Help with (possibly) butchered CM870

[Rawze]

(10-15-2016 )Rig Wrench Wrote:  Depending on what your doing, the 870s do very well with the fixed vane turbo so long as the tune is correct. The air vgt is somewhat inferior to the 871 electronic vgt. The fixed vane does help drop back pressure for high torque load applications. I'd just have one of the aforementioned verify the cal is safe. Wore fuel system components will cause a bit of a rough idle, but soo won't increased timing and fuel in the idle areas.

That statement is only somewhat valid...

Most big-boy, bad, fixed-vaine deletes use an undersized 12-litre turbo and/or that crap of a big-boss junk. -- The only half-decent Borg Werner for the ISX is the 16-litre turbo they make,.. and it STILL is less efficient than a Holset.

Yes, the engine can be re-tuned for the fixed turbo but no matter what you do,... It will never be nearly as efficient as a VG can provide for most highway applications.

I tend to not give false hope for any kind of miracle-program fix to many of those who do already have bad del;etes.

Not everyone is bent on big power etc., and even if they are, a bigger Holset still wins. For most, doing the right thing and putting it back the way it is supposed to be is the correct solution.

Sure, there are some people who remove the VG turbo's off their engine for various legitimate reasons,... but it is mostly high-torque-only applications, trading away efficiency in lower torque bands and lower RPM ranges to get those slight gains. Even so,.. It has been proven over and over that even in the case of higher than normal power applications, that a bigger Holset still wins, and for everything else, a VG is much better by leaps and bounds towards overall engine efficiency. It is just a matter of size and/or staying within the bounds of its design, and last I checked,.. A Holset HX series turbo (holset big fixed-type turbo) only starts to give flow advantages ABOVE about 640-HP or so HP on an ISX so if your engine is BELOW this HP,... YOU ARE LOOSIONG SOMETHING BY NOT HAVING A VG TURBO ON IT!!!

Do it right -- FIX IT and solve your problems CORRECTLY AND THOROUGHLY then Don't look back! -- this means PUTTING BACK OR LEAVING INTACT THAT HOLSET VG TURBO for most highway applications! -- PERIOD!

This is ALWAYS THE ARGUMENT...

AND EVERY SINGLE ONE OF THOSE ARGUING TOWARDS THOSE FIXED TURBOS ARE ALL HELL BENT ON AND ARE PROPONENTS OF HAVING BIG POWER AND SHORTER ENGINE LIFE!. I COMPLETELY DISAGREE WITH IT!!! -- THAT IS ALL THEY WANT AND DO AND THEY GO AROUND AND PROMOTE IT AND ARGUE IT TO MAKE THEMSELVES FEEL BETTER LIKE IT IS SOMETHING GOOD --- WELL IS IS NOT when it comes to actually making a profit!!! -- AND IT IS WRONG!!! -- If you need that much weight moved,.. RE-GEAR THE TRUCK!

> I AM NOT A PROPONENT OF MORE HP IN YOUR ENGINE === I AM NOT A PROPONENT IN BUTCHERING YOUR ENGINE BY PUTTING A LESS FUEL EFFICIENT TURBO ON IT EITHER!!!

Even in cases where Holset HX fixed turbos are used, I have seen some really good tuning get them close,.... but even those really good tuners will say that a VG Holset is the correct solution above the inferior crap usually seen slapped onto someone's engine as the result of a bad delete. 99.9% of the time those bad delete companies DO NOT GO WITH A HOLSET HX SERIES but vastly inferior turbos. But even an HX knocks the truck back into the stone-age and they always end up with lower fuel mileage, higher EGT's, black smoke at the tail pipe in lower RPM ranges, black oil, higher fuel costs per year, and weaker engine brakes. -- Just because there are some short-sighted people out there hell bent on making those fixed turbos work for them does not mean it is a correct solution at all for anyone else.