Spark Plugs

[1toofastlt1]

Im running denso uridiums (<--- spelling?) and im not sure if that a good plug for FI. Sometimes at wot it will be pulling hard then it will feel like its missing around 5K rpms. any ideas?? Thanks

[popo8]

I was told that LT1s dont like "special" plugs... I run Autolite (cant remember number). I also run 2 deg colder than required...

[1toofastlt1]

are you running a blower?

[popo8]

Procharger!

[1toofastlt1]

nice is it on a stock motor? how much boost?

[popo8]

Its on a forged internal 388ci LT1 (was a 383 and now .10 over that). Honestly right now I am only seeing about 7.8 lbs of boost. Depending on where I post, I either write 7 or 8 lbs.....

Ported and polished heads, intake, longtubes...etc.... check out my car domain in sig...

[1toofastlt1]

o wow you car is hot!!! so is your bike and GF! so your running auto light plugs in yours just 2 deg cooler then the factory? did you tune it yourself?

[popo8]

No, i had it tuned at PSI motorsports in NEW TRIPOLI PA.
Last time on the dyno we had a killer misfire problem, but Im sure its because my friends 9 year old son dropped my box of plugs on the ground before the swap.

WHen the new motor went in, we put the car on the dyno and had no misfire, but when he went to adjust the tune, the LT1 EDIT software took a crap in his computer, or his computer did. SO as he took a week to get everything straightened out, I decided to order plugs, and my friend decided to suprise me by putting them in.
Well back on the dyno and now the car was acting up (misfire) my friend tells me what happened to my plugs..... so I have another two boxes of plugs waiting to go in...

This is the advice I was givin by Frank at PSI and Ray of PERFORMANCE SPECIALTIES... so I went with it....

[popo8]

o wow you car is hot!!! so is your bike and GF!


THANK YOU.... if they werent... I WOULDNT HAVE THEM....:metal:

[1toofastlt1]

awsome :D thanks for your help i will try those and see if it fixes it. how much power do you think you will make?

[popo8]

At 4,000 rpm, with the mis, Im at 450....

I plan on spining it to 6k, and no mis

And I plan on doing the smaller pulley for MORE BOOST.

[1toofastlt1]

so your look for 600 rwhp?

[BLOWNDFIZ]

Put a set of NGK TR6 or Autolite 104's in it and you will be good. Iriduim and plalinum plugs turn into "glow plugs" with the increased cylinder pressures of forced induction. You want a standard copper core plug with a blower.

[popo8]

Put a set of NGK TR6 or Autolite 104's in it and you will be good. Iriduim and plalinum plugs turn into "glow plugs" with the increased cylinder pressures of forced induction. You want a standard copper core plug with a blower.


Thanks man, I didnt know the WHY, I just the knew the YOU SHOULD...

[1toofastlt1]

Put a set of NGK TR6 or Autolite 104's in it and you will be good. Iriduim and plalinum plugs turn into "glow plugs" with the increased cylinder pressures of forced induction. You want a standard copper core plug with a blower.
which of the two would you run.

[popo8]

I think he listed them both because they are equivalent....

[Fire67]

There are alot of people that run iridium plugs with FI... Myself included. They dont have the heat issues that platinum has at all. They are supposed to be the best of both worlds, small center electrode for great spark exposure and no heat/glowing issues like the good ol copper plugs.

Recently I have gone to copper plugs because they're cheaper to replace as often as I replace them.

[CALL911]

I don't have any experience with iridiums, but I also run Autolites and would highly reccomend them. I would also reccomend AGAINST running NGK plugs.

Popo8, if you are getting a miss, you may want to check your spark plug gap. When I initially dyno'd my car I had an issue with the spark getting blown out at higher RPM pulls due to the larger gap.

[Fastbird]

Put a set of NGK TR6 or Autolite 104's in it and you will be good. Iriduim and plalinum plugs turn into "glow plugs" with the increased cylinder pressures of forced induction. You want a standard copper core plug with a blower.

Ditto.

How much boost are you running, what kind of power are you putting out, what are your plugs gapped at??? You could just be blowing the spark out if the gap is too wide.

[Fire67]

Good point on the gap guys... IIRC, I used to run .030 - .035 or so on the stock motor and 10psi.

[1toofastlt1]

o im only running 5 psi with the stock gap. I will work my ass off to put in a set of autolites 104s and i will let you know how it runs

[Z28pr0jekt]

o im only running 5 psi with the stock gap. I will work my ass off to put in a set of autolites 104s and i will let you know how it runs
yeaaa stock gap is WAYYYY too much for any boosted setup on an LT1, let alone stock compression too.

[1toofastlt1]

yeaaa stock gap is WAYYYY too much for any boosted setup on an LT1, let alone stock compression too.

ok so i should gap them to .035?

[BLOWNDFIZ]

ok so i should gap them to .035?

Yes.