Tune, AFRs, options

[aeronaut]

Kinda 2 questions.

1st Question:
After mods and tune (currently I'm running an RKTune), I'm seeing 14.4 AFR under load at mid-rpm. Drops to 13.5 AFR above 6300 rpm.
Seems a bit lean? Dangerously lean?
(And, the idle hunts, but I've run every test known to man to find a vacuum leak, and nothing found).


2nd Question:
Jordan is working with me to fine tune (I think), but honestly, it takes 4-5 days to get an answer, then my response to ask a better question, repeat. I need a 5 min phone conversation with him, but that seems impossible with these remote tuner guys.
I'm considering:

- Custom dyno tune, call it $600.
- Megasquirt Plug and Play, call it $1200.

I know the MS P&P is a lot of up front work to get there, but at least I'd get there AND have options later if needed.

Thoughts?

[ScotcH]

Yes, far too lean. With 98 Sunoco, we run around 13.2 .... for pump gas, you really want to keep it under 13. 12.9 seems to make the most power. Mid rpm (where peak torque is) is where engines blow up, so you want to make sure that part is perfect AFR.

Assuming you won't be adding more parts, a custom tune on the dyno is fine ... it should be good for years without thinking about it.

If you're thinking standalone, think about the Link G4+ PnP for e36. It's a bit more money, but it's a FAR better solution than MS. Many pro race cars use Link, and it rivals Motec for features and tunability, and expandability. It can also run any engine ... we use ours with s54 in the e36, just needed the vanos wires added to the harness, so it gives you future options without changing the whole wiring.

Edit: If the AFR is stable, just a bit lean overall, an adjustable Fuel pressure regulator could easily solve that ... just a bit more fuel pressure.

[aeronaut]

Yes, far too lean. With 98 Sunoco, we run around 13.2 .... for pump gas, you really want to keep it under 13. 12.9 seems to make the most power. Mid rpm (where peak torque is) is where engines blow up, so you want to make sure that part is perfect AFR.

Assuming you won't be adding more parts, a custom tune on the dyno is fine ... it should be good for years without thinking about it.

If you're thinking standalone, think about the Link G4+ PnP for e36. It's a bit more money, but it's a FAR better solution than MS. Many pro race cars use Link, and it rivals Motec for features and tunability, and expandability. It can also run any engine ... we use ours with s54 in the e36, just needed the vanos wires added to the harness, so it gives you future options without changing the whole wiring.

Edit: If the AFR is stable, just a bit lean overall, an adjustable Fuel pressure regulator could easily solve that ... just a bit more fuel pressure.

Thanks for the info, good stuff.
Hmmmm.....push a touch more fuel pressure.
Got a recommendation for an adjustable regulator? I never cared for that OEM thing behind the intake anyway. lol.

[aeronaut]

Screw it...taking it to Frank at Tuning Tech FS. I had tried before but never successful in getting a response.
This time, called, answered, scheduled for Thursday.
Done.

[jonb94118]

Yes, far too lean. With 98 Sunoco, we run around 13.2 .... for pump gas, you really want to keep it under 13. 12.9 seems to make the most power. Mid rpm (where peak torque is) is where engines blow up, so you want to make sure that part is perfect AFR.

Assuming you won't be adding more parts, a custom tune on the dyno is fine ... it should be good for years without thinking about it.

If you're thinking standalone, think about the Link G4+ PnP for e36. It's a bit more money, but it's a FAR better solution than MS. Many pro race cars use Link, and it rivals Motec for features and tunability, and expandability. It can also run any engine ... we use ours with s54 in the e36, just needed the vanos wires added to the harness, so it gives you future options without changing the whole wiring.

Edit: If the AFR is stable, just a bit lean overall, an adjustable Fuel pressure regulator could easily solve that ... just a bit more fuel pressure.

+++on the Link G4+ and running way too lean. I ran the Link PNP on my s52 and loved the interface and ease of adjustments if needed. Very easy to log, look at AFR's and adjust Fuel map if needed. Now running an s54, so curious Scotch how you were able to adapt the Link G4+ to run it - any details would be much appreciated. For example - are you using the s54 harness or e36 harness with it?

[Def]

I'll add that I wouldn't pay a huge premium for a PnP standalone.

