Here are some action shots of the new SteamSpeed STX 78R Turbocharger being installed into a N55 equipped BMW 335i. This car has successfully been running our STX 67 (aka stage 1) turbo for about a year now. The owner was able to put down 400 whp with the 67 on pump gas + meth.
We’ll see what he can do with the STX 78R. As you can see it is quite a bit larger than the STX 67, about +11mm on the exducer side. Based strictly on the comp wheel, this turbo should be able to make between 500-600 whp, but the OEM turbine housing should limit that to some degree. Initial dyno testing will show to what degree.
Base purely on inductive reasoning, this turbo should perform somewhat better than the currently popular Pure Stage 2 turbo: their turbo has wheels somewhat larger than a GTX3076R, our 78R is somewhat larger than a GTX3076R, they remachine the OEM housings, so do we, but the main difference is that our turbo has a BB center section, and Pure reuses the OEM JB CHRA. Given that the only main difference that impacts performance is that our has a BB CHRA, what does that impact?
BB CHRAs have some standard advantages over JB: it is more responsive especially with transient boost, it is more efficient, it is more durable, etc. In this case, the biggest difference, I think, will be the fact that BB CHRAs can be stay efficient in spite of backpressure much better that a JB CHRA. Normally JB is fine up to 2:1, but BB can still be efficient at much higher ratios. This matters a lot in this case, because the OEM manifold/turbine housing is going to generate a lot of backpressure when you try to make over 500 whp.
The BMW N55 STX 78R turbo going in.
This is what SteamSpeed STX 67 “stage 1” looks like next to the STX 78R “stage 2.5.”
SteamSpeed STX 67 “Stage 1” for BMW N55 installed.
SteamSpeed STX 78R “Stage 2.5” for BMW N55 installed.
Introducing the SteamSpeed STX 71 for Mitsubishi Evo X
You’ve asked, we listened. SteamSpeed now supplies turbos for the Evo X. To start with, we brought over our same proven 59 lbs/min STX 71 CHRA we have used since the beginning on the STI. On the STI, it typically puts down 400-450 whp and ft*lbs on pump gas. How do you recon it would perform on a Evo X? We set out to find out. More pictures here…..
SteamSpeed STX 71 for Evo X Specs
Make no mistake, the STX 71 is designed to be a 18k. How does it compare?
As you can see from the basic specs, the wheels are a somewhat smaller than the 18k; yet, the STX 71 flows 5.5 lbs/min, or about 10%. In simple terms, the STX 71 will be a more responsive than the 18k while being capable of making ~10% more power.
Initial Dyno Results:
We’ve had a few testers out there, and the intal results are looking good. It looks like they are getting a little more response with a little more power vs the 18k.
Here is some plots from data logs produced by Aaron at English Racing. this is the STX 71 vs the OEM turbo. As you can see, you gain +100 whp, and give up close to nothing. It feels the same as stock.
Here is the same car on their DynoJet dyno:
Here is the result from one of our customers in Florida.
[STX 71R for FA20 Performance Performance Hypothesis [Pre-Test]]
The OEM style twin scroll turbine housing is restrictive for turbos larger than the OEM unit and our STX 67 JB turbo.
This means for our big turbos, exhaust back pressure ratios can get well beyond 2:1 that is efficient for a JB CHRA.
If you are going 5:1 or 7:1 makes it hard to build power and it wears out the journal bearings and especially the thrust bearing.
Tuners that have a good strategy to manage this backpressure can make good power with the larger STX 67+ and 71 turbos, but if they didn’t, sometimes our customers would be disappointed.
The main point of that post was that a BB CHRA actually solves all of these problems:
The CHRA can stay efficient even if the pressure ratios are 5+:1
This means, it will be a lot easier for all tuners to build power with the BB version of our turbo.
The turbo will just make more power under the curve in general
The the thrust bearing is more durable, so the CHRA will stand up to more punishment.
[STX 71R for FA20 Test Results]
We set out to actually prove if the BB version of the STX 71 would perform as well as we had hypothesized, and solve the issues we had with the JB CHRA on the larger turbos. The short version is that yes, the SteamSpeed STX 71R BB Turbo for FA20 did exactly what we thought it would. It was a lot more efficient that the JB version of a similar size; therefore, it made more power everywhere. I suspect that tuners all over will be having an easier time getting results their customers want.
