PCM Options for Supercharged 454 / 4L80E

[1project2many]

Dave, I can understand your situation. Many good technicians won't want to get involved with that engine as soon as they see the S/C installed, and rightly so. No one wants to be held responsible when a good fix is made bad by incomplete, improper, or badly implemented prior work. And when it comes to custom tuning, I'm sure you're well aware that everything down to faulty brake light bulbs and bad music on the radio will be blamed on the computer and the tune once you make a single change. I've been there myself plenty of times. If I were trying to sell the MAP conversion I would sell it by comparing it to adding a set of high quality aftermarket gauges to a truck with factory gauges. The factory gauges are still there, but they're just not as accurate as the ones you're putting in. If he goes for the swap I'd make a simple 3 column chart to include for anyone using a traditional scan tool: "If your scantool show this kPa, or this MAP voltage, the real MAP is this." All other scantool readings will look normal. I'd give the guy a few copies of my card and I'd probably tape one to the ecm and another to the hood so tech support is available in case he's broken down. And I'd probably point out that he's already been a guinea pig by installing an aftermarket part on a computer controlled engine which is not understood by the computer. Again, that's if I felt making the sale was worth the effort.

Good luck.

[EagleMark]

Plus it's an OEM part used on factory turbo and supercharger applications! It looks the same and will mount the same and plug in the same...

I'm curious what the manufacturer of the Supercharger says about tune after installation?

[dave w]

Dave, I can understand your situation. Many good technicians won't want to get involved with that engine as soon as they see the S/C installed, and rightly so. No one wants to be held responsible when a good fix is made bad by incomplete, improper, or badly implemented prior work. And when it comes to custom tuning, I'm sure you're well aware that everything down to faulty brake light bulbs and bad music on the radio will be blamed on the computer and the tune once you make a single change. I've been there myself plenty of times. If I were trying to sell the MAP conversion I would sell it by comparing it to adding a set of high quality aftermarket gauges to a truck with factory gauges. The factory gauges are still there, but they're just not as accurate as the ones you're putting in. If he goes for the swap I'd make a simple 3 column chart to include for anyone using a traditional scan tool: "If your scantool show this kPa, or this MAP voltage, the real MAP is this." All other scantool readings will look normal. I'd give the guy a few copies of my card and I'd probably tape one to the ecm and another to the hood so tech support is available in case he's broken down. And I'd probably point out that he's already been a guinea pig by installing an aftermarket part on a computer controlled engine which is not understood by the computer. Again, that's if I felt making the sale was worth the effort.

Good luck.

The technical information exchange about converting the Supercharger to a 2 BAR MAP is good stuff. I'm in hopes others find the exchange of information on a 2 BAR MAP conversion useful. I really appreciate the input 1project2many!

I'm not going to get rich by selling and servicing EFI Systems, but it helps support my "Toy" addiction. I sure can't quit my "day job" on the few sales I get each month. Ultimately, I'd like the vehicle owner to have a good tune. Seems the best option available for a good tune is a 2 BAR MAP conversion.

dave w

[JeepsAndGuns]

Not to hijack the thread, but as always, I want to learn a little here. I understand what a 2bar map sensor is.
From what I am reading, swapping to a 2bar map sensor is about the only real hard part that needs changed when going to forced industion? Since the 2 bar has the same output signal (if I am reading this thread correctly) then the only real mod to the code or tune would be whatever is needed for the fuel and spark parameters? I was thinking there was a lot more to it than that. I thought you had to use a forced induction specific ecm/pcm, and a forced induction specific cal/bin.
So again unless I am misunderstanding it, all thats really needed is to edit the XDF to display the correct map numbers in place of the old numbers?
I'm still a noob and still learning.
I have had a few dreams of installing two small turbos on my engine, one on each header. (where the little smiley that sets there and drools...lol)

[dave w]

Plus it's an OEM part used on factory turbo and supercharger applications! It looks the same and will mount the same and plug in the same...

I'm curious what the manufacturer of the Supercharger says about tune after installation?

