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Discussion Starter #1
Lets say in an F/I app. you have the car tuned for 93/94 octane, you fill your car up with 91/92 because the gas station your at doesn't have 93/94. Do you have to redo the timing/fuel maps you set for 93/94 for the lower octane level, or will the car run just fine?, can the piggyback or ECU/standalone your using compensate provided you have all the right sensors, A/F targets set, and etc?. Thank you.
 

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Well don't take my word as the final say, but what manufacturers suggest doing from the factory is getting enough gas at the lower octane to cover you until you can get to a station with the appropriate octane, then fill up there
 

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Originally posted by DiRN@Oct 19 2004, 09:52 AM
Well don't take my word as the final say, but what manufacturers suggest doing from the factory is getting enough gas at the lower octane to cover you until you can get to a station with the appropriate octane, then fill up there

I have heard this to be true also ^

That way, the lower octane fuel is burnt and gone before the sensors start to compensate for it... It takes somethin like 100 miles before the car gets used to a certain octane level.
 

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Originally posted by Chi-TownWarrior@Oct 19 2004, 08:47 AM
Lets say in an F/I app. you have the car tuned for 93/94 octane, you fill your car up with 91/92 because the gas station your at doesn't have 93/94. Do you have to redo the timing/fuel maps you set for 93/94 for the lower octane level, or will the car run just fine?, can the piggyback or ECU/standalone your using compensate provided you have all the right sensors, A/F targets set, and etc?. Thank you.

If your car is tuned to that octane level, and you add a lower octane your asking to break something. Your car will abnormally start knocking/detinating (sp).

Lets say you burn up a piston, and the shop that tuned it discovers you put in the wrong gas your SOL. :thumbsup:

Most good tuners will tune your car as a daily driver. Meaning not fully maxed, just for your own protection.
 

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I think it depends at what psi you set your maps for that octane. If you want to run at higher psi, you'd have to get a higher octane to prevent detonation (like FairladyZ said). I think you could get by for a short amount of time on a lower octane, but don't push it.

This is just a guess, but if running higher psi requires higher octane, would running below normal psi be okay with lower a octane? I hope someone with FI can answer this.
 

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Discussion Starter #6
Originally posted by fairladyz+Oct 19 2004, 01:36 PM-->
<!--QuoteBegin-Chi-TownWarrior
@Oct 19 2004, 08:47 AM
Lets say in an F/I app. you have the car tuned for 93/94 octane, you fill your car up with 91/92 because the gas station your at doesn't have 93/94. Do you have to redo the timing/fuel maps you set for 93/94 for the lower octane level, or will the car run just fine?, can the piggyback or ECU/standalone your using compensate provided you have all the right sensors, A/F targets set, and etc?. Thank you.

If your car is tuned to that octane level, and you add a lower octane your asking to break something. Your car will abnormally start knocking/detinating (sp).

Lets say you burn up a piston, and the shop that tuned it discovers you put in the wrong gas your SOL. :thumbsup:

Most good tuners will tune your car as a daily driver. Meaning not fully maxed, just for your own protection.

Thanks for the answers. Now in that case is it possible to tune the car to run both, or is that not possible. The reason I ask is as soon as things settle down for me in the Marines, I plan to do a buildup (internals, turbo, etc) When I get some leave time I plan on driving back to Chicago, go to shows in the area. If I remember correctly chicago has 91 octane.
 

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Yes so long is your tuner is still in business. :clap: I believe some engine managment system can be programed for different levels. Say 1 is 91 octane, 2 is 93, and 3 is race gas (for the strip).

With the domestics such as the LS1/LS6, I had my programs on a floppy disk (no cheesy stand alones/piggy backs, complete computer reprograms). So all I would need to do is find a shop with LS1 edit and have them use the stored info to change my settings.
 

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The e-manage and Profec E-01 allow the user to store three maps and set values/parameters for boost pressure, ignition timing and fuel delivery.
 

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Discussion Starter #9
The two that I was looking at were the E-Manage, and the AEM EMS. I would concider the F-Con but I'm not a pro dealer, nor do I plan on visiting one every time I want to tweek something, and that can get to be a pain. I looked at the EMS, and the E-Manage manuals, and those two look like the easiest to self tune should I need to. GQ_626 said on that one site (forget which one) a ECU that the end user can use is way better, and these two look like the best choices.

KShep, Do you have mulitple maps stored on yours, and how hard is it tune/switch maps
 

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Originally posted by Chi-TownWarrior@Oct 19 2004, 01:21 PM

KShep, Do you have mulitple maps stored on yours, and how hard is it tune/switch maps

I have the stock Greddy map and a custom tuned map that I purchased from (ACP on the my350 forum).

The Profec display has a hardwired remote for navigation thru its' screens; which is where and how you select between alternative maps.
Simple.
 

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If you dont' do something when the lower octane is intorduced, it is very possible that you could do engine damage, if an FI setup is tuned to higher octane. The OEM knock algotithm cant' pull engouh timing to compensate fro boost induced detonati0on.

A couple CYA methods.

a) carry a can of good octane booster. "NOS Red can" can add about an equivalent od 2 real points . Note most octane boosters do next to jack. NOS brand is for real. If you get a 91 tank on a 93 tune , add the can you carry along.

b) use a piggyback that stores multiple maps. Greddy emanage,HKS, APS "Unichip" all provide such capablity. Have at least two maps tuned and available.

c) add a J&S safeguard , if detonation does occur due to the lower octane , timing will be pulled and protect your mill. Note the J&S unit also provides a switch 2 (4) degree retard input . Hook this into a toggle switch and use as "crappy gas switch".

