PCM Tuning Service

I am thinking about remote tuning some PCMs. I used credits on my HPT to unlock all 1998 Rivieras, and I have an offboard (I can hook up to the PCM without a car...) Maybe we can work something out... I'll have to get a PCM core, but I know what these cars like and I can customize based on the scan you send me... so all you need is a scanner.

Thinking about it... is there interest? What's a fair price? $50 for a 'basic' tune, plus $25 every time we re-tune?

Of course I understand the desire to have your own tuner, but maybe there can be something for a 'deekster tuned' PCM! Just ask Rick.

Do I get a royalty for each one you tune using the transmission shift values I sent you?

Mark up the cost for each PCM that gets the "AA Shift Mod"!

AA wrote:

Do I get a royalty for each one you tune using the transmission shift values I sent you?

Mark up the cost for each PCM that gets the "AA Shift Mod"!

I never did load your shift tables

I am not really sure how to offer this, as I haven't done anything like it before. But I am willing to give it a whirl if there is interest.

I suppose I'll have to make a disclaimer somewhere about not being responsible for your safety, or your engine/transmission parts if something goes terribly wrong.

I'm kidding - the shift table values are posted (free) for anyone who wants to use them.

I would definitely make that disclaimer to protect you from anyone who might doubt the reliability of altering OEM tuning. The owner of the AAMCO shop that did my rebuild said that disabling TC lock-up in 3rd gear would void his warranty, as "the these transmissions need TC lock-up, will run hot without", but everyone knows the performance tunes delete lock-up from 3rd gear.

Another idea - you could back up your tuning claims by carefully tracking specific tunes in (similar) customers' cars. For example, if you tuned six cars exactly the same, and each one had 50k trouble free miles, that says something, imo. However, if two had slightly different shift patterns, and both suffered trans failure within 10k miles, that also says something. Ideally you would research this stuff with your own car, but unless you drive 10 different vehicles, it's pretty difficult to come to any real conclusions. People say vendors shouldn't use customers as guinea pigs to do their R&D, but at the same time, it's irresponsible not to track each customer's car and use the data as a kind of rolling case study.

Good thoughts.

No interest from other parties yet, though! C'mon there must be like 5 cars I could tune from this site!

Seriously, if anyone has any questions or interest, please ask away.

I might be interested, for the wife's 98. But its in the future a little. It will need a tune for the n* TB , LQ4 MAF, and Gen V sc...
(I bought her a gen V cause I want her m90 rotors for *another* project)

Karma wrote:

I might be interested, for the wife's 98. But its in the future a little. It will need a tune for the n* TB , LQ4 MAF, and Gen V sc...
(I bought her a gen V cause I want her m90 rotors for *another* project)

Sounds good, I'm familiar with all those parts. You can tell me whatever else you want included, I'll add some basic trans stuff if desired (slightly firmer shifts at heavy throttle, stock at light throttle, etc). If you don't want stuff like that changed that's fine too.

Do you have a way to include a scan of multiple data points? (autotap, etc)

How much do they charge you to add another year, or a single VIN?

Eldo wrote:

How much do they charge you to add another year, or a single VIN?

It costs $50 for credits to a single VIN, $100 for credits to unlock an entire model year. I can't go back to '96, but I can do this for '97-'99. If there is enough interest I wouldn't mark up the unlock costs, but I would have to have two PCMs to tune to unlock your year. If you can find someone else with a '97 who wants tuning, I will do it gladly. To unlock a single VIN just isn't cost effective in my mind.

Someone locally who tunes GPs suggested he charges $100 to anyone he tunes to unlock their vehicle. If he hasn't unlocked their year, he does at the cost of $100 and that tune is basically for the cost of the unlock. If anyone needs a tune on a car he has already unlocked the year for, he makes $100 on that tune...

Call the new business "Deek's Tweaks".

AA wrote:

Call the new business "Deek's Tweaks".

Nice!
PCMs by the world famous deekster_caddy!

That'll be $200, thank you (PR/Marketing costs).

Def have a disclaimer!, but i would charge depending on the modds.

If a couple other '97 owners were interested in getting that year activated, there are a few things I'd like to do. I've already had my car down for over a week once, when I did the sequentials, seat wiring and brake pedal, so I could plan ahead and do it again for pulling the PCM out. (Hmmm, I wonder what the shipping weight of that sucker is for Priority Mail... I think one of the tuner sites estimated about $25 each way.)

I think the biggest problem would be the "order form".
What I mean by that is that the rest of us, I assume, are ignorant of the variations in the parameters, i.e. how many choices are there in tranny fluid pressure settings, or how many 'steps' are there for making throttle-induced downshifts more cooperative?

On the other hand, I'm sure that eliminating the speed limiter is pretty straight forward, and I imagine Deek, AA, and others have already figured out the optimal cooling-fan on & off temps for 180 thermostats... At a guess, I'd say Hi-215, Lo-200 and Off-190?

