KawRider

iTrader: (8)

Im moving out of California in the next few months. I will have access to 93 Octane (Cali has 91 ****-tane). Will I pick up some power? I guess I will need to re-tune for the 93? Maybe add a degree of timing, since mine is only advanced like one from stock. Add a PSI or so of boost? Any info will be appreciated.

Thanks!

Warrtalon

iTrader: (6)

It depends on the mods, tune, and boost you have now. If you are at a level of modding where 91oct keeps you from running enough boost, timing, and AFRs, then yes, you will probably gain some power from 93oct as long as you retune for it and run the proper level of boost. You can get away with mid 11 AFRs, 22psi, and pretty aggressive timing without knocking on 93oct...

DrMerl

Maybe I need to search, but I remember my VIII responded nicely to 91+100 (to get at least 93oct). And I remember something about the ECU "detuning" itself based on federal numbers to 91oct.

I've been doing that with my IX, did 6.5 gal of 100oct + 91 and the butt dyno notices smoother pull past 5K and more "impact" of boost, overall it does feel faster (as an M5 can attest to

Anyone happen to do a dyno with a totally stock Evo with 91 vs 93? Is it about a 10hp spread?

What will a stock Evo IX ECU respond to as far as octane? is a 93oct max, or if it sees no knock (to maybe 94 or 95 oct) how far will it go?

Warrtalon

iTrader: (6)

Well, the stock tune is so conservative and stock boost is so low that there is usually very little difference in 91oct and 93oct on a stock Evo. It is possible that since we actually run lean at peak boost that 91oct causes a little knock that the ECU then responds to with less timing and thus lesser peak torque, but I don't think it affects peak HP, which occurs up above 6k rpm where the boost is around 16psi and the tune is very rich.

Honestly, though, with the IX ECU as sophisticated as it is, it may very well retune itself for different octanes. In the past, adding 100oct to at stock VIII like you did was really just a waste of money, but maybe it's different with a IX.

Cannonballer

iTrader: (3)

My VIII MR is faster with some extra octane mixed in. I think you are underestimating how sh1tty our gas in CA can be. At times the ever precise *** dyno can even feel the difference between various vendors of gas, 76 generally being the best. It is weird to get into your car to think wtf is wrong, why is it so sluggish today? Oh riiight, Chevron gas...

DrMerl

It would be nice to hear about a value range on the stock ECU. Without actually dyno'ing anything I can't confirm, but I always seem to notice better tip-in and more umph up top, but then again the weather probably has the same effect =) All this I'm guessing is a little more agressive timing curve, vs. save the engine mode on 91.

Every now and then I'll hear a slight det (on 91) at freeway speeds, usually when the engine temp (oil) gets a little hotter after zooming, I would hear more on the VIII. The IX seems to react very quickly, and seems to adapt a little faster (within 2-3 tach sweeps) to higher oct.

It's all hair-splitting until I feel more comfortable (Driver Mod) in this IX before adding more power.

DrMerl

True that. I have a Chevron and Mobil that I frequent, ick mpg on Chevron in the Evo, not too bad in the Leg. The IX gets very thirsty on 76 91oct, maybe due to more ethanol. Supposedly all gas here is monolithic in CA, with just additives introduced at tanker fill. It's nice to get a taste of 93oct once in a while like the rest of the "normal" country.

Cannonballer

iTrader: (3)

https://www.evolutionm.net/forums/sh...hlight=chevron

KawRider

iTrader: (8)

Im the guy with the Works BMF 02 sensor back system and Bored TB. Remember the Ex$pensive system? I made 300Hp at the wheels on a mustang dyno (Full Function) with a custom tune (2 hrs road and 1 1/2 dyno). My car never pulled any timing with this tune (I need to hook up my pocketlogger to re-confirm this). Pete (Owner of Works) was going to add one more degree of timing (I think he only added one total at this point), but I said don't worry about it, I will keep the extra margin of safety in case I get some crappy gas. For boost Im not really exactly sure what Im at (05 MR with the factory gauge package), except he took a lot of the taper out and my car hauls butt. Doing conversion, my boost spikes to around 1.6 bar (22 or so PSI) and then tapers slightly (around 18-19 maybe). Its hard to tell when you are trying to drive and monitor the boost. Im thinking that I could probably benefit from 1 more degree of timing once I get to the 93 Octane... what do you think, War Talon? It was amazing the 1 degree added like 15 HP when he added it. It would be nice to pick up some more... maybe another PSI of boost too? I know that would be worth some power. Bottom line is I want to continue with a safe tune, but I don't see why I can't improve the tune a little bit when I get the 93 gas. BTW- My AFRs were 11.2 accross the board.



Thanks for the comments and information.

KawRider

iTrader: (8)

I (Think) I do know one thing about the 9 ECU. It has more maps built in. My understanding is that it downgrades to safety maps (more rich, and retarded timing) when the knock count gets to a certain level. I know that the 8 did this too, but my understanding is that the 9 has more maps, and is less agressive with it's de-tuning until it really needs it. Please correct me if Im wrong.... Im here to learn.

Warrtalon

iTrader: (6)

Yeah, I know your mods - I just didn't recognize the name at first. I do think you'll be able to pick up some power with 93 as long as you get retuned. You are probably only able to run 22psi now, because of low AFRs and weak timing. You don't need to run more than 22psi on 93oct, but you can probably go to 11.5 AFRs and more timing (not just one degree) through the whole rpm range.

Psycodave

Ok this is going to be pretty noobie of me but you guy's have lost me on this whole thing. Simply because I have an 05 RS and have been putting 93 in it since I bought it but have nothing done to it performance wise exept for a FMIC which I had to get because I hit a deer but anyway you all are talking about gaining horse power by adding 93 aslong as he gets "tuned" for it. Our are cars not already tuned for 93, am I putting the wrong gas in or am I putting the right gas in and am I benifiting from puting 93 in or..... I'm sorry I'm confused and I now that I'm going to get flamed for this but oh well I will learn something in the prossess

Warrtalon

iTrader: (6)

You are still on the stock tune, which is very rich and weak. He is completely and fully tuned to optimize the performance of his mods on 91oct. Since he is tuned closer to the edge, he makes more power, but he doesn't make as much as he could if he had 93oct all the time. That's why he will be able to make more power on 93oct. You are using the proper octane, but you won't ever make full use of it until you get tuned.

KawRider

iTrader: (8)

Thanks for the input. Are you running 11.5 AFR? Is that still considered conservative and on the safe side? I seem to still get soot on my tailpipe with my tune, so I know Im still pretty rich. One more question. Do you have a Warbro fuel pump? Some people have been saying that the 9 has a better fuel pump (therefore the upgrade is not necessary), but I am undecided. My next mod will be cams (if they get the Mivec cams out.... or just an exhaust cam if they don't) and a 93 Octane tune. Im debating on the fuel pump upgrade.

Ludikraut

iTrader: (17)

Based on my experience, 11.5 AFR is slightly too lean. I used to run my '03 at 11.5 AFR and 22-23psi boost. On really hot, humid days it would pull timing in 4th gear (read: interstate, 75mph, downshift to 4th and then accelerate to pass). I'd keep it at 11.0-11.2 on 93 Octane, 22psi, and semi-conservative timing (sorry, I do not know the absolute values). However, you have an IX, so you may be able to get away with more timing or slightly more boost. Ultimately it's always about risk vs. reward.

l8r)