Dont Be Fooled Into Buying Cheap Coil Packs.

[STATUS]

I've been meaning to share my experience. It's been a positive one regarding the purchase of performance coilpacks off ebay.

I'm not arguing the validity of claims made in OP nor quick to jump to conclusions around speding the big $ for quality. Everyone knows you get what you pay for.

This view may help those thinking of buying second hand.

Given my budget I was rather disenchanted with paying big dollars for second-hand brandname coils - generally some only seemed to be a 20% discount to what you would buy new.

To put things in perspective: 1. They're second hand. 2. Private sellers do not necessarily have a reputation to uphold or trade as a business. 3. Km's and/or their performance for the parts are generally unverified 4. No warranty 5. Recourse for disputes generally don't exist.

20% discount doesn't seem very attractive after-taking the above into consideration, a risk I would avoid all together and simply buy new if I could have afforded it.

The ones I use claim to have a 2-year warranty. Local Aussie seller. Recourse in Aus. - replacement. Ebay Powerseller 99.8% feedback.

I currently make 260rkw with them. $265 NEW and am currently very happy.

Happy to answer any questions. Not interested in people knocking me for using them. I'm simply spelling out better alternatives to secondhand. -knock the ones selling second hand ones at a 20-25% discount to new.

i run a tune shop and have to break the news to customers that their skyline needs decent coil packs .. im sure just about every other tune shop has the same experience with coilpacks and skylines... paying $265 and then having to cough up for something decent is no bargain.

[Ad's]

I forked out the money for splitfires about 2 years ago when i dropped the 25 into my coupe, even though they are pretty much bran new i dought id be replacing them anytime soon.

Do it once and do it right. Poor man pays twice if you cheap out. Not bagging other cheaper brands and im sure there is storys been as good as the top of the market brands but i only go for the best of the best.

That's my 2C.

[tranman]

I agree with what everyone is saying - pay the $ do it once do it right etc.

But it comes to a point where over-engineering for headroom for each single performance part that you won't actually end-up using may see you spend $$ unecessarily. e.g. instead put those dollars towards a bigger or highflow turbo where it will make the biggest difference.

We'll see if my coils will hold up at 300rwkw but by that stage, I have reservations about the stock motor anyway.

An interesting point I would like to make: Maybe it's not a function of power but how much PSI they can handle?? i.e. OP mentioned this particular set were breakdown / blowing-out at around 17psi?

Mine are fine but I'm only running 15psi max.

Might be useful for people to know. e.g. similar to the way we've come to a consensus around the stock rb25det turbo not doing more than 12psi.

[Humbla]

I can vouch for the stock turbo not doing well at high boost,hubby and son playing around with a home made boost controller.

17psi,lasted about an hour before it popped.This happened in 05 got gcg to hi flow and fix it been perfect ever since.

[copycutter]

No its actually the opposite the coils will work fine until they are required to work under high load.. then the missfire. Car ran fine at 12psi but could not light the fires above 16psi

That is kind of what I meant actually. IE you could audibly hear that they are not up to the job?

So with the graph in the OP, the "low power" condition with the cheap coils weren't clean power runs, those cheap coils actually had misfire? What I'm getting at is whether or not it's possible for coilpacks to sound totally normal even at full noise (no misfire sounds) and just produce less power?

[jiffo]

No its actually the opposite the coils will work fine until they are required to work under high load.. then the missfire. Car ran fine at 12psi but could not light the fires above 16psi

Yes, that's what happens.

I've got an old Repco spark plug cleaner/testing machine. Modern workshops wouldn't waste their time with such gear but it's useful to actually see what happens when you increase cylinder pressure.

Brand new plugs will perform perfectly at around 80psi but increase the pressure to 120 and they'll be breaking down. Go to 150 and you'd be surprised how poor the spark is. Close the plug gap and away you go again.

Before take off aero engines drop each mag and run load conditions observing the rpm drop per mag.

Poor spark equates to predictable loss of hp when under load.

Showing my age but as DC3 passengers, we'd be listening for a weak cylinder as the pilot's ran up and tested each engine's mags at the end of the runway.

[ezy_09s]

Buy once cry once . Brand new OEM , Splitfires or Okada Projects if you can afford them .

[rob82]

That is kind of what I meant actually. IE you could audibly hear that they are not up to the job?

So with the graph in the OP, the "low power" condition with the cheap coils weren't clean power runs, those cheap coils actually had misfire? What I'm getting at is whether or not it's possible for coilpacks to sound totally normal even at full noise (no misfire sounds) and just produce less power?

