turbo missfire
 

any one faced misfire problem with force induction?

the car misfire @ 4500 @ stand still
miss fire full throttle @ 5000 and no power

we think its the spark plugs? but any idea

hopefully you're running something with a cooler heat range

I agree... try fresh plugs properly gapped two steps cooler. How fresh are yours? Have you taken them out and looked at them?

http://www.ngksparkplugs.com/tech_su...qs/faqread.asp

2 steps colder plugs? Those are going to foul out real quick.
To the op you need to make sure your tune is 100% before thinking its something else, if it is in fact, gap the plugs down to .022. Also if you were tuning it and ran very rich for a while then you might have fouled out the plug. Any vacuum/boost leaks after the maf will also make the car misfire.

Are you tuning on e85, pump or racegas? What boost level are you at?

Two steps colder from the NA plug on a turbo application has worked perfectly for me for many years.

You know the FRS already has a 9 in it right?

Also heat range will depend on Amount of boost and power you plan on running. If you just throw too cold of a plug in it you will just foul them out all the time.

this.

check your logs/tune depending on ecu of choice and pull the spark plugs and inspect then correct the issue causing the problem. if you have fouled your plugs we can hook you up with a step colder plug that we have been using in our turbo setup

What brand of plug are you using?

Going from an 8 to a 7 generally means a HOTTER plug.

That was really bone headed on my part. You are absolutely right. I am two steps colder on the K, but it was from a 7 *facepalm*. Had to check when I got home. Apologies.

If your running 93 on this car your probaley not even going to be running enough boost to need to change the plug to a colder unit. If your running a different fuel and higher boost then yeah you should. Just my 2 cents.

Unless it's E85, then you don't need (nor want) colder plugs.

In the 45 degree celcius heat that you may be trying to tune/operate in, you should be a couple of heat ranges colder

Also, how much boost pressure are you making?

And, what is current AFR in the rpm ranges you mention?


A miss like that doesnt sound great to me, especially on a neutral throttle, I would be having kittens if I was you.

I hardly see these plugs missing. they are a good heat range for turbo, and they come gapped at around .032. That gap is good for quite a bit of boost with a proper high power ignition system and iridium plugs.

On a GT30r type setup I could only see spark blow out after 18psi or so... perhaps running too rich?

but isn't checking the plugs a 4 day arctic expedition on these things?

:-)

The ign system is not as powerful as you think, even at lower boost it will blow the spark out at .032 gap. You'll have to bring the gap down some

Thanks guys.

i think its the spark plug is what making problems that when we were running the car @ 5psi it was running ok but we faced problem after we increased the boost to 9 psi @ 93 pump gas.

Hmmm interesting. Perhaps the higher CR contributes to this?

I was running 22psi on a .032 gap and a GT30R on my SR20VE and stock coil (inside distributor, not COP). So it is surprising that the stock COP system wouldn't be able to handle 10psi boost.

Anyone else with turbo having issues with spark blowout?

I didn't need to drop gap to .025 when I went 6262 and started making over 500whp. Perhaps a 15 year old Nissan ignition is still better than a brand new Suby ignition?

So, what is procedure for lowering gap on this engine anyway? Drop the engine slightly and install from underneath?

factory says raise engine just above frame rails to R&R spark plugs

I never had to jack the engine up at all, I pulled the plugs from the top. Used a 1/4 ratchet with a short 10mm to remove coil pack bolt then pulled those out then used a standard 14mm socket, slid that in, then used a short extension, push that in, then just barely stuck a 3/8 standard snap on ratchet on it. As long as the car is cold I can do a plug change in about 10 mins.

Work on a 300zx turbo and it makes this car a breeze...

any pics of the turbo kit?

It is more then likely the tune. These cars are a little tricky if you are dealing with stock ecu's

I think without user programmable engine management it's harder to figure out the root of the problem. It may just be that your ecu tune is too rich, set up for fuel cut, detonating, who knows.

I think the heat range on the plug should be fine but I would tighten up that gap some as suggested. Sometimes a colder plug is a quick fix for detonation but really the right move would be to adjust the tune correctly. I mean I run a 6 heat range spark plug at 700 whp. LOL! Unless your spark plug shows signs of overheating at the insulator you don't need to change the heat range.

Good luck.
Phil Grabow

Good to see you here Phil. Hows the hydra working out on the frs? Seeing good things from tuning?

Did you pull the plugs and take a look at them?

I would say its more to do with tune.

My current set up on my MR2 is 2 colder than N/A with 15psi and the gap 0.44.

Ill be reducing the gap as im going higher psi

I agree 100%. There is no need to "upgrade" plugs in this car. They are iridium/platinum and a very cold heat range straight from the factory. I've used heat range 7 to over 600whp builds without issues. Even a heat range 6 will be good for 400whp, but there is more to it than just the heat range.

Likely the plug gap it a little too big. Like others have said. But there is no need for a colder or different plug set.

I would be wary of gapping too small as well, as this can disrupt the part-throttle driveability and startup.

turbo missfire
 

Bro, can you be an angel and idk, post a vid.... I'd really appreciate it!


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