RS7 colder plugs in an S3

[sansian5016]

Hey guys,

I wanted your thoughts about putting colder plugs in the S3. I have a Unitronics Stage 1+ ECU and TCU tune on my 2017 S3. My shop is recommending the RS7 plugs as those are colder and better suited for performance than the plugs that the S3 comes with. I would like your thoughts and comments (pros and cons).

Thanks!

[mroberte]

Denso IKH24 is what I use. Cheaper and same "performance" benefits. However if you are just once in awhile being hard on the engine just keep using the stock plugs.

I changed mine because I take the car on the track quite often and am pushing the engine alot.

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[613B6]

I'm on stock plugs at 400whp/410wtq, so go figure..original plugs too with 20km on them!

[TCHUN003]

I'm on stock plugs at 400whp/410wtq, so go figure..original plugs too with 20km on them!

What turbo and tune?

[sansian5016]

Are there any cons to getting them. I drag the car a couple times a year and drive spiritedly lol. I don't race on tracks often like you guys. So if it's only a benefit, I might get them as they are $64. Just waiting to see the installation costs.


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[murda face]

Put rs7 plugs in my a3 yesterday. plugs were a bitch to get out. One in particular...34 k stock plugs apr stage 1 for 15k. Car idles much better now stock plugs didnt look bad


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[sansian5016]

My car idles fine with the Unitronics tune. The plugs plus install will be around $173 from my shop. If there really is no benefit, then why waste the money. I came from the Subaru world and I know when you go to stage 2 on an STI, colder plugs were recommended and that did make a difference. It seems as though for stage 1, it really is not necessary unless you track the car monthly or more frequently.

[mroberte]

Not really a con but you can use the money elsewhere honestly. Run them when you know your pushing the car quite a bit and often. For a few drag strip days, better off getting race gas or e85 mix.



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[sansian5016]

Not really a con but you can use the money elsewhere honestly. Run them when you know your pushing the car quite a bit and often. For a few drag strip days, better off getting race gas or e85 mix.



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Thanks for advice. I think I will hold off on replacing the plugs for now. Also, I am running the Unitronics map for 93 octane as I am in NJ. At my local track, I can buy 100 octane. Back in the day, I used to add 2-3 gallons to my tank for safety reasons even though my car was not tuned for it. Would the same logic apply to this S3 motor? My STI was super sensitive to bad gas. I just do not know enough about this engine. Thanks for the advice!

[mroberte]

Thanks for advice. I think I will hold off on replacing the plugs for now. Also, I am running the Unitronics map for 93 octane as I am in NJ. At my local track, I can buy 100 octane. Back in the day, I used to add 2-3 gallons to my tank for safety reasons even though my car was not tuned for it. Would the same logic apply to this S3 motor? My STI was super sensitive to bad gas. I just do not know enough about this engine. Thanks for the advice!

I run 91 daily because it's what the west coast is stuck with but I've also run 100 and 110 octane. I honestly did not feel much significant gains from either... and it was about $160 bucks for two tanks worth. The car did just the same as with 91 and jb1 logging didn't show any weirdness from all three.

The only significant gain was from e85/91 blend. Ethanol has cooling properties and it was very apparent on the track pushing the car so much that I melted my bumper.

So the ecu will adjust quite well for many octane of gas and without you really knowing it. It's really some crazy engineering they did.

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[sansian5016]

I run 91 daily because it's what the west coast is stuck with but I've also run 100 and 110 octane. I honestly did not feel much significant gains from either... and it was about $160 bucks for two tanks worth. The car did just the same as with 91 and jb1 logging didn't show any weirdness from all three.

The only significant gain was from e85/91 blend. Ethanol has cooling properties and it was very apparent on the track pushing the car so much that I melted my bumper.

So the ecu will adjust quite well for many octane of gas and without you really knowing it. It's really some crazy engineering they did.

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Thanks man. good information to know.

[jpy1980]

I also ordered some RS7 spark plugs for my s3 from USP: https://www.uspmotorsports.com/Engin...-set-of-4.html

Phil said that it needs to be gapped and I asked my tuner (Eurodyne) for the gap info, but they have yet to get back to me.

The thing is is that people are saying that this is a side firing spark plug, so no gap is needed. Can someone corroborate this info?

[jpy1980]

Ok apparently there is no need to gap them.

[TCHUN003]

How's everyone liking Denso IKH24 and the RS7 plugs? I've heard someone had part of their rs7 plug break off and get into the engine in the Facebook group. I'm planning on changing the plugs and I'm contemplating my options.

[chris164935]

Some good reading about spark plugs and, specifically, heat ranges of spark plugs and the pros/cons when determining the correct range: http://www.ngksparkplugs.com/about-n...rk-plug-basics

Also, the RS7 plugs look to be a single ground electrode. They may come pre-gapped from the factory, but I would always check the gap of a spark plug in case they got beat up during shipping.

[Spinnetti]

Couple notes assuming healthy plugs:
1. You won't see any more power unless you run a bigger gap - that's the benefit of better plugs, the ability to run a wider gap
2. Manfuacturers tell you NOT to gap Iridium plugs. Not to say you can't, but odds are good you may regret it (fatigued components, popping off or chipping the bonded Iridium)
3. With crummier plugs, a smaller gap with lots of boost may fire more reliably.
4. Colder plugs with lots of boost may prevent the sparkplug from getting overheated and acting as glow plug - depends on the engine and tune if that is needed or not.

All that said, in my past "Stage 3" builds I've run Denso Iridiums with a .044 gap one step colder than stock and had great results up to about 30PSI. If I can find out what the gap is on those RS7 plugs I may try those instead this time as they look like a good design. If you want to do more than guess or follow "Internet wisdom", This is a good book that while pimping his stuff also has lots of good info to help you understand all the variables that go into ignition and how to get the most out of your plugs https://www.amazon.com/Doctors-Step-.../dp/0965085600