mgarfias

Hey all, I'm in the process of building a new motor for my C5Z, and while I'm in there, I'm considering dropping in an aftermarket ECU. Note: considering. I'm trying to figure out if its a worthwhile idea.

If so, I'd want to be sure I can do full datalogging via can bus, and I'd have to figure out the ABS connectivity (I could goto the BMW abs system if needed). If this is a good idea, which ECU do I go with, and I'd want to put a PDM in there while I'm at it, and just rewire the car completely. Oh, intended use is autox/roadrace, not drag race. Also would like decent drivability.

Or do I leave it alone, and just buy HPT?

minytrker

iTrader: (13)

stock pcm and hp tuners be your best bet

NSFW

Or stock PCM plus LS Droid (free) or PCM Hammer (free, open-source) plus an OBD2 interface that they work with ($50-$100) plus Tuner Pro (free).
If you're adept with computers the learning curve isn't too bad.
If you're not, HPTuners is probably worth the extra cost.

The main thing that deters me from aftermarket ECUs is how much time it would take to integrate, maybe troubleshoot, and tune. If you're not in a hurry and you do can spare the money, I'm sure that approach is better in every other way. But if you just want to enjoy the car, there's something to be said for sticking with the stock electronics.

SLOW SEDAN

iTrader: (13)

You can easily install Holley and tune it in a day for under $900. By the time you get a wideband, misc software, etc for stock ecm you could be close in price for less capability.

That said I’ve also built a turbo kit in ~8 hours threw it on the dyno and made 900whp with hptuners with no issues for $2000. Granted HPT was basically free due to having multiple make/models unlocked.

Either way has its positives and negatives. Things you can do on a stock ECM are often safer with an aftermarket ECM.

minytrker

iTrader: (13)

Your not going to install and tune holley on a C5 in a day and have everything work or have it look nice.

SLOW SEDAN

iTrader: (13)

Perhaps you aren't, I work fast. Kinda like turbo kits, shops bojangle on those and they literally only take a few hours.

I've done it on a C5 and a C6, neither was very hard and both are tucked away where you would never see them. In both cases everything controlled by the BCM still works as before. Holley controls the engine, boost control, two step, fan, etc it really isn't that hard. I know some shops like to say things are overly difficult to milk hours, but I'm not down with that.

minytrker

iTrader: (13)

I agree none of it is very hard but Im not believing it can be done all in one day when a dyno tune alone takes 4-6 hours normally. We charge a flat rate for tuning and on most installs so its defiantly not about trying to milk some hours on a bill. I guess we could be talking about two different types of quality installs also. Are you piggybacking the holley to factory harness or piggybacking the factory ecm to the holley harness?

SLOW SEDAN

iTrader: (13)

Perhaps if you're limited to an 8 hour workday spending that kind of time on the dyno could pose an issue. 4-6 hours on the dyno is pretty nuts, I've never been in a situation that its taken that long, personally I don't think it should if you have a large assortment of base maps to choose from. There's only so much you can do before you have to get off the dyno to hit the street and/or the track. Typically I do the street tune before the dyno, just seems easier and eats up less time that way.

minytrker

iTrader: (13)

I believe 8 hours is considered the typical workday at most shops. I have been tuning twenty years so I have pretty big library of tunes, doesn't speed it up that much IMO. 30-45 mins to put on dyno and hook up fuel psi and boost check tires etc. Build base tune and setup I/O's and advance tables another 30 mins- 1 hour or more. We have several cars running 10-20 inputs that all have to be setup. We do alot of 1,000+hp cars mostly with big stalls. Drive them 30+ plus minutes varying the load cell and then do steady tuning all burns up time. Once you do a few pulls have to let it cool off (mainly transmission). We do 99% of the tune on the dyno using the load cell vs driving them all around. We take cars straight off the dyno and run full 1/4 mile and also mile passes with the mile cars.

Are you piggybacking the holley to factory harness or piggybacking the factory ecm to the holley harness on these same day install and tuned builds.

SLOW SEDAN

iTrader: (13)

Typical indeed, but sometimes ya start at 6AM and on the dyno at 9PM or later. Not sure why you are hooking up fuel PSI and boost when you can just log it. I agree I dont mess with much under 900-1000hp, dealing with the other stuff was more trouble than it was worth. If you keep the I/O map the same on all your builds it makes things easier. I prefer manuals, but I know the drag guys love their autotragics and they do take more time.

I've left the stock ECM at first until I sorted out what was really needed, turns out it wasnt that much so now I can delete the majority of the stock ECM wiring and ECM and just use what I need. In the OP's case he referenced it being a road race car so I would treat it as such and go straight for the weight savings, the weight I was able to take out was staggering and only took a few mins to powerprobe and rewire what was required. But that would be up to him as to how hardcore he wants to go, I hear race car and rewire the car completely I assume HVAC, stereo, heated seats, airbags, etc is nixed.

gjestico

iTrader: (5)

Depends on how much of your stock functionality you want to keep . Dash cluster ? HUD display ? Suspension ?
Remember, different guys have wildly different ideas on what is a "complete" swap.

minytrker

iTrader: (13)

We log boost so the customer can what boost made what hp and fuel psi to show there isnt any fuel psi issues. We also tune alot of cars we didnt build and alot with factory ecm's so not everyone has a fuel psi transducer. I didnt think it was that useful until we started doing it. We now use a the same I/O on our builds but over the years I have had four different people wiring and we didnt have a standard and we also tune alot of cars we didnt build so you still have to set them up by hand.

mgarfias

Not W2W road racing, TT and autox. Plan is to build for optima/USCA and keep it a "street" car. So, no cage, but it'll have an interior, stereo and HVAC. And its an '01 C5Z, no heated seats here. But it'll be dry sumped when the motor goes back in.

I think for now, I've decided to keep the factory ECM in place, and consider a swap later. Plus I have to pay for the dry sump system first.

SLOW SEDAN

iTrader: (13)

True, GM's version of HUD is so terrible most people don't use it stock.

Gotcha!

I checked out a bunch of those Optima cars at SEMA, some cool builds. The rear mounted in cabin turbo C6 was quite the contraption.

aaronc7

If you're staying NA (which I'm guessing so if you plan to road course it)..... stock PCM is plenty sufficient. HP tuners is your best bet for a well developed suite of tuning and logging.