First off, a recap of my situation: I am in FL in Navy flight school. The car is in Virginia being sorted out. I haven't actually driven it yet, my father has done the testing and tweaking.

Based on what I had read in the Aurora FSM, I had initially thought that the Aurora calpak did not have all of the torque reduction responses from missing system components that the Cadillac did. After trying the Aurora calpak, it was evident that the FSM was incomplete, and that the Aurora did in fact have all of the torque reduction responses of the Cadillac, if not more. The car ran terribly, had only 10-15% useable throttle, and got ~12 mpg. It also didn't have a stable idle and would cycle the IAC motor from max to min quickly several times after engine shutdown.

Fortunately the Aurora calpak spontaneously died. Having nothing else to install, we replaced it with the original Caddy chip. Driveability improved dramatically. It had much more useable throttle, and idle stabilized at 1000 indicated RPM (750 actual since I haven't recaled the tach yet). However, the trained ear and backside could still tell that the timing was retarding at full throttle. Gas mileage in this configuration is still unknown.

After that, the delivered torque output of the ECM was looped to the desired torque input of the ECM. This improved driveability even further, eliminating perceived timing retard at full throttle. Gas mileage in this configuration is also as yet unknown.

The rest of the setup: '95 N*, computer & PROM w/ Getrag trans & CF DF201502 clutch; resistors in place of shift solenoids, TCC PWM solenoid, and trans temp sensor; no VSS signal reaching ECM; P/N line grounded during cranking, released on engine start.

It is close to full power, but not quite yet. It should be operating in a torque reduction mode because of the lack of VSS input.

My dad says it doesn't have quite the punch he remembers is 360 GHP Corvair having. In theory, it should, as the cars weigh about the same and should have about the same FHP.

He came off the clutch hard at 3000 RPM. It spun for about a car length then hooked up and ran out first gear VERY FAST.

I drove my N*/Getrag back and forth to work all week and then went to the dragstrip and made 4 passes on Wed. When I filled it up I still had logged 25 mpg.

I think it will be interesting to see how your clutch arrangement holds up. I have the Quartermaster dual disk clutch with organic facings. Normally these are drag clutches, but normally they have metalic facings, also. QM told me not to rev and pop as the life of the clutch may be greatly reduced. So leaving the line at the strip I just eased off the brake and clutch and gave it full throttle. I had quick launches and a lot of wheel spin. Several witnesses said I spun 1 tire all through first and second. I would have had much better times if I hadn't missed 3rd every time. My last run I had to go back and grab 3rd. I was still winding up 4th through the traps at 104 and 13.5. I can't say how much I lost because of the missed shift, but I do remember not having my foot all the way down on the gas when I went through the traps. Write it off to not knowing what I was doing.

On the ECM, the real issue with the PROM is not WOT response, but rather drivability. How well does the car return to idle? How well does it drive along in gear at idle? What happens when you do a NTCD (no throttle coast down)? I had several chips that performed great at WOT, but sinply couldn't be driven.

This is a stock chip. Dad says it's quite liveable and he can understand how people actually drive the average Northstar Fiero in that condition.

However, it just doesn't have anything more to give beyond a certain throttle percentage. That percentage with the Caddy chip and looped TCS line is MUCH higher than it was with the Aurora chip, but still isn't 100%.

The fact that it was actually able to hook up in first gear is another indication that it's running in a torque reduction mode. I think that this particular mode is due to the lack of VSS signal. The ECM thinks the car is always standing still, so it limits torque to prevent "abusive manoeuvers" which might damage the transmission.

