Ok so finally had some time to compile some info for an all together "Sticky Icky". Feel free to add additional info but will be deleted upon putting into OP so it doesnt get off topic.



8.1 General Info

- Exhaust - Cutting off the cats is not going to do a thing for power. If anything you may loose some. Typical cat back exhaust will be fine. Shorty headers will not provide any power gains either. Long tubes will however provide some gains but how much is not really known. Check here (http://www.broaderperformance.com/muffler_flow_tests.htm) for flow tests between major brand mufflers.

- Aftermarket hard parts - Look into Raylar Engines or Arizona Speed. Bring a fat wallet.

- TB spacers - No gains from users.

- Bigger TB - See here (http://www.dieselplace.com/forum/showpost.php?p=3156600&postcount=16)

- 8.1L motor part numbers and such. PDF (http://www.bucksengines.com/Data/23.pdf)


Common Problems

- Crank Positioning Sensor - May or may not throw a code. Common symptoms include stalling, lack of power, and hard starting to name a few. There is a new design on the new ones that offer less problems. Can be done yourself.

- Loss of oil - Common and nothing to worry about if less than 2 qts between changes. Using a thicker oil such as 10W-30 will help this.

- Low oil pressure - Also common. Norm is ~26-30 idle and 40+ cruising. Again thicker oil will dramatically increase this and not all have this problem.


Tips and Tricks

- Plug Mod - Use AC Delco 41-932 (newer # now) and gap them at .045. This helps combustion and throttle response among other obvious things.

- Thermostat - Use a 180* thermostat to help with detonation and under hood temps. Can be purchased at Auto Zone. PN 15898 Duralast. Can use with no other mods. Double check PN's when at parts store.

- Cold Air Intake - This is debatable. Amzoil got rated highest in filtering capabilities while still maintaining more air flow. Again you decide.

- Tuning - While there are a few hand held tuners out there they provide only marginal gains. Plain and simple if you want the most out of your motor go EFI Live or equivalent. There are many mail order tunes that offer roughly the same gains and are significantly cheaper. If you dont plan on using all of EFI Live's features and want a mail order tune some examples in no order are: Westers, Nelson, and Blackbear. Use at your own risk.

- Nitrous - PM Tierod on here :D


Ok Im sure I missed something but I got other stuff to do so add what you feel should be added.

A GREAT thread, much needed.

The Duralast 15898 t-stat is a 180* F. version and not a 185* F. Some slam open and shut, brand new, always test in a pan of water, heated on the kitchen stove, using a thermometer. Check for smooth operation with a 10* F. span.

The main and most important reason for using one is to keep the BB out of coolant heat caused spark retard. The OE brainbox begins to yank timing out at an indicated 212* F. point. The spark retard is linear, it pulls timing based upon an equation of more heat = more retard.

The AC Delco 41-932 plugs are (for the most part) no longer available. Any you find will be from new old stock.
There is a new number, a slightly warmer plug, IIRC.

My L-21 BB quit using oil after the 180* F. install...only deduction I can make is that the oil was being vaporized from high heat, and being passed thru the PCV system.
It never smoked out the exhaust (because of the cats) and it never leaked a drop, either.

Cold Air intake: The temperature sensor in the intake air stream flow pulls out timing at 86* F. That said, it is important for maximum timing advance to insure that cool outside air is drawn into the system at all times. Do not let higher temperature under hood air into the intake.

Aftermarket CAI: The OE stock air cleaner assembly will out flow the Throttle Body, any bigger inflow tubing is a moot point. Save your money...

Aftermarket oil-impregnated air filter elements: They flow more air and silica because the openings (think mesh size) are bigger than the filter media contained in an OE (paper) element. Use an OE type paper filter element and avoid getting oil on the MAF wires. Again, save your money.

Use Mobil 1 Syn Oil...why? It does not burn off like other oils and will freeze all engine wear at the point it is at when you make the change over. It has a significantly better additive package and forms no sludge. It is very kind to roller lifters. Once a year oil changes are possible after a few 3000 mile change outs to clean the engine internals. Because of the severe duty placed upon my engine and drivetrain, I went to Mobil 1 15W-50 wt. oil. 42 PSI at hot idle and 70+ PSI at warmed-up highway speed. To contain this, I use a Mobil 1 spin-on oil filter, as it has a thick outer shell.

The infamous cold start knock: I do not have it. Once, the guts came loose in one of my OE cats and it sounded just like CSK..another time, I had a leaking gasket at the cat flange, and it, too, sounded like CSK and went away when warmed up. If you are having CSK issues, get a heavier bodied oil in it, and check for exhaust leaks and cat rattles....

Chevrolet and GM seem to be very good at building engines.
But not Transmissions.

The BB Chevy is a Torque Monster and as such it has been de-rated time and time again. This was done to prevent damage to the powertrain and excessive GM Warranty claims. It is accomplished through timing retard in the brainbox of the later Vortec BBs. It is called "Torque Management". Many consider it to be the Work of the Devil..:D..

There are many factors surrounding TM..a little knowledge here is a good thing. These later Vortecs are drive-by-wire with an electronic throttle (gas pedal). The brainbox looks at the pedal position "rate of change" and applies timing retard based on pedal position. This fact can be easily discovered by attempting a "brake stand" burnout, where you stand on the gas and brake and quickly remove the brake at high RPMs. If the TM is functioning correctly NOTHING HAPPENS, no burnout.

Other than a complete re-tune, where all or a percentage of the TM is removed through re-programming, you are stuck with it. It is there "protecting" the transmission, the U-joints and rear end.

There is a somewhat lame mechanical work-around and that is to always "ease" into the throttle, avoiding the point of throttle advance where the timing retard occurs.
This point in time varies with engine and transmission combos, but is generally a sudden 20% change in pedal position. The BB Chevy creates so much torque, so quickly, that it can and does break things.

Kenn Bell, of blown BB Chevy fame, claims that, on his engine dyno, every degree of timing retard costs you 4 HP. That said, how much timing can the brainbox pull at
maximum retard?? 20 degrees. 20* x 4HP = a whopping 80 HP LOSS of power, based on what's in there, in the programming.