[drapzzy]

Hi all,
so i have been tuned for about 3k miles on bm3 on stock plugs, car has about 38k miles. I guess im really asking when I should change my spark plugs because car has been stock before and just tuned for the first time so I would assume the plugs still have some life, can anyone tell me otherwise

[Billfitz]

Along with most maintenance items it's in your Service and Warranty document.

[drapzzy]

Originally Posted by Billfitz

Along with most maintenance items it's in your Service and Warranty document.

does it say for modified cars though?

[sspade]

Change at 50k with NGK 97506

[BMWILUVU]

Originally Posted by drapzzy

Hi all,
so i have been tuned for about 3k miles on bm3 on stock plugs, car has about 38k miles. I guess im really asking when I should change my spark plugs because car has been stock before and just tuned for the first time so I would assume the plugs still have some life, can anyone tell me otherwise

If you are on stage 1 and there are no problems, I would leave the plugs as-is but have a spare set around if trouble rears its head.

[johnung]

Originally Posted by drapzzy

Hi all,
so i have been tuned for about 3k miles on bm3 on stock plugs, car has about 38k miles. I guess im really asking when I should change my spark plugs because car has been stock before and just tuned for the first time so I would assume the plugs still have some life, can anyone tell me otherwise

Rule of thumb for spark plugs with a stock tune is to replace them every 60k miles. When an engine is tuned, that drops to about 30k miles.

Stock plugs are fine. The stock OEM Bosch plugs for my N55 engine are about $9 each. Really not worth quibbling. If you think that your plugs might need to be changed, then change them. Use the stock gap right out of the box. I know that the stock Bosch plugs for my engine are not made to be gapped more narrowly and easily break.

Unlike other parts like brake pads, shocks or tires that can obviously be improved with aftermarket parts, there is no such thing as a spark plug upgrade. BMW engineers have chosen the optimal plug (and gap) for each engine. Changing that can often lead to the engine running worse.

There is a caveat to this. Engines that are tuned with much higher than stock boost can experience something called spark blowout. It's a misnomer because the spark doesn't actually blow out.

With very high boost, the engine cylinder is packed tightly with a high number of extra fuel and air molecules. It can prevent the spark from even getting started across its stock gap. There are typically two solutions to this issue, either much stronger power from the ignition system or a colder plug with a shorter gap. The latter is more cost effective to implement.

So you'll hear guys say to throw in colder plugs and to gap the plugs down to a narrower gap. This is NOT an upgrade! If an engine is running smoothly on stock plugs & gap, colder/narrowly gapped plugs is likely to make it run worse.

Installing colder, more narrowly gapped plugs in an engine that is tuned for much higher than stock boost, should be a reaction to that engine not running well- showing physical signs on visual examination of its stock plugs and in its engine logs, of spark blowout.

Note: On highly boosted N55's the plug of choice is the one-step colder NGK 97506 gapped down to about 0.022". (This gap is too narrow for most automotive spark plug gap gauges so a motorcycle gap gauge has to be used.) Users report that they wear out much sooner than stock plugs 30k miles. The NGK 97506 plugs on highly boosted N55's have been wearing out at 19k-20k miles.

Guys always ask about coils too. Typically coils need replacement at about 60k miles. That pretty much stays the same with a tuned engine. I've heard of people buggering up their coils when changing plugs though. Precision Raceworks makes a coil upgrade but again really not needed unless you're building a race engine. I've read lots of issues with guys thinking that they are upgrading and causing themselves problems.

In the coil replacement market you'll see original BMW coils, Bosch coils and Delphi coils. There is an actual upgrade to coils- Eldor coils. Eldor is a high end coil manufacturer in Italy who makes coils for many high end exotic cars.

I've heard that BMW has actually switched to Eldors and photos of the current Genuine BMW coils sure look like Eldors. So you can save money over Genuine BMW if you just install Eldor coils. Eldor is not highly distributed in the US under their own brand. It's difficult to explain their marketing/distribution, but they are definitely available.

Hope this helps!