[This message has been edited by Will (edited 04-27-2002).]

bump

hah so you're gonna be one of those zeroes ey? hehe.. kool. what type of pilot are you shooting for? gl..just be kind to the avionics (was a Hornet/Intruder/Hercules/helo/xxx avi tech

quote the delivered torque output of the ECM was looped to the desired torque input of the ECM. [/B]

can you elaborate on how drivablility improved?

quote no VSS signal reaching ECM[/B]

why not?

just some questions about weird ideas
I have not a clue about N* CPU GUTS
but am asking QUESTIONS trying to learn
not stating FACTS

VSS=speed sensor?? with caddy having anti lock and anti-spin-control does it expect to see 4 VSS sensor readings???, one input from each wheel???/ but is/willbe happy if one is repeated 4 times so it gets allways from each the same value = [no slip]????
or is it a tranie sensor????? like our cars use but different values output????
can you just tell it a speed or does it want it to change or it will get mad [limp mode]???

------------------
Question wonder and be wierd

yeah.. vss = vehicle speed sensor.
our fiero speedometers requires 4Khz sinewave i believe. the 95 N* pcm speedo output is also a 4khz but squarewave i believe also.

i see said the blind man!.. in stock form, the 95 N* vss output to N* ECM is 24Khz whereas the fiero vss itself is 4khz output--so thats why he has no proper vss input to N* ECM.

hmm...i wonder if a 6x multiplier circuit would work to alter the fiero vss output to 24khz, to keep the N* ECM happy.(attn. electronic (not electrical) gurus hehe)

I'm curious about the VSS as well....can we fake the signal? I work with a guy who claims to be an electronics geek...if I knew what the signal from the Fiero and the signal for the N* is, I could see if we could fake it.

Bryce
88 GT

quote Originally posted by birdpoo: can you elaborate on how drivablility improved?

quote Originally posted by Will: However, it just doesn't have anything more to give beyond a certain throttle percentage. That percentage with the Caddy chip and looped TCS line is MUCH higher than it was with the Aurora chip, but still isn't 100%.

Will;

I know Jay here in ontario had some issues because the traction control module wasn't connected and getting signals to the ECM so hit wasn't running full power either.

Have you looked at this scenario?

quote Originally posted by grinthock: Will; I know Jay here in ontario had some issues because the traction control module wasn't connected and getting signals to the ECM so hit wasn't running full power either. Have you looked at this scenario?

I suggested looping the TCS signal to him. He said he'd look into it, but I never heard anything else. I don't think he was terribly interested as he was selling the car. He shouldn't have the VSS problems I do as he's using the 4T80E.

quote Originally posted by Will: The VSS issue isn't that simple. If it were just necessary that the ECM know when the car's moving, I could wire the Fiero signal directly to it and not worry about it. And we also played with the idea of a 6x frequency multiplier. However... The Caddy ECM checks the ratio of transmission input speed (a signal for which I don't have) to axle speed (VSS) to make sure that the trans is in the gear it's supposed to be and isn't slipping. In this application, the trans input speed sensor has been deleted, and an externally controlled trans with totally different ratios has been substituted. If I supplied a VSS to the ECM, it would get really pissed off that it wasn't getting the trans input speed signal and that none of the ratios match. I'm better off without a VSS signal. The VSS's are described by pulses per mile, not pulses per second. The N* is expecting 24,370 ppm.

Good info Will, and if you don't mind, I'd like to pick your brain some more...I don't know if you call this theoretical or hypothetical application!

So, if the ECM is looking for a VSS and "transmission input speed" (I'm guessing basically the RPM in the trans after the torque converter?) where does the problem lie the most, in your opinion, in creating those? The signal from the VSS could be used to create a "fake" trans input speed signal, which would basically be a matrix that told it what the N* engine RPM would be at that vehicle speed in the tallest gear (max RPM with the N* gears and without clutch slippage?) and then told what calculation to run for each range (each gear). Did that make sense?

Hmm..another way of saying it is this: Use the given Fiero VSS and relate that to a table of N* vehicle speeds. The N* table will show what gear the N* would be in at that speed at maximum performance (max RPM gear before redline). The gear, however, wouldn't be a gear, rather, it would be the method of how to convert the VSS to a trans input signal (A formula to convert the proper gear ratio).