Here is the dyno result. 470 whp on E50 and 410 on 91 octane pump gas, and not measured on this chart, a ton more response everywhere. Note: this is at high altitude in Utah.
[Technical Notes From Jessie at FNP]
Jessie: “Hey, First let’s go over what we saw, liked and disliked with the unit.
It’s big, if the new unit has a clearance for the oil pan and obviously ships with hardware we are good. Obviously as the prototype it is going to have clearance issues, and fitment issues. There were literally no other issues noted from Luke on install.”
SteamSpeed: This will actually be a non-issue for retail units. We have actually already resolved all fitment issues on our production 71R. The production model has a modified turbine housing with a cutout to clear the OEM oil sump without modifying it. We also designed and manufactured custom studs that we include with the 71R install kit. This is how the retail unit will work:
Sounds epic. Do yourself a favor a crack open the boost nipple when running. The ball bearing turbo sounds incredibly mean at idle. With a catless exhaust it should sound great out the tail pipe. Think diesel turbo, screaming at idle.
Response, Response, Response. This turbo is incredibly responsive compared to the previous version. Transitions in and out of boost are much quicker.
More linear boost curve via WGDC input. What do I mean? Check out this boost profile compared to WGDC on the old vs new turbo. The new unit is much MUCH more linear with interrupt cycle. This tells us the effects of back-pressure are far less of an issue with this upgraded unit. You can also see the old turbo have more “Creep” under the curve. The new unit doesn’t not do this. The compare for RPM isn’t valid, as the previous tests were done in 4th, the current in 3rd.
67+ JB WGDC
71R BB WGDC
Makes more boost in the upper RPM’s. This also is a direct causation from the upgraded cartridge. It seems to be able to operate at higher levels of back-pressure with ease.
Red JB vs Yellow BB
Less oscillation of MRP than the outgoing cartridge. Just one of those anecdotal observations, normally we see much greater fluctuations in boost on the FA20 with our incredibly fast sample rates. This unit fluctuated much less, the average was 18% realized lower fluctuations. This is a great indication of how much more air is being delivered.
Much more efficient flow from the turbo. Check out the new vs old charge air temps!
New unit held much better boost. From 1.9bar avg on the old unit at redline on 100% interrupt, to 2.3bar avg.
Output: Was increased by 12.35% over the older unit. This was also impressive as the turbo could have easily generated around 8% additional output, but the owner of the test vehicle was very specific to “Take it easy”. Based on the airflow averages and their changes, I’d say this observation is fairly precise.
Check out these airflow differences: Old Turbo 229 average max, New over 300! (it was 309 average when extrapolated up). That is an increase of 35%. Same intake, and injector scalings were used on both turbos. Compared to the stock turbo this is over 56% increase in flow!
Well, hope this helps you guys. I poured over all the data and these were the things that popped out at me.
In that iteration, it made ~360 whp at PRE facility on pump gas. For comparison, the SteamSpeed STX 71 on a 2015 STI made about 420 whp on the same day. With that turbo it was rewarding to push the car, and if you kept the revs up, you could keep it in boost, but realistically it was a 4.5k+ RPM turbo on a stock EJ207.
We would manufacture small batches of this turbo, and we would sell them all out before we could install one in Domino, but we able to finally get one installed. It has the smaller 67mm compressor which should make it more responsive, but the “+” means that it still has a GTX30 spec turbine which is a little better suited for a 2.5l. I think a GTX29 size wheel would be perfect for the EJ207. Next update to the turbo we can make the change. 🙂
The STX 67 wheel did get us close to 4k RPM, but it still feels big. In fact, doing pulls, it feels similar to the 71; however, everywhere else, it is night and day. The BB CHRA is super responsive. Going on and off the petal, the turbo is a lot more responsive. It could also be related to the fact that we went to speed density from a MAF based tune.
What is the final result? It made about 10 whp less with a 4 psi more boost. Not a bad trade off.
The turbo still feels a little big. Andy at FTW thought going to a top mount could give back about 500 RPM of spool. It would probably be best for our usage of the car, but for vanity reasons we like having the huge FMIC. We could just go to a 2.5l displacement, but it seems like it goes against the spirit of the ej207 swap.
Where do you think we should take the build next? Let us know what you think.
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.
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.
