What does make an aftermarket better?

[bruce]

Originally posted by V6 Beast
I didn't mean to imply that you never did anything under the hood. I have visited your sight before. But how often do you try stuff on the car without running it through it's paces on the bench first? How quick would you be to just start trying this and that directly on a car after dropping 5 grand in the motor. If you didn't have a bench, would have just put on a 749 ecm and made a few WOT blasts to see what happened?
I don't think so.. So how much does the ECM bench cost so we can tune at the same level as you do?

I've been hot rodding for a few decades now, and have worked on enough engines that I have enough respect for them that money isn't an issue to how I treat an engine. 100K mile junker or $15K hotrodded Nitrous BB, they all get the same level of, me doing the best I can do.

Starting off with the 749 for me is a MUCH better known then with an aftermarket. The 749 is proven oem EPA'd blessed piece. It was specifically designed for v6 turbo application, and hence is much closer out of the box, then some one size fits all would be. Millions of dollars were involved with it's design, so I full confidence in it. By prerunning it on the ecm bench I was able to rough in the tables, to what I thought would work. If I was using a FAST, I would do the same thing. It's alot cheaper to run an ecm on the kitchen table, then the wear and tear on the car.
I begin tuning with idle, and then progress from there, by the time I'm ready for a WOT blast, I'm ready for a WOT pass. And it'll be for a sec at a time and slowly build from there. I'm meticulous in my tuning.

An ECM bench is what YOU want to make of it.
I have about 7 years of evolution in mine. Component wise, maybe $60 in parts.



The ECM has equal value on an oem as well as an aftermarket.

 

[V6 Beast]

Originally posted by bruce
An ECM bench is what YOU want to make of it.
I have about 7 years of evolution in mine. Component wise, maybe $60 in parts.

Yep.. seven years is about how long it would take to cut that 2 acres with those custom made rigged hand clippers.. for me, I'll use the mower and do it in half an hour so I can enjoy the fruits of my labor more.

Well I'm out.

Peace
Sully

 

[bruce]

Originally posted by bobc455

For the injectors, you have pulsewidth (duration), the resolution of that width (if I recall, some systems have a finer control resolution than others), and the timing of the pulsewidth (sequential vs. bank-to-bank, etc.). You also have the ability to easily switch from a low-impedance injector to a high-impedance. Is there anything else that a system can control?

Then for timing, you have the accuracy of the spark, and how tightly you can control that accuracy. I have not heard of any system blamed to be inconsistent (i.e. timing jumping around a couple degrees, etc.), so really the only key factor here is how accurately you can set the timing. On the FAST, I think I can set timing to 1/4 degree (as far as I know it also controls to 1/4 degree), and I think Bruce said the stock OEM can do 0.3 (1/3?) degree. DFI = ???

All the ECMs seem to be able to start the car, have warmup enrichment, etc., so I'm not aware of any major differences there (except for maybe 4th gear input, etc., that I don't think the aftermarkets usually consider). (What is FAPE, anyhow?)

Corrections? Additions? Is there some magic in one system's algorithm that gives something extra that I'm not mentioning?

This may turn into a bit of a "mine is bigger than yours" contest in some ways, but if it's all technical then go ahead and show me your pulsewidth resolution!

All of the software that I know of, can outperform the hardware.

I can only address the oem's accurately since the Aftermarket guys are refusing to admit or show any real data about what they do, but in the GM VE tables each entry is 0-255, and that represents 0-100% VE. Injector size, engine displacement, all figure into how much actual resolution you effectively have. A small injector on a huge engine will give you more room to wiggle the numbers for a smooth idle, 160's are going to suffer from cycle to cycle variations of their own, as a function of a short PW at idle. Looking at all the pics of injectors firing they all show there is alot of dribbling going on as the injector opens and closes, and the ecm has very little to do with that. Not to mention on big cammed motors, the self EGR'ing of the engine at low speeds comes into play.

