EFI
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RockinRobin
Well-Known Member
I'm using Holley sniper 4500. If you don't take it and have it dyno tuned, it takes forever to get it calibrated right. Steep learning curve if you have no tuning experience.
I've finally got it close to being right. If you let it continue to compensate as you go down the track the E.T. will be more consistent than carb. Or you can lock the tune and it will behave like a carburetor and your numbers will vary according to weather. I highly recommend you have it dyno tuned. Also, I have no experience with alcohol carbs.
I have a complete Dominator EFI system. Was just kicking the idea around in my head. Thanks for replying.
Bluecuda340
Well-Known Member
I posted on your moparts thread also. My setup has been extremely consistent. Its is a Megasquirt system that I do all the tuning on.
The "self learning" stuff is only as good as the info you give it. Everything really needs a good base tune to hit the AFR targets you choose for your combo. For example my car runs the best at 13.0:1 AFR. That is my target and after enough time the tune is close enough to the target that it can easily make small corrections to hit the ratio even as weather changes. That being said 13.0:1 AFR in 500ft DA goes way faster than 13.0 AFR in 4000ft DA.
I just did Drag Week and we raced at tracks 130ft above sea level and a track at almost 3000ft above. My car hit the target AFR on every pass and I made zero changes to the wide open tune. The ET varied with the DA as expected with any combo. The only changes I made all week were drivability stuff like overrun fuel cut and part throttle AFR targets.
The "self learning" stuff is only as good as the info you give it. Everything really needs a good base tune to hit the AFR targets you choose for your combo. For example my car runs the best at 13.0:1 AFR. That is my target and after enough time the tune is close enough to the target that it can easily make small corrections to hit the ratio even as weather changes. That being said 13.0:1 AFR in 500ft DA goes way faster than 13.0 AFR in 4000ft DA.
I just did Drag Week and we raced at tracks 130ft above sea level and a track at almost 3000ft above. My car hit the target AFR on every pass and I made zero changes to the wide open tune. The ET varied with the DA as expected with any combo. The only changes I made all week were drivability stuff like overrun fuel cut and part throttle AFR targets.
RockinRobin
Well-Known Member
Sounds great! Beats the hell out of frequent jetting changes doesn't it?
Bluecuda340
Well-Known Member
Absolutely, coil near plug and efi takes so much work out of tuning changes its unreal. There has been many a test and tune where I made passes, reviewed data logs, and made changes, then made more runs without ever taking my belts off.
RockinRobin
Well-Known Member
Here is what it is doing now that I have other mechanical issues fixed and EFI tuned good:
This was Saturday 10-7-23 in Ardmore, OK
Nice pass
rmchrgr
Skate And Destroy
In general, what kind of changes do you usually make? I’m familiar with the Holley software but not the MS stuff. Do you make changes based on weather or the last time slip.
Bluecuda340
Well-Known Member
I usually make small adjustments to the VE Table. The Megasquirt data log viewer has a "VE Analyze" feature that will take the data in parameters you set and adjust it to help it reach your target AFR. I use this a lot, its quick and easy. Sometimes it needs a little smoothing out but usually its suggestions are very good. Then when the car is running I allow it to make a certain % of change to help reach the target if for some reason the tune isn't spot on.
I seldom to any manual tuning, if I am working directly on the VE table it is for smoothing adjustments or a flat spot. The tools the log program has can really nail things down. It can also adjust the table live with the laptop plugged in but I only use that if I make some big change. Its a quick way to point things in the right direction.
I like megasquirt, its dollar per feature is amazing. However I think Holley has huge advantages in the software and self learning department. I thought I had a problem that would require replacing my ECU. I priced a dominator out which is what I would need to match my features. Just the ECU with no wiring or anything cost way way more than my entire electronics package.
RockinRobin
Well-Known Member
When I got all my issues fixed I took it to the track and tested to find what WOT AFR it liked. I would change target AFR and just let the efi adjust the fuel table. 3 or 4 passes at each setting to find out it went fastest at a WOT AFR of 12.8. Since it was 100 degrees outside, I richened it to 12.7. In the heat it was doing great. When Temps started to drop in October I changed the amount of fuel it could add from 5% to 10% and log files show that when temps were in the 60's it was adding 8 or 9% at times. But my E.T.s were staying the same. Just wish I had known to do it this way 2 years ago.
