Category Archives: FrankenTurbo

Posts with a significant portion of the discussion involving FrankenTurbo products

Big power FT21’s

During some of the recent activity showing the TTE 550’s and FT21’s on E85 tunes I forgot about this car’s results.  While the survey results thus far would indicate more are interested in quick spooling of the turbocharger, under the condition I outlined, it is still fun to look at what can be accomplished with these K04 hybrid turbochargers.

The S4 dyno’d below has the FrankenTurbo FT21 turbochargers, aftermarket rods, 2.8 cams, and using E85, no WMI.

Frankenturbo F21 E85 Dynojet

The car was also recorded on a FATS pull, a nice cross check to see how ‘legitimate’ the dyno numbers are.  It managed a 2.63 time in that acceleration exercise, which corroborates well with the dyno results.  Based upon the two results it would seem that around 500 whp is a decent estimate for the car’s power.

My personal experience with comparing FATS to dyno numbers has been positive, I found when comparing my TiAL 605 setup on 100 octane race gas during a FATS pull with the results produced on EPL’s Mustang dyno that the two matched up quite well.

In the chart below the light blue line is what was recorded on the dyno (shown further down the page), and the other colored lines were FATS pulls of 2.69-2.71 seconds.

605 100 Octane Race Gas; FATS vs Dyno Results Compared
605 100 Octane Race Gas; FATS vs Dyno Results Compared

From the dyno chart below I have extracted the numbers for the solid red line to plot versus the FATS line above.

TiAL 605 results. 93 and 100 octane tunes. Stock S4 motor, no WMI.
TiAL 605 results. 93 and 100 octane tunes. Stock S4 motor, no WMI.

 

FrankenTurbo F21 Mixed Flow

As I wrote about a few months back, the prototype FrankenTurbo F21 with a mixed flow turbine wheel (referred to as F21MF hereafter) is an update to a product that was already on my candidate list.

When the details of the prototype design started to firm up I became more interested in how this third update to the FrankenTurbo offering for the S4 would measure up to my goals of having a quick spooling turbo with good power potential.

The mixed flow turbine is supposed to have greater efficiency at lower blade speeds, and with slightly less wheel mass the potential for quicker spool up.  I’m interested in seeing how this mixed flow design does with high mass flow rates as I believe the K04 hotside is what is limiting the K04 hybrid turbochargers from delivering better performance.

frankenturbo mixed flow turbine
FrankenTurbo F21 Mixed Flow Turbine

The compressor wheel is also seeing significant changes, even more so than the turbine wheel which was based on the outgoing F21 design.

The new compressor wheel is billet, not in itself all that important, but the design is quite a bit different from other K04 hybrid offerings that I’ve been able to dig up information on.

frankenturbo f21 billet compressor wheel
FrankenTurbo F21 Billet Compressor

The inducer is 45.3 mm, compared to the older F21 size of 42.6 mm, and the exducer is 54.5 mm, versus 56.3 mm for the outgoing model.  The closest comparison product I know of is the JHM RS6-R which I believe uses a 45/56 compressor wheel.  The new compressor wheel also has a slim hub, which theoretically should allow the wheel to grab more air.

With what is apparently an overall larger compressor wheel my concern is how well the product will spool up.  I was not a fan of the boost onset hit that the F21 took relative to its predecessor, the F4H, but if the top end delivers and the boost ramp up does not take too much of a penalty I might keep the F21MF on my contender list.

Some early results I’ve seen on the F21MF show that it doesn’t appear to give up any response compared to the previous product.

f21mf_boost_onset
F21MF Requested vs Actual Boost

The remaining question is still, how will it perform on the top end?

For now the F21MF will stay on my candidate list as it looks to be an excellent option for maximizing the power deliver from a stock motor without giving up (too much) boost response.

The candidate list now stands at:

  • BorgWarner K04
  • FrankenTurbo F21-Mixed Flow
  • ProjectB5 RS6-X
  • SRM Billet K04
  • TTE 550

Next: Project: B5 PB550

FrankenTurbo F4H Boost Data

After starting this to evaluate the effect of putting turbo blankets over BorgWarner K03 turbochargers I decided to keep the effort going by adding logs that I have of my car with K04 turbos, and some other K04 equipped cars, and then my F4H data logs.  F21 data hasn’t been as easy to come by but I have a couple data points.

Turbocharger Boost Response Time versus Engine Speed
Turbocharger Boost Response Time versus Engine Speed

I’m a bit surprised to find that the short lived FrankenTurbo F4H spools as well as the K04.

Next I’ll be adding TiAL 605 v1 data to the chart.