Good to know... I'll check my gaps too!

 

I doubt a gap difference of 4 or 6 thousands of an inch is going to make much difference. What are you using to measure??

 

I doubt a gap difference of 4 or 6 thousands of an inch is going to make much difference. What are you using to measure??

.4 and .6 thousandths may not sound like much, but when you realize it's 12.5% to 18.875% off it actually is a lot.

If anything else in the motor was 12-19% off, I bet it wouldn't run very good.

 

it could. although thats a very small gap difference, these cars might be real finicky when it comes to the gap. especially since its direct injection. some cars run fine with out of whack gaps, others not so much.

 

Being that it is a turbo and direct injected, spark plug gaps are important. It was the same with my SAAB 93. If it was gapped incorrectly, you could tell. Since I bought this car with 34 miles on it, it had the same "stumble" that my Saab did. So i checked the plugs and VOILA, they are all were incorrect. And a correction, the plugs will last till 45k, but with a decrease in performance and mpg. 30k is what Denso is recommending replacement.

 

You guys are right, 4 thousands (.004") is roughly .1mm, which may be significant enough to cause a difference. I was thinking 4 ten thousands. (.0004") which is .010mm, a very small difference. If the gap is too large, the cylinder may misfire, if too small, the spark may be weak and not last long enough. Both critical in this application.

This is the problem when you mix metric and standard units. Anyone recall what happen when nasa did this many years back....

 

Anyone recall what happen when nasa did this many years back....

Isn't that the one where they burned up a Mars orbiter? Seemed like it was supposed to orbit @ 80,000 M and they took it to 80,000'. Or something like that.

 

Wow.... 30k miles. I wonder what Hyundai's stance is on that. Definitely gonna pull my plugs this weekend and check gaps; didn't realize stock gap was so tight.

 

wow, we got a few former speed3 guys in here. lol. im gonna do the same thing this weekend. i remember when i had a couple plugs out of whack on the speed. holy crap it ran like ****. lol.

 

Keep us posted! I'm gonna try to see if I can get a chance to check mine also. I'd like to know if anyone else notices a difference in performance after the gaps are corrected.

 

Tight gap too on mines (all four!). Put some anti-seize on the threads. After 8500 km, they were not easy to unscrew so i can imagine after 30k mi....

 

What size socket was required to remove ... 5/8 or 11/16?

 

A 5/8" spark plug socket and extension is needed.

I just checked mine last night, and had to re-gap all of them. The car seems to be running good now, but it was running good before. I'll wait to see if my mpg increases.

 

Does anybody know how much torque is required when putting the plugs back in or is it the standard, not arm wrenching tight, but firm?

Thanks in advance...

 

Straight from hmaservice

 

Am I the only one who see's that hyundai recomends gap values different than the reported denso numbers?

 

Thank you!

 

Where can we actually buy the Denso ZX20hCR8 and are actually in stock?

 

dealership?

@ $20 a pop lol

 

Anybody have hyundai part # for these plugs? every site I go to doesn't allow me to select 2.0t, im sure its different plugs then the 2.4L.

 

I'm checking my plugs this weekend too. I'd love to hear NAMELESS chime in on this issue, seems widespread. Also seems like a potential warranty issue that needs a TSB.

 

Okay, so I went to the track last night, and my best time was 14.64. My previous best was 15.46, but I was trying to load the engine up and launch the car. This time I just hit the gas at the line. As for improved performance from gap... I don't know. However, I can say that on the way home from the track I was averaging 7.1 L/100 km's. So it is possible that the re-gapping has helped my fuel economy. Either way the car is running good!

 

Not bad compared to others, but **** do we need a tune. What was the temp out? were you using premium? TC on or off?

 

I've seen a few threads about getting less than par gas mileage; this would be a good idea for those who are not achieving the same gas mileage as others...

*edit: mine needed a little adjustment according to my feeler guage, but were pretty close to .032; also, look to be in good shape for 8k on the clock. At least was able to get some anti-seize and di-electric grease in there.

 

What was your mph?

 

It was 15C or 59F outside. I tried with TC on and off, in auto and manual mode. My best run was with TC on in manual. I had a lot more tire spin than before, and suspect it is do to my new NP motor mount. I need better/wider tires to hook up. I'm gonna be putting the stock motor mount bushings in for the winter, because I won't be racing again until the spring. I don't really like the extra vibrations at idle, but can overlook them if I am racing, and I get petter performance.
My MPH was consistently around 97.5, and 60' around 2.3 seconds. My 60' was the same the last time I ran, but I could only get to 92 MPH.
I think if I could hook up better, and run with TC off, I could run a little quicker, by maybe a couple tenths of a second.
I definitely agree that we need a tune, and I WANT ONE SOON!!!

 

Checked mine yesterday, all 4 were around .6mm to .65mm so I made the adjustment to around .8mm. I noticed the discrepancy between what Denso said and the manual, I figured go with Denso for now. Does anyone know if one is better than the other?

Running fine, seems a little smoother but don't have any hard evidence of this. I have had some misfires with startup a few times before, not enough to pull an engine code but my OBD listed it, so maybe this will help that.

 

Going with densos numbers is at least a step in the right direction. Their numbers may be optimal for that plug but not neccesarrily our car.

 

There is no compatible alternate known to this denso plug.
Wow thats the first time I came remember that.
I traded in a 2006 scion tc for this car. When the TC came out it had iridium plugs which were rare but there were still alternates.

 

My response has seemed a bit sluggish lately and I've also had a couple of random misfire stumbles at cold start so I checked mine this afternoon. All were gapped close to .026 so I regapped to .032 all the way around. A quick test drive and there did seem to be improvement. I'll have to watch and see if my MPG improves.

I'm tempted to go on and push them all out to .040 as the manual recommends.

 

I'm tempted to go on and push them all out to .040 as the manual recommends.

Go for it then...it is what Hyundai recommends after all.

 

I just finished checking mine and they were all set at .032...so I guess i'm fine. They did look like they get pretty **** hot. Also had some orange rust color on the ceramic.

 

Are you running a fuel additive? When the fuel additives burn they leave that color ash. Race fuel does that to....tell me your not.......