NOTHING about tuning!

The Supercharger Manufacture recommends more fuel, recommending fuel pump upgrade and adding an adjustable fuel pressure regulator!

dave w

[dave w]

Not to hijack the thread, but as always, I want to learn a little here. I understand what a 2bar map sensor is.
From what I am reading, swapping to a 2bar map sensor is about the only real hard part that needs changed when going to forced industion? Since the 2 bar has the same output signal (if I am reading this thread correctly) then the only real mod to the code or tune would be whatever is needed for the fuel and spark parameters? I was thinking there was a lot more to it than that. I thought you had to use a forced induction specific ecm/pcm, and a forced induction specific cal/bin.
So again unless I am misunderstanding it, all thats really needed is to edit the XDF to display the correct map numbers in place of the old numbers?
I'm still a noob and still learning.
I have had a few dreams of installing two small turbos on my engine, one on each header. (where the little smiley that sets there and drools...lol)

The original thinking of this thread was to install forced induction specific ECM / PCM. Possibly the "Best Option" is to upgrade ECM / PCM. The idea / option of converting the current PCM to use 2 BAR was an excellent idea from 1project2many! Like mention earlier, all vacuum / Kpa parameters will need to be re-calibrated to a 2 BAR scale. Ultimately, converting the PCM to use a 2 BAR MAP has trade-offs in drive ability. I personally would like a VE / Timing table extension for the Boost and still use all the original VE / Timing table for natural aspiration!! Loosing about 1/3 of the VE / Timing table for boost will only hurt overall drive ability.

dave w

[EagleMark]

As fast as that PCM is? I doubt it...

[dave w]

As fast as that PCM is? I doubt it...

Good point, but I'd like having the faster computer speed (compared to a 7747) through out current VE / Timing tables of the '7060 Natural Aspriation and expand VE / Timing tables for boost.

Typically a day at the "Dyno" in my area is about $500. I honestly don't know what a 2 BAR conversion is really worth? How can someone compare prices for such a conversion and be fair in pricing? Honestly, if it was my money I would not venture into a 2 BAR conversion without including a PCM / ECM upgrade. Currently I'd favor Dymanic EFI for the ECM upgrade, and use the original '7060 to control the 4L80E. The "Catch 22" is a PCM / ECM upgrade is not "Scan Tool Technician" friendly.

dave w

[EagleMark]

$OE would be?

[1project2many]

NOTHING about tuning!

The Supercharger Manufacture recommends more fuel, recommending fuel pump upgrade and adding an adjustable fuel pressure regulator!

dave w

I've been through something similar. The customer did a no-no and improved the airflow of a stock 8.2 by changing cam and having head work done before adding the S/C. S/C maker refused to give any help... S/C system is designed for stock engine period. I asked for injector flow... "Proprietary." Silly... numbers were on outside of injector. I also asked about mfgr adjusting separate controller PW for fuel based on dyno readings. "Nope." I even threatened to pull the controller apart and make changes myself. "It's encoded and you can't read it." I didn't buy that story but it was ultimately the customer's decision and he didn't want to upset the S/C maker. About a month later he called to tell me he'd burnt a valve and was replacing the non-stock components with stockers. All because one company didn't want to play ball.

Loosing about 1/3 of the VE / Timing table for boost will only hurt overall drive ability.

For this application you would likely be ok. The weight of the vehicle and relatively slow changes in speed won't require high resolution tables to correct for transients. It is possible to rewrite the VE and fuel tables to make up for some lost resolution.

The 2 BAR calibration conversion without XDF and ADX file modification should be a 2 hr job. Changing the MAP sensor and modifying the connector probably won't require an hour's labor. Additional tuning cost depends on how much time is required.

[dave w]

Here are more pictures for Mark.

As for tuning, I have driven the vehicle 4 times now, for a total drive distance of about 80 miles. Time in Excel and time for the Test Drive for each tune is about 1 1/2 hour ~ 1 3/4 hour. About 8 hours total for now. The pictures show I'm just about done.

