Ok .. Onto the PCV
In general terms -- As you all are at different stages - Elevations an so on .....
You've installed a PCV on your N/A engine and presumably are running one of the canned fuel maps. Now you want to add an item to the motor and install the Autotune. So far so good.
Now -- What method of tuning will you select ?? Under Autotune Style you have 2 choices -- TPS or Pressure. For most -- The easiest method of tuning is TPS. And looking at the choices one then thinks -- Gee ....... I can't select both for when I go to a Turbo. Actually you can select both -- Just not at this point in the program. Dynojet does have some quirks on the programming -- One just has to have an open mind and experiment and learn and understand the big picture.
Add Boost to the equasion - With the PCV/Autotune. You will need a MAP sensor. Select the PCV PTi version and it comes with the MAP. I suggest for the MAP sensor -- Go with the GM universal 3 BAR MAP with the short pigtail and wiring guide.
Wiring the MAP -- It must be powered by a regulated 5VDC source. Yea -- Great ... Where do I find one ?? Well -- There is no spare sources on the ECM or on the PCV. NO issue if using the PCV PTi as it has a regulated source within. For those with the older PCV - You got to come up with your own source. Couple of devices on the machine that require 5VDC -- The TPS and the TBAP sensor. Personally -- I tap into the TBAP.
The output of the MAP simply wires into the PCV - No issue here.
Let me comment on Timing -- On the 800's ...... Polaris warrantees the CVT belt for life. I'm not interested in discussing this point but you will be interested in this point. To hedge their bet that they would have to warrantee a blown belt -- Polaris did something that most don't know and maybe don't understand. They de-tune the engine so it doesn't build HP during clutch shift out. I've commented on this over the past several years and made many posts on this. Search for the information and how to correct if you've an interest. Run the PCV PTi and you can make the appropriate timing adjustments within. Run an older style of PCV and you will have to run a Programmable Ignition Box.
One can run any type of fuel one wants -- Even dual fuel setups. Want to run more than 2 injectors or more than 1 bank of injectors -- It is possible but beyond what I'm willing to post.
Injectors -- Stock for the 800 ........ 2 injectors at a flow rate of 18.25 lb/hr. One can overdrive these under Boost -- UP to about 6 PSI and maintain a relatively safe A/F ratio.
I suggest running just 2 injectors -- Just larger. Personally I'm on my 5th set -- I used to have John at Injector Dynamics build them for me -- During this early time and long before I went to the PCV -- I experimented with several other fuel boxes and well -- Had a miserable time tuning.
Enter the PCV -- Now one can select fireplugs and still have complete control and engine idle. I suggest 72lb/hr injectors. Either the USCAR style from the LS2 -- Cheep but only matched within 6% of each other or go straight to the head of the class and go with a set from Injector Dynamics -- Their 72's.
Programming the PCV - Method. Up until this Summer -- I've tuned via TPS with a Pressure referrence and helped many along the way to do the same. It takes a good understanding how to properly program and a good understanding of what's happening to make it work correctly.
With Boost and tuning via TPS with a Pressure referrence -- Autotune builds the Fuel map. This map starts off with all zero's populated. After excepting the Autotune Trims -- The Fuel map is built. You have no need to ever touch this map.
Run bigger injectors -- Now one must manually correct the injector pulse for these larger flowing injectors. This is done via the Fuel (Pressure) table. Populate all cells. Which brings up another point --
Dynojet recommends that the Autotune not be enabled during engine idle. 2 points to be made here. When the manual was written -- It was for the old PCV (Nothing wrong with it as I run one) -- And this comment was directed at the motorcycle engine. Specifically the Harley and tuned pipes. 2nd point -- No thought for Forced Induction.
I suggest that the Autotune be enabled in all tuning cells.
AS I think about all this -- There is so much I could write about but just don't the desire to write a book so let me get to my final Tuning points.
For absolute ease of Tuning and something you will know nothing about -- I suggest one Tunes via Pressure only and tune via Kilopascal. Yea -- I know .... What the Hell is that ??
Let me make this real simple and not go into the theory of Atmospheric Pressure and the US Stand of Measurement of PSI or the Metric form of Pressure Measurement -- Kilopascal or KPa or define Absoluite Pressure.
As I said -- I'll make this real simple .... Here is a chart that has all the information you will need - And a 2nd supporting chart for referrence only --
Ok -- Trying to keep this on track and short and simple -- Onto the Voltage table. One can select 1 - 10 colums. Select only 2. Don't worry -- The software scales perfectly between the range you have entered. By the way -- This table is for the MAP sensor as the PCV has no way to distinguish or register Boost - But a voltage it understands and can compute.
