Jump to content
SAU Community

Recommended Posts

has anyone noted how much an octane booster can actually affect AFRs, as I was thinking if I run E85 as my only tune but then cant find E85 on a cruise somewhere that I could possibly use 98 and some octane booster...

would that work or am I asking for trouble... otherwise I'll be limited to 250ks before I need to find E85 or pay the price get datalogit to change maps over to 98 tune...

it doesnt work that way. octane doesnt change the volume required. E85 physically requires 30% or so more fuel for the given power vs petrol. running 98 on an e85 tune is going to be driving around at 10:1 or so (fubar the plugs in 5-10 mins)

you will not find massive difference in the octane rating from E70 to E85 in terms of detonation tune for E85 and drive on it year round be it from E70 or E85.

Noel, I suspect some of the reason they call it E-Flex is so that they don't have to adhere to a consistent ethanol content. Would like to confirm with Caltex, but rumour was a while ago that they weren't going to be strict about it - in conjunction with the major seasonal switch between 70 and 85. Maybe it's all in the name...E-Flex(ible)!

has anyone noted how much an octane booster can actually affect AFRs, as I was thinking if I run E85 as my only tune but then cant find E85 on a cruise somewhere that I could possibly use 98 and some octane booster...

would that work or am I asking for trouble... otherwise I'll be limited to 250ks before I need to find E85 or pay the price get datalogit to change maps over to 98 tune...

Will octane booster affect AFRs? Should only change the RON. E85 fuel maps deliver a lot more fuel than ULP, it would be ridiculously rich with a tank of ULP.

I see. So is monitoring AFRs and changing maps the only way this caltex fuel is going to work? Tuning conservatively and just absorbing the difference doesn't seem optimal

May not be optimal but it's still going to be better than ULP for power. As long as it runs okay I could car less about the differences between tanks of it. Could be like a bonus each time you fill up and your AFRs are perfect :D

  • Nope 1

E85 user here. I stick to good stuff and use eflex only when needed to get home and use light throttle with it in the tank.

May be a bit too cautious, but I don't care cause it's not exactly a commodore with a tune that allows for varying fuels :)

E85 user here. I stick to good stuff and use eflex only when needed to get home and use light throttle with it in the tank.

May be a bit too cautious, but I don't care cause it's not exactly a commodore with a tune that allows for varying fuels :)

Funnily enough my tuner has already sussed out the "sniffer" used by holden to allow for variations in fuel quality and or E content.

Reckons he can make it work on our modded cars a piece of piss so if all else fails there's the answer.

  • Like 3

May not be optimal but it's still going to be better than ULP for power. As long as it runs okay I could car less about the differences between tanks of it. Could be like a bonus each time you fill up and your AFRs are perfect :D

Yeah of course, if the difference is purely academic then I wouldn't care either. It's the possibility of damage that concerns me.

You try it and let us know how it goes :P which turbo are you running?

Funnily enough my tuner has already sussed out the "sniffer" used by holden to allow for variations in fuel quality and or E content.

Reckons he can make it work on our modded cars a piece of piss so if all else fails there's the answer.

Yep, as long as you can get a 0-5 volt output or something from it, and know what the voltage means in terms of ethanol content, you could wire it into a ViPEC ECU (among others) and set it up as a fuel and/or ign timing trim

Funnily enough my tuner has already sussed out the "sniffer" used by holden to allow for variations in fuel quality and or E content.

Reckons he can make it work on our modded cars a piece of piss so if all else fails there's the answer.

the links and vipecs already have support for them coded in, the catch is that they cost from $300-600 for the sensor.

Yeah of course, if the difference is purely academic then I wouldn't care either. It's the possibility of damage that concerns me.

You try it and let us know how it goes :P which turbo are you running?

Havent decided on turbo yet, although Arthur pitched an interesting idea to me earlier...see how much of an increase we can get out of the standard turbo on E, assuming a safe boost level (circa 12psi) and all the supporting fuel mods (which I'd have to do for the larger turbo anyway). Unfortunately an expensive exercise in tuning (and possibly a blown turbo), but if I could net 230-240rwkw out of it...would almost be worth keeping the standard turbo for the response value. Someone tell me this is a bad, late night, unnecessarily idea?

  • Nope 1

If you tune to the e70 that's in the tanks now, you may run a little leaner IF they switch. It wont be till later in the year if ever.

Birds, run a wideband for visual inspection,(Mine is only $200) if you happen to notice the afr's leaning out then add 5L of petrol while you are there, the petrol nozzle is right next to it... I will let everyone know if they switch mixes at the Blackburn road pump.

Don't be too worried, there is that much more fuel spraying in, a little lean shouldn't heat things too much.