1project2many
I really appreciate the input that the old '7060 PCM is most likely good enough for the 2 BAR Conversion becase the vehicle is a C3500.

dave w

[EagleMark]

Here are more pictures for Mark.
dave w

I know you can tune! Just wanted to see the cool rig!

But now that I look at data to 100 KPA what does fuel do at 110 and up? Are you just making sure it does not go lean? I've never tuned boosted so with out 2 bar map data I wouldn't know what to do as your data is only showing no boost? So your VE at 100 kpa has to handle 100 kpa up to? that does not sound like a good idea compared to doing the 2 bar thing which would give VE/BLM 100 kpa up as well.

I think if your customer knew 2 bar MAP was factory part and bolted in, but gave tuning ability from 100kpa up it would be a no brainer. He may do it next time after he melts a motor towing toys up a 8 mile 4-6 % incline...

Do you know for sure there's no drop in fuel pressure high load? hope he's got exhaust temp gauges for right and left side.

[dave w]

I know you can tune! Just wanted to see the cool rig!

But now that I look at data to 100 KPA what does fuel do at 110 and up? Are you just making sure it does not go lean? I've never tuned boosted so with out 2 bar map data I wouldn't know what to do as your data is only showing no boost? So your VE at 100 kpa has to handle 100 kpa up to? that does not sound like a good idea compared to doing the 2 bar thing which would give VE/BLM 100 kpa up as well.

I think if your customer knew 2 bar MAP was factory part and bolted in, but gave tuning ability from 100kpa up it would be a no brainer. He may do it next time after he melts a motor towing toys up a 8 mile 4-6 % incline...

Do you know for sure there's no drop in fuel pressure high load? hope he's got exhaust temp gauges for right and left side.

All the reasons above are why this engine needs either a different PCM / ECM capable of controlling boost , or a 2 BAR Conversion. For now I have spiked the VE tables for 90 Kpa and 100 Kpa into the mid 90's an attempt to avoid a melt down. The one bar map only goes up to 103 Kpa! It's just a guess spiking the VE tables will prevent an engine melt down. All the 100 Kpa timing tables all below 15 degrees. Knock counts are down from 34 to about 10 or so. The latest tune has even less 100 Kpa timing.

dave w

[EagleMark]

I agree! And if he refuses to do it properly you should remove your tune, leave it stock and walk away. Or? You need a signed waiver that you are not responsible for melted engine! Because he does not want to replace PCM and 2 bar to tune correctly. Right now it's just a guess and closer to not melting. This is a tow rig for toys and the location dicatates he may haul over Snoqualmie pass! That's a long uphill haul to be running a guess tune under boost hauling a load!!! Tuned properly he will find cooling system issue first.

Why bother 2 bar on that PCM? OK it could be done, but wouldn't it be better with one of your 427 conversions with 2 bar added in $OE for the 4l80E, then you could do a proper tune developed for a well supported PCM... that could still be scan tooled anywhere, with notes on MAP readings and your card as suggested and he is covered anywhere.

Or do an internet search to find all the melted motors from that supercharger and no tune, print and show him what's not reported in magizines... the famous first twin turbo LS1 corvette in magizines is here in my town with a melted motor, that never made it back in the magizine. Motor is new but no one will touch it to tune, it's still sitting... looking pretty. 1000 hp does not last long without proper fuel... I calculated what he has for fuel and it's only half what's needed...

[dave w]

Here is what I'm thinking for a $85 2 BAR Conversion, see pic below. Currently the engine idles at about 40 Kpa. All feedback welcome!

dave w

I have revised my thinking on the chart posted in the above tread. The supercharger is rated for 6 psi boost, so I'm thinking the 2 BAR MAP will not show 5 VDC at 6 psi boost. I'm thinking the 6 PSI boost will have a maximum voltage of about 3.4 ~ 3.6 VDC from a 2 BAR MAP sensor. That's not really a good range of voltage for tuning from 20 Kpa to about 140 Kpa.

dave w