LS ECU options

[another69]

HP Tuners is an established well supported and widespread platform.
Here is the sticky general HowTo for Gen4 Ls if you go that route:
http://www.hptuners.com/forum/showth...al-Information

See the first item "Engine Modes" describes the MAF/MAP situation for these engines.

Thanks for shedding light on the factory ECU. You are steering me towards just going with the Holley, but the detailed response is appreciated!

[71RS/SS396]

Tim, are you talking about the HP or the Dominator.....or both?

I believe the Dominator has the option to connect 2 O2's, but it's an option, I don't THINK it does bank to bank tuning. Most of the aftermarket ecus I've seen ultimately get the tune all jacked up over time if you leave the O2 correction turned on. Get the tune right and leave it alone, no reason to keep fiddling with it imho.

[another69]

I believe the Dominator has the option to connect 2 O2's, but it's an option, I don't THINK it does bank to bank tuning. Most of the aftermarket ecus I've seen ultimately get the tune all jacked up over time if you leave the O2 correction turned on. Get the tune right and leave it alone, no reason to keep fiddling with it imho.

Do you mean the self learning feature? I was curious when & if it should be turned off, but according to Holley they said leave it on. Your logic of turning it off after the tune is right makes more sense to me.

[howehot]

I had FAST ez efi running my LS1 383 to start. Liked the idea of self learning being in NE Iowa a tuner was far away. Long story short it ran at 12:1 afr at best down to 18:1 wot. West Bend Dyno help correct it but it was far from ideal.

I switch to GM with a PSI harness and gain 150 rwhp. Yes, a knowledgeable tuner is required. I was told by a very smart man at one point, who has a bigger budget to perfect efi, GM or some aftermarket. Best advice out there.

[andrewb70]

Thanks for the responses. Andrew- I'm curious why you dislike the cable TBs, because I am totally opposite with my thinking on that. It probably just boils down to personal preference, but still curious...

It would be great if Holley had a base calibration for an LS3, but the closest looks to be the LS2 480 HP. Maybe the self learning function will help, I don't know.
I do plan to make changes, which makes the HP more desirable for that.

I like DBW because running wires is much easier than running a cable. I also like the extra tuning flexibility. The Holley (Dominator only) system has a table for adjusting %pedal vs. %TPS. This allows you to tune how quickly the throttle blades open relative to the pedal travel. This is great because you can slow down the throttle blade movement at low %pedal so driving slowly in traffic is easier. This feature is also vital for me since I have dual TBs.

The 480HP LS2 tune will get you close and you can tune from there. Once the self-learning is done, it is advisable to reduce the % correction in case the O2 sensor goes out. This is easily done in the software.

I had FAST ez efi running my LS1 383 to start. Liked the idea of self learning being in NE Iowa a tuner was far away. Long story short it ran at 12:1 afr at best down to 18:1 wot. West Bend Dyno help correct it but it was far from ideal.

I switch to GM with a PSI harness and gain 150 rwhp. Yes, a knowledgeable tuner is required. I was told by a very smart man at one point, who has a bigger budget to perfect efi, GM or some aftermarket. Best advice out there.

A good tuner is required regardless of what system is being used. I don't know anything the FAST systems, but I can guarantee you that any competent tuner can get the same power from any number of different EFI systems.

As I mentioned before, WOT tuning is easy. Stuff that is hard is part throttle, and believe it or not, idle. It's not so much just the fueling, but spark, and other IAC parameters that can take a long time to get right, especially on engines with big camshafts and low idle vacuum.

Andrew

[Rhino]

Thanks for the responses. Andrew- I'm curious why you dislike the cable TBs, because I am totally opposite with my thinking on that.

I think I understand your viewpoint. I used to be against DBW TB's because they seemed like black magic. I didn't like the fact that there wasn't a mechanical link between what the throttle body and my foot. What changed my mind was putting a new 6.0 in place of one of my truck's existing 5.3. Since it was already DBW I didn't want to swap it out. Tuning is a little different, but easily attainable. Now that I've worked with it on a few projects, I do prefer it. Maybe it's just me, but idle tuning seems simpler with DBW.
As it turns out I was afraid of DBW for no reason other than it wasn't familiar.

My '68 (w/LS1) is still a traditional TB. After working on a few projects with DBW it feels like I'm stepping backwards in time.

[andrewb70]

I think I understand your viewpoint. I used to be against DBW TB's because they seemed like black magic. I didn't like the fact that there wasn't a mechanical link between what the throttle body and my foot. What changed my mind was putting a new 6.0 in place of one of my truck's existing 5.3. Since it was already DBW I didn't want to swap it out. Tuning is a little different, but easily attainable. Now that I've worked with it on a few projects, I do prefer it. Maybe it's just me, but idle tuning seems simpler with DBW.
As it turns out I was afraid of DBW for no reason other than it wasn't familiar.

My '68 (w/LS1) is still a traditional TB. After working on a few projects with DBW it feels like I'm stepping backwards in time.

Idle tuning with DBW is easier because there is no need to strike a balance of correct throttle blade opening with proper IAC values. With DBW there is no actual IAC solenoid.

Andrew

[howehot]

I like DBW because running wires is much easier than running a cable. I also like the extra tuning flexibility. The Holley (Dominator only) system has a table for adjusting %pedal vs. %TPS. This allows you to tune how quickly the throttle blades open relative to the pedal travel. This is great because you can slow down the throttle blade movement at low %pedal so driving slowly in traffic is easier. This feature is also vital for me since I have dual TBs.

The 480HP LS2 tune will get you close and you can tune from there. Once the self-learning is done, it is advisable to reduce the % correction in case the O2 sensor goes out. This is easily done in the software.



A good tuner is required regardless of what system is being used. I don't know anything the FAST systems, but I can guarantee you that any competent tuner can get the same power from any number of different EFI systems.

As I mentioned before, WOT tuning is easy. Stuff that is hard is part throttle, and believe it or not, idle. It's not so much just the fueling, but spark, and other IAC parameters that can take a long time to get right, especially on engines with big camshafts and low idle vacuum.



Andrew

FAST said I didn't have enough injector with the stock units and sold me 60lbs units that made zero difference. Also there programmer only read to 14:1 so I thought not good but driveable.

West Bend determined the problem was the FAST unit was not supplying fuel fast enough so the adjusted the afr rich so the FAST pulled fuel out instead of trying to add it. It was still far from ideal. FAST, although they tried, never came up with a solution. Starting was always a crape shoot. One time a touch of the key it ran, next you frantically pump the gas and cranked. It often stall from a standing start when you nailed it. Just ask Chad Reynolds, he laughed at me on occasion as I took a second shot at the start of many an autox. These problems all went away with GM's system. FAST cost me a lot of money in the unit itself, injectors, Dyno time, the 5 hour drive to the Dyno, and the process of redoing the system.