Man, I'm even confusing myself...

So, if you were really going 16 mph (XX pulses per second), you could first figure out what gear the N* would be in (say 1st gear in the auto is from 0-49 mph until redline) and then use that number of pulses to mimic the N* trans input signal:

(XX Fiero pulses/second)*(1 Fiero mile/XXXXpulses)*(X N* miles/1 Fiero mile)*(XX N* pulses/N* mile)=X N* pulses/second

Now, with a table of maximum pulses/second for each gear (max rpm's in each gear) you can compare what gear would be best for that pulse/second. Then you do some multiplication to find out what the engine RPM would be with that given gear ratio and no slippage:

(X VSS pulses/second)*(1st gear ratio)=XXX trans input pulses/second

Of course, if the trans input signal is based on 52 signals per revolution, and the VSS is based on 60 signals per revolution, you'd have to tweak that for the RPMs to jive. This is just my thought, as cluttered as it may be.

*Disclaimer: I'm not an electronics whiz in the slightest, and I personally don't know how to build such a circuit...this is just me asking questions, perhaps creating some new thought.

If this is totally retarded, by all means tell me that. I'm just trying to help out and hopefully be able to use some of this experience when I do my N* swap in a couple of years.

Bryce
88 GT

[This message has been edited by Nashco (edited 04-29-2002).]

That's called the N/V ratio. Divide the RPM by MPH and you get a factor that is constant. There is a table for look up to determine the gear. The table is actually a window like 38-42 for example. You can also determine TCC slip from that.

Works fine for manual trans over all of the gears, but only works with the TCC locked on automatics since the TCC is otherwise slipping throwing off the number.

I'm a couple of steps ahead of you. I've been toying with this idea for a while.

Yes, a "transmission impersonator" could be built. It would have to be programmable logic, not a simple oscillator.

Its inputs would be the N* ignition signal, shift A, shift B, and TCC PWM solenoid lines.
It would output wholly manufactured trans input shaft and VSS signals. It would read the shift A & B solenoid lines to find out what gear the ECM wanted, then select the appropriate ratio. It would read the TCC line to determine whether the ECM wanted the converter locked or unlocked. It would read engine RPM from the ignition signal, subtract the proper amount if the TCC were locked, then do the appropriate ratio math to output the proper signals.

It shouldn't be hard to implement. It's just that I've already got a large (although related) programming project on the table.

It can't be a simple oscillator because engine RPM and trans input speed are related by a difference, not by a ratio. I think the ECM looks for a 16 RPM difference between the two when the TCC is unlocked, and obviously a 0 difference when it is locked. However, once the proper trans input signal has been established, one of four specific frequency multipliers could be selected based on the Shift A & B lines. Or the programmable logic could do it internally, which would be significantly easier. Chosen method just depends on the designer's area of expertise. I'm closer to computer engineer than electrical engineer, so I'd opt for the programmable logic.

quote Originally posted by terryk: That's called the N/V ratio. Divide the RPM by MPH and you get a factor that is constant. There is a table for look up to determine the gear. The table is actually a window like 38-42 for example. You can also determine TCC slip from that. Works fine for manual trans over all of the gears, but only works with the TCC locked on automatics since the TCC is otherwise slipping throwing off the number.

Hmm...

I got the assumption that what Will referred to as the "trans input" signal was after the torque converter, as the torque converter is obviously going to allow slippage unless locked. I figured the only "slippage" that would be referenced, and avoided by the ECM in torque reduction mode, was when the post-TCC (actual input) varied from the VSS....thus showing the actual clutches were slipping.

Thoughts? Can anybody tell me what the "trans input" signal is referencing, and where it's located?

Bryce
88 GT

quote Originally posted by terryk: That's called the N/V ratio. Divide the RPM by MPH and you get a factor that is constant. There is a table for look up to determine the gear. The table is actually a window like 38-42 for example. You can also determine TCC slip from that. Works fine for manual trans over all of the gears, but only works with the TCC locked on automatics since the TCC is otherwise slipping throwing off the number.