And while you might think your working at a 1/4 degree ignition resolution there is always what the code does to that number as is runs thru the calilations. Even an ecm rounds off numbers.
And if your looking for a 1/4d remember there is that ugly spur geared oil pump and those cam lobes bumping the valves open and closed adding some jitter to the timing sensors themselves.


FAPE is adding extra fuel as a function of time in PE.

And you'll notice that the aftermarkets are getting more complex as things progress. The is a min level of complexity needed to get a car running WELL.

The fueling calculations vary in the GM world.
What seems most meaningful to me is the trims the tuner uses. ie the air temp correction, and coolant temp corrections. Since this varies by engine. Or at least in BruceWorld.

 

[suns68]

ecm ??

i have been reading the post on here and i have run a stock ecm for many years,( blown 383 in a formula ) i also have blown up many motors not noing what was going on for the tune !! i bought a fast system because a friend had one in his gn ! he picked up alot after all the tunning was done .ya it took a little while but he didnt break any parts doing it either ! so i bought on this year , after installing it , is was hard at first, but i have learned so much off of this website it is now so easy to change any thing i want on my car ! (i love it ) no brocken parts either , oops ! i did break an axel with the new found power !! my opinion is i dont know anything abought chip burning , but the fast system has a really fast learning curve that did not brake any parts ! BUT THATS ONLY MY TWO CENTS WORTH !!!

 

[Laterrr]

C'mon Bruce,
The question was, "What is the PW resolution of the ECM?" We all can figure the effects of various sizes of injectors. We're trying to compare ECM's here. This seems like a reasonable thing to do. So far, the timing resolution of a FAST at 0.25 degrees appears to be superior to the 0.3 degree of a stocker. Before you get too defensive, I do agree this is probably too close to make a meaningful difference. The jitter producing things you mention probably swamp that resolution. I have an older DFI (not Gen VII). The injector PW table range goes 1-255 with each count being 128 microseconds. That'd be 0.128ms - 32.64ms in 128us steps. That's the PW range and resolution of an old DFI. What does your ECM Bench show for a stocker? Note, we have to rely on you here because the original manufacturer (GM) doesn't publish _any_ specifications or programming documentation. Maybe other folks can chime in here with the newer ECM specs?

craig

 

[Steve Y]

Well I can add something to this thread....

The operator of a MaxE R can move the PW in as little as 3/100th of a MS increments.

Steve

 

[HighPSI]

Originally posted by bruce
And if your looking for a 1/4d remember there is that ugly spur geared oil pump and those cam lobes bumping the valves open and closed adding some jitter to the timing sensors themselves.

Just trying to understand what you are saying, not disagreeing.

Are you saying the crankshaft is jittering back and forth during its rotation? If so, I could see how it would cause the signal at the crank sensor to vary? I suppose this would also show up as a varying rpm. I have seen this on cars with the camshaft jittering, but never thought about the crankshaft jittering, before.

 

[Birdzilla]

factory ecm

My ride is a '93 Formula (speed density LT1). I was burning my own chips with Tunercat. I hit a wall when I wanted to build my motor to spin up into the 7300rpm range. The factory ecm would not do this, regardless of what I set the rev limiter to. I've read the factory ecm cannot process properly at that rpm and/or that there are a limited # of cells. Either way, the engine would pull hard right into a 7000rpm ceiling and fall flat on its face. So I got a F.A.S.T. Solved. No more burning & swaping out chips, and I can tune from the driver's seat.

 

[Scott231]

Originally posted by bruce
I maintain that given a certain pulse width, and amount of timing at a given engine condition, there is no difference between an oem and aftermarket.

That is probably true, but the aftermarket computers can be purchased to work with MAP sensors that read to 60 psi. Shirley you could figure out how to make the stock ECM work with a 5-BAR MAP sensor and there are prolly a dozen people on this board that could also figure it out. With the aftermarket 'puters, its already there.

There may also be the matter of better open & close injector times with one system or the other. I don't know the answer.