Reasons:

1. Making a jumper harness to utilize some/most of what's in your stock harness isn't that hard or expensive.

2. You're going to add a TON of extra stuff to make a standalone work well. IMO, you want at a minimum a standalone that can take into account fuel pressure, and provide safeguards based on oil pressure/oil temp, and I'd think about just going speed density to remove the MAF. That's about $120-350 of sensors right there depending on options and how fancy you get. But make no mistake, these will make it easier to troubleshoot what's going on, AND you can save your engine if something happens and the ECU is getting enough data to respond.


The Link isn't a bad unit, but I honestly think they're kinda pricey once you start getting to a reasonable level of mid-range options IMO. I have to agree with everybody else that I'm not really impressed with Megasquirt, and the PNP still seems perpetually 4+ months out right? Honestly, I would stay away from the MS ecosystem if buying new (variety of reasons, but the main one is I think their hardware quality is subpar in general to hit a lower price point).

I've used 2 AEM Infinity 506's, and I keep coming back to them. Pretty easy to setup, and very flexible. I'd like to try a Link, but I was a bit freaked out once I priced one out to be comparable to the Infinity 506 and it was about $500 more. Nope.


I do suggest you get off the ROM tune train - it's just not worth it as you are finding out. There's something small that you want changed, and you don't have a ton of data to go off, so it's hard to tell if it's a hardware problem (i.e. fuel pressure dropping at load, sensor reading off etc.) or a tune issue. With a standalone you have a ton of data, and it's easy to dial it in on what you want. It takes some time, but you'll know what your engine is doing, and you can change anything you want plus make it ultimately safer to operate on track.

[ScotcH]

+++on the Link G4+ and running way too lean. I ran the Link PNP on my s52 and loved the interface and ease of adjustments if needed. Very easy to log, look at AFR's and adjust Fuel map if needed. Now running an s54, so curious Scotch how you were able to adapt the Link G4+ to run it - any details would be much appreciated. For example - are you using the s54 harness or e36 harness with it?

I used the e36 harness, then added a small sub-harness for the dual vanos control, and some some other stuff that we run (air temp, FP, etc). The ne36 harness and sensors are all nearly 100% compatible with the s54 stuff. I wasn't much work.

Def: The PnP from Link is not much of a premium ... I think like 200$ over the regular G4+. You'll easily spend that on terminals and shit to build a harness. And you can very easliy add the additional sensors (100% agree that you want FP, oil P, etc going to the Link for logging and tune). Also, 100% agree to remove the MAF. All our tunes just use RPM and TP, and temp compensation, and they are rock solid.

[jonb94118]

I used the e36 harness, then added a small sub-harness for the dual vanos control, and some some other stuff that we run (air temp, FP, etc). The ne36 harness and sensors are all nearly 100% compatible with the s54 stuff. I wasn't much work.

Def: The PnP from Link is not much of a premium ... I think like 200$ over the regular G4+. You'll easily spend that on terminals and shit to build a harness. And you can very easliy add the additional sensors (100% agree that you want FP, oil P, etc going to the Link for logging and tune). Also, 100% agree to remove the MAF. All our tunes just use RPM and TP, and temp compensation, and they are rock solid.

Thanks Scotch as always. Of course I'm now kicking myself for giving away my old harness. What about throttle pedal? Were you able to keep Drive By Wire somehow or did you convert?

Agreed on the simplicity and price point of the Link, but who knows. Maybe Def has some use cases I'm not taking into consideration. All I know is that for my racecar, the PNP made it very simple, all in the Link was @1k$ USD, and the Support of Link as a company was great. Other racers I know who are using the A...M options cannot say the same and continue to have random issues that neither they nor their tuners have been able to figure out and the manufacturer isn't providing support.

[ScotcH]

Thanks Scotch as always. Of course I'm now kicking myself for giving away my old harness. What about throttle pedal? Were you able to keep Drive By Wire somehow or did you convert?

Agreed on the simplicity and price point of the Link, but who knows. Maybe Def has some use cases I'm not taking into consideration. All I know is that for my racecar, the PNP made it very simple, all in the Link was @1k$ USD, and the Support of Link as a company was great. Other racers I know who are using the A...M options cannot say the same and continue to have random issues that neither they nor their tuners have been able to figure out and the manufacturer isn't providing support.

We do not run DBW ... the VAC cable conversion it perfect But no reason it would not work ... Link can control it just fine apparently, but never tried it myself.

