STX 67 Turbo for Focus RS Prototype Dyno’ed!
Have you been wondering what our stock turbo STX 67 upgrade could do, the Results are in!!!
For this unit, we started with an OEM unit and increased the compressor wheel around 3mm on the inducer and 4mm on the exducer. The turbine section remained the same for this prototype. It is not clear if the OEM turbine housing can support a larger turbine wheel; there is not much room in there.
Our N55 turbo with similar enhancements on the cold side, and is able to make about 60-70 whp more power than the stock unit + stage 2. Lets see how our Focus RS prototype does.
We couldn’t be more pleased with the initial performance gains of our STX 67 prototype for the Ford Focus RS. Our friends at English Racing in Camas, Washington helped us reached 345 WHP and 383 wft*lbs @ 22psi (recorded with map sensor). That’s 55hp & 77 ft*lbs over the factory tune.
– Stock 2016 Focus RS
– SteamSpeed STX 67 turbo prototype
– SteamSpeed front mount intercooler kit prototype
– COBB AccessPORT
– 92 octane WA pump gas
Here are the dyno results from our car at English Racing.
Green: Baseline, Stock RS with Stock Tune – 92 octane
Red: Cobb Stage 1 Base Map – 92 octane
Blue: SteamSpeed STX 67 turbo + SteamSpeed FMIC
What does our turbo look like vs a full “stage 2” car (FMIC, turbo-back, intake, etc.) on the same dyno? There was still the same ~40 ft*lbs torque gains, and about 11 whp on top.
Some initial thoughts:
We saw some solid gains on our mostly stock car. It was in fact the most power and torque a Focus RS has put down at English Racing on pump gas.
Since we left the turbine section as is, we didn’t expect to see huge gains on the top-end that one could probably be achieved with a larger A/R turbine housing. Accordingly 11-33 whp gains on the top end are not huge, but still a significant improvement. 40 ft*lbs on the low end is a good result. That is something you’d feel daily driving. It is clear that Ford really wanted to optimize for low end torque with this design, so it may be a challenge to overcome that housing’s limitations without replacing it all together.
All in all, there were gains around 5-15% across the entire rev band, so we are pleased with the result. It really doesn’t lose any of the benefits of the stock unit in terms of responsiveness and so on while making solid gains everywhere vs the OEM unit. As is, it is a no-downside upgrade vs the stock unit.
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It would be interesting to see how this turbo would do with more bolt ons like a turbo back and upgraded intake. Our car was mostly stock otherwise. I think we see some modest gains.
The wastegate duty cycle was about maxed out, so that could improved with a different waste spring preload or changing out the boost controller.
I think we could make the compressor somewhat larger without overpowering the turbine section. That might net another 10% more power.
And the car still got 28 average mpg on the way back.