RockinRobin
Well-Known Member
I forgot to mention that a tuner told me this type of motor usually likes around 12.9, so I started way rich, 12.5, and leaned it by .1 every step until it wouldn't run any faster. Also checked plugs in between passes.
Thank you for all the good information. I put a alcohol carburetor on the AMX and still tuning on it. Made 6 passes with it so far 60 ft and 330 fr were within a thousandth of each other. So if it stays that way I probably won't switch. But I do have a complete Dominator EFI that I can put on it.
Bluecuda340
Well-Known Member
Just a follow up on this. I ran a local Mopar race here in Tulsa on this past Saturday. I made 6 time trials trying to get my head right with the tree(without much luck).
1/8th
6.623
6.617
6.633
6.627
6.623
6.615
1/4
10.500
10.486
10.528
10.494
10.502
10.476
We started off with really good air of about 200ft and ended the time runs at about 950ft. I had a little trouble pushing in the beams so a lot of the variance was likely roll out. I didn't touch the tune in the car all day.
This is a 3550lb A body barracuda with a 418" motor on 91 octane.
1/8th
6.623
6.617
6.633
6.627
6.623
6.615
1/4
10.500
10.486
10.528
10.494
10.502
10.476
We started off with really good air of about 200ft and ended the time runs at about 950ft. I had a little trouble pushing in the beams so a lot of the variance was likely roll out. I didn't touch the tune in the car all day.
This is a 3550lb A body barracuda with a 418" motor on 91 octane.
67Dart273
Well-Known Member
Megasquirt has gone up in price a LOT. Plus, unless they have changed, you have to add 200 bucks or more to your "savings" to interface an O2 setup. Holley has that integrated. The ONE thing I will defend for Megasquirt is that you can do a lot of custom configuration, and if it breaks you have a shot at repairing it. The Holley ECUs are potted in what resembles JB Weld
Bluecuda340
Well-Known Member
To replicate my setup it would be $1025. ECU kit, MS3X expansion card, MS3 Harness, MS3X Harness, 14point7 can bus 02 sensor controller.
RockinRobin
Well-Known Member
I have the Holley dominator 4500, which is probably the most expensive of the Holley units, but everything I needed was in the kit. As I recall it even came with the O2 sensor.
The 4150 style units are probably cheaper, but Holley is expensive.
In their defense, my unit was starting to have issues with the secondaries not closing fully. They replaced both throttle shafts and butterflies and tested it for holding vacuum and closing properly. The unit was 3 years old, but they fixed it for free and sent it back to me on their dime.
The 4150 style units are probably cheaper, but Holley is expensive.
In their defense, my unit was starting to have issues with the secondaries not closing fully. They replaced both throttle shafts and butterflies and tested it for holding vacuum and closing properly. The unit was 3 years old, but they fixed it for free and sent it back to me on their dime.
RockinRobin
Well-Known Member
Thanks! As you can see, he was on a breakout. I would have won if I hadn't turned it red by -.002
Congrats that's a really good string of passes. I was really thinking about putting a Holley Dominator EFI on the AMX since I already have it. But we finally got the Pro Systems alcohol carb dialed in. We made six passes. all 6 passes the sixty foot was 1.28, the 330 foot time on all six was 3.74 and the 8th mile on each one was between 5.871 and 5.859. I'm very please with the alcohol carb. So I think that I'll put the Dominator EFI on my 1968 Valiant street car.
rmchrgr
Skate And Destroy
That's awesome. Consistency is the name of the game and not having to do anything (at least engine-wise) to get the car to be consistent is huge. I suppose not having to mess with the tune might also result in fewer chassis changes as well. How would you predict your dial in that situation?
Out of curiosity, did you notice other racers making changes when the D.A. changed?
Bluecuda340
Well-Known Member
I dialed 6.62 first round. I ended up with a 6.65 dial later on because the track was going away. It dead hooked in the final and I broke out by .002 after killing 3mph.
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