Does anybody know the differences between the io-550 vs the tsio-550?

So far this is what I have determined:

io-550 8.5 compression vs tsio-550 7.5 compression  TSIO550 is 7.3 to 1
different fuel pump on tsio with aneroid and a reference port
different injectors with reference ports on tsio
tsio has a scavenge pump lines and turbos.
different exhaust obviously
tsio has wastegate and fancy expensive stuff to control it
tsio has a different throttle body part#  The TSIO 550 fuel metering device has a cylinder with a hole thru it and then a cam that rotates with the throttle shaft.  The cam uncovers the hole allowing more and more fuel flow as you increase manifold pressure (open the throttle).  You set the idle mixture by adjusting the location of the pass-through hole with an external screw.  After that, the cam does what the cam does without any easy adjustment from you.  If you are too lean at any high power setting…..you must modify the cam.

 

All in all, the TSIO 550 has a lot of nifty stuff for a turbo charged engine.  However, I can assure you that you will become an “engine builder” when setting up a proper fuel curve when you use the TSIO 550 stuff and limit the boost to 30 inHg.  I also don’t know for sure what kind of challenges you may face limiting the boost to 30 inHg.  I am in the process of doing the fuel stuff with my modified TSIO 550.  I have already had to change the wastegate to fix a runaway boost problem.

 

I could also get a tsio-550 core and put different pistons/cylinders on it.   I think this is the best way to go.  You will also want intercoolers.  You may want to talk with Lynn Farnsworth about Legacy cowl issues. I would definitely go with 8.5 to 1 CR pistons when turbo normalized.  That is, if I didn’t go with 9.0 to 1.

 

Some good people:

Dave Dewell

ddgpfm@tulsacoxmail.com

Great Planes Fuel Metering, Inc.
740 South 142nd East Avenue
Tulsa, Oklahoma 74108
918 695 4356

He is one of the best people in the country on these fuel systems.

 

Main Turbo

234 S. Cotta Court
Visalia, CA 93292

800-847-8815

 

Craig Berland

IV-P N7VG

 

The reason I ask is I am trying to create a turbo normalized io-550 and I am not sure if I should get an io-550 core and add the tsio fuel pump, injectors, scavenge pump and turbos.
I could also get a tsio-550 core and put different pistons/cylinders on it. I suspect the cylinders are the same and the pistons are the only difference.

I also talked with Continental about this and supposedly the throttle body is different between the two but they could not say why. Only that they had different part #'s. They did say that something as simple as a 45 vs. a 90 degree fitting or different color paint can cause a different part# with their stuff so there is a chance that the throttle body on the two is mechanically the same. I was wondering if anyone knew the differences between the two.

Also, which core would likely be the better to get, io-550 or the tsio-550.

This engine is going on a Legacy so I am comparing the io-550G or N vs. the tsio-550c.

Thanks for any info you might have on this.

Matt