EFI Tunning Tips Here

[robains]

slaughtr,

I have the exact same issue also - seems to drop to lower cam even with higher rpm and just looks at TPS (guessing here). Is the map currently setup to be like this so the car is driveable on the street?

Couple of question I have:

1. How many complete maps can the EFI store?
2. If more than one, is it possible to have a Street map and a Track map?
3. Low rpm run-on during shifts - can this be adjusted?

When I say low rpm run-on -- how I define this is shifting at 4K rpm under street driving and the rpm will continue to go up briefly even after I've removed my foot from the throttle and then encage the clutch. It's as if the EFI is seeing throttle input when there is none or some delay in recognizing the input so by the time I engage the clutch the EFI is still thinking I have throttle so the end result is what I call "run-on" during shifts. It's like a "power shift" (never lift from the throttle) during clutch/gear change.

Hopefully I'm being clear? Can be hard to describe.

Rob.

[turbophil]

Slaught and Rob- I hear ya about cam changes. You want them predictable and smooth... And you an get there with a little tweaking....

Use those cam settings in the map I sent you. That will cure much of your issues...

Here's the best situation. Load a track map and a street map... Obviously you don't have to do this, but since you can- why not since we know what works best on the track isn't always the best on the street. You can switch between maps just by flipping a switch in the cabin, so there's no reason to compromise with a single map

On the track map, you basically make your cams switch at the best RPM for power (probably in the low 5,000 range), and never let them switch back down from a TPS drop. So, set your TPS trigger for something very low like 15 degrees (remember idle is between 10 and 12). That way you won't have your cams switch back down unless you drop below the rpm limit or come completely off the throttle..... You might recal that's similar to how the stock ECU worked. It didn't have a load based cam change. It just switched even if you feather-footed past 6,200 rpms...

The above is not great for the street if you lower your cam switch RPMs because your cam will be switching on light accell through town everytime you rev past your engagement rpm, which is now low enough (in the low 5,000s) that you'll be switching cams about the time you want to shift when you don't want to be around town. In our cars even light accell has you in the 5,000 rpm range--- for me anyway...

So the ideal street map will switch the cams with some load on the engine. I like the switch to take place around 43 degrees TPS. It has been a good compromise for street and aggressive driving. That allows a nice load based switch when I'm feeling froggy, but when I crusie to dinner with my wife, she doesn't have that loud high lift switch over despite shifting at 5,500 rpms or so...

For the track, flip the "map flipper switch" that came with the EFI kit and switch to your track map that will keep those cams on strong in high lift even as you modulate around the sweeper.

Slaughter (and possibly Rob), As far as the abruptness of the change, that's not the EFI, it's the tune. As I recall, your map has a boatload of fuel and hardly an ounce of timing. Those two put together, will cause your car to basically burp on all the gas (which isn't burning) and lack of timing it's getting (or not getting) during the change, and if I had to guess that burp is the abruptness you're feeling at the change. The physical cam switch is instant for both the stock and EFI ecu's, but the feeling you get during the switch is inevetably related to fuel and timing...

Hope that helps a bit...

Best,

Phil

[slaughtr]

Originally Posted by turbophil

Slaught and Rob- I hear ya about cam changes. You want them predictable and smooth... And you an get there with a little tweaking....

Use those cam settings in the map I sent you. That will cure much of your issues...

Here's the best situation. Load a track map and a street map... Obviously you don't have to do this, but since you can- why not since we know what works best on the track isn't always the best on the street. You can switch between maps just by flipping a switch in the cabin, so there's no reason to compromise with a single map

On the track map, you basically make your cams switch at the best RPM for power (probably in the low 5,000 range), and never let them switch back down from a TPS drop. So, set your TPS trigger for something very low like 15 degrees (remember idle is between 10 and 12). That way you won't have your cams switch back down unless you drop below the rpm limit or come completely off the throttle..... You might recal that's similar to how the stock ECU worked. It didn't have a load based cam change. It just switched even if you feather-footed past 6,200 rpms...

The above is not great for the street if you lower your cam switch RPMs because your cam will be switching on light accell through town everytime you rev past your engagement rpm, which is now low enough (in the low 5,000s) that you'll be switching cams about the time you want to shift when you don't want to be around town. In our cars even light accell has you in the 5,000 rpm range--- for me anyway...

So the ideal street map will switch the cams with some load on the engine. I like the switch to take place around 43 degrees TPS. It has been a good compromise for street and aggressive driving. That allows a nice load based switch when I'm feeling froggy, but when I crusie to dinner with my wife, she doesn't have that loud high lift switch over despite shifting at 5,500 rpms or so...

For the track, flip the "map flipper switch" that came with the EFI kit and switch to your track map that will keep those cams on strong in high lift even as you modulate around the sweeper.