Most transmissions only know engine RPM and VSS.
The 4T80E, however, has an input shaft speed sensor so that it knows both TC slip and N/V ratio exactly, and can measure transmission slippage as well.

[This message has been edited by Will (edited 04-29-2002).]

quote Originally posted by Will: I'm a couple of steps ahead of you. I've been toying with this idea for a while. Yes, a "transmission impersonator" could be built. It would have to be programmable logic, not a simple oscillator. Its inputs would be the N* ignition signal, shift A, shift B, and TCC PWM solenoid lines. It would output wholly manufactured trans input shaft and VSS signals. It would read the shift A & B solenoid lines to find out what gear the ECM wanted, then select the appropriate ratio. It would read the TCC line to determine whether the ECM wanted the converter locked or unlocked. It would read engine RPM from the ignition signal, subtract the proper amount if the TCC were locked, then do the appropriate ratio math to output the proper signals. It shouldn't be hard to implement. It's just that I've already got a large (although related) programming project on the table. It can't be a simple oscillator because engine RPM and trans input speed are related by a difference, not by a ratio. I think the ECM looks for a 16 RPM difference between the two when the TCC is unlocked, and obviously a 0 difference when it is locked. However, once the proper trans input signal has been established, one of four specific frequency multipliers could be selected based on the Shift A & B lines. Or the programmable logic could do it internally, which would be significantly easier. Chosen method just depends on the designer's area of expertise. I'm closer to computer engineer than electrical engineer, so I'd opt for the programmable logic.

Cool, I'm glad that "question" didn't turn out to be a waste of time for me to figure out.

So, what is shift a and shift b? I'm not getting that input. Also, I'm not familiar with what TCC "PWM" stands for. Sorry, I'm learning.

I'm completely with you on the programmable logic over electronic alternative! I guess I'm just much more comfortable with making a new chip than resoldering components.

Bryce
88 GT
*typo*

[This message has been edited by Nashco (edited 04-29-2002).]

quote Originally posted by Will: I suggested looping the TCS signal to him. He said he'd look into it, but I never heard anything else. I don't think he was terribly interested as he was selling the car. He shouldn't have the VSS problems I do as he's using the 4T80E.

A turbine shaft sensor would do it. Yep.

[This message has been edited by terryk (edited 04-29-2002).]

quote Originally posted by Will: I suggested looping the TCS signal to him. He said he'd look into it, but I never heard anything else. I don't think he was terribly interested as he was selling the car. He shouldn't have the VSS problems I do as he's using the 4T80E.

I did hook up a TCM (as best as I could) and it did seem to make a difference. The problem was I didn't have all of the inputs it wanted! I was running 13.4 with the auto all day long, so I was happy with that. Yes the car is sold to someone in California. Last I heard it passed the emmisions test but failed on the visual inspection. I sent down a few vacuum lines (for the oil breather) which had been removed. Haven't heard anything in several months, I hope it is okay. Will, it must be easier not driving the N* since you can fly!

------------------
Jay

quote Originally posted by Nashco: Cool, I'm glad that "question" didn't turn out to be a waste of time for me to figure out. So, what is shift a and shift b? I'm not getting that input. Also, I'm not familiar with what TCC "PWM" stands for. Sorry, I'm learning. I'm completely with you on the programmable logic over electronic alternative! I guess I'm just much more comfortable with making a new chip than resoldering components.

Shift A & B are two lines operating the two solenoids which determine which gear the transmission is in.