[gameson]

You can take out the plug and check if it’s black. If still looks new, then it’s ok. If it looks bad, replace

[sqwinny]

I do a change once a year as I bought my spark plugs from fcp euro. Takes 10 minutes and they are gapped + replaced. Otherwise every 30-40k or so if tuned. I'd do the same with coils but I have the PR coil upgrade.

Curious to see if b58 Eldor coils will work on the n20 with a harness adapter as I want the space back in my engine bay.

[drapzzy]

Originally Posted by johnung

Rule of thumb for spark plugs with a stock tune is to replace them every 60k miles. When an engine is tuned, that drops to about 30k miles.

Stock plugs are fine. The stock OEM Bosch plugs for my N55 engine are about $9 each. Really not worth quibbling. If you think that your plugs might need to be changed, then change them. Use the stock gap right out of the box. I know that the stock Bosch plugs for my engine are not made to be gapped more narrowly and easily break.

Unlike other parts like brake pads, shocks or tires that can obviously be improved with aftermarket parts, there is no such thing as a spark plug upgrade. BMW engineers have chosen the optimal plug (and gap) for each engine. Changing that can often lead to the engine running worse.

There is a caveat to this. Engines that are tuned with much higher than stock boost can experience something called spark blowout. It's a misnomer because the spark doesn't actually blow out.

With very high boost, the engine cylinder is packed tightly with a high number of extra fuel and air molecules. It can prevent the spark from even getting started across its stock gap. There are typically two solutions to this issue, either much stronger power from the ignition system or a colder plug with a shorter gap. The latter is more cost effective to implement.

So you'll hear guys say to throw in colder plugs and to gap the plugs down to a narrower gap. This is NOT an upgrade! If an engine is running smoothly on stock plugs & gap, colder/narrowly gapped plugs is likely to make it run worse.

Installing colder, more narrowly gapped plugs in an engine that is tuned for much higher than stock boost, should be a reaction to that engine not running well- showing physical signs on visual examination of its stock plugs and in its engine logs, of spark blowout.

Note: On highly boosted N55's the plug of choice is the one-step colder NGK 97506 gapped down to about 0.022". (This gap is too narrow for most automotive spark plug gap gauges so a motorcycle gap gauge has to be used.) Users report that they wear out much sooner than stock plugs 30k miles. The NGK 97506 plugs on highly boosted N55's have been wearing out at 19k-20k miles.

Guys always ask about coils too. Typically coils need replacement at about 60k miles. That pretty much stays the same with a tuned engine. I've heard of people buggering up their coils when changing plugs though. Precision Raceworks makes a coil upgrade but again really not needed unless you're building a race engine. I've read lots of issues with guys thinking that they are upgrading and causing themselves problems.

In the coil replacement market you'll see original BMW coils, Bosch coils and Delphi coils. There is an actual upgrade to coils- Eldor coils. Eldor is a high end coil manufacturer in Italy who makes coils for many high end exotic cars.

I've heard that BMW has actually switched to Eldors and photos of the current Genuine BMW coils sure look like Eldors. So you can save money over Genuine BMW if you just install Eldor coils. Eldor is not highly distributed in the US under their own brand. It's difficult to explain their marketing/distribution, but they are definitely available.

Hope this helps!

Thanks for all the info, I did go ahead and order a set of ngk 97506 and I am eager to see how black my current ones are. I have been tuned for about 3k miles like I stated but the previous owner has driven it stock for 35k, I am planning on going stage 2 once my intercooler comes in so I will probably gap it to .022

[johnung]

Originally Posted by drapzzy

Thanks for all the info, I did go ahead and order a set of ngk 97506 and I am eager to see how black my current ones are. I have been tuned for about 3k miles like I stated but the previous owner has driven it stock for 35k, I am planning on going stage 2 once my intercooler comes in so I will probably gap it to .022

If you have a free flow catted or catless downpipe you can flash Stage2 now. Car will protect itself if you over do it

[drapzzy]

Originally Posted by johnung

If you have a free flow catted or catless downpipe you can flash Stage2 now. Car will protect itself if you over do it

Yea I am catless, and I'll just wait it's really cold although but I get really anxious when doing stuff like that, plus I'm not sure how worn my plugs are

[jdrock]

Is there any performance Spark Plug recommended with the standard stock gap for F32 435i?