More TTE550 data

As I am continuing to refine the initial tune, a 22 psi boost profile for the TTE550’s, the boost onset data is concurrently accumulating.

Shown below is the boost profile and then next the TTE550’s vs K04’s.

TTE550 Boost & AFR (Tune Revision 3)

TTE550 Boost & AFR (Tune Revision 3)

TTE550 vs BWK04 Boost Onset

TTE550 vs BWK04 Boost Onset

Claim: TTE550 has RS4 K04 response

With the TTE550 turbochargers installed on my S4 I can start to measure the performance of this product and compare the results to those obtained with some of the other turbochargers that I have used.

The performance claim that leads off the description for the TTE550 is:

RS4 K04 response with near RS6 unit power yet still keeping RS4 turbine housings.

Because keeping K04-like response is one of my top features to have from a turbocharger I am quite interested to see how that claim works out.

Initial results do not bode well for the product to live up to the claim.  Shown below is a chart comparing the 2-11 time for the K04’s and TTE550’s.  This metric is used to illustrate how long it takes for each turbocharger to build from 2 psi to 11 psi, for a given starting engine speed, that is when 2 psi is produced.

TTE550 vs. BW RS4 K04 2-11 psi response time

TTE550 vs. BW RS4 K04 2-11 psi response time

This chart does a good job at showing that the K04’s, the blue dots, increase pressure measured by the MAP sensor more rapidly than the TTE550, for all of the engine speeds I have measured thus far.

A couple of points about the data on the chart.  The K04 data was collected when the temperatures were generally cooler than during the two days that I recorded TTE550 data.  The lines would likely get closer together, meaning more similar performance, under the same temperature conditions.  With that, I do not believe temperature affects would be great enough to bring the lines together.

I’ve also not completed tuning with the TTE550’s.  Past experience has shown that fine tuning is more about controlling overshoot on initial boost ramp, not how quickly the turbocharger spools up.  I believe it is very unlikely that tuning will do anything more to increase the 2-11 time of the TTE550’s

While these initial results cleary show that the TTE550’s do not have RS4 K04 response, from the perspective of looking at the turbocharger dimensions this is not at all surprising.  The TTE550 is essentially an RS6 center stuffed into a K04 housing.  Beyond that, it uses a compressor wheel that is larger than the RS6 compressor, and it uses an extended tip compressor wheel on top of that.  On the turbine side an RS6 size turbine wheel is found, but also with a clipped wheel, not a feature that increases responsiveness.

Given the physical differences between the two products it is not surprising at all that the TTE550 does not match the RS4 K04 in response.

 

Dirty Airbox

This is an example of why I have tried to keep the added openings on my stock airbox on the forward facing side and have retrofitted a baffle on the lower opening I created.

Dirty Bottom Airbox

Dirty Bottom Airbox

After driving in some rainy conditions the dirty water from the road has coated the bottom of the airbox.  If this area was more open it would be possible for the water to coat the air filter instead.

White Dog Racing IC Inlets

In addition to the White Dog Racing Bipipes that I flow tested a couple of days ago the box contained a set of the intercooler inlet pipes that replace the stock components for use with the Silly Rabbit Motorsport RS4 side mount intercoolers.

Picture of White Dog Racing intake parts

White Dog Racing intake parts

These inlets in addition to being made of metal are larger in diameter than the stock components they replace.

For the flow testing I attached the inlet to the SRM intercoolers and mounted them onto the flowbench.  I began with the stock hardpipes and couplers supplied with the SRM intercoolers.

SRM Stock Inlet Pipe

SRM Stock Inlet Pipe

Both the driver and passenger side flow performance was measured.

Then I swapped to the White Dog Racing inlet pipes and checked the airflow again.

White Dog Racing Inlet (Driver side)

White Dog Racing Inlet (Driver side)

White Dog Racing Inlet (Passenger side)

White Dog Racing Inlet (Passenger side)

 

Finally, for comparison with a completely stock setup I used the stock S4 intercoolers with the stock inlets.

Stock S4 components

Stock S4 components

Results:

Airflow through each of the setups was measured at a depression of 28″ of H2O.

Inlet Pipe Flow Test Results

Inlet Pipe Flow Test Results

The chart above illustrates a number of pieces of data:

  1. The red bar and purple bar are the airflow readings from a stock intercooler and the SRM RS4 intercooler – without any inlet piping attached.  It is clear that in this configuration the SRM RS4 IC greatly outflows the stock intercooler.
  2. The green bar shows the reduction in airflow through the stock intercooler when the stock inlet piping is attached.  There is a modest decrease in airflow as compared to the IC alone.
  3. The orange and blue pair of lines are showing driver versus passenger side results of swapping inlet pipes between stock and WDR.  The passenger side has a higher airflow for each pipe arrangement.  Their is a small improvement in airflow when switching from the stock to WDR parts. (It should be pointed out that readings taken under operating conditions would be different as charge air under boost is denser and thus develops more back pressure).
  4. Finally, the SRM RS4 intercooler undergoes a substantial drop in airflow with the addition of the inlet piping, regardless of whether it is stock piping or the WDR piping.

Conclusion:

The airflow through the intercooler and inlet is increased measurably, but only slightly, by using the larger White Dog Racing hard pipes, when evaluated on the flow bench.

For a typical user the larger inlet pipes may not provide much performance benefit, but for the all-out build where optimizing every part matters, the White Dog Racing hard pipes do provide measurable gains.

Solo shakedown drive

Things progressed this weekend with the TTE550 turbochargers, but it’s been a bittersweet continuation of the project with the sudden unexpected passing of “Daz Dillinger”.  Daz is a person with whom I have partnered on several projects since we were first introduced several years ago.  It has been his knowledge and generosity that have provided the foundation upon which this project, as well as others, have been built.  I will have more to say about Daz’s work with me in a separate posting.

The first drive with the TTE550’s has been successful, although with two issues to address.  First was a high pitched siren sound when boost hit about 20 psi, something I immediately thought was a boost leak.  After hooking up the boost checker I confirmed my hunch, that yes there was a hose clamp on the upper passenger side intercooler that was not tight enough.  It was a relief to have the problem be located in such an easily accessible location.

The second issue, which is a known obstacle to overcome with the changing out of turbochargers, is that the TTE550’s use an 8 psi-preload on the wastegates, and the FT21’s used about 14 psi.  Thus the tune now will under-boost on account of the wastegate differences.

TTE550 First Boost Log

TTE550 First Boost Log