Denso Irridium plugs...

[Forbidden Snake]

Denson Irridium plugs...

What do you guys gapp your Iriddium plugs at? At first mine was gapped anywhere between .030 - .032. I just recently re-gapped them to .035 - .037. The car seems a little stronger now on the low-end. Top-end seems okay too. This may explain why my 1st gear don't wind out as quickly as before when I had the NGK-TR6 plugs.

My Q to you guys is... where do you set your gap at? Is it true that the irridium plugs can be gap a little wider than, say, the NGK-TR6 plugs?

Comments?

** EDIT: Title should state Denso..., not Deson....

 

[CobraBob]

Mine were gapped exactly as yours -- .035 - .037.

 

[2F2F]

Vehicle Emissions Control Information (VECI) indicates a recommended gap between 0.042-0.046", or a 0.044" median. General rule of thumb for forced induction gapping is minus 0.004" for every 50 HP gained.

 

[Forbidden Snake]

Thanks. I might try .040 and see if that does any better or worst... My gut feelings are that it'll perform better on the low and mid-range, but blow out on the top-end....

 

[03DOHC]

Re: Denson Irridium plugs...

Originally posted by Forbidden Snake
What do you guys gapp your Iriddium plugs at? At first mine was gapped anywhere between .030 - .032. I just recently re-gapped them to .035 - .037. The car seems a little stronger now on the low-end. Top-end seems okay too. This may explain why my 1st gear don't wind out as quickly as before when I had the NGK-TR6 plugs.

My Q to you guys is... where do you set your gap at? Is it true that the irridium plugs can be gap a little wider than, say, the NGK-TR6 plugs?

Comments?

I have mine at .035".

** EDIT: Title should state Denso..., not Deson....

Changed it for you.

 

[trey193]

Mine are also at 35, I have thought about moving them up to 40 and see if the car felt better! Who knows!

 

[BigBeez03]

did you guys really notice anything different as far as performance after installing these aftermarket plugs? What is the reason for these different plugs? Are they colder or hotter? Feedback appreciated.

 

[n2fords2003]

What heat rang are you guys running???

 

[fryingricecobra]

Double post sorry.

 

[fryingricecobra]

I thought you weren't supposed to gap denso's?

They break to easy.

 

[Jon]

I have IT22 plugs and originally gapped them at .035" just like the TR-6 plugs before them. The car runs poorly with this close of a gap . I drive 80 miles a day and can DEFINATELY tell the difference between .040 and .035 --it's like night and day.

With .035 gap the engine studdered a lot at part throttle while gas economy dropped 2-3mpg. Most people recommend .035" with a setup like mine: 2.93" and chip. But I cannot understand how one can live with the part throttle hessitation I was getting. Maybe it is just me. One of those "princess and the pea" things...

Last night I could not stand it any longer and regapped at .040". Ahhh, everything is back to normal.

The whole saga....
Previously, I was running TR-6 plugs originally gapped at .040", or so I thought. Months later, on dyno day, the high speed miss was so bad that we ended my session early. As it turns out the gap had grown to about .050" after 7500 miles. So I gapped them down to .035" and immediately experienced the low speed studdering. That's when I ordered the IT-22 plugs. They were not an improvement over the TR-6 plugs at this gap. However, I am hopeful that the IT-22 plugs will fair better in the upper rpm range with a .040" gap.

 

[03DOHC]

So the .035" on the Denso's didn't work for you? When are you going back to Apex?

 

[davidmax]

Mine are gapped at 40,dont use the Densos for Dyno tuning as they dont color up well enough to burn a good chip.
We use the coppers and then switch to Densos after chip is burned,theres a noticible improvement,Dave SmilovicPS:The TR6''s are great for dyno tunning,Dave.

 

[SolidSnake]

davidmax can you elaborate on what you said about "coloring up"....I was going to switch plugs at the dyno....???? :shrug:

 

[umustdv8]

Mine are gapped to .32. Is it possible, that's why my torque number is low? Why should I go wider?

 

[03Sssnake]

Originally posted by umustdv8
Mine are gapped to .32. Is it possible, that's why my torque number is low? Why should I go wider?

low timing and the amount fuel at lower rpms are the probable cause's for your low torque number, that or perhaps your clutch is slipping some..

The 1st chip I had burned had no timing added and the fuel tables were a bit dry down low. Added 2 degrees and more fuel = 40+ ft/lbs of torque...

 

[trey193]

Jon very interesttin info, I too have that slight miss while driving in town around 1800-2200, my Densos are gapped at 35, I will move it up to 40 and see what I get, the Densos should be able to handle 40 and I have always heard the more fire you can put in a Cyl. the more power you can make. The IT 22's should be able to handle a 2.80 upper dont you guys think without experiencing any blowout???

 

[Jon]

Originally posted by trey193
Jon very interesttin info, I too have that slight miss while driving in town around 1800-2200, my Densos are gapped at 35, I will move it up to 40 and see what I get, the Densos should be able to handle 40 and I have always heard the more fire you can put in a Cyl. the more power you can make. The IT 22's should be able to handle a 2.80 upper dont you guys think without experiencing any blowout???

Let me know how the .040" gap works for you. I use feeler gauges to adjust the gap, if that makes any difference.

I am not an expert but it looks like there there are two issues going on here:

1) small gap is needed for high-rpm, high boost. Ingnition failure here is refered to "blowout" and it very noticable on the dyno.

2) wide gap is needed for low-rpm driveability. Ingition failure here is more like inefficient burn. It does not seem like a real miss but maybe a "puff" rather than a "bang". After all, the reason why the gap is so large is to light the (smog compliant) lean mixture.

I am trying to figure out how I am going to balance the two. Maybe I need an MSD or something.

 

[Jon]

Originally posted by 03DOHC
So the .035" on the Denso's didn't work for you? When are you going back to Apex?

I am kind of afraid to now. I mean, what's the point in paying $100 just to see my car missing all over the place. Maybe if it is a slow day they'll let me make multiple runs with differenct plugs and gaps.

 

[umustdv8]

Originally posted by 03Sssnake
low timing and the amount fuel at lower rpms are the probable cause's for your low torque number, that or perhaps your clutch is slipping some..

The 1st chip I had burned had no timing added and the fuel tables were a bit dry down low. Added 2 degrees and more fuel = 40+ ft/lbs of torque...

Thanks for the info. I'm planning a retune next week, so I'll mention that at the tune.