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BC3S
'95 RT/TT
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Discussion Starter · #1 · (Edited)
what? why?
well, are you data logging your car? no? turn it down! if you are datalogging and not getting any knock, disregard this thread.

on stock boost (8.7psi) you will get knock counts as high as 14, if you've done the free boost mod (raising to 11.6psi) you are knocking as high as 20 count. even more psi and you peg the knock sensor at 28count on a stock fuel system+94oct! this is even true when hotwiring and doing a relay bypass on the stock pump.

if you are running stock ecu with no fuel management or fuel mods please turn down your boost. I guarantee you are knocking like crazy. after a bunch of tests on 4 different gto's with stock fuel systems+stock boost including mine, I've come to the conclusion that the jdm ecu is mapped for higher octane than we have available here in Canada at the pumps. yes, 94 from chevron isn't enough. all 4 cars gave same results. the main test was a 3rd gear WOT run from 1500rpm to red line. a sticker on one of the cars gas cap shows a rating of 100, assuming this is a RON rating, its equivalent to ~96aki.

please don't be stubborn, unless you are logging your car, you have knock and are damaging your engine under boost! the skylines have known this for a while and can reflash their ecu for our gas...but unfortunately we cannot.

how can you turn down boost if you don't have a boost controller?
unplug both vacuum lines to the solenoid and cap them. it will return your boost to waste gate (5.8psi) and save your engine until you can figure out an alternative.

what are the alternatives?
meth/water injection, usdm ecu, race gas, fuel management etc.
find a way to get that octane up at least 2 count and your good to go until you upgrade your fuel. swapping for a fed spec usdm ecu is also an option, though i have not tested this yet.

edit: UPDATE June 15
my solution
meth kit. check post #11 in this thread.
 

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Welcome to my world.. Nice to hear results from 4 different cars show the same thing!.

Methanol injection is your friend, I could run my 9bs/ 13g`s /16g`s open wastegate with enough meth and no knock.
 

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Premium Member
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hmmm very interesting... like to hear some other people chime in there thoughts on this... do we have any people in japan that can confirm octane rating of 100?
 

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BC3S
'95 RT/TT
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829 Posts
Discussion Starter · #4 ·

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Premium Member
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my puma GTO ran 14psi without issues. i always used 97-99 ron fuel and no meth with hotwired fuel pump. i noticed some of my cars wouldn't run above 9psi without fuel cut. but do the fuel pump hotwire run super and log it.
 

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Amsterdamn
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4,036 Posts
my puma GTO ran 14psi without issues. i always used 97-99 ron fuel and no meth with hotwired fuel pump. i noticed some of my cars wouldn't run above 9psi without fuel cut. but do the fuel pump hotwire run super and log it.
Dave, you have the same rated fuel as we do on the mainland, its higher octane than 94 mon in the states.

hmmm very interesting... like to hear some other people chime in there thoughts on this... do we have any people in japan that can confirm octane rating of 100?
Not Japan, but Europe here, cars are mapped similar here, we also have higher octane. We can get from 91 to 108 RON, mostly 95 and 98 RON here in Holland. Your premium fuel is different than our premium.

+repped the starter of the thread

EDIT: could this just be a problem of first gen JDM GTO TT's?
 

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most places here in canada we can only get 91 octane, but theres a few stations around that offer 94 and thats the highest pump ive seen.
 

