probably should have spent more time on this but it did feel like there would be a LOT to cover to get on the same page.   I guess this simplest way to try and illustrate it - and PLEASE people don't take this as gospel, this is again - more to illustrate how this can vary, and why I am confident that this would be fine on an RB25.

What I've done here is taken the power we pushed the S362SXE and assumed we're using about 66lb/min of air to achieve that using a high ethanol blend on a hub dyno, and drawn a line (in red) which represents that max airflow requirements of the RB30 at different pressure ratios until it hits the choke line of the compressor graph.

I've then drawn a green line which is simply scaling the RB30 airflow needs by 83% (from 3litre to 2.5litres).  This is coarse AF, realistically this would depend on the head and bolton mods etc - given @Looney_Headhas upgraded cams and a ported head etc and the RB25 in this story is going to be limited by the stock cams, it'd be a pretty conservative estimate.   You can safely assume that an RB25 would sit somewhere between the two lines at any given boost level, and in this particular case the fact that it needs more boost to make power means that an RB25 would be able to make MORE power than the RB30 with this turbo.

On 26/04/2022 at 4:16 AM, Rand0b said:

Since you recommended it do you have any thoughts , experience, or resources for historical reviews?

Sure.  The turbos weren't available before 2020 that I know of, I know of no failures with them, we've had no issues with them (have used a few now), the performance has if anything exceeded our expectations so far.

The only "question mark" things I can think of, which are really not-big-deal-things, is needing to do things like make sure that the speed sensor plug is tight if you aren't using a speed sensor (we lost one and developed a big boost leak haha), and general "make sure everything is tight" checks are well recommended. 

At least in my experience so far, turbos which are going to be a problem due to quality control etc will show their issues in the first 1000km/first "hard push" which is why things often get a bad name quite quickly.  As I mentioned above, I've STILL not heard of a failure with them - which is part of why we started giving them a go in the first place.   Obviously can't guarantee anything, but just sharing my experience so far.... I'll be the first to raise a red flag if I have reason to think a product is going to give issues.

[Lithium]

Dang.  Forgot to attach my S361SXE compressor map with the RB25 (green) and RB30 (red) lines on it and SAU immediately blocked me from editing the post, so here is the previously promised map