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Discussion Starter #1
A m8 of mine (without internet access :() has resently purchased an imported R34 GTT. He is currently having problems with performance (due to the knock sensor - we think) due to the high RON level the car is mapped for.

We have had a look around on the internet and it talks about adding the octane booster and replacing the sparkplugs for Iridium ones. I can understand the need for the octane booster to get UL or SUL upto the 102 RON it requires, however, what are the benefits for replacing the sparkplugs??


Thanks in advance


G.W
c/o BOO
 

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Hello, little lady!
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You would want to replace the sparks if you are running a higher than normal boost level i.e. with a boost controller. This is because the platinum sparks can't spark reliably under higher boost pressure. I know this for a fact because I had EXACTLY that problem with my GTS-T a couple of months ago after installing an EVC5 and upping the boost to .8 bar.

One set of GReddy Iridiums later and all was fine.

One suggestion I would make to your friend is to reset his ecu, which will then relearn its map based on the fuel he is running at the time. Most Skyline owners do this every now and again - all you have to do is fill up with your fuel of choice (optimax is my personal choice), then disconnect the battery for a few minutes. Pumping the brake pedal helps drain the systems of any excess charge remaining.

When you reconnect the battery the ecu will be ready to relearn your fuel map, so get your mate to take it for a spin and drive the car like it's been stolen! ;-)

This should help alot.

:D

J.
 

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can you be more specific about the symptoms?

Changing the spark plugs should eliminate any mid range misfiring and can improve throttle repsonse this more commonly seen on cars running higher boost, but you can change the gaps on the current plugs to see if that will help any, somewere around 0.8mm is the ideal gap

Pope
 

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bugger, you beat me to it Jamie
 

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Discussion Starter #5
Jamie, thanks for the tip on the ECU...should have thought of that myself as I now remember being told to do that on my old Scooby, when changing from UL to Optimax...still use the O'stuff for the STI8, you going to kick me off the board now :D:D

I take it their are no issues with the alarm if you do this, or is it best not to do it at 1am :)

Pope, As far as I know this is a standard GTT quoted at 280BHP. The problem seems to occur at approx 4-4.5k rpm, there is alot of noise and no go. For some reason the air-con speeds up ???? If he drops a bottle of Octane booster in, the problem goes away and he smiles alot :):)

Therefore at this point in time, I take it that the Iridium sparkplugs would be a waste of money until he starts playing with it??

I'm sure he will be on here himself at some point. He has only had the car a few weeks and it has the import plates on.

Thanks again

G.W
 

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Sounds like the plugs to me, id regap what you have to 0.8mm and see igf that helps... I'm sure others will give their comments but this is a subject covered here on a regular basis that most of us has suffered from and a decent set of plugs normally solves this

Pope
 

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As I'm no expert, the first thing I'd do when importing an unfamiliar car is take it to an expert for a full check.

The last thing he wants is his pride and joy going pop just because there's a dodgy hose of something.

Drop it down to Abbey or something and enjoy :)
 
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