PWM stand for pulse width modulated. The PWM solenoid is operated by a square wave. The ECM ramps the duty cycle from 0% to 100% to smoothly and seamlessly engage the TCC. As the duty cycle ramps, the width of the pulses increases: pulse width modulation.

nice...hey if you need a micro soldering on multilayer PCBs or SMTs i'll gladly assist, even generate CAD schematics

Will could you tell me how to loop the torque desired output to the torque delivered input? do you just jump the terminals or do you need to do something more?

quote Originally posted by Fiero STS: Will could you tell me how to loop the torque desired output to the torque delivered input? do you just jump the terminals or do you need to do something more?

We just twisted the wires together.

quote Originally posted by Will: Shift A & B are two lines operating the two solenoids which determine which gear the transmission is in. PWM stand for pulse width modulated. The PWM solenoid is operated by a square wave. The ECM ramps the duty cycle from 0% to 100% to smoothly and seamlessly engage the TCC. As the duty cycle ramps, the width of the pulses increases: pulse width modulation.

Ah ha! I have seen PWM meaning pulse width modulation, but I didn't know that's how the converter locked up....cool.

So, Will, is this something you've been *thinking* about, or something you're actually in the process of. You said that you're pretty busy with a few things trying to get the factory components to work, rather than using the chrfab.com computer...is this part of the puzzle? Obviously it is hard for me to jump into the project without a test bench to try things with, but if there's ANYTHING I can help with, I'd love to be of service. I'm a whiz with internet searches. I'm sure the GM DIY-EFI list would be of some help with this too, are you on that list?

Thanks

Bryce
88 GT

quote Originally posted by Nashco: Ah ha! I have seen PWM meaning pulse width modulation, but I didn't know that's how the converter locked up....cool. So, Will, is this something you've been *thinking* about, or something you're actually in the process of. You said that you're pretty busy with a few things trying to get the factory components to work, rather than using the chrfab.com computer...is this part of the puzzle? Obviously it is hard for me to jump into the project without a test bench to try things with, but if there's ANYTHING I can help with, I'd love to be of service. I'm a whiz with internet searches. I'm sure the GM DIY-EFI list would be of some help with this too, are you on that list? Thanks Bryce 88 GT

I'm on the GMECM list, but not the DIY-EFI list or the EFI332 list.

The impersonator is one option I am considering.
wcapman has an engine management only N* chip, which I intend to buy from him when he goes to the Holley setup.
There is also the possiblity of using other friendlier engine controllers to run the N*.

That's why I'm learning Microchip PIC assembly language and going here a lot: www.microchip.com

The Holley is really rather friendly. I like it better than Electromotive's TEC-II infact. (better software. I think.)

Anyway, yeah. Holley 950, you know you want it

Best!
Ben

quote Originally posted by Will: There is also the possiblity of using other friendlier engine controllers to run the N*. That's why I'm learning Microchip PIC assembly language and going here a lot: www.microchip.com

------------------

Ben Cannon
88 Formula, T-top, Metalic Red. (2:13.138 at Sears Point) "Every Man Dies, not every man really Lives"
88 Formula, Northstar, Silver, In-Progreess. -Mel Gibson, "Braveheart"

quote Originally posted by artherd: The Holley is really rather friendly. I like it better than Electromotive's TEC-II infact. (better software. I think.) Anyway, yeah. Holley 950, you know you want it Best! Ben

Hehe... maybe I do want it. It would be an immediate (expensive ) solution.

I think want to find a few more things that don't work first

I was thinking OEM controllers...

Paraphrasing Allen Cline: "The control algorithms we [GM] use are about 10 generations beyond those of the current aftermarket offerings"

[This message has been edited by Will (edited 04-30-2002).]

Thanks for the info Will. I am using the 4t80e trans so to go to aftermarket controls would be real expensive as I would need one for engine and another for trans. After buying them they would need to be set up for application. Would need access to dyno and drag strip, plus use of onboard test equip to get it right. with fuel maps, ignition curves, trans shift points etc. etc. etc.

quote Originally posted by Fiero STS: Thanks for the info Will. I am using the 4t80e trans so to go to aftermarket controls would be real expensive as I would need one for engine and another for trans. After buying them they would need to be set up for application. Would need access to dyno and drag strip, plus use of onboard test equip to get it right. with fuel maps, ignition curves, trans shift points etc. etc. etc.

