spark plugs, which ones to use

[michaelb]

Hi

I had recently Apexi fc fitted by ant on here.  I still have a cat but a HKS back box.

Boost has been turned up a little too  The car is a daily driver.

Ant recommended that I change my spark plugs for something better then standard RX7 plugs.  Next month I am going to service the car.

Can some one kindly explain to me the difference between 9s 10s and 11s and which ones are suitable for my car or rather which ones will give me increased performance with out starting problems..

Thanks in advance

Regards,
Michaelb

[Joeh]

If you\'re having starting problems, use 7\'s and 9\'s I think.

[michaelb]

Hi

Thanks for that.

I am not having starting problems but I heard that if you chnge your sparkplugs to a different type you may end up with them...

Regards,
Michaelb

If you\'re having starting problems, use 7\'s and 9\'s I think.

[John Yorke]

The numbers indicate the heat rating 7\'s being the warmest and 11\'s the coldest, the more boost you run the colder the plug [in simple terms] if you have upped the boost above .9 bar I would have thought 9\'s all round if you have gone higher 9\'s & 10\'s I would add I am no tuner and I am giving this advice as a fellow driver, if in doubt consult you prefured tuner.

[michaelb]

The numbers indicate the heat rating 7\'s being the warmest and 11\'s the coldest, the more boost you run the colder the plug [in simple terms] if you have upped the boost above .9 bar I would have thought 9\'s all round if you have gone higher 9\'s & 10\'s I would add I am no tuner and I am giving this advice as a fellow driver, if in doubt consult you prefured tuner.

Thanks for the input

The boost on the commander show at the highest 0.92 mmhg  

As far as I remember ant put up the primary and secondary by 0.5 each…

I must say that the car got much faster…

Shall I use 10 for better performance?  Will the car start during winter?

Can I have a mixture of 2 9s and 2 10s ?

Regards,
Michaelb

[shaunwil]

You should be ok for 9\'s all round. If you run any higher boost you will want to use racing 11\'s. I had to swap over to 11\'s with 0.98bar. I could use 9\'s if i didn\'t rev it to the redline ! The car starts to misfire at top end otherwise.

Shaun

[AtomicRex]

I use an 11 in the lead plug and a 10 in the trailing plug.

It isn\'t wise to be using that cooler a plug if you are going to be using the car around town as the cooler the plug the more likely it is to foul up.

If you want to use a different heat rating then go for a 9/10 but you might as well go for 9\'s all round

Having spoken to the Rx7 store they recommend a bike plug....and at only £5 per plug makes it cheaper.

Ive put an order with Mark for some Iridium plugs.  But usually use Sparkplugs.co.uk

[michaelb]

Hi

Thanks for that.  I
 went on the site and is this the ones you mean NGK--BUR9EQP ?

Regards,
Michaelb

I use an 11 in the lead plug and a 10 in the trailing plug.

It isn\'t wise to be using that cooler a plug if you are going to be using the car around town as the cooler the plug the more likely it is to foul up.

If you want to use a different heat rating then go for a 9/10 but you might as well go for 9\'s all round

Having spoken to the Rx7 store they recommend a bike plug....and at only £5 per plug makes it cheaper.

Ive put an order with Mark for some Iridium plugs.  But usually use Sparkplugs.co.uk

[AtomicRex]

Which site were you looking at?

I spoke to the guys at sparkplugs.co.uk and to be honest they werent able to offer me anything I really wanted.  NGK dont sell the race plugs to the UK, they even checked out the european arm.  The alternatives were very expensive.

Either chat to Mark (blitzboy) and order some through him, or see if Gary at Rotaryarts can get you some.

[shaunwil]

If you want the racing plugs pip at wgt does stock them but they arn\'t cheap.

So what bike plug would you be able to use (very interesting)

Shaun

[AtomicRex]

The plug details are on a mail at work, but I will post it on here tomorrow

And as for cheap....er no!  Although for my old K-Series I was paying almost £50 per plug!

Having said that dont go to Merc for a spark plug change....£500 :-o

[Mazdarotaryparts]

Hi Michael,

As many have said on this thread, you only need 9\'s in both leading and trailing spark plug holes in your car and would advise not to even think about anything different.

btw, We sell these at £38 a set delivered which is £2.00 cheaper than Sparkplugs.co.uk

I don\'t think 7\'s are available any more but you would only need to put these in a nearly dead low compression engine in an effort to stop it flooding.

Not that you need them but 10.5 plugs are readily available in the UK but cost £32+vat per plug :3Confused

Hope this helps

[Carl]

I use an 11 in the lead plug and a 10 in the trailing plug.

It isn\'t wise to be using that cooler a plug if you are going to be using the car around town as the cooler the plug the more likely it is to foul up.

If you want to use a different heat rating then go for a 9/10 but you might as well go for 9\'s all round

Having spoken to the Rx7 store they recommend a bike plug....and at only £5 per plug makes it cheaper.

Ive put an order with Mark for some Iridium plugs.  But usually use Sparkplugs.co.uk

Hi John,
I think you mean that they are 10\'s in the leading and 11\'s in the trailing.
That is how they should be,and most important to be that way around too.
Regards
Carl

[AtomicRex]

Oops sorry Carl....yes that is the way I meant :eek

And I thought I was actually sounding as though I knew what I was on about then!

[michaelb]

Hi Carl

How are you doing!!!  I finally got the Apexi fc and commander ( remember we had a chat about it at JAE, had it fitted it by ant on here, had the boost lifted a little and you were right â€" much better performance then using the stock ecu…

I guess I will be getting the spark plugs from you next month for the service.

I wonder if I should try and change them my self as I have been told that they are difficult to get to

Regards,
Michaelb

Hi Michael,

As many have said on this thread, you only need 9\'s in both leading and trailing spark plug holes in your car and would advise not to even think about anything different.

btw, We sell these at £38 a set delivered which is £2.00 cheaper than Sparkplugs.co.uk

I don\'t think 7\'s are available any more but you would only need to put these in a nearly dead low compression engine in an effort to stop it flooding.

Not that you need them but 10.5 plugs are readily available in the UK but cost £32+vat per plug :3Confused

Hope this helps