Category Archives: Turbo Selection

Misc., The Turbo Engineers, Turbo Selection

TTE550 First Look

A set of TTE550’s has arrived for evaluation.  The turbochargers came well packed and even included a balance sheet for each turbo, a nice addition for turbo’s that have been rebuilt to upgrade the BorgWarner K04’s to a hybrid using a variant on the RS6 center.

pair of tte 550 turbochargers
TTE550 RS4 K04 Hybrid Turbochargers

 

Looking them over it dawned on me that the ring that goes around the wastegate canister increases the effective diameter of the canister, and I have encountered problems fitting the TiAL turbo inlets past the BW K04 wastegate canisters.  This could lead to future headaches when I start installing these turbo’s.  The ring can be loosened and rotated, hopefully that will be enough to avoid problems fitting them alongside the inlets

tte 500 turbocharger compressor housing

 

I next turned my attention to giving the TTE550 a turn on the flow bench, something I have done with the BorgWarner K03 and K04 products in the past.  First though I’d have to remove the turbine housing studs so I could fit the turbine housing flush to the flow bench.

tte 550 turbocharger turbine housing

 

I’ll just twist this first stud out, or maybe not.  Vice grips, nope.  Penetrant oil & heat, nope.  F*******ck.  Not coming out.  Looks like I’ll be making a trip to a machine shop to have the studs removed.

TTE 550 turbo stuck stud

 

Until that takes place I won’t be making any progress with further evaluating these TTE550 turbocharger’s.

To be continued…

 

Turbo Selection

K04’s setting the bar high

One of the main goals I have in my search for the best stock motor turbo’s is to find something that has close to K04 spool.  I’m still in the early stages of getting the tune dialed in, and this boost level is greater than what the car will be operating with going forward, but it is a good representation of how quickly the RS4 K04’s can generate boost pressure.

Chart of BorgWarner RS4 K04 Boost Onset
BorgWarner RS4 K04 Boost Onset

25 psi of manifold pressure is achieved at 3080 rpm.

The Turbo Engineers, Turbo Selection

TTE 550 vs TTE 600

The TTE 600 turbocharger has not been one that I’m interested in obtaining due to the RS6 turbine housing that it uses necessitating a different downpipe or flange.  Still, I was curious how it would compare with the TTE 550 model and when I came across a set of dyno sheets from MRC Tuning showing one RS4 with the TTE 550’s and another with the TTE 600’s I decided to match them up.

A quick scan of the product descriptions shows that the TTE 600 is an RS6 K04 based turbo with a larger compressor wheel and some refinements made to the turbine wheel utilizing the RS6 turbine housing.

The TTE 550 is one of the candidates I’m considering and uses the same internals as the 600, (so far as I can tell), but packages them in the RS4 K04 housing, so the smaller K04 turbine housing.

It would appear the the main difference is the turbine housing, RS6 vs RS4.

Results:

I pulled some data from the dyno charts and after converting them to post-drivetrain loss at the wheels HP and Ft-Lb units I plotted them out.

Here’s how they compare:

tte550_vs_tte600

The results are generally what one would expect to see given the physical differences in the turbochargers.  The smaller 550 generates torque more quickly and the larger 600 is able to develop additional power at upper engine speeds.

Of interest to me is just how much greater the torque produced by the 550 is below 4000 rpm.  At 3000 rpm the 550 car is making 100 ft-lbs more torque, growing to about 160 ft-lbs more by 3500 rpm.

I decided to take a look at the ‘area under the curve’, the term describing the overall torque being produced across the engine speed spectrum.  Using a trapezoidal numerical integration at 500 rpm intervals the ‘area under the curve’ was remarkably close for these two turbochargers.  The TTE 550 edges out the 600 by about 3%.

Conclusion:

The results shown here have reinforced my belief that the TTE 550 is probably the best product from the TTE lineup to achieve the goals I have for my S4.