dan0h

Beautifully put Mycroft. Once again your wisdom clears a path through the fog of mis-informaiton!

Cheers,

Dan

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planet dan0h

Dynapack Operator and Engine mapper @ Abbey's ... Responsible for Tim's BNR34 Nur, tokyodrew's BNR34, Rocket Ronnie's 3xTOTB Winning BCNR33, Harry's BCNR33, Big Marks BCNR33, Jae's BCNR33, Zenon's (Nemesis) BCNR33, Ron Kidell's (RK Tuning) BNR32, m6beg's BNR32 & m6beg's missus's GDB Subaru!, Daz's BNR32, Knight's BNR32, GBH Motorsport JZA80 ... And quite a lot of other cars people don't know about...

TOKYO

Are you a Vampire?

You've gotta sleep during the day to come out with these sayings this time of night .

Plus you do scare me sometimes .

glen

Mycroft

somberg

hehe sniffed too much toluene have you

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Bananaman..

Mycroft

Nah, sniffin's kids stuff, 'on the rocks' is the way to go.

Edit, this thread is getting WAAAYYYYY too many hits, nigh on 12,000, poor (literally?) Cem.

TOKYO

Rights thats it, I'm off to bed .

glen

Syed Shah

Mycroft,

Saying that lead is bad for engines and valves goes against everything I've ever heard, some from very knowledgeable people, which in my mind, cancels out what you have said.

As for 116octane fuel only being used in extreme vehicles, well, a lot of people in the states run this fuel in 'BPU' Supras, when at the track etc. Not the most extreme of setups.

BTW, you are simply being pedantic about the octane ratings, 93vs94 is not a huge amount of differnce, and the point still stands.

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Supra MKIV x 2
R6 *rip*
Soarer TT

somberg

Syed Shah,

I don't think you quite understand the concept of searching the limits of an engine. In the quest for max power output, you want to find the limit where detonation starts (and consequently engine life is shortened ). As you can (or should have if you will) read from various other posts on this board, and I'm sure you can get this verified by your expert friends, this also depends on the octane rate of the fuel used. Using fuel with an octane rate lower than used to program the ECU (even if it "only" differs 1 octane), will (dependant on the ECU used) in the best case cause loss of power and in the worst case destroy your engine.

Andre.

BTW can you explain what the heck BPU is ?

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Bananaman..

Syed Shah

Basic performance upgrades (Tm ) Like decat +exhaust and BC etc.

As for your post, well I dont think any stock-turboed skyline would detonate on US 93octane.

As for the ECU mapping, the ECU 'adapts' to the fuel used, ie if too low, timing will be retarded causing power loss, but use of a very higher octane fuel (leaded or unleaded) will result in a power gain due to timing not being retarded.

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Supra MKIV x 2
R6 *rip*
Soarer TT

somberg

If that stock turboed Skyline has a std ECU mapped for Japanese fuel (100 oct), then it probably will detonate, yes.

Re. use of a "very higher octane fuel": if your reference point is the octane rate of the fuel used to map the engine, it will not result in more power, but merely "not less power" due to the timing not being retarded.
Note that the means used to detect detonation in most ECU's (like the ones in the Skyline) is done with piezo-effect det sensors. The electronics hardware and software with which the signals are analyzed, are not very elaborate. In other words, it's quite an "over the thumb" method, meant to protect the engine from destruction. Timing is retarded quite drastically, resulting in quite some power loss. That's why you don't really want to use 97 octane if your ECU is mapped for 98.
The ECU's as such are basically open loop systems. Next generation ECU's will be based on closed loop control, using det sensing techniques ("ion sensing") that go far beyond the possibilities of the piezo sensors. See also earlier on in this thread. Result will be better adaptability of the engine to various octane fuels, better fuel economy and less pollution.

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Bananaman..

Syed Shah

Well, not sure about Skylines, but in Supras, due to the ECU 'learning' the fuel octane, then a better octane will mean more power.

This relates to Mycroft's post a while ago about toulene reducing his 1/4 mile times by over a second (this much of a difference is unrealistic IMHO). This would be due to the car making use of the higher octane.

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Supra MKIV x 2
R6 *rip*
Soarer TT

Mycroft

#Mycroft,

Saying that lead is bad for engines and valves goes against everything I've ever heard, some from very knowledgeable people, which in my mind, cancels out what you have said. #

Interesting...do me and all of us a favour, run you car on unleaded for the 3 months, then return with you 'findings' please do this if you can. I will be quite happy to eat my words if I am wrong.

Try also running your car on 116oct but before you do take readings of your timing before 116 and after, then post just how much your ECU has 'learnt' about its rating. this will also be interesting, I have de-programmed a few Toyota ECUs' and they don't quite behave in the way you describe.

I have to advance the ignition by deceit, the ECU doesn't do this, it can retard and can back off from maximum retardation but it can never fully recover the Factory settings, that is why they have a simple 'reset' mechanism of removing for 30secs the fuses, this would be un-necessary if the system was 'fully-recoverable'

As for the pedantry, you maybe right, but accuracy is important here, so if I correct you it is for the sake of accuracy, this thread is read all over the World and 'guestimates' just don't cut it here.

Syed Shah

1 second, 3/4 of a second, eirther way, too much for JUST adding toulene.

De-programming Toyota ECUs??? For which Toyota?

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Supra MKIV x 2
R6 *rip*
Soarer TT

somberg

Syed Shah

Why do you think that ?
Do you believe it's due to for instance the removal of an ingrown toenail ?

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Bananaman..