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I am in the process of converting my tune to E85 and have a couple of queries mainly related to using the Map A (Power)/Map B (Econ) items to allow 2 different fuel types. For the purpose of my questions lets assume I am using petrol in Map A and E85 in Map B.

1. I have heard from a few tuners and read on various tuning forums that it is common for people just leave the target AFR tables as per petrol ones (tuning via lambda). I assume they would just multiply the VE table by 1.5 to get the required additional fuel (14.7/9.8=1.5). In the delco hacking manuals it explains to convert the target AFR's in Map B to suit E85. I assume the reason for this is there is only 1 VE table and it should be the same for both petrol and E85, allowing you to effectively tune both your petrol and E85 tunes at the same time using either fuel? If this is correct does it work well in practice under real world conditions or is there usually tweaks that still need to be made to the VE table to suit each fuel type?

2. I have noticed that there is also only a single table/value for:
- cranking BPW's vs coolant temp
- Injector flow rate (kinjflow)
- A/F Ratio - Boost Cold Engine A/F Ratio vs Coolant Temp and MAP
- A/F Ratio - Idle A/F Ratio vs Coolant Temperature
Given that I need 1.5 times more E85 I would expect these to be different for each fuel type (especially the cranking BPW's and kinjflow)

Based on the above am I better off having 2 completely separate tunes (1 for petrol, 1 for E85) and just forget about the map switching?

3. My last question is relating to the Spartan wideband controller and sensor (bosch LSU 4.2) and how I can use it to read AFR's for E85 in TunerPro. As fas as I can tell this sensor reads in lambda and whatever logger you use needs the calibration data entered into it.
So from 14point 7 website 0.68 = 10 AFR and 1.36 = 20 AFR (with 14.7:1 being stoich)
Does this mean I can simply set the min/max values for wideband in TunerPro to:
0.68 = 10/1.5 (6.66 AFR) and 1.36 = 20/1.5 (13.33 AFR) (with 9.8 being stoich) and it will show the correct AFR in TunerPro? or is it not that simple.

I have already done conversions for deka 80lb injectors and a map for E85 based on information on this site and manuals and fired the car up on both E85 and petrol and it starts, idles and seems to run quite well straight off the bat (E85 and Petrol) so I am pretty happy that changes for both the injectors and fuel type are reasonably close. Note this is on 2 completely separate tunes (not using Power/Econ modes). Reason for all these queries is I am putting in on the dyno in the next couple of weeks and the tuner said he typically doesnt touch the AFR tables when changing from Petrol to E85. I really want to have as much info handy as possible to minimise wasted time.

Car is KE30 corolla with 355 Stroker, F288 solid cam, COME Twin Throttle body, 11.6-11.8 compression. Expecting around 400rwhp (hope a bit more on E85). Dedicated burnout car.

Any input is greatly appreciated.
Jason

I dont have all the answers but for 1 - yes you are better of changing the target AFRs. Because:

1) unless your whole ve table is at less than 75% you cant multiply it by 1.5 without going out of range.
2) the VE is a measure of your engines efficiency and using it to tune around different fuel types will be feeding your computer incorrect data which will effect other corrections it applys.
So 3) if your injector rate, injector dead times and ve are correct you will get the most accurate model on both of 2 different different fuels by changing target AFR.

But 4) some things are measured in injector ms, such as cranking injector time and power enrichment which wont suit both fuels perfectly. So yes ideally 2 different tunes with the map jumper wired through a switch while retaining power/econ switch for its regular purpose is ideal.

Note that this is theory and in reality the issues i mention may not be as significant as i make them sound. But that is how it works and i have seen tuning alternate fuel by target afr work very well in holden202t's methanol drag car and it makes sense to me to do it right.

First question is, I assume you are using a 4L60E (or similar) gearbox to want to run 11P over 12P? As there were very few people using both maps in 12P for different fuel types I did not add this to 11P. It instead only has a selection of a few items, it takes up space and requires a fair bit of coding time so unless there is a need it does not get added. Space is less of a concern in 11P so can be added if there is demand.

Wideband with E85 is as easy as changing the 0V and 5V afr in the cal to 6.7 and 13.4 respectively), but it wont switch with maps. You can setup tunerpro to do the switching for you with some tricky calcs, leave the cal as your petrol AFRs (10 and 20 AFR) and then the calc for wideband can look at the map switch flag to use two different equations.

Unless you are buying E85 in a drum it wont always be E85. With no flex fuel sender support to trim the fuel you will need to keep that in mind.

antus wrote:I dont have all the answers but for 1 - yes you are better of changing the target AFRs. Because:

1) unless your whole ve table is at less than 75% you cant multiply it by 1.5 without going out of range.
2) the VE is a measure of your engines efficiency and using it to tune around different fuel types will be feeding your computer incorrect data which will effect other corrections it applys.
So 3) if your injector rate, injector dead times and ve are correct you will get the most accurate model on both of 2 different different fuels by changing target AFR.

But 4) some things are measured in injector ms, such as cranking injector time and power enrichment which wont suit both fuels perfectly. So yes ideally 2 different tunes with the map jumper wired through a switch while retaining power/econ switch for its regular purpose is ideal.

Note that this is theory and in reality the issues i mention may not be as significant as i make them sound. But that is how it works and i have seen tuning alternate fuel by target afr work very well in holden202t's methanol drag car and it makes sense to me to do it right.