Here is a good dyno result of a SteamSpeed STX 67 on pump gas done at Bren Tuning with a before and after, green being before, and red being after. Obviously there are gains everywhere. You can see their post on NASIOC here. The short of it, the customer go a 85+ WHP and 70+ WTQ gain on pump gas!
Here is a standard STX 67 for 2015+ WRX tune at COBB Surgeline. Unfortunately it does not have the before plot, but it was a 60 whp gain on pump gas. This car had a 3″ turbo back, intake, and front mount intercooler. It was tuned at COBB Surgeline. We have to give these guys at COBB Surgeline props. This customer was initially impacted by the wastegate flapper defect a few units had from the first production batch. The guys at COBB took the time to correctly diagnose the wastegate problem.
SteamSpeed STX 67+ for 2015+ WRX
Here is a nice dyno plot comparing a fully modified 2015 WRX without the SteamSpeed turbo [green], then with the SteamSpeed STX 67+ [red]. This with some ethanol blend, around 50%. This was tuned in Utah at FNP by Jessie. It looks like about a 100+ WHP gain and 65 WTQ.
PRE recently did a test that pitted lots of Subaru stock location turbos against one another. This is what the plot of our smaller Steam STX 67 looked like against a Forced Performance HTA 71. The STX 67 basically made power sooner, had better low down power, and made 10-25 whp across the entire rev band.
Here are some unboxing pictures of our new Steam STX 67 turbo for FA20 (eg. 2015 WRX). This is our design validation (DV) prototype turbo. It doesn’t have as perfect machining as the final retail version will, but I think it does give you a much clear picture of what will be included in the box.
This is a design validation (DV) prototype, so it does represent a final retail product. For example the housings aren’t fully machined in these pictures, and they are just showing OEM accessories to illustrate that this turbo is a direct replacement for the OEM turbo. The retail version will have custom fittings. The final turbo will just reuse the stock turbo oil pan.
Steam STX Turbochargers are manufactured with the highest quality components, equipment, and procedures as possible. When installed, maintained, and operated correctly, these turbos can provide many years of reliable service. Incorrect turbo installation can lead to premature turbo failure and voids the warranty. Professional installation is recommended.
Make sure the engine, oil, and cooling systems are healthy, clean, and in good working order.
If you’ve had an engine or turbo failure, make sure the root cause has been identified and addressed.
Change the engine oil with clean new oil and a new filter.
Make sure the pre-turbo intake and pre-turbo exhaust systems are free of foreign objects.
We recommend replacing the OEM oil feed line, but if you are reusing the stock line, make sure it is clean and unobstructed. We sell upgraded stainless steel oil feed lines at affordable prices to help our customers avoid oil starvation problems caused by clogged oil feed lines.
Ensure the crank case ventilation system is operating correctly.
Turbo Installation 1. Remove the old turbo. If you are unsure how to do this, refer to the service manual for the car. Generally this involves these steps:
– Remove the down pipe.
– Remove the connected intercooler and/or intercooler piping connected to the turbo.
– Disconnect and temporarily clamp the turbo’s water lines.
– Disconnect the oil feed line. Note: take care to not crack or over bend the stock oil feed line if you intend to reuse it.
– Disconnect the vacuum line from the compressor housing (if applicable).
– Unbolt and remove the turbo from the up pipe. The oil return hose and clamps will be reused.
2. Install the new Steam STX turbo. Perform the turbo removal steps in reverse. Note:
– Make sure all of the hoses and fittings are tightly clamped post install.
– Always replace old gaskets with new SteamSpeed gaskets or OEM gaskets.
– Make sure all flange surfaces are flat and clean before replacing the gaskets.
– Pre-turbo exhaust leaks and post-turbo boost leaks are the main cause for slow turbo spool up.
– Replace corroded or otherwise damaged hardware as needed.
– Use OEM torque specs.
3. Prime the turbo by cranking the engine without firing for at least 30-60 seconds. You can disable the ignition by removing the ignition fuse, or disconnecting the sparkplugs. Skipping this step will lead to premature turbo failure and will void your warranty.
4. Start the engine and let it idle for at least 3-4 minutes. While the engine is idling, check for leaks, and if any are detected, stop the engine at once and fix the leak.
5. Stop the engine and recheck the engine oil level.
6. Enjoy boosting with your new Steam STX turbocharger!