Havent decided on turbo yet, although Arthur pitched an interesting idea to me earlier...see how much of an increase we can get out of the standard turbo on E, assuming a safe boost level (circa 12psi) and all the supporting fuel mods (which I'd have to do for the larger turbo anyway). Unfortunately an expensive exercise in tuning (and possibly a blown turbo), but if I could net 230-240rwkw out of it...would almost be worth keeping the standard turbo for the response value. Someone tell me this is a bad, late night, unnecessarily idea?

It would be an interesting excercise indeed birds but in the long run it could only lead to shit and disaster.

The standard turbs are getting a bit long in the tooth to be leaned on to any degree.

If you had the funds to rebuild it to stock specs it would make for some very interesting comparisons pre and post E85.

  • Like 2
  • Nope 1

has anyone noted how much an octane booster can actually affect AFRs, as I was thinking if I run E85 as my only tune but then cant find E85 on a cruise somewhere that I could possibly use 98 and some octane booster...

would that work or am I asking for trouble... otherwise I'll be limited to 250ks before I need to find E85 or pay the price get datalogit to change maps over to 98 tune...

that will not even be close to working mate. an E85 tune then run on regular pump 98 with octane booster won't even be close. it will be so rich the car will barely run. I would strongly advise to not even consider running 98 (without or without any octane booster) on an E85 tune it just wont work and even the best octane booster on the market (bit of a misstatement as they are all rubbish) won't raise your 98RON fuel much past 99RON. so you'll be going from an ethanol rich 105RON fuel to a 100% petrol 99RON fuel, then tune will be about 20% too rich and timing WAY too advanced. not good.

if you really want to run on 98 and E85 then you need 2 tunes and a way to switch them over as needed (datalogit).

Havent decided on turbo yet, although Arthur pitched an interesting idea to me earlier...see how much of an increase we can get out of the standard turbo on E, assuming a safe boost level (circa 12psi) and all the supporting fuel mods (which I'd have to do for the larger turbo anyway). Unfortunately an expensive exercise in tuning (and possibly a blown turbo), but if I could net 230-240rwkw out of it...would almost be worth keeping the standard turbo for the response value. Someone tell me this is a bad, late night, unnecessarily idea?

Its the exhaust housing on the standard turbo that's the real issue... it just won't flow enough air to make much more power

when I finally destroyed the stocker on my 25 and went to a 2835 it just felt a whole lot nicer... the motor revved out cleaner and it was easier to drive... tuner commented that the motor sounded happier too

I wouldn't bother highflowing the standard turbo... get something with bigger housings... highflow is a bodge job IMO

has anyone noted how much an octane booster can actually affect AFRs, as I was thinking if I run E85 as my only tune but then cant find E85 on a cruise somewhere that I could possibly use 98 and some octane booster...

would that work or am I asking for trouble... otherwise I'll be limited to 250ks before I need to find E85 or pay the price get datalogit to change maps over to 98 tune...

Octane booster will make almost no difference to the AFR. AFR is air-fuel-ratio and the amount of fuel is barely changing (200mL in 50L+ of fuel).

E85 uses roughly 25% more fuel just to make the same power. So the tune for E85 will roughly have 25% (rough estimate) more fuel in it, so when you run 98 on an E85 tune it would be 25% richer. Is that right? The other issue is that the timing for the E85 tune would most likely be too much for 98 fuel so some octane booster would help that part. But I think the car would be running so rich that it wouldnt matter. I believe the amount of fuel is the issue not the octane in that case.

cars will still detonate even when super rich. in fact go too rich and it causes det. a car with 30% more fuel and ign timing suitable for 105+RON E85 being suddenly run on 98RON ULP is not going to be a happy car. it would almost certainly be pinging with that much fuel and the high amounts of timing people run in an E85 tune.

cars will still detonate even when super rich. in fact go too rich and it causes det. a car with 30% more fuel and ign timing suitable for 105+RON E85 being suddenly run on 98RON ULP is not going to be a happy car. it would almost certainly be pinging with that much fuel and the high amounts of timing people run in an E85 tune.

Woops I replied to a post on the first page not realising there was a second page where the questions were already answered!

Havent decided on turbo yet, although Arthur pitched an interesting idea to me earlier...see how much of an increase we can get out of the standard turbo on E, assuming a safe boost level (circa 12psi) and all the supporting fuel mods (which I'd have to do for the larger turbo anyway). Unfortunately an expensive exercise in tuning (and possibly a blown turbo), but if I could net 230-240rwkw out of it...would almost be worth keeping the standard turbo for the response value. Someone tell me this is a bad, late night, unnecessarily idea?