We do need to do some more testing to be absolutely sure of the improvement coming from looping the TCS signal. The improvement may be intermittent or placebo. We may still ahve to build a 200 Hz 90% DC oscillator to fool the thing correctly.

But give it a shot. It won't hurt.

[This message has been edited by Will (edited 04-30-2002).]

"advanced"... I wouldn't quite say that "more complicated" I definately would!

GM (and automakers in general) have to deal with a ooouldlum of things the race-computer guys don't. EGR just one very over-simplistic example.

The OE computers are actually much more complicated, typically with much more processor power, to perform their myriad of tasks in a modern automobile. Way too many to begin listing here, I could write a book. (or at least a table of contents :P)

All said and done though, the aftermarket computers almost always make more power (and yes, the Chrfab/Holley at $1300 isn't exactly cheap, but it is a drop-in solution, with a harness, as you mentioned :P) I totally understand about your desire to conquer the caddy electronics though. I'm the same way in many respects. More power and then some too you if you do manage it! )

Anyway, my point here was that *very generally* an aftermarket computer can liberate ~5% more ponies than the general stock OE perfectly running unmodified counterpart. Despite running 1/10th (or less) code.

Best!
Ben.

------------------

Ben Cannon
88 Formula, T-top, Metalic Red. (2:13.138 at Sears Point) "Every Man Dies, not every man really Lives"
88 Formula, Northstar, Silver, In-Progreess. -Mel Gibson, "Braveheart"

quote Originally posted by Will: I'm on the GMECM list, but not the DIY-EFI list or the EFI332 list. The impersonator is one option I am considering. wcapman has an engine management only N* chip, which I intend to buy from him when he goes to the Holley setup. There is also the possiblity of using other friendlier engine controllers to run the N*. That's why I'm learning Microchip PIC assembly language and going here a lot: www.microchip.com

Yeah, I had a dialogue going with him (wcapman) about his chip that he's running. He made it clear that he wasn't letting it out of his hands until he had the Holley setup on and completely functional. I had planned on gaining access to a chip reader/burner and giving access to the chip to anybody who wanted it.

What plans do you have for the prom, if you get it? Just for you, or copy and make available? Feel free to PM me, or just ignore the question, if you'd rather not broadcast.

True, other ECMs can be used to control the N*, but that's equivalent to using the aftermarket ECM but cheaper. Easier, but less functionality, in my opinion.

Bryce
88 GT

quote Originally posted by Nashco: Yeah, I had a dialogue going with him (wcapman) about his chip that he's running. He made it clear that he wasn't letting it out of his hands until he had the Holley setup on and completely functional. I had planned on gaining access to a chip reader/burner and giving access to the chip to anybody who wanted it. What plans do you have for the prom, if you get it? Just for you, or copy and make available? Feel free to PM me, or just ignore the question, if you'd rather not broadcast. True, other ECMs can be used to control the N*, but that's equivalent to using the aftermarket ECM but cheaper. Easier, but less functionality, in my opinion. Bryce 88 GT

I'll upload the chip P/N's, .bin files, etc. to www.diy-efi.org
I'll probably copy it at a nominal fee for anyone who wants it.

Less functionality? Hehe... check out www.carputing.com

quote Originally posted by artherd: "advanced"... I wouldn't quite say that "more complicated" I definately would! GM (and automakers in general) have to deal with a ooouldlum of things the race-computer guys don't. EGR just one very over-simplistic example. The OE computers are actually much more complicated, typically with much more processor power, to perform their myriad of tasks in a modern automobile. Way too many to begin listing here, I could write a book. (or at least a table of contents :P) All said and done though, the aftermarket computers almost always make more power (and yes, the Chrfab/Holley at $1300 isn't exactly cheap, but it is a drop-in solution, with a harness, as you mentioned :P) I totally understand about your desire to conquer the caddy electronics though. I'm the same way in many respects. More power and then some too you if you do manage it! ) Anyway, my point here was that *very generally* an aftermarket computer can liberate ~5% more ponies than the general stock OE perfectly running unmodified counterpart. Despite running 1/10th (or less) code. Best! Ben.