Personally, those are the only things I really want to mess with. I can't imagine how many variables there are in the fuel & spark maps, and I'm pretty happy with my current mechanical modifications as is...

I don't want to slam you with too many questions at one time, but I figure the more ideas & answers we get on here, the closer this might come to actually happening.

Here's where Derek's familiarity with tuning can be a big help. When it comes to ordering, instead of a form with hundreds of parameters for the customer to guess at, it makes sense to offer basic choices for things like trans shift settings. Forget about the fluid pressure settings and shift points, maybe just focus on how you want it to shift.

For example, a customer may want firm shifts all the time, or he may want softer shifts at lower RPMs with harder shifts at WOT, or he may want a gradual merge from one to the other up through the throttle range. There are 3 options right there. Derek can turn that "feel" preference into needed tuning parameters so the customer doesn't need to be concerned with it, at least not up front.

Same with upshifts & downshifts. The customer could request upshifts happen late (higher RPMs), and specify where: at low or high RPM, or both. Downshifts work the same way but in reverse. Maybe there could be a % value for shift "delay" (early/late) compared to stock. Again, Derek's experience will allow him to translate the customer's choice of shifting behavior into the needed code for tuning the BIN.

A few things, like cooling fan settings, speed limitation, and RPM redline could be specified by the customer more directly. A few other tweaks you may never even know about, but are great additions for improving the engine's durability, like skewing the flow rates for cylinders #3 & 4, so they get a little more fuel to keep them running cooler.

The fact that you have a 3.5" MPS means you could benefit from adding some fuel under boost. Derek could use a mild % increase in the upper MAFF band, where WOT activity occurs, to help keep KR down. No harm in that. It'll be better than any generic aftermarket 3800 PCM upgrade.

AA wrote:

... a customer may want firm shifts all the time, or he may want softer shifts at lower RPMs with harder shifts at WOT, or he may want a gradual merge from one to the other up through the throttle range. There are 3 options right there. Derek can turn that "feel" preference into needed tuning parameters so the customer doesn't need to be concerned with it, at least not up front.

Same with upshifts & downshifts. The customer could request upshifts happen late (higher RPMs), and specify where: at low or high RPM, or both. Downshifts work the same way but in reverse. Maybe there could be a % value for shift "delay" (early/late) compared to stock. Again, Derek's experience will allow him to translate the customer's choice of shifting behavior into the needed code for tuning the BIN.

A few things, like cooling fan settings, speed limitation, and RPM redline could be specified by the customer more directly. A few other tweaks you may never even know about, but are great additions for improving the engine's durability, like skewing the flow rates for cylinders #3 & 4, so they get a little more fuel to keep them running cooler.

The fact that you have a 3.5" MPS means you could benefit from adding some fuel under boost. Derek could use a mild % increase in the upper MAFF band, where WOT activity occurs, to help keep KR down. No harm in that. It'll be better than any generic aftermarket 3800 PCM upgrade.

Great info, Aaron, especially about #3 & 4 injectors... I didn't realize that individual cylinders could be adjusted. And with Left Coast Gas, extra fuel across the board at (I'm guessing) 85% throttle is probably a good idea.

As far as the tranny, are the "shift pressures" what is adjustable, or is it the "main pressure"? My shifts could be maybe "20% firmer" at most, but through wear of some poorly designed valve(s), engaging Drive & Reverse takes way too long...

BTW, what did you think of my guesses for fan temps? What do you run?
.

The number of parameters that can be adjusted is huge, definately in the hundreds, maybe close to a thousand. And there are probably an equally large number of opinions on how to skin the tuning cat. Lots of secrets that can make your car perform better and last longer - for example, Rivieras have a factory "defect" in the PCM that tells the computer to ignore input from the knock sensors until coolant has warmed up. We all know that WOT is bad for a cold engine, but no one knew that Rivs had this problem until we found it (other SC 3800 cars aren't the same). Don't do this, but if you go WOT before temp is 158ºF, especially running a smaller SC pulley, you will hear the "tap-tap-tap" as the mixture detonates. The PCM has no way to pull timing, because it can't hear the knock. Why GM did this I haven't a clue, but the minute you let a 3rd party drive your car, if he fills it with 87 octane, then floors it cold, you have a serious problem on your hands. The tuner lets us erase the possibility of this occurring.

On shifting, it's about much more than shift pressures. The main pressure can be limited, but the tuner allows adjustment of pressures for all gears, each in several throttle steps. Also, the shifting time period itself can be set. Finally torque management probably has the biggest effect on how abrupt shifts occur. Since pressures, shift time, and TM all affect the "feel" of the shift differently depending on speed, RPM, gear, and throttle, there is no way to calculate it from the PSI value alone. Best leave that to the tuner. Tell him when you want it to be "20% firmer" and see how it goes.

Fan temps... I think 215 is way too hot. My fans turn on at 185 and turn off at 180. Even on the coldest winter days and hottest summers, rarely does the temp go outside 180-190. I get great MPG at these temps, and less knock.