But I think you are either missing the point of reason for buying an aftermarket engine management computer or your statement is mis-written. People don't buy the aftermarket computers because they do a better job of computing Xms of fuel, Ydegrees of timing or Zpsi of boost. They are purchased for:

• Their ease of use,
• Their relatively quick learning curve,
• Flexibility in supporting various engine combinations,
• The wide band feature with ability to tune to desired A:F Ratios,
• Their all-in-one package simplicity, and
• You have some new bells and whistles (i.e. with the Gen 7+, the "Boost Builder" function).

From the DS runs I've looked at for .25 mile passes once you reach the stall speed of the converter at launch you pretty much run between 3.7K to 6K. And other then some chips with a 3rd gear timing step the timing is a constant. Well, at least in the ones I've seen, and that includes some 9 sec passes.

I would agree that the timing should vary by gear (albeit minimally), but this is getting pretty nitpicky in pursuit of the "perfect tune." The arguments here about a quarter degree of timing resolution are also quite nitpicky, IMO. Cars ran pretty fast for years on wieghted distributors.

Now in some cases folks might be using a MAF and those can drop the HP some. But, with the ME MAFless, or going to a blow thru with a Translator, you approx having a MAP system.

That is correct. But with the aftermarket systems you usually have the option of running a MAP or a MAF based system at the click of a button. At least my 'ol Electromotive TEC has this.

Now we have the Tunercat RT that gives real time tuning, and numerous aftermarket WBs, those issues are mute. Unless you LIKE TUNING with a feedback WB with NO REDUNDANCY.

Not sure what your last statement means there. The aftermarket systems do make adjustments while you are going down the track and the 'puter records them. Yes, you have to take the recorded adjustment values and alter your VE table manually, but the people at Accel did that on purpose so people do not overly rely on the system.

And like I've mentioned before you can use the TurboLink Boost Sensing Harness and incorporate it, so then you can have a boost sensing MAF/MAP set up.

Again, how many people really know how to incorporate this into the chip altering ROM code? With an aftermarket system, it is all included.

Yes, I'll admit to the aftermarkets having pretty screens and sort of friendly software, but where is the real performance gains?

As has been stated many times here before me, the performance gain mostly comes from the ease of use to get the motor into a better state of tune. Whether you have an Accel Gen 7+ or a Bruce Plecan-modded ECM with 8-Gig of memory and every feature under under the sun, neither will tell you the best A/F Ratio for the current weather conditions and your motor's capabilities...but most people can easily get their aftermarket system setup to easily change A:F Ratios at various RPM/Load levels. The screens don't excite me much. Numbers are numbers.

So someone please tell me, FACTUALLY what I'm missing. Leave the opinions at home, and let's discuss facts. What can an aftermarket ecm do that the GN ecm can't or can't be made to do?

I've tried to limit my comments above to the facts. It is not so much what can the aftermarket systems do that the GN ECM can't (because we have now seen for years that both chips and ECM ROM code can be altered heavily), its a matter of what do the aftermarket systems already do so I don't have to learn ROM code changes. I haven't seen Tunercat, but will bet that it doesn't have little radio buttons for switching between a MAF and a MAP, buttons that turn on or off some features like Lean Cruise (for instance), scalability of axis points for the main tuning tables, or the ability to control the ECM to run in Batch-fire mode, Bank-to-Bank, Phased Sequential or true Sequential. Am I right?

I would also assume that with your knowledge you could add some code to the ECM to mimic the Boost Builder funtion of the new Gen 7+. This feature, which originated with the MSD DIS-4, is a God-send for Heads-Up racers. As stated before, how many people could really do this to the ECM ROM code?

 

[bruce]

Re: Re: What does make an aftermarket better?

Originally posted by Scott231

I would also assume that with your knowledge you could add some code to the ECM to mimic the Boost Builder funtion of the new Gen 7+.

I've been impressed with just twisting the stock settings around.
ie
The lower PE TPS thresholds are so low that you stage in PE.
And that starts the FAPE.
So depending on how long you stage, you burn down the FAPE adder.
Set the TPS enables up some, and then you can stage cleanly, and then have the add fuel down track function right.