Some credit has to be given to using the factory ECM! How many of the aftermarket ECMs will tell you your mileage? I bet none of them, because they don't want you to know that the added power you're getting is because you're using 20% more fuel!

Really, I think just being able to get codes from the factory stuff is worth that minor loss in power. Modern ECMs are becoming very good troubleshooters, and when you're having slight driveability problems they make life much easier. I'm not extremely familiar with the Holley system yet, but I question if it is able to monitor the status of EVERY sensor on the car.

To be completely honest, many aspire to have that factory 300 horsepower without plopping down an EXTRA 1300 bucks in addition to the already expensive engine, ECM, and wiring harness. If factory driveability can be obtained for very little cost, all will benefit. Joe Blow may want a N*, but doesn't know how to tune the Holley and doesn't want to pay 1300 for the ECM plus another 500 getting the car tuned on dyno....can you blame him? Anyway, how many tuners can give you the same driveability that Cadillac created....you do realize how much effort is gone into creating a near perfect calibration, don't you? You try to convince me that you can replicate that driveability with an aftermarket system!

Ben, we know you're all about getting the best money can buy, you've shown that....but is the Holley really the best? Easy, yes...expensive, yes....the best? Depends on what you're looking for. Not everybody needs 400 hp, 12 pound clutch and flywheel, and 10" wide tires....ease up big guy!

I applaud Will, and all the others like him, that are determined to find a better way to do things. With a lot of effort from a few "frontiers" many can gain in the long run. You think you'd have EVER completed a N* swap into your Fiero if several others before you hadn't done it, and worked out all of the bugs? Leave Will alone, he's doing a GOOD thing!

*Steps down from the soapbox*

Bryce
88 GT

quote Originally posted by Nashco: Ben, we know you're all about getting the best money can buy... and 10" wide tires....ease up big guy!

I have 10" wide tires too!
Ben's not being hard on me (I think... :wathout We just see things a little differently.

If I can get 80% of the performance for 20% of the cost, which I pretty much will, I think that's a good deal.

My father had a business putting SBC's into Jaguars for a while. Everyone who saw one of his conversions had nothing but praise. I think the best compliment he ever got was when he was out of town and mom had to take one of the cars into the shop for some service. After standing around the engine compartment scratching their heads for a while, one of the mechanics came over to mom and asked "Lady, did it come like this?" That's the way an engine swap ought to be.

I'll have done my job right if I ever enter the a N* Fiero in a show and it loses because "it looks too stock". I'd love to show it a GM engineer and hear him say "That's the way I would have done it for production".

The cheaper and easier I make things, the more unmodified OEM parts I use, the more off the shelf applications I borrow from, the easier it will be for some Joe to reproduce what I have done and put one more N* Fiero on the road.

That's my soapbox.

Given equal access to the calibrations, I think the OEM ECM's are better hands down. There is, on average, 10-15 engineers and 3-4 years of work in the calibrations and hardware design. I doubt any aftermarket system could afford 60 engineer-years.

I don't see how anyone can claim that you can get "more power" from either. The calibrations are either right or wrong. I do agree that since the OEM information is more difficult to get, that the aftermarkets might allow someone to tune the engine better, but if GM handed you the XDE docs for their ECM's you'd find them to be far better. I believe that the OEM systems allow for far better fine tuning.

The hack jobs done by some of the chip companies is no indication of the real potential of the OEM ECM's (when they actually change something meaningful.)

Terry