Just a note you would need to run larger than stock injectors to make 230-240rwkw with E85, which adds cost in both the injectors and more involved tuning. Even the standard AFM runs out about 220-230rwkw. So you would prob have to stop there unless you want to buy a Z32 AFM as well.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • Well, after the full circus this week (new gearbag, 14 psi actuator on, injectors and AFM upgraded, and.....turbo repair) the diagnosis on the wastegate is in. It was broken. It was broken in a really strange way. The weld that holds the lever arm onto the wastegate flapper shaft broke. Broke completely, but broke in such a way that it could go back together in the "correct" position, or it could rearrange itself somewhere else along the fracture plane and sit with the flapper not parallel to the lever. So, who knows how and when exactly what happened? No-one will ever know. Was it broken like this the first time it spat the circlip and wedged itself deep into the dump? Or was it only broken when I tried to pry it back into place? (I didn't try that hard, but who knows?). Or did it break first? Or did it break between the first and second event of wierdness? Meh. It doesn't matter now. It is welded back together. And it is now held closed by a 14 psi actuator, so...the car has been tuned with the supporting mods (and the order of operations there is that the supporting mods and dyno needed to be able to be done first before adding boost, because it was pinging on <<14 psi with the new turbo with only a 6 psi actuator). And then tuned up a bit, and with the boost controller turned off throughout that process. So it was only running WG pressure and so only hit about 15-16 psi. The turbo is still ever so slightly lazier than might be preferred - like it is still a bit on the big side for the engine. I haven't tested it on the road properly in any way - just driven it around in traffic for a half hour or so. But it is like chalk and cheese compared to what it was. Between dyno numbers and driving feedback: It makes 100 kW at 3k rpm, which is OK, could be better. That's stock 2JZ territory, or RB20 with G series 550. It actually starts building boost from 2k, which is certainly better than it did recently (with all the WG flapper bullshit). Although it's hard to remember what it was like prior to all that - it certainly seems much, much better. And that makes sense, given the WG was probably starting to blow open at anything above about 3 psi anyway (with the 6 psi actuator). It doesn't really get to "full boost" (say 16 psi) until >>4k rpm. I am hopeful that this is a feature of the lack of boost controller keeping boost pressure off the actuator, because it was turned off for the dyno and off for the drives afterward. There's more to be found here, I'm sure. It made 230 rwkW at not a lot more than 6k and held it to over 7k, so there seems to be plenty of potential to get it up to 250-260rwkW with 18 psi or so, which would be a decent effort, considering the stock sized turbo inlet pipework and AFM, and the return flow cooler. According to Tao, those things should definitely put a bit of a limit on it by that sort of number. I must stress that I have not opened the throttle 100% on the road yet - well, at least not 100% and allowed it to wind all the way up. It'll have to wait until some reasonable opportunity. I'm quite looking forward to that - it feels massively better than it has in a loooong time. It's back to its old self, plus about 20% extra powers over the best it ever did before. I'm going to get the boost controller set up to maximise spool and settle at no more than ~17 psi (for now) and then go back on the dyno to see what we can squeeze out of it. There is other interesting news too. I put together a replacement tube to fit the R35 AFM in the stock location. This is the first time the tuner has worked with one, because anyone else he has tuned for has gone from Z32 territory to aftermarket ECU. No-one has ever wanted to stay Nistuned and do what I've done. Anyway, his feedback is that the R35 AFM is super super super responsive. Tiny little changes in throttle position or load turn up immediately as a cell change on the maps. Way, way more responsive than any of the old skool AFMs. Makes it quite diffifult to tune as you have to stay right on top of that so you don't wander off the cell you wanted to tune. But it certainly seems to help with real world throttle response. That's hard to separate from all the other things that changed, but the "pedal feel" is certainly crisp.
    • I'm a bit confused by this post, so I'll address the bit I understand lol.  Use an air compressor and blow away the guide coat sanding residue. All the better if you have a moisture trap for your compressor. You'd want to do this a few times as you sand the area, you wouldn't for example sand the entire area till you think its perfect and then 'confirm' that is it by blowing away the guide coat residue.  Sand the area, blow away the guide coat residue, inspect the panel, back to sanding... rinse and repeat. 
    • The detail level is about right for the money they charge for the full kit... AU$21.00 each issue, 110 issues for a total of $2,300 (I mentioned $2.2K in the first post when the exchange rate was better). $20/week is doable... 😐
    • If planning on joining us for the day(s) please indicate by filling in this form. https://forms.gle/Ma8Nn4DzYVA8uDHg7
    • You put the driver's seat on the wrong side! Incredible detail on all of this. It looks like you could learn a lot about the car just from assembling the kit.
×
×
  • Create New...