Slaughter (and possibly Rob), As far as the abruptness of the change, that's not the EFI, it's the tune. As I recall, your map has a boatload of fuel and hardly an ounce of timing. Those two put together, will cause your car to basically burp on all the gas (which isn't burning) and lack of timing it's getting (or not getting) during the change, and if I had to guess that burp is the abruptness you're feeling at the change. The physical cam switch is instant for both the stock and EFI ecu's, but the feeling you get during the switch is inevetably related to fuel and timing...

Hope that helps a bit...

Best,

Phil

That helps a ton Phil and makes a lot of sense. Thanks.

[robains]

Yes that helps a lot Phil -- certainly allows me to clear up how I describe the issue.

I'll ask Casey to setup a dual map switch. Sounds like it might need to be on the dyno for this?

It is good to know that these EFI systems can be tuned to provide both street and track drivability.

[xtn]

Originally Posted by slaughtr

Is it possible to stop the ECU from reverting to the lower cam at light throttle inputs? Why would it be like that in the first place, fuel economy?

Anyone?

I don't know anything about tuning, but from TPhil's description it sounds like you could set the TPS requirement to 0%, and that would make the cam switch purely RPM dependent regardless of throttle position.

Does that sound right TPhil?

edit: read further along the thread and see that up to the 12%-15% range would have pretty much the same result.

xtn

[slaughtr]

Originally Posted by xtn

I don't know anything about tuning, but from TPhil's description it sounds like you could set the TPS requirement to 0%, and that would make the cam switch purely RPM dependent regardless of throttle position.

Does that sound right TPhil?

xtn

Sounds right. I personally don't mind the motor switching to the more aggressive cam on the street and staying there, so I think I'll just set the TPS low and use the same map for both. If I make another map, it will be for higher octane gas. Any recommendations on where to start for that, i.e 100 octane, Phil or Kris? Every millisecond counts in autocross.

[Kris from DRS]

Originally Posted by slaughtr

One issue I have, particularly at the track, is that the second cam change-over can be very abrupt. Phil, you and I have talked about this and I will see how it does after the raised second cam switchover, but...

It also seems to me that, even above the cam switchover point, the engine management will revert to the lower cam if throttle input is low. For instance, going around a long sweeper, even if I'm at 6,000 RPM or so, if I'm only modulating the rear with the throttle with light throttle inputs, when I come out of the turn and put the hammer down, I feel an abrupt cam change. It's very disconcerting.

Is it possible to stop the ECU from reverting to the lower cam at light throttle inputs? Why would it be like that in the first place, fuel economy?

Anyone?

Ronnie, what you are describing is the need for a lower TPS limit, not raised, for the "Exhaust Cam" TPS limit. The original base maps had values ranging from 40 to 45 deg. The idea was to gain fuel economy, as you mentioned, by only using the second cam when it is really needed. For track cars we find a lower values to be better overall. A car I set up recently had it set as low as 20 deg and it worked very well in the conditions that require careful modulation. Try the map I sent you recently and let us know if that is an improvement.

Kris

[Kris from DRS]

Originally Posted by xtn

I don't know anything about tuning, but from TPhil's description it sounds like you could set the TPS requirement to 0%, and that would make the cam switch purely RPM dependent regardless of throttle position.

Does that sound right TPhil?

edit: read further along the thread and see that up to the 12%-15% range would have pretty much the same result.

xtn

The throttle is measured in degrees. It can be set to a value as low as closed throttle and it will be of no detriment to anything other than MPG if you are cruising steady-state at higher revs.

To include more insight on this. Part of the reason why there is a TPS limit in the first place is b/c in the earlier days of R&D all of the cars were turbo charged and we found a low rpm switch-over to be beneficial to create exhuast energy and spool the turbo quicker in the region of 4,200 to 4,800 rpm. The results were huge torque gains in the midrange. The combo of this tuning and boost curve tuning per gear could accomodate a variety of powerbands. It's just a matter of making adjustments at your local track or autocross. So the idea was to allow for a load input if you did not want the second cam to come in premature. This concept does not apply as much to the SC cars, or cars that are driven on the track only.

With so many possibilities it is difficult to have a perfect map ready for ALL cars right out of the box. However, we do have a huge inventory of maps lately as more and more people are using these systems.

Forums like this will help make it easier for everyone to help each other.

Kris

[robains]

Kris,

There is no BOV in these SC cars so I would definitely think a SC map would need to be significantly different than a Turbo map during off throttle? (question, not a statement as I've seen SC cars with a BOV).

I'm not concerned about fuel economy, driveability on the street and track is most important -- but dual map seems to be the answer here. Agree, forums do help and it's hard for any tuner to know exactly how the car responds in all situations, only those that drive it regularly can describe the situation.

