Cold Crank Issue With Rb25/e85/emanage Ultimate Combo.

[stageaharts]

Gents,

Does anyone have any tuning suggestions to improve cold cranking ability on cooler mornings (6 degrees and cooler) for my rb25/e85/emanage ultimate combo? Apparently the cold crank adjustment is capped at +20% on the emanage and my set up requires a bit more adjustment.

Setup includes:

98 series 1 Stagea, rb25det, manual conversion.

Greddy emanage ultimate with map sensor

Deatschwerk 1000cc injectors

Walbro e85 fuel pump

Nismo adjustable fpr

3076r ext gate

Apparently the car idles perfectly at all times (even after a cold/difficult start) and starts easily at warmer temps but seems to be much more difficult to start at lower temps and cold crank fuel adjustment has now reached its limit (+20%). Is there a work around for this?

If you would like any more information about the set up that may be pertinent to the issue, please ask. I am not tuning the car personally, so my knowledge of the entire tune is limited. Any help is appreciated

Cheers,

Harts.

[Dose Pipe Sutututu]

e85 doesn't vapourise properly in the cold, if you're having issues just feed some start ya bastard into the plenum via a vacuum line then crank the car

[stageaharts]

Aparrently start ya bastard works a treat Hehe, but we are hoping for a more permanent solution as opposed to a can of start ya bastard in the glove box he he he

(That being said I'll probably keep one there anyway )

[GTSBoy]

Permanently plumb the can into the plenum?

/jokes

[Dose Pipe Sutututu]

Permanently plumb the can into the plenum?

/jokes

lol... imagine start ya bastard like a NOS setup, and you could set it on your ECU to trigger the spray only on crank and only when the intake temp sensor reads under 10 degrees C..

there's an idea

[stageaharts]

He he he, I wonder if speed flow make the appropriate fittings in black...

He he he

[GTSBoy]

Black gaffa tape?

[stageaharts]

Fixes anything

[battery]

Apparently in south America where they run e100 a lot of cars have a small secondary tank filled with some solution that's used to aid in starting.

[scotty nm35]

I used to run a small 1L petrol canister in the engine bay with a single injector welded into the plenum and a stock fuel pump (no reg), powered by a momentary switch on the dash. It worked a treat for winter and lasted months.

I learnt simply putting 5L of petrol in the tank then filling on e85 helped immensely, and later we ended up tuning a lot of the issue out by lowering the injector size and letting the stock ecu do all the work.

United is definitely harder to start under 15 degrees than Caltex, but if you are tuned to run United and you fill at Caltex anyway your issues should disappear also.

Further to this, I am trying to get my hands on some cheap flex fuel sensors and wire them into a customers Emanage Ultimate, through the spare front panel input. Hopefully that would give the tuner an 8x8 map dependant on ethanol content, and negate the need to fill on e85 only. A 50/50 mix would be plenty for winter. I will be fitting the Flex sensor into my Fcon also, for practicality.

[stageaharts]

Awesome, thanks for the replies

Scotty, would you mind briefly explaining the mechanics of adding 5l of 98 or filling with some Caltex e70? I had assumed that if you had your car tuned on united e85 (which I have) then it would be detrimental to add e70 or 98 to the mix, in the same way that using 91ron would make a car meant to run on 98ron ping more readily. Is this not the case?

The flex fuel sensor is definitely something that I intend to have done for the practicality side of things, but it would certainly be nice to solve this issue before we close the books on this (first) e85 tune. If the issue can't be solved with the emanage ultimate then I may have to look into a new ecu, the ultimate has been in the car since it was an auto hehe.

Cheers,

Harts.

[GTSBoy]

It's actually very simple. Most of the "extra octane" or knock resistance of E85 is available once you get above about 40% ethanol. As such if you have tuned for (real) E85 and add some extra petrol to the mix, all that happens is you make the stoichiometric air requirement of the overall fuel greater (meaning you end up running richer mixtures if in open loop) and it won't really want to ping just because of teh reduced ethanol content.

[stageaharts]

Awesome, that all makes sense apart from the 'open loop'part. Forgive my ignorance, but what dictates whether I am running in open versus closed loop in this case?

[stageaharts]

and later we ended up tuning a lot of the issue out by lowering the injector size and letting the stock ecu do all the work.

Also scotty, would you mind elaborating on this? I think I had read somewhere that reducing injector size on the software would be of some use...

