1989 stock, auto, 51000

in the future I want to make some mods to my engine. I know some of them will require re-tune to run correctly. I don't want to go thru that each time I want to try something new

I know there are lots of different units out there, but I am looking for one with the least modifications to make, will use existing control panel warning lights as well as dash warning lights, and must be self learning Is there such an animal?

mike

 

I don't agree that you are going to need to tune each and every mod you make. That said, I would start with intake and headers. Tune. Later on you can do heads and cam, tune.

 

Seriously doubt ODB1 has that kind of support.

If there IS something that sophisticated, you'd need to pay someone to install it -- replacing or interfacing with all the electronics, sensors, and ECM in your car. Can you imagine the price?

If you are smart enough to do that yourself, you are smart enough to learn how to tune yourself.

I think you are looking for a magic bullet and/or the EASY button. It's called the C6!!!

 

..... I use Holley , they aren't cheap but its good stuff . Just override the engine controls , do some basic input through a laptop or their handheld and their systems are self learning . Almost all of the existing dash functions remain active with the exception of the fuel economy info . Holley has base tunes in their free software that will get you close . Their tech support guys are available on Saturdays . Visit their web site , download some software and check it out . ..... If you think you might be doing some serious mods downstream , you don't want to be hurdled by the OEM ECM anyway .....

 

You should define "serious mods". Debate and example have been used (over the years) to show engines with 500hp can be managed. I was even surprised on what size injectors could feed that level of power (e.g., 24lb SVOs). Seems like that thread might have been started by "ski_dwn_it" or "Corky"?

Corky was running a 434ci motor into the 10's on 24lb injectors. Can't recall is it was the stock MAF...or a MAP system? Seems like it might have been an 85 though (with MAF).

I'd be curious (after my post above) to know what cost/effort is involved with a self-learning system?

Also, when you say "override the engine controls" how is a system going to "learn" when sensors are bypassed?

 

How much is the OEM going to support? I don't see it being unable to support 500 since I think I am already there and I have heard of 600 being supported.

 

I suppose you can increase the fuel pressure but how much more can you increase it till you have issues? I don't recall the number that there was something about 60 psi maybe? But if you have more duty cycle, there will reach a point it cannot flow properly. Sure, you can also pump the pressure up but at some point the injector may have difficulty opening too.

 

85-90% bpw is what you're supposed to look at....to make sure your injectors don't go "static" and stay open all the time.

Here is one thread that demonstrates people going 500+hp (and into the 10's) using 24lb injectors. Granted, they were probably SVO's that are rated at 24lbs at 39 bar (26.5) in our rails.


Here is another thread explaining how to get around MAF limitations...and what they are.


Oh yeah...max pressure will vary based on the injector brand/type being used.

 

..... The engine sensors are connected to the aftermarket ECM and bypass the factory unit altogether ... the OEM ECM doesn't need to know if the engine is running or not if its not controlling it .....

 

..... My comment is less about how much it will support but more about how easy it is to tune whatever you have ..... The OEM system is biased toward emission controls and fuel economy and automatically performs a variety of tests on those systems to see if they are working as intended ... that stuff can interfere with performance goals .....

 

So exactly at what point does the OEM ECM become at limitation?

 

Fair enough but how often do you need a tune that makes it worth the while to run a different harness and all that? I haven't made any major changes so tuning isn't necessary. Last time I had it tuned was years ago when we did major stuff. So if you are making major changes often, sure. In my case, I would have to find some way around the ABS, FX3 and make the gauge cluster work.

So if I were making changes several times a year that required me to tow it hours away for a dyno tune, you are right but the way I see it, it is less of a hassle to just get a dyno tune once every say 5 years even if I have to tow it. If I am missing something, I apologize for the omission.

 

..... Stick with the system you like .....

 

Liking is one thing that isn't relevant. The question is whether the benefit outweighs the cost or not.

 

Ahhhh....That's the opposite of what I thought you meant. The ECM is bypassed in lieu of a new one. And, I presume the new system needs to be patched into the old sensors.

To be fair, I'm not looking to steer someone away from a viable solution. Again, I considered the cost and effort likely to be substantial....and, as such, way more than almost all C4 owners would be willing to invest. Would it double the cost of a typical 383 upgrade?

 

..... Do you do your own tuning on your OEM ECM ? .....

 

I don't. I would have to rent a dyno and invest time, money and effort, not to mention risk of breaking something in the learning process. I haven't had to tune often enough to DIY so I do the old "push, pull, drive" routine to get it to the tuner. Probably did it twice or maybe 3 times in the last 10 years which is why self tuning wasn't worth the investment for me.

On my Powerstroke, the chip is plugged in the J3 port and you don't lose the stock functionality. So if the new system Xander do that or get over the limitations of the stock ECM, it may justify the investment. So far example, if I need to have sequential fire in the injectors, sure.

 

..... That was not the O.P.'s question , its yours ... there is a true cost in dollars and an aggravation expense that is difficult to determine ... in my case , I tried to tune the OEM ECM with Tuner pro and some Moates hardware ... I quickly became frustrated ... so I sold the Moates stuff and bought a FAST Classic , then a Holley Commander 950 , Holley HP , and now I use a Holley V4 Dominator ... I would NEVER recommend that anyone try to tune the OEM unit simply because its very difficult and requires a lot of research time with a fairly large learning curve ... far more effort than ANY of the aforementioned ECM's ... FYI ... the ABS doesn't care about the ECM , neither does the gauge cluster (with the exception of the instant fuel economy readout) I believe the FX3 has its own module as well and doesn't need the ECM to function ..... Its not getting any easier to find someone able or willing to tune the C4's computer and simply put ... the latest versions of nearly every aftermarket controller will do the tuning for you with a few taps on a touch screen or laptop being your only input necessary ..... If you are comfy tuning your own or you "have a guy" , then you are all set ... I was just trying to HELP the O.P. figure out a way to accomplish his goal .....

 

..... My elderly aunt (87) still watches a 25" CRT Television ... my brother asked her why she won't buy a big flat screen ... her response "This is good enough for me" ... God Bless her ! .....

 

..... NEW , self tuning Controllers and appropriate harnesses can be had for $1500 or less ... How much did you invest in your tuning hardware/software ? (please include any mail order tunes and dyno tunes) and figure it out ..... The effort comes in mounting the new ECM , Corvettes are notoriously deficient in "extra" space ... then you actually have to unplug the old connectors from the injectors and other engine sensors and plug in the new ones ... hook up a few power wires , enter some engine info on the handheld or your laptop and follow the quick set-up guide ... then let the controller do its thing .....