[jonb94118]

For the OP - what are you using to measure your AFR's? I ask as I have a wideband sensor (which I'm guessing you use and log perhaps) and last season had an issue where its readings were not accurate as the Lambda sensor was hosed, apparently. I dynoed at the track one day and we saw that I was running very lean, whereas wideband and logs were showing it to be pretty normal if not a bit rich. Changed the sensor and it was back to normal and matched pretty well to the exhaust sniffer readings. You might just try checking sensor to make sure it's accurate - or bring an extra one along if you are going to do a Dyno tune in case what your tuner sees at the exhaust differs greatly from your wideband. I would also ask RKTunes where he is usually targeting AFR's as 13.5 at WOT might be ok for a street car that doesn't see extended time at WOT. His tunes are likely targeted for street cars

[aeronaut]

For the OP - what are you using to measure your AFR's? I ask as I have a wideband sensor (which I'm guessing you use and log perhaps) and last season had an issue where its readings were not accurate as the Lambda sensor was hosed, apparently. I dynoed at the track one day and we saw that I was running very lean, whereas wideband and logs were showing it to be pretty normal if not a bit rich. Changed the sensor and it was back to normal and matched pretty well to the exhaust sniffer readings. You might just try checking sensor to make sure it's accurate - or bring an extra one along if you are going to do a Dyno tune in case what your tuner sees at the exhaust differs greatly from your wideband. I would also ask RKTunes where he is usually targeting AFR's as 13.5 at WOT might be ok for a street car that doesn't see extended time at WOT. His tunes are likely targeted for street cars

A new bosch wide band, innovate LM-2 lambda controller, and MXm logger. Yea, there's the chance I'm simply reading lean. I'll find out Thursday.
I did tell RKTunes this was a track-only car. But good point, I'll remind him. That said, I can't wait 1-2 weeks between emails to get this fixed. Hence....dyno tune day!!

A stand alone might be in my future as a winter project. Knowing then what I know now, yea, would have gone there from the get go.

[Def]

I used the e36 harness, then added a small sub-harness for the dual vanos control, and some some other stuff that we run (air temp, FP, etc). The ne36 harness and sensors are all nearly 100% compatible with the s54 stuff. I wasn't much work.

Def: The PnP from Link is not much of a premium ... I think like 200$ over the regular G4+. You'll easily spend that on terminals and shit to build a harness. And you can very easliy add the additional sensors (100% agree that you want FP, oil P, etc going to the Link for logging and tune). Also, 100% agree to remove the MAF. All our tunes just use RPM and TP, and temp compensation, and they are rock solid.

I’m not saying PnP is bad, it’s just a bit pricey when you still need to build an auxiliary harness. I made a jumper harness for my car for about $120ish, but again, That also includes all the “auxiliary stuff” that costs quite a bit to add onto a PnP unit in connectors, pins etc. again, I added about 25-28 pins beyond my factory harness for basic sensors and a UEGO sensor. That’s a decent bit of connector expense depending on what the PnP unit would allow you to toss in extra inputs.

[ScotcH]

Totally agree, if you can go with the regular unit, and build a proper harness, it's the way to go. But for e36, the PnP is very nice to be able to just plug in the OE harness, and drive. Then add other sensors as needed ... it's a great option for many use cases.

[aeronaut]

Posted this in my build thread, but meant to post it here. Copy/paste:

Got my local dyno tune done at Tuning Tech FS (Frank), Crofton MD.
I'll just say this, I'll never do another off-the-shelf tune.

The list of things in the off-the-shelf tune 'not the way I expected' is long.
Target idle speed, wrong. (I guess there's idle rpm, and then a target the engine shoots for on decel, and the second one was wrong.)
Speed governor, wrong.
Ign Timing "very aggressive for 91 Oct, looks like 93 Oct ", wrong.
RPM redline fuel cut-off ramp started at 7050, hard redline at 7200. Not quite wrong, but misleading.

Got another 15 HP in mid-range, and 12HP peak, to boot.

[olemiss540]

Wow. Amazing results. This was in comparison to which tune again? I know you went through a couple....

[aeronaut]

The base run from TTFS was with the RKTunes chip. So TTFS improved on that.

First tune/chip was 22RPD. Out of the box, idle was set wrong (which he admitted), so I was like, what else did I get? And AFRs looked high. In the end, he offered to adjust his tune if I sent him dyno numbers.
Second was RKTunes. Car ran good, but I had some questions about idle and AFRs, and it's been over a week since I've heard from him. Last I heard from RK was him asking if I had a vacuum leak.