VEMS Community Forum

VEMS => Calibration & Mapping => Topic started by: boostcrap on January 07, 2010, 05:32:31 AM

Title: E85 and gas with one map?
Post by: boostcrap on January 07, 2010, 05:32:31 AM
How accurate is the wideband function? Is it possible to run both fuels with one map? Is the ecu fast enough to control the air fuel ratio at Wot?

I want to boy the v3.3 but need this feature
Title: Re: E85 and gas with one map?
Post by: [email protected] on January 07, 2010, 02:37:04 PM
Even if it were fast enough, it wouldn't be something you'd want to do because the whole system then depends on a sensor that by its nature has a finite life and always has the chance of being contaminated or fouled - which would then mean that your fuelling is way off.
Title: Re: E85 and gas with one map?
Post by: boostcrap on January 07, 2010, 03:46:24 PM
I would use the e85 map, so it would never run lean. I only use gas when I am in areas where no e85 is available, maybe 10time a year. Now I used an p28 ecu tuned for e85 on my honda civic, it runs great. But the mpg is off, when I use gas
Title: Re: E85 and gas with one map?
Post by: [email protected] on January 07, 2010, 04:44:01 PM
Use the switchable map option on the VEMS.

For a Honda I'd need a lot of convincing not to use a Hondata with a VEMS Wideband&EGT guage.
Title: Re: E85 and gas with one map?
Post by: gunni on January 07, 2010, 04:52:00 PM
Get a ethanol content sensor like flex fuel cars have.
VEMS people then add another dimension to the unit for ethanol content changes.
And you map doesn´t have to change.
Title: Re: E85 and gas with one map?
Post by: boostcrap on January 07, 2010, 05:21:55 PM
Ok I didnt know that you can swith the map onboard. How much maps can you upload on the vems? I used CROME for years, but I want to use individual coil packs. Too much trouble with distributors, they are all over 10 years old, and a new one would cost more than 2 VEMS
Title: Re: E85 and gas with one map?
Post by: [email protected] on January 07, 2010, 05:39:14 PM
I think there are two maps, I've not seen mention of it in the new 1.1.6x code.

I've asked a question on this thread, hopefully a grown-up will be able to help.
http://195.159.109.134/vemsuk/forum/index.php/topic,1050.msg11487.html#msg11487
Title: Re: E85 and gas with one map?
Post by: dnb on January 07, 2010, 07:26:33 PM
Just looked at my 1.1.64 config and map switching is still there.

The wideband IS fast and accurate enough (when the sensor is new) to compensate for 10% inaccuracy in mapping at WOT, but it's absolutely not good practice.

Not seen the ethanol content sensor in use on a VEMS yet, but it's something I would be extremely interested in using.
Title: Re: E85 and gas with one map?
Post by: gunni on January 07, 2010, 07:48:23 PM
It´s really a necessity as ethanol is in all fuels now and the petrol companies vary the amount depending on the time of year.
It´s a simple device and many standalones are now implementing it.
Title: Re: E85 and gas with one map?
Post by: [email protected] on January 07, 2010, 07:56:41 PM
There is a lot of reliance on the wide band to clean up the fueling, and while the lambda sensor will sort the problem it really should not be relied on, its a secondary sensor.
Anyone got any info on these ethanol sensors?
Title: Re: E85 and gas with one map?
Post by: dnb on January 07, 2010, 07:57:20 PM
Do you have a link to any sensors?  Are they resistive output devices (like CLT sensors etc)?   There's a couple of spare ADCs on a VEMS, so it would be worth me having a play.
Title: Re: E85 and gas with one map?
Post by: gunni on January 07, 2010, 08:35:12 PM
http://zeitronix.com/Products/ECA/ECA.htm

Here is some info.
And more to find from the part numbes I´m sure.
Title: Re: E85 and gas with one map?
Post by: boostcrap on January 08, 2010, 07:39:08 PM
Ok thx, it has switchable maps