EFI Tunning Tips Here

[turbophil]

Ronnie,

That's GREAT news and thanks for the kind words. I'm really happy that you two got it going so well.

I'm was pretty smitten with my EFI setup today as well (another day at the dyno)...

Have a great evening.

Best,

Phil

[Kris from DRS]

Originally Posted by slaughtr

An update on my car...

After some track related car repairs I finally went out and finished (for now) the tune on my car. With a base map from Kris and some excellent advice from Phil, my mechanic and I hooked it up and went at it. I installed a wideband O2 sensor from Innovate as well as A/F ratio and boost gauges. The gauges went into the aluminum center stack gauge pod from Blackwatch racing which I have to say looks excellent.

My base tune was pretty good, but had some areas with too much fuel, for safety sake. The whole thing only took about an hour and a half, making small adjustments in the air fuel ratio at idle, cruise and full throttle. We added a bit of timing too.

The car runs better than it ever has. I'm really happy. We may have taken a bit too much fuel out at cold start-up, but we only got one shot at that so it will have to wait. Other than that, the idle is rock steady, cruises without any hiccups and is scary fast.

Thanks Kris and Phil!

Ronnie

Very glad to see you guys are happy with the results. Good job!

Kris

[slaughtr]

Originally Posted by Kris from DRS

Ronnie

Very glad to see you guys are happy with the results. Good job!

Kris

Thanks again, Kris.

[slaughtr]

One more question, on abrupt throttle tip in, I'm immediately going lean before the accelerator pump has a chance to kick in, just for a second. I know there are parameters to control the accelerator pump, but so far what we've done doesn't seem to do anything. Any tips?

[Kris from DRS]

Originally Posted by slaughtr

One more question, on abrupt throttle tip in, I'm immediately going lean before the accelerator pump has a chance to kick in, just for a second. I know there are parameters to control the accelerator pump, but so far what we've done doesn't seem to do anything. Any tips?

Please email me your latest map so I can review the accel parameters.
thanks,
Kris

[slaughtr]

Originally Posted by Kris from DRS

Please email me your latest map so I can review the accel parameters.
thanks,
Kris

Will do. Thanks Kris.

[2-Y-CHROMOSOMES]

Originally Posted by Kris from DRS

Please email me your latest map so I can review the accel parameters.
thanks,
Kris

Kris, did you get my PM on pulley size? Do you know what size pulley did you put on Kaz's car to net 10 psi?
hijack done

[Kris from DRS]

Originally Posted by 2-Y-CHROMOSOMES

Kris, did you get my PM on pulley size? Do you know what size pulley did you put on Kaz's car to net 10 psi?
hijack done

Sorry for the delayed respons. I will measure the pulley tomorrow AM.

Kris

[2-Y-CHROMOSOMES]

Originally Posted by Kris from DRS

Sorry for the delayed respons. I will measure the pulley tomorrow AM.

Kris

Thanks Kris !

[elise/europa]

Hi Phil and other,

I saw that the program have an option for the knock sensor. The ECU pin out did not indicates any thing about that. That's mean what? Is it possible to use a knock sensor? Or just not possible, and the software is made for more thing than what the specific ECU supplied by DRS is design for?

I asked the question few times at Kris via e-mail, but nice reply from Kris are not that easy.

[Kris from DRS]

Originally Posted by elise/europa

Hi Phil and other,

I saw that the program have an option for the knock sensor. The ECU pin out did not indicates any thing about that. That's mean what? Is it possible to use a knock sensor? Or just not possible, and the software is made for more thing than what the specific ECU supplied by DRS is design for?

I asked the question few times at Kris via e-mail, but nice reply from Kris are not that easy.

I thought we already discussed this. I apologize if I forgot to mention before.
Knock Control is in the software and is an option. The new version of the ECU will have it installed by default for those who choose to use it. I must warn though that knock control is not a 100% safety device. If it was no engine would ever ping (spark knock). There is more info here that you may find interesting, DRS Engine Control Support

Kris

[elise/europa]

Kris,

If I understand right, it is not possible to have it with my actual ECU???

Is it possible to update my ECU in the future?

I understand that the knock sensor is not 100% full proof. I did not spend time yet to find where I can program custom input output, is it because it is not available by the software?

Thanks

[Kris from DRS]

Originally Posted by elise/europa

Kris,

If I understand right, it is not possible to have it with my actual ECU???

Is it possible to update my ECU in the future?

I understand that the knock sensor is not 100% full proof. I did not spend time yet to find where I can program custom input output, is it because it is not available by the software?