If your tuning via TPS You can Tune with a Pressure referrence either in the US Standard of PSI or the Metric Standard of KPa. If by PSI then for the 1st colum: 0 PSI = 1.592 and the 2nd colum: 25 PSI = 4.37 -- Hit OK and your done with this table.
Tune via Pressure only and I suggest populating the Voltage table this way:
Voltage 0.75 = 48 kpa and the 2nd colum: Voltage 4.75 = 300 KPa. Click OK and your done with this table.
The Fuel (Pressure) table. Build it exactly as I've sketched in the 1st picture in this post. This chart takes into consideration engine intake operating in a vacuum and also under Boost up to and including 21 PSI. If you want to run more Boost -- I've included the formula's at the top of the chart.
On the Fuel (Pressure) chart -- Select 26 colums. The 1st 4 - are for engine vacuum - The 5th is for engine at atmospheric pressure and the remaining 21 colums are for Boost - At 1 PSI referrence.
On entering the KPa values to the 26 colums -- An easy way to do this is enter only values for the 1st colum and the last colum and hit the Interpolate button. The software builds all intermediate colums automatically. SWEET -- We got this far !!
Now-- Tuning this way -- This point on the Autotune. It no longer builds a Fuel table - When one excepts the trims. It Re-Builds the Fuel (Pressure) table that you have manually built. I'll try and remember to talk about how to build .. ..
So -- No matter how bad you screw up building the Fuel (Pressure) table -- Autotune corrects it. Tune via TPS and screw up the Fuel (Pressure) table and your going to have one strange looking Fuel table.
One comment on the Autotune -- It does not correct the injector pulse in real time. And -- Not in the next Power Stroke Cycle -- Or the next. And so on -- It may take several hundred engine revolutions for the Autotune to make an injector pulse correction -- In it's Trim table. This is one reason one has to except the Trims and Send Map back to the PCV. Turn on Cell Tracker and although it now displays the current tuning cell that is active -- No value is displayed.
A/F table -- Populate every tuning cell with a value that your comfortable with. Generally speaking -- As the load on the engine increases (Boost) -- The lower the A/F ratio. I tend to run a bit leaner than most -- I also blend a bit of oil in my fuel to help with detonation.
Ok -- Last tidbit as It's Beer Time and we're goin out for Dinner -- Yea !!
Building the Fuel (Pressure) table. As stated -- This table must be fully populated manually in the beginning. Yea -- Great ........ HOW ??
1st -- Identify the size injector your using. The motor particulars are not relivent.
Run a set of 72's -- This is 400% larger than stock. Don't populate the table and try starting the engine. It will start and if one pumps the throttle to keep it running -- For grins look at your dash Boost gauge. Blip the throttle and you to can Boost over 10 PSI !! Don't do this as this rich fuel mixture washes down the cylinder walls.
Now -- Lets look at what's happening with these injectors. One needs to trim the injector pulse so the engine will idle at the target A/F value in the Target AFR (Pressure) table. What your doing is helping the Autotune out here. For the 1st 5 colums enter a value of -60. This is just a starting point so you can start the engine and look at the software screen and see what the A/F ratio is. Simply change this value in all 5 colums and watch the displayed A/F change. Get it close to the value in the Target A/F table and your Golden. Now for the remaining 21 colums that represent Boost. On a scale of -3 .. And from the value that you ended up with in the 1st 5 colums -- Simply deduct 3%. As in the example .. -60 in the 1st 5 colums ......... The 6th colum then would be -57 and so on for the remaining colums.
As you except the Autotune trims -- This table is re-built .. .. SWEET !!
Now -- In closing ........ These are only my suggestions. You may wish to change your method of tuning and in the end have the engine operate within the specified A/F range also. There is no one correct way to Tune. Just some ways are better than others. And on that note --
Short Story ...... I've even seen one fellow tune his Boosted engine without a MAP sensor. I's possible but extremly difficult to build the tables this way.
I'm just a retired OLD Man who has a Shop and an Old Classic RzR with a couple of Built Motors and 2 complete Turbo Systems - And Like to tinker .. As there are so few Pleasures left in Life anymore .. .. :rofl3:
Speaking of Pleasures .. .. Beer Time -- Then Dinner OUT -- SWEET .. :rofl3:
From this point on -- One should be in good shape to take over and enjoy your Boost ..
:ride:
