People are now starting to turbo the new Coyote 5.0 and I am sure other manufacturers use variable cam timing (BMW, etc.) in turbo motors so I was thinking of this.
Just wanted to see what some of the experts think about this in a turbo application as far as performance potential.
I'm assuming you will need much more tuning experience to take full advantage.
I know FAST has a new XFI box ready for the new 5.0 but it specifically states no cam timing control.
Anyway, any thoughts?
-J

 

Lots of OEMs (American OEMs) have been playing with TiVCT and boosting for a while.

There are many advantages on a street legal vehicle as far as "Time to Torque" and of
course different cam phasing at different parts of the torque/horsepower band.

It would take lots of time on a dyno to find the optimal settings for a full rpm curve.

You could easily put in 1000 hrs on a dyno completely "mapping" the engine as you changed different parts (Turbos, Intakes, timing curves, TiVCT camshaft positions, and still have more stuff to test, IMO.

You could spend a few hours and find the HP/ Torque settings and how much to limit the TiVCT components for a "performance only" engine.

Richard Holdener, a writer for Mustang Muscle and Fast Fords, has a bunch of experience
Ford VCT tuning. Give him a call. I am sure that you could track down a number for him.

Tom Vaught

 

Thanks Tom, good to know the American OEMs are doing this, I had expected at least Ford to be doing it with the Ecoboost 4s and 6s. I can't remember if the SHO has VCT.
I would assume even just some basic tweaking of the factory Ford TiVCT 5.0 in turbo and supercharged kits would show significant gains.
I wonder if the new SCT stuff can do this?
Any insight as to what the basic changes would be?
I definitely know of Richard Holdener, miss his regular column in MM&FF.
That would be very cool to work with him on a project. Maybe I'll contact him to see if he wants to write about a 1200hp TT Coyote motor to replace my turbo 427W
-J

 

Quite honestly the VCT affects the torque curve of the engine. If you're making a flatter torque curve (read:more power across a wider RPM range) then the size of the turbochargers you can use before boost threshold becomes a problem increases Surge also becomes less of an issue at lower RPM. This is also important when dealing with things like stall speed. If you can run less stall that typically pays dividends at the track for high HP cars all things being equal.

I never did any real life testing of this HOWEVER I did play with something similar in engine analyzer. I was designing a variable runner intake and wanted to get an idea of what kind of power increases I could see by messing with the runner lengths. The actual average power output increase was actually about 30hp overall if I remember correctly. When I stuck a turbo on it I believe I got 4-500 RPM less before I was in boost as well.

The problem I found with this is that for a drag application it actually was poor economy. The reason for that being that due to the ratios in the transmission you can assume that your RPM will be roughly the next gear divided by the previous gear times the shift RPM. As an example a power glide equipped car with a 7000 RPM redline would be:1/1.76*7000=3977.27 RPM or roughly 3800 RPM. Who really cares if it makes 90% of peak torque to 2000 RPM at this point. There will be some deviations to this due to torque converters etc. so your milage may vary.

 

Thanks, I also thought it would be least effective in a drag application but still could help.
I thought it may be beneficial in shift recovery, building launch boost and maybe some small gains with 60' in combining limited boost/timing/VCT for torque management in the front half.
-J