Thanks

The way the knock control currently works for ECUs already out in circulation is an unused pin can be assigned for this function. You will need to use an external amplifier, i.e. JLS or other brand that has a knock output. Then it is easily enabled in the current software.

The new generation of ECU will have the knock built into the box. When this product was originally developed we opted to not include knock b/c in past experiences knock systems can be temperamental if not set up properly. I.e. noise from external devices, like a rattle from a loose clutch spline can trigger a false knock. Since there has been so much interest in having this as an option we are going to put it in. If proper time is taken to set it up and it is used without leaning on it too much it can work fine overall.

We can currently offer the EFI X5 (aka 4.0 ECU) with dual-knock, dual-wideband, staged-seq injection, pit limiter, internal EGT, and many other features if someone needed these advanced features. These are the units we currently use for BMW dual-VANOS engines and other applications. We can set this up for a Lotus if someone were interested.

Kris

[robains]

I prefer to use EGT for my tool to determine detonation. Here is a good link to how EGT can be used and what signature detonation produces with EGT. I used EGT a lot on my 2 stroke Kart but the concept doesn't change for 4 stroke engines.

Knock sensors aren't reliable with perhaps the exception of those used in the Nissan GT-R (at lot of R&D was put into them) -- don't see them used in racing much at all, it's primarily for street use to help with "Bad gas" when one thinks they're pumping in 91 octane (and paying for it) but due to a mess up at the station they're getting a 87 or some less mix (this does happen more frequently than it should and the fines if "caught" are relatively low -- not suggesting stations do this on purpose but...).

But from manufacturers stand point, a false positive is fine by them cause it errors on the side of caution (and hence saves warranty claims). It might be good to monitor the knock sensor, but it might not be so good to actually allow the ECU to pull timing based on it.

[robains]

DBW EFI users, would like to get your input/maps if possible -- specifically interested in the DC Motor and Accel/Decel sections.

I've got a low rpm "run-on" (<5K) that I'm trying to tune out. What I mean by "run-on" is that if I accel to 4K rpm, lift throttle and then press in clutch the rpm's will continue to increase (about 1K or so). I've read up on PID tuning and also looked at the Accel section and have a few questions:

DC Motor - Constants
Base Duty Cycle - currently at 50% - not sure how this factors in there is no table?
Proportional Gain - 100
Integral Gain - 40
Integral Timer - 8
Derivative Gain - 20
Integral Band - 10 (degrees)

Final output is defined as P+I+D so in case above 160

Integral timer and Integral band aren't really explained much. What I can gather from the documentation is that all of these values are used to basically smooth the DBW input/output and increase it's accuracy -- does that sound right?

Accel / Decel - Constants
Accel Decay - currently 8 bits, docs suggest 2-5 bit, reduce value perhaps?

So, these are the elements I'm looking to adjust to try and solve the low rpm run-on issue. I start with Accel Decay since docs suggest 2-5 bit and I'm at 8 bit.

Any hints/suggestions are most welcome.

Cheers, Rob.

[robains]

Quick update to my DBW tuning -- changed Integral Timer from 8 to 2 and this has greatly reduce my rpm "run-on" issue. A value of zero actually worked the best for run-on, but it had a side affect of creating throttle flap oscillation during moderate throttle input at <4K rpm.

WARNING: I don't really know what Integral Timer does -- I'm guessing it's some type of delay used to smooth output to throttle unit. Since Kris's tuning doc suggests NOT TOUCHING these constants I would have to urge DBW users proceed with caution.

I wish I had a more methological approach ... but I don't as I just don't have a good understanding of these constants yet.

Rob.

[RCHAD]

good reading material...i have the stuck air conditioning thing going on too. I installed a kill switch for it but it never goes off even in the summer while using it. does anyone have a solution yet??? the problem seems to have surfaced after my dbw controller was installed
thanks

[robains]

Kris suggested that it could be a result of the stock ECU going into limp mode and triggering the AC to stay on somehow. I tend to agree as my AC will work fine so long as I don't exceed 4K rpm -- which seems to be the trigger rpm that put the stock ECU into Limp mode and hence AC get stuck ON and as do my radiator fans.

I disconnected the AC clutch wire until I can find a good solution (fortunately hot days are 5 months away).

[Kris from DRS]

The AC turn-on and fan control will both be resolved in the new firmware currently being worked on. It is almost done...very close.

This was an unknown issue at the time of R&D b/c the early DWB controller systems were only fitted to cars that did not have AC and had manually controlled cooling fans (track only cars).

thanks,
Kris

[turbophil]

Yum, new firmware