Discussion
Hi All, I am looking at fitting one of Holley's new HP ECU's. They are full featured, support drive by wire and are completely self tuning - no more trips to the rollers. Would appreciate your thoughts. Cheers Tony
http://mooreracecraft.com/holleyhp_efi.html
http://mooreracecraft.com/holleyhp_efi.html
Lots of ecu's out there have an auto tune function. Unless they come with a base map you still won't get it running without some basic tuning knowledge. Also the load sites will need to be adjusted to something close before you go holding it on load or you will lean it out and kill an engine. For example I use auto tune for all the off load cruise parts of the map but all on load stuff I do myself. Auto tune isn't quick enough to adjust.
Also it only does fuel. What are you going to do for timing. Again you will need tuning knowledge.
Also at the end of the day cause auto tune is a bit slow it needs you to hold the load site on the axis for up to 20 seconds. It's just too hard to do that on the street and hold it spot on.
Also it only does fuel. What are you going to do for timing. Again you will need tuning knowledge.
Also at the end of the day cause auto tune is a bit slow it needs you to hold the load site on the axis for up to 20 seconds. It's just too hard to do that on the street and hold it spot on.
rs_man said:
Why the scepticism, with lambda sensor feeding back air/fuel mixture to ecu, why cannot they 'self tune' surely thats all a tuner on a rolling road does when they set maps? ECU can also be mapped manually for the old school :-)
oh i don't know, maybe it's the nearly 20 years of powertrain calibration experience that tells me it aint that simple 
For example the ecu, with a wide band lambda sensor, can easily control it's own fuelling to a target lambda value, but what should that target lambda value be? Do you want 0.89 or 0.85 lambda at peak power, what about at peak torque? are you going to run lean on cruise, what about setting the gains for the transient fuel correction. And then we get to ignition angle optimisation and it gets even more hazy...............
The OEMS now actually use "self mapping" systems for engine dyno base engine parameter optimisation (due to the large number or degrees of freedom in the latest control systems where EVERYTHING is varriable!). But these systems still require the basic "laws" and "Limits" to be calibrated before the system will start doing things like spark or fuel sweeps etc. (you also need to sign a cheque made out to "AVL" for an amount with 5 or 6 figures before you get something that actually works!)
I am using a system by FAST ie comp cams and it works brilliantly. Initially used a dizzy for spark but am now using a wasted spark system. Their latest XDI2 system which is the all singing all dancing race car ecu also now has a self tune function built in to it. It also controls spark! However all these units require some initial set up but rollers are certainly not necessary.
I have also looked at fast ecu, very similar to Holleys latest trio. I am looking at the mid range HP, however the features on all of the ecus are broad, the top of the range one has dual lambda sensors allowing one for each bank, however I have been told that this isn't required. All of the ecus allow extra lamda channels via cam bus cable, so in theory you could have sensor per cylinder, allowing very precise fuel control. They all control spark as well as fuel, but I agree they do need a base map, this is provided and can be quite away out from standard. I personally think the beauty of closed loop 'self tuning' is that the ecu can recalibrate itself depending on factors such as different grades of fuel. Everybody to there own I guess.
I agree with the other comments regarding auto-mapping, Its just marketing spin. If you have a map that is close, it would probably clean up the midrange / cruise areas quite well. But I would want to be on the laptop for full power runs.
And you will still need to use a dyno, because you cant do full power runs on the open roads. I once helped a friend map a TVR griff 500 down the local bypass - I had my head buried in the laptop and just told him to floor it down the hill - at the bottom I said "good - spin it round and do it again" - he said "urr, we were doing over 150mph down there - do you really want me to do that again?"
And you will still need to use a dyno, because you cant do full power runs on the open roads. I once helped a friend map a TVR griff 500 down the local bypass - I had my head buried in the laptop and just told him to floor it down the hill - at the bottom I said "good - spin it round and do it again" - he said "urr, we were doing over 150mph down there - do you really want me to do that again?"
why you looking aftermarket Tony? It makes no sense, even if you tune the engine you will still have far better road manners, performance and economy from a GM setup and its cheaper.
I know i sound like a stuck record but here is one example
A stock LS7 running a leading brand aftermarket ecu
6.0% co
750ppm hydrocarbons
1.30 lambda
that has not got a hope in hell of passing IVA, it was running cats and idling well so there was not a huge amount to find in the map if you want to pass the driving element of the IVA test.
Gm setup
0.07 co with cats .90 without
100 ppm with cats 250ppm without
.90 lambda
tuning the GM setup is not a problem, granted it isnt as easy as aftermarket ecus
Gm has spent millions of dollars developing the ecu and 1000's of hours mapping.
At Stoneleigh have a look at how a Gm ecu starts the car in preference to aftermarket!!! there is no comparison
Just trying to help.
I know i sound like a stuck record but here is one example
A stock LS7 running a leading brand aftermarket ecu
6.0% co
750ppm hydrocarbons
1.30 lambda
that has not got a hope in hell of passing IVA, it was running cats and idling well so there was not a huge amount to find in the map if you want to pass the driving element of the IVA test.
Gm setup
0.07 co with cats .90 without
100 ppm with cats 250ppm without
.90 lambda
tuning the GM setup is not a problem, granted it isnt as easy as aftermarket ecus
Gm has spent millions of dollars developing the ecu and 1000's of hours mapping.
At Stoneleigh have a look at how a Gm ecu starts the car in preference to aftermarket!!! there is no comparison
Just trying to help.
Kyle obviously has a point with which I agree. My engine is old sbc so I can't use gm ecu and maps. I have done full power runs on a dyno with my learning ecu and no settings needed to be changed. Cold start is just a press of a button. Throttle does not need to be touched car drives straight away.
MarkWebb said:
Kyle obviously has a point with which I agree. My engine is old sbc so I can't use gm ecu and maps. I have done full power runs on a dyno with my learning ecu and no settings needed to be changed. Cold start is just a press of a button. Throttle does not need to be touched car drives straight away.
Not quite true Mark, it does take a bit of work but can be done, either DIY or with a now purpose made kit for a mere few hundred dollars.. I thought I had come up with a unique idea until I surfed a bit deeper and found the US kit available....check out EFI connection. If I were building an SBC from scratch Id belt drive it, put the cam and crank sensors where they should be, get a GM run kit and all else can be adapted from what you have.. But getting your head around EFI live or similar is the fun part !!Good luck.
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