I appreciate folks like Kris and Phil for their information, because it ultimately helps me express the situation better to find the tunable balance to fit my car and my driving style. Keep the info flowing!

[slaughtr]

Originally Posted by Kris from DRS

Ronnie, what you are describing is the need for a lower TPS limit, not raised, for the "Exhaust Cam" TPS limit. The original base maps had values ranging from 40 to 45 deg. The idea was to gain fuel economy, as you mentioned, by only using the second cam when it is really needed. For track cars we find a lower values to be better overall. A car I set up recently had it set as low as 20 deg and it worked very well in the conditions that require careful modulation. Try the map I sent you recently and let us know if that is an improvement.

Kris

Thanks Kris!

[Kris from DRS]

Everyone, I've been working on a fairly basic support article for the editor software that comes with every DRS EFI system. The reading is intended to not be too technical, just a brief synopsis with some tips here and there. There is still a lot left to complete it, and even then it will be updated as questions and comments arise.

Please go to DRS Engine Control Support

[robains]

Thanks Kris!!

Note: Drive-by-wire cars will not use any of the functions in the Idle Speed section. These applications will be explained later in the DC Motor section.

Can't wait for more information in your DC Motor section. Really appreciate this. - Rob.

[turbophil]

More on Saving... I added he below to first post instructions...

*Important* All maps MUST be saved in the “maps” folder found within the Power to Win software folder or the maps will not function properly. In other-words, when we all are trading maps back and forth, be sure to save the file directly to “maps” directory that was created when you first installed the EFI software (known as “Power to Win”).

I recommend that you back up good working maps in a directory outside of your “maps” directory just incase you do something really silly in your tuning attempts

Best,

Phil

PS- Kris can do the proper technical west coast style instructions. I'll stick with writing the watered-down Kansas variant of the instructions

[Kris from DRS]

Phil,

I think your tips are great. The simple little things that I overlook (i.e. like saving the maps in the right folder) are just the types of little nuances that will help people.

I'll be at Boneville for most of next week, but I intend to also keep working on the article (as well as others) soon.

thanks,
Kris

[robains]

Hi Kris,

Unfortunately my car is still stalling regularly -- but driveability on the street is better (except the stalls).

So I dug into the car today, couple of factors I found that may influence the tune:

1. Spark plug #1 was less than finger tight and oil was up around the crush washer. It had a very different burn signature from #2,#3, and #4. Based on the burn signature cylinder #2, #3, and #4 seem very Lean.

2. My AC is always ON, even with button off and fans off, I still feel cold air coming out of the vents -- have not successfully located the switch/wire or how I could disconnect the AC at the compressor? Any pics/hints are welcome.

I will contact Casey on Monday. But your input is most welcome.
I don't know if these items would have affected the tune, I assume they would.

Rob.

[turbophil]

Rob,

The AC doesn't interact with the EFI, so it sounds like an issue outside of the tune.

Need to get that plug screwed in tight before we can diagnose a bad idle. The idle isn't that tough to get ironed out. It's actually quite easy. You/Casey just need to take the time to tune the idle...

Best,

Phil

[2-Y-CHROMOSOMES]

Originally Posted by turbophil

Rob,

The AC doesn't interact with the EFI, so it sounds like an issue outside of the tune.

Need to get that plug screwed in tight before we can diagnose a bad idle. The idle isn't that tough to get ironed out. It's actually quite easy. You/Casey just need to take the time to tune the idle...

Best,

Phil

I am having the same idling problem while my AC is on. Just need to drop by and have Casey tweak it. May give it a shot myself.

[turbophil]

Hi Mark,

If you're having a hard time finding the time to visit Casey, I'm quite certain you can do this yourself. I'd be happy to walk you through it over the phone, if you hit a wall...

You need to be have access to the idle stop screw on the throttle body and otherwise it's all tuning----and the tuning isn't hard at all. I addressed that part in my little write up... Remember you can't really screw this up too bad. It's just the idle. No blown engine will result from tinkering around with these parameters...

Best,

Phil

[Dave]

Mark,

Check your email for the P2W zip...

--dave

[2-Y-CHROMOSOMES]

Originally Posted by turbophil

Hi Mark,

If you're having a hard time finding the time to visit Casey, I'm quite certain you can do this yourself. I'd be happy to walk you through it over the phone, if you hit a wall...

You need to be have access to the idle stop screw on the throttle body and otherwise it's all tuning----and the tuning isn't hard at all. I addressed that part in my little write up... Remember you can't really screw this up too bad. It's just the idle. No blown engine will result from tinkering around with these parameters...

Best,

Phil

Thanks Phil and Dave!