We finally got some dyno time for the 335i at CarbConn in Kirkland WA. The tune still isn’t done, but, it is the current state of where we are at. There is still a problem with the knock pulling timing, so the timing and boost are set low for now.
[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.
We are excited to announce our final revision to our Focus RS intercooler! We’ve gone through three design revisions and this is the perfect design.
[Mounting & Fitment Improvements]
The first prototype core design showed huge efficiency gains vs the OEM unit; however, we saw room for improvement. In the next two prototypes we iterated and improved the end tanks and mounting tabs to further increase the efficiency of the core and ease of install.
After the intercooler had been mounted and driven nearly 1000 miles of road conditions including freeway cruising, data log pulls, dyno time, and spirited drives, we found ways to improve its mounting to the chassis vs the OE. In our final version, we increased the thickness of the mounting tab material from 3mm to 5mm and adding a perpendicular support to the lower tabs for greater strength and durability. This insures a rigid mount to radiator chassis. We also found that utilizing openings in the bumper frame to support the intercooler from the top was much more effective then the OE mounting points; the factory cooler is only suspended from the lower tabs and held vertical by the upper tabs that engage hooks into the casting of the cooler tanks. Due to the increase in weight of our cooler we knew the lower supports would never be sufficient without the extra bracing. To utilize the bumper frame, we installed a bolt and nut through the opening. This was fine for our final prototype but we look forward to using a plastic insert and screw to secure the upper mounts. This will ensure ease of installation with minimal effort.
Here you can see just how massive this thing is. There’s also a good view of the upper bumper frame mounts. This holds the weight nicely and gives great support for the cooler.
[Intercooler Performance Testing]
Our upgraded Focus RS intercooler, uses quite a bit more heat removing aluminum vs the OE unit. It is about 30-40% larger by volume and more than 50% larger by mass and surface area vs the OE unit. The performance of the intercooler core of our first prototype was stellar, so final prototype’s core remains the same.
Our Focus RS intercooler upgrade brings intake temps well below 100 degrees F. It doesn’t get terribly hot here in Washington State but we did manage to have a day with an ambient temp of 80 degrees F and a resting 101.9 degrees F. You can see in the graph how the Charge Air Temp (white line) drops rapidly when the throttle body opens. And makes its way back down to 86.7 degrees F when grabbing 3rd gear. That’s great! Many tuners are happy with and consider an intercooler “good” if it can manage to get below 100. The temp does start to climb as expected in the longer gears but as shown in the second graph the charge air temp only climbs 5 degrees to 92 degrees before lifting off the throttle. In comparison, the OE core is much less efficient. We’ve recorded increased charge temps of around 30 degrees F. That means our upgraded Focus RS intercooler around 25 degrees (6x) cooler than the OE intercooler!
Above is the data log of a 1st through 3rd and into 4th gear acceleration. The white line shows Charge Air Temp. The Charge Air Temp is around 100 degrees F when the throttle plate is closed. The induction air is moving slowly and heat from the engine heats the air. When the throttle plate opens is when the largest drop in Charge Air Temp occurs. Lots of fresh air is let in and the heated induction air passes through quickly. As the vehicle hits 3rd gear it is apparent the turbocharger is now working very hard. There is a slight increase in Charge Air Temp towards the end of 3rd gear. If this data was done without the cooler we would see. Data log continued (same log as previous graph)
We have had questions of what to do if the OEM water lines are not long enough. The short answer is to make a new water line. It is simple to do and effective. What you don’t want to do is to force your stock line to fit if it is not long enough. In the worst case, it will crimp you line and prevent your turbo from being cooled correctly.
How do you make a new water line?
Buy a length of antifreeze safe hose from your local auto part store. Generally it is sold by the foot, and 12″ is plenty. In our example, we used Gates 3/8″ fuel injection hose because it is the right diameter, and it works.
Remove the old water line.
Next determine how long to cut the new hose. Put it in the engine bay and test fit the line. Make it long enough such that the hose is not pinched and has a nice curve. It doesn’t need to be too long such that it rubs against anything.
Cut the hose to the correct length.
Remove the sliver heat shielding off of the factory line.
Put it on the newly cut line.
Connect the new line with the heat shield onto the turbo and cylinder head.
Ensure that the line is properly clamped on both ends.
After starting the car for the first time, make sure there are no leaks.
Here is the finished product. Note there are no kinks and we are reusing the OEM heat shielding. We used common 3/8″ Gates fuel injector hose.