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BC3S
'95 RT/TT
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Discussion Starter · #8 ·
my puma GTO ran 14psi without issues. i always used 97-99 ron fuel and no meth with hotwired fuel pump. i noticed some of my cars wouldn't run above 9psi without fuel cut. but do the fuel pump hotwire run super and log it.
even with relay bypass and pump hotwire it does not go away. none of the cars i tested got fuel cut (except mine which i did on purpose for testing by turning boost up past what the injectors could handle)
EDIT: could this just be a problem of first gen JDM GTO TT's?
i will know soon, there is a member in alberta with a late 93 that will be logging soon and letting me know.

caswell, remember 100 is RON not AKI like we have here. its equivalent to ~96aki. two of the cars had a 100RON sticker right on the fuel door.

bunch of stuff has already been discussed in the main canadian forum not on this site: ATTN: all RHD GTO turn down your boost! - Canada 3/S Community
 

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my puma GTO ran 14psi without issues. i always used 97-99 ron fuel and no meth with hotwired fuel pump. i noticed some of my cars wouldn't run above 9psi without fuel cut. but do the fuel pump hotwire run super and log it.
Did you log for knock in 3rd+ gears, what logger were you using?.
 

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BC3S
'95 RT/TT
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829 Posts
Discussion Starter · #10 ·
to the top so more canadian gto owners see this.

im actually also curious of the numerous cars in the USA that are using jdm ecu's. if you guys have any insight please post (no datalogg = no opinion).
 

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BC3S
'95 RT/TT
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829 Posts
Discussion Starter · #11 ·
so just an update. i installed dsm side mounts and although they helped, i still got knock.
then i installed a basic meth kit. problem solved. even more proof that the base map is 96oct. 0 knock even at 14psi, didnt try any higher clutch started slipping. i see a meth kit as better investment than getting a usdm ecu cause i can use it in the future as well with bigger turbos.

if you want details, just ask.
 

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I`ve gone over to running meth with the petrol in tank 20% works very well (you`ll need to re-tune for it though aprox 15% more fuel needed).
 

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SDSU Alumnus
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Great job with the research! Are you able to run Pump-91 now? or are you just doing 94+meth? Boo for no option to +rep! :mad:

I`ve gone over to running meth with the petrol in tank 20% works very well (you`ll need to re-tune for it though aprox 15% more fuel needed).
Cool! Are you just adding a measured amount of straight methanol into your tank? or is it that Toluene stuff?

I saw this chart in the following article: Octane Boosters Tested

Toluene might be another alternative since you have Pump-94 and would only need a small mix in tank.
 

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Twin Turbo
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might start adding an octane booster till i get a data logger.
 

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BC3S
'95 RT/TT
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829 Posts
Discussion Starter · #16 ·
Great job with the research! Are you able to run Pump-91 now? or are you just doing 94+meth? Boo for no option to +rep! :mad:
im just doing 94+meth for now since 94 here is only 3-5cents more than 91.
(fun fact, yesterday 94 hit $4.90/gal) i will try 91 from shell when this tank is dry.
interesting..will have to have a look at this a bit more seriously..I don't normally see any knock logging on 98 ron australia fuel though..
very interesting. i believe your ecu is OBDII correct? i would like to see a pull or two to compare with the OBDI logs.
might start adding an octane booster till i get a data logger.
dont bother with octane boosters[i tried them], they dont work. the amount of points they raise is in the decimals. so if it sais raise by 15 points = 0.15 octane increase :\


remember guys, i only have solid evidence for the OBDI jdm ecu's. im only speculating with the hybrids and OBDII's
 

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Great job with the research! Are you able to run Pump-91 now? or are you just doing 94+meth? Boo for no option to +rep! :mad:


Cool! Are you just adding a measured amount of straight methanol into your tank? or is it that Toluene stuff?

I saw this chart in the following article: Octane Boosters Tested

Toluene might be another alternative since you have Pump-94 and would only need a small mix in tank.
Yeh I put in 16l fuel at the pump and 4l methanol on a normal weekly fill.
 

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I think the petrol available in Japan is of higher octane personally, quite a few turbo cars imported from Japan have to have the timing reduced to run on UK fuel at least.

I`d like to try a 1st Gen 3000gt ECU in mine and see how it goes.
 

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BC3S
'95 RT/TT
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829 Posts
Discussion Starter · #20 ·
I wonder if the GTO has a knock sensor issue?
nope, all knock sensors on all the cars are fine. including mine. on one car we even replaced it and still same results.
 
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