Thanks Antus, that clears things up a little. "What about all the other little calc's that are based on AFR" was exactly my reply. This is mainly in LS engines that they work on, and I am only assuming that they adjust the VE table and injector flow rate to get it to work.

When you say you have seen tuning by target AFR work well do you mean actually adjusting target AFR to tune rather than VE table? For example in my situation getting the VE table spot on for petrol, apply the scale factor to the AFR maps for E85 (divide by 1.5), then make changes to the new target AFR for fine tuning? It certainly makes more sense to me to do it right, and I cant argue with the results I have had on initial test run. I have never heard of an engine running and idling perfectly on 2 different fuel types (2 different maps) after a 4x bigger injector change. My main concern was doing something completely different to what my tuner is used to, and wasting time going through the methods rather than tuning.

First question is, I assume you are using a 4L60E (or similar) gearbox to want to run 11P over 12P? As there were very few people using both maps in 12P for different fuel types I did not add this to 11P. It instead only has a selection of a few items, it takes up space and requires a fair bit of coding time so unless there is a need it does not get added. Space is less of a concern in 11P so can be added if there is demand.

Wideband with E85 is as easy as changing the 0V and 5V afr in the cal to 6.7 and 13.4 respectively), but it wont switch with maps. You can setup tunerpro to do the switching for you with some tricky calcs, leave the cal as your petrol AFRs (10 and 20 AFR) and then the calc for wideband can look at the map switch flag to use two different equations.

Unless you are buying E85 in a drum it wont always be E85. With no flex fuel sender support to trim the fuel you will need to keep that in mind.

VL400, no I am running a turbo 350, with a 424/699 ecu (from VR auto). I think $11P is the preferred for this ecu. I also wanted to keep my options open and ensure I can run boost at some point if I wanted to. I am not fussed on running the 2 fuel types off 1 map, it was more for curiosity's sake. Just seen that it was a possibility in the manual's and a couple of the things that needed switching didn't appear to be there. My intention is to burn 2 bins to chips (one E85 and 1 petrol) so I can just run E85 at the burnout comps, then switch chips and run petrol through fuel system to flush (as it sits for a month or 2 between comps).

I dont really want to leave the NVram in during comps as I had a few issues last time with it just dying (at 6000+rom). Appeared as though the NVram was a little loose and when I touched it I seen the blue light come back on and then car started again. However I could not make changes afterwards (went to read only - corrupted tune and after I reprogrammed I could write again). I am not sure whether this was caused by loose NVram, or because my old ECU was dodgy (I have a new one now and seems much tighter). When I checked the write wire and gave it a bit of a tug the solder pad kind of "pulled off" the board. Might I add I finished the comp with a factory chip and it worked ok. I just want to burn final tunes onto chips, to ensure there is no chance of corruption etc.

The place I get E85 from brings it up in drums and tests prior to filling anything to ensure it is actually E85. I will likely tune fairly rich anyway to add some margin of safety.

Thanks guys appreciate the help.

what VL400 was trying to point out, is that although he didn't add all of the required items into the 11P code to allow you to do fuel switching via the map switch, if you are not using a 4L60E gearbox, then there is no reason you cant switch to an 808 ECU and use $12P, which has got every item you need to do petrol/E85 split via the map switch.

Jayme wrote:what VL400 was trying to point out, is that although he didn't add all of the required items into the 11P code to allow you to do fuel switching via the map switch, if you are not using a 4L60E gearbox, then there is no reason you cant switch to an 808 ECU and use $12P, which has got every item you need to do petrol/E85 split via the map switch.

I see I see. I do have an 808 laying around. What are the other benefits of running $12P over $11P given that I don't really care about being able to switch fuels with a switch? Aren't the pinouts a little different on an 808 as well?

Cheers

With no flex fuel sender support to trim the fuel you will need to keep that in mind.

Is this something that may be added later? These sensors are cheap and easy to get now

if your not going to use a switch ever then its probably not worth the effort of re-pinning the loom to suit 808 .....

having an eprom with a backup tune is always a good idea for any race car, at the very least allows you to get the car back on the trailer or driven home etc ..... having said that I leave nvrams in my race car almost exclusively and haven't had an issues for years with them corrupting, but almost mine plugs in nice and tight!

im sure the sensor is, but its more than likely the coding to make it work that's the hard part ... or the time part.

Holden202T wrote:if your not going to use a switch ever then its probably not worth the effort of re-pinning the loom to suit 808 .....

having an eprom with a backup tune is always a good idea for any race car, at the very least allows you to get the car back on the trailer or driven home etc ..... having said that I leave nvrams in my race car almost exclusively and haven't had an issues for years with them corrupting, but almost mine plugs in nice and tight!

im sure the sensor is, but its more than likely the coding to make it work that's the hard part ... or the time part.

Yeah I dont think I will be re-pinning just for the switch. I did successfully use the NVRam on my previous engine without issue, so I am beginning to think my old PCM was toast. The NVRam is much tighter in the new PCM. I will see if it is going to work on the dyno. I like the idea of running a std style chip/eeprom for safety just in case the large vibrations I get from hitting the rev limiter all the time shake things too much and cause the ram to corrupt or something odd like that.

Cheers

also another option if you wanted to, you can have two tunes on the nvram and just switch between them via the jumper on the nvram board! .... you'd need to have the car off to do the switch but otherwise no issues....

and you can also buy from the for sale section memcal boards which will allow you to use the same feature without having an nvram in there ... if you so wish that is