Honestly it's a good idea to ideally use more than one of the afore mentioned methods if money permits.
 

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Discussion Starter #12
About the J&S. If your Piggyback/Standalone is already detecting knock and starts to pull timing, will the J&S interfere, and posibly cause problems?. And what would happen if I fill up on a higher octane 100-110 on a 93/94 tune?.
 

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How much boost can you run safely on 92 octane gas ? And how much timing retard would you run for 92octane for each lb of boost on ?
 

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Originally posted by Chi-TownWarrior@Oct 19 2004, 04:03 PM
About the J&S. If your Piggyback/Standalone is already detecting knock and starts to pull timing, will the J&S interfere, and posibly cause problems?. And what would happen if I fill up on a higher octane 100-110  on a 93/94 tune?.

Most piggyback systems do not monitor the knock sensor or pull timing with respect to knock sensor telemetry.

Most Piggybacks pull timing based upon these input variables: RPM, MAF and/or MAP , TP.

So a J&S will work "in addition" to the timing being pulled by the Piggyback. So it shouldn't cause problems, you'd just will be more protected against detonation. If you use higher octane , the J&S just wont' pull any timing since no knock shoudl be detected.

If you use the switched (2/4 degree) input , you'd need to set to "no retard".
 

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Originally posted by booger@Oct 19 2004, 04:46 PM
How much boost can you run safely  on 92 octane gas ? And how much timing retard would you run for 92octane for each lb of boost on ?

From the same shop; for a pretty much stock 350Z I was told no more than 5.5lbs of boost, reffering to the greddy kit daily driven. For 500-600 more dollars they can tweak the system to run alittle more boost. By tweak I mean a different fuel system w/bigger injectors, etc which they say will eclipse the 400rwhp mark.

You have to remember these cars have alot of compression, which is a no no to boost.
 

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Discussion Starter #16
I was just talking to a frined of mine, and he said Chicago has 93. So now I ask this. We have 94 here in SC, and if I fill up with 93, will that make any difference. I would hope not since its only one octane point, but you never know.

I like the switch idea for good gas and crappy gas. But with the J&S if it picks up on detonation, and doesn't pull timing till the next firing sequence will it only pull timing every other time in the sequence, or will it just pull timing till it thinks the detonation is gone?.

Sorry, I just need to pick someones brain
 

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Originally posted by Chi-TownWarrior@Oct 19 2004, 01:21 PM
I would concider the F-Con but I'm not a pro dealer, nor do I plan on visiting one every time I want to tweek something


Not true. If you bought a HKS F-CON V PRO or HKS F-CON SZ you can use the navigator to tune it. Not as elegant as a laptop but it does the job
 

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Discussion Starter #18
Originally posted by MR RIZK+Oct 20 2004, 05:48 AM-->
<!--QuoteBegin-Chi-TownWarrior
@Oct 19 2004, 01:21 PM
I would concider the F-Con but I'm not a pro dealer, nor do I plan on visiting one every time I want to tweek something


Not true. If you bought a HKS F-CON V PRO or HKS F-CON SZ you can use the navigator to tune it. Not as elegant as a laptop but it does the job

So the Software comes with the F-Con V PRO/SZ? I was under the infulence that you you had to be a pro tuner to get the software, and the F-CON was sold w/out the software so HKS could cover themselfs. After seening what Phunk did with the F-CON, I like the F-CON above all the others, because it seems like it has more stability over the Greddy and the AEM, and stability of the system is moreimportant to me.

Anyway.

After looking at the AEM forum the EMS looks like a very good system as far as stability and user friendlyness. The only problem I have is it looks like the EMS cannot store mulitple maps. Yes I can just carry a laptop with me (I plan on doing that anyways), but from what I have read its good to have a system that can store more then one map. AEM did say they are for sure coming out with the EMS it's just right now it's on the back burner. As soon as that comes out the AEM EMS and the F-CON will be the two most popular systems out there.

http://forum.aempower.com/bbs/login.php
 

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Originally posted by Chi-TownWarrior@Oct 19 2004, 10:23 PM
I was just talking to a frined of mine, and he said Chicago has 93. So now I ask this. We have 94 here in SC, and if I fill up with 93, will that make any difference. I would hope not since its only one octane point, but you never know.

I like the switch idea for good gas and crappy gas. But with the J&S if it picks up on detonation, and doesn't pull timing till the next firing sequence will it only pull timing every other time in the sequence, or will it just pull timing till it thinks the detonation is gone?.

Sorry, I just need to pick someones brain

It will pull timing wither on each individual cylinder individually or on all together, until the knock signature is no longer detected. It implements a type of leaky bucket algorithm to keep timing below the threshold if needed over time. With the J&S it is a good idea to use the "knock guage" so if knock is persistent so you can alter your driving habit unit you can get a good tank. More info on the J&S site.
 

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Chi-TownWarrior

As per my previous response

Not true. If you bought a HKS F-CON V PRO or HKS F-CON SZ you can use the navigator to tune it. Not as elegant as a laptop but it does the job

The navigator is an additional unit that can be used as a hand controller.
 
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