Yes it is possible for a weak coil not to misfire but produce less power.

Usually the discharge time increases on faulty coils. Normal inductive coil discharge time can be anywhere from 10-50us, I've personally seen twice the dicharge time in comparing a good coil vs bad, can't remember the discharge time but it was a ba coil. If you look at an engine at 6000rpm with a coil discharge time of 50us and a bad coil at 100us that means if you are knock limited on the good coil cylinder than you will be 0.05/10x 360 = 1.8degrees retarded on that cylinder.

[copycutter]

Wow didn't know this. Thanks rob.

I've got yellow jackets on there and they appear fine etc misfire-wise. How can you test if the discharge time is good/bad?

[(OO)SKYLINE(OO)]

OEM or SPLITFIRE are the only real options.

+1

[tranman]

Powerloss attributable to misfire aside, how much less are we talking e.g 1 cylinder @1.8 degree retarded as per the example above?

Could it reach as high as say 20rwkw loss with everything appearing to be 'normal'?

Edited March 19, 2013 by tranman

[rob82]

Powerloss attributable to misfire aside, how much less are we talking e.g 1 cylinder @1.8 degree retarded as per the example above?

Could it reach as high as say 20rwkw loss with everything appearing to be 'normal'?

Well it depends, if you have 1 good coil with 5 bad you could have real problems. Also where your peak power occurs will affect power loss. The higher the rev range the more retarded the ignition event becomes which means the greater the power loss becomes. Using the same figures as before at 7500rpm the ignition retard will be about 2.25deg.

Dropping 2degrees on a knock limited rb25 could reduce power by 10-20rwkw quiet easily.

You can test the coils response by scoping the coil high voltage side, kind of need to know what your looking at though.

[copycutter]

What if the engine was not knock limited IE e85?

[rob82]

Yes it is possible for a weak coil not to misfire but produce less power.

Usually the discharge time increases on faulty coils. Normal inductive coil discharge time can be anywhere from 10-50us, I've personally seen twice the dicharge time in comparing a good coil vs bad, can't remember the discharge time but it was a ba coil. If you look at an engine at 6000rpm with a coil discharge time of 50us and a bad coil at 100us that means if you are knock limited on the good coil cylinder than you will be 0.05/10x 360 = 1.8degrees retarded on that cylinder.

I meant to say "1.8degrees retarded on the other cylinders".

If the engine is not knock limited than generally you can get around the dodgy coils by advancing the timing past MBT to account for the slower coil discharge rate/coil voltage rise time.

[sonicz]

I've been using yellow jackets for a about a year and havent had a probelm with them. When doing the research I actually came accross of lot of guys who said they have had spitfires fail on them, or had problems etc, but nothing negative about the yellowjackets, so I deceid to go with them even though I could afford the spitfires.

If you actually look at a yellow jacket carefully you can see the coils and contacts are very high quality and they are not messing about like the cheap chinese red ones, which i have also seen and used and they are horrible.

Thats said there was nothing wrong with my stock ones. They wroked flawlessly. I just felt they were old. I sold all 6 for a measly $90 kind of regret it now.

Edited March 20, 2013 by sonicz

[GTSBoy]

Stock coils are all old and waiting to die. Don't be sad. I had access to a lot of sets of them at the time when mine were dying, and all the replacement ones were no better than the 6 I had to start with.

[WMDC35]

i've gone to ls1 coils, no more spark issues, bit of a hassle though

[STATUS]

500hp @ wheels OEM coil packs.

[tranman]

I agree with what everyone is saying - pay the $ do it once do it right etc.

But it comes to a point where over-engineering for headroom for each single performance part that you won't actually end-up using may see you spend $$ unecessarily. e.g. instead put those dollars towards a bigger or highflow turbo where it will make the biggest difference.

We'll see if my coils will hold up at 300rwkw but by that stage, I have reservations about the stock motor anyway.

An interesting point I would like to make: Maybe it's not a function of power but how much PSI they can handle?? i.e. OP mentioned this particular set were breakdown / blowing-out at around 17psi?

Mine are fine but I'm only running 15psi max.

Might be useful for people to know. e.g. similar to the way we've come to a consensus around the stock rb25det turbo not doing more than 12psi.

Just wanted to let people know- going for 300kw + on e85. Tuner has come back telling me coilpack #5 is arcing out all over the place. Told him to drop in Splitfires STAT.

We were still both impressed they managed 260kw though.

So when the mod bug bites, you'll eventually need them.

[copycutter]

What coils were in there during that last tune? Stock ones or some aftermarket?