If you want to know more about my tune, give my DHP log a read:

https://rivperformance.editboard.com/series-ii-scans-tuning-pcm-f5/aa-s-dhp-powrtuner-log-t41.htm

AA wrote:

The number of parameters that can be adjusted is huge, definately in the hundreds, maybe close to a thousand...

Precisely what I was worried about.

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On shifting, it's about much more than shift pressures. The main pressure can be limited, but the tuner allows adjustment of pressures for all gears, each in several throttle steps. Also, the shifting time period itself can be set. Finally torque management probably has the biggest effect on how abrupt shifts occur. Since pressures, shift time, and TM all affect the "feel" of the shift differently depending on speed, RPM, gear, and throttle, there is no way to calculate it from the PSI value alone. Best leave that to the tuner. Tell him when you want it to be "20% firmer" and see how it goes.

So you're saying that the line pressure AND the actual shift time (e.g. 0.6 seconds) can be specified?

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Fan temps... I think 215 is way too hot. My fans turn on at 185 and turn off at 180. Even on the coldest winter days and hottest summers, rarely does the temp go outside 180-190. I get great MPG at these temps, and less knock.

Remember, I said HI at 215... I was just extrapolating from what I'd garnered from my stock configuration, but I also don't want to wear out the fan motors... Stock Hi=230, stock Lo=212-215, and I think the cut-out is 200. So, I was just taking 10-15 degrees off of each. And I figured that you don't want the Lo-speed kick-on to be TOO close to the actual stat temp...

I will look at that link. Thanks.
.

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So you're saying that the line pressure AND the actual shift time (e.g. 0.6 seconds) can be specified?

Yes, as well as torque management values.

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Remember, I said HI at 215... I was just extrapolating from what I'd garnered from my stock configuration, but I also don't want to wear out the fan motors... Stock Hi=230, stock Lo=212-215, and I think the cut-out is 200. So, I was just taking 10-15 degrees off of each. And I figured that you don't want the Lo-speed kick-on to be TOO close to the actual stat temp...

Umm... think of it like this (analogy): would you downshift an auto transmission from high speed every time you slowed down, in order to save wear on the brake pads? Probably not, because the transmission costs a lot more to replace, and you really don't know - those pads may last a long time even if you use them a bunch.

Same with fans. They won't burn out if you use a 180ºF t-stat, because the only time they will come on is when you are sitting idle for a minute. Once you get up to speed, the fans will stay off because the turn on temp is 5º higher than the t-stat rating. In the summer mine turn off/on at every long light for the past 4 years. Still going. So is the engine.

If you ever get a chance to scan during seasons, you will not believe how much ambient, intake, and coolant temps directly affect KR. Plain and simple, knock comes from heat. A shift of just 5º will create noticeable performance loss, and increased KR. To be honest, if my coolant temp was any above 200ºF, I would not got WOT to win a $50 bet. The OEM settings are ok for the NA 3800, but not a good idea for the supercharged version. At 220º (stock fan turn-on), it's time to panic.

Btw, there is only one fan speed that I'm aware. Maybe '97 is different.

Well I wouldn't expect them to "dumb it down" going forward, so yes, there are definitely 2 fan speeds...

I think we covered this in another thread last year - Rather than the "old fashioned way" of having 2 separate fans, one for regular engine use, and another for A/C use, our cars have a series/parallel relay for the 2 almost-identical fans... just like the DRL's run at half-power in the high-beam bulbs.

At Low, the two fans run 12V through each other in series, resulting in half-speed fans. When the 230* setting is reached, they switch to parallel, so each motor is receiving the full 12V individually, and therefore run twice as fast.

Ah, so for the most part, we'll never experience the high speed operation, at 230deg.

I personally think this a great option for us rivi owners!Once I complete my mod's that I'm working on I will most eagerly take you up on this deal deekster.I think having you do my tuning being an experienced riv owner and successful with modding yours would be much better than even me having a tuning device and no experience using it.I'm installing my new SLP headers and full exhaust system also 180 deg t-stat.Then I will be going to do 1:9 ratio roller rockers w/push rods to go along w/my already installed fwi with K&N filter. Oh yeah and lastly the modular pulley system after all the other mod's are completed.I may even wait until the tuning is done dependent on you're opinions on when to install it and what size pulley is best(3.3 or 3.4)?Thanks in advanced for all this site does!

Thanks for the large vote of confidence AA!

I have done all these things, and more. One thing I don't see mentioned - I retuned my PCM for my 3.29 geared transmission too. I can do ANYTHING! MUHAHAHAH!!!!

Okay, is there a second '97 owner on board? I'll look into getting a spare PCM or two so we don't have to be backed up waiting for shipping with downed cars.

Actually, maybe I'll take a "test drive" PCM for the 98 before the Gen V swap... Just to see how it responds. Its a DD, so you would need to get a spare PCM first. PM me when you want to get the ball rolling.

Sounds good. I will track down a PCM. I'll need your VIN and a full mod list for the car as it stands.