[scotty nm35]

The EMU is always going to be a compromise but it also has the benefit of running like the stock ecu, because essentially it is. Great for us auto owners. If you are running a manual box, the Adaptronic is hard to go past for flex setups simply as it's cheaper than it's competitors.

Have a play around with mixes, you should barely notice 20% 98 mixed into the tank and cold starts would be greatly improved. Worst case it runs a little rich on boost and begins to break down spark. How good are your coil packs?

When you tune at over e40-e50 there is little chance of detonation, unless you are pushing the tune hard.

[scotty nm35]

Also scotty, would you mind elaborating on this? I think I had read somewhere that reducing injector size on the software would be of some use...

As there is very little adjustment for cold start and cranking enrichment the EMU requires the factory ecu to take care of it. I think my 1000cc injectors were set to around 5-600cc to get the car to start and idle fine on e90 (United). Then your tuner or you can fiddle with the maps to fine tune the cold start enrichment. The car may need twice the fuel to crank nicely on a cold morning.

[GTSBoy]

Awesome, that all makes sense apart from the 'open loop'part. Forgive my ignorance, but what dictates whether I am running in open versus closed loop in this case?

ECUs that look at the oxygen sensor to trim the mixture are running in closed loop. If the O2 is low, they cut a little fuel. If the O2 is high, they add a little fuel. Trying to hit 14.7:1 fuel air ratio (for petrol anyway). This is fine for idle and light load cruise conditions where you can run at stoich.

When you get onto the gas (so pretty much any time you're on boost in a turbo car) these oxy sensors can't cut the mustard - we need to be able to run at richer mixtures but the oxy sensor can't tell you anything about the mixture except that it is "rich". So the ECU stops looking at the O2 sensor and just runs off the fuelling values in the map. That's open loop.

[discopotato03]

What I did was this , I run a Vipec and Tech Edge Wide band BTW .<br />My car was tuned on Caltex Eflex because that was what I could easily get in three localish servos at the time . Now United E85 is close to where I work so I'm trying E85 with 15% BP pulp to home brew E70 with at least 15% "real" PULP .<br />I worked out that 8.25L Pulp in a tank of E85 makes E70 so not hard to do .<br />My ECU has a target AFR table so it can chase set AFRs at part throttle loads provided the variation isn't too great . My car didn't like going from E70 to E85 so obviously the approximately 15% less petrol was a bit lean for it to cope with , it was very quickly and easily fixed by adding 5 1/2L of PULP in a nearly full tank .<br />I don't know if the effect is as noticeable going from E85 to E70 because a tad rich rather than a tad lean probably isn't felt so much . My tuner said to me that my engine probably isn't making enough power to really hurt it if I got it a bit lean though I never play with the full load settings only the up to positive manifold pressure stuff . I would like to have an ethanol content sensor and readout so I can see and the computer can monitor though people should be able to tell themselves if their car feels a bit flat or flat spots under normal acceleration transients , I can .<br />My computer can have flex fuel tuning though if I ever did that I reckon I'd only have it cover E40 to E85-90 . I think there is too much variation in what we call ULP particularly octane wise and it clouds the whole flex fuel thing if the tuner has to cover increasing petrol percentages AND a variation in petrol octane ratings . Obviously the higher the petrol percentage content is the greater the importance on ULP octane becomes . I guess if we could have a petrol octane sensor as well as an ethanol content sensor an ECU/tuner could cover the whole fuel content range but I don't know if this is possible .<br />Anyway I think asking a tuner to start out with say United E85 or preferably E90 then add more of whatever octane ULP you normally by say in 10% jumps down to E40 or E50 would be quite workable . I think this would make the tune vs ethanol availability wide enough to get by without adding the straight petrol with who knows what detonation resistance vulnerability . The ethanol content sensor would tell you which way to go to stay inside the 40-90% range and you could tailor it towards performance or extended range with the higher potential petrol content . Maybe not totally flexible but flexible enough .<br /><br />Sorry if I've gone a bit off the OPs track but it's all food for thought , cheers Adrian .<br /><br />

[scotty nm35]

I agree Adrian, it makes it quite hard to tune to straight 98 unless the ecu can reduce load (boost). As I have a separate controller I was planning to run a relay to disconnect the boost solenoid at a certain point, say e40, and run off wastegate pressure.

[stageaharts]

Awesome info guys, let me digest it and I'll get back to you