Not to mention the TPS % opening scaler, playing with it, and you can even leave so room to feather the gas, and not restart the FAPE.

Yes, this has/had been covered before, but I was hoping that maybe someone had something new to add. Unless ya revisit some old topics from time to time, they don't get updated.
Thanks

 

[Two Lane]

Re: Re: Re: What does make an aftermarket better?

Originally posted by bruce



Unless ya revisit some old topics from time to time, they don't get updated.

Right!

This thread has helped to illuminate what is generally a "dark" area for many.

All of the preceding posts where people took the time & effort to participate in the discussion are very helpful & appreciated!

 

[HighPSI]

Not sure what was accomplished here, but FWIW, I have almost convinced Laz (gotta work on Roy next) to let me put a FAST box on Roy's car. I am interested in seeing what kind of performance I can get out of his car vs his current setup. I chose his car since it was probably the best tuned and fastest car with a stock ecm in my area.
Perhaps we can get a chip guru to put a stock ecm and chip in one of my FAST customers car (since no-one wants to attempt putting one in my car).
It would be interesting to compare how quickly each car gets dialed in and how close to the previous performance level we can get.
Do you think this would be a valid comparison, Bruce?

 

[86brick]

Originally posted by HighPSI
Not sure what was accomplished here, but FWIW, I have almost convinced Laz (gotta work on Roy next) to let me put a FAST box on Roy's car. I am interested in seeing what kind of performance I can get out of his car vs his current setup. I chose his car since it was probably the best tuned and fastest car with a stock ecm in my area.
Perhaps we can get a chip guru to put a stock ecm and chip in one of my FAST customers car (since no-one wants to attempt putting one in my car).
It would be interesting to compare how quickly each car gets dialed in and how close to the previous performance level we can get.
Do you think this would be a valid comparison, Bruce?

Cal, I don't think Louie would be too happy if you made Roy's car any faster than it already is!!!

That would be cool to see if his car picks up from the FAST system though

 

[HighPSI]

LOL!! That's exactly what Louie did say! Will see if Roy let's me do it. I'm not saying I can make it any faster, just want to compare systems.

 

[86brick]

Originally posted by HighPSI
LOL!! That's exactly what Louie did say!

I know how he thinks

Here is a crazy idea of mine, but why don't you also ask Louie to try the ME-R MAFless chip with a stock ECM in his car (he has a FAST system and his car is doing very well with it running bottom 10's in TSM trim so he would also be a good test bed).... Sound too crazy??

 

[Louie L.]

Crazy idea indeed !

UMMM No thanks .... I LUV MY F.A.S.T. !!!!

My daddy used to say "experiments are for scientists" And so far I see no scientists

 

[86brick]

Originally posted by Louie L.
Crazy idea indeed !

UMMM No thanks .... I LUV MY F.A.S.T. !!!!

My daddy used to say "experiments are for scientists" And so far I see no scientists

Yeah I see where you're coming from cause my daddy always said "Don't mess with a good thing"...... Hopefully Roy doesn't read that last statement I made cause his car is running very well with the ME-R chip and stock ECM!!! As good a system as the FAST is and as good a tuner as Cal is I still really wonder if Roy would go any faster?? Maybe we'll find out

 

[Laterrr]

But Louie, this is your chance to _be_ a scientist.

 

[quickt]

Originally posted by Glen
It's more like two guys standing on a street corner saying their crank is bigger/better than the others with neither side willing to drop their drawers in public to prove it.

That is good

 

[Dusty Bradford]

Cal

I'll volunteer my car for the experiment. Are we talking the plug and play system that installs in minutes. I am running the Trans+ Extender setup right now with a 4 inch MAF. The chip has been tweaked by Bob Bailey so it's about as good as it's gonna get. It's no where near as fast a car as the top TSM guys but the tune is about maxed for the current setup.

We could see how much is to gain and then I could maybe use the F.A.S.T data for Bob to plug back in my stock ecm. I'd really like to see what the wide band looks like during that hard 3rd gear pull. It might scare me enough to upgrade my fuel lines.