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normal or Iridium plugs?

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Getting ready to do an A service on the beast. Been looking for Spark plugs the standard plugs are


Amateurs built the Ark

Professionals built the Titanic

"I haven't ridden in cars pulled by cows before" "Bullocks, Mr.Belcher" "No, I haven't, honestly"

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The theory is that the central electrode is a lot thinner on iridium plugs giving a stronger spark for a few thousand volts less resulting in a more complete combustion IMO there is a benefit on V8 cars in that you can leave them in longer causing less aggro re-sealing covers


Dave Hopwood

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my 2 cents we have never run them on race teams with turbo engines because the platinum or iridium acts like a heat sink and can lead to predetonation . . . who knows

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I put some iridiums in my Esprit and knocked like crazy!

Artie


89 White Esprit SE

...a few little upgrades....

93 RX7.....Silverstone

....slightly modded...Muahaha...

New Addition:

1990 300ZX TT......Hmmm

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I had densos on mine for couple years I am very pleased,

same starting, response and performance like stock ngk

but I have 2 step colder then denso recomends,

run free scan on the road and dyno on full load no knocks

but also have 550cc secondary injectors keeps it rich and safe

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Huchhhhhhhhhh .... 550cc secondary injectors !!!??? :D

The stock ones are only a third of that size !

Are you planning to power-wash your pistons and liners ;o)

IMHO, 550cc is way too big. The secondaries only come on with high rpm and high boost.

Look:

Secondary%20Injectors%20Base%20DC%20-%20RPM%20vs.%20MAP%20chip6.jpg

Cheers

Marcus

I had densos on mine for couple years I am very pleased,

same starting, response and performance like stock ngk

but I have 2 step colder then denso recomends,

run free scan on the road and dyno on full load no knocks

but also have 550cc secondary injectors keeps it rich and safe

Edited by Paula&Marcus

Marcus

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Huchhhhhhhhhh .... 550cc secondary injectors !!!??? :)

The stock ones are only a third of that size !

Are you planning to power-wash your pistons and liners ;o)

IMHO, 550cc is way too big. The secondaries only come on with high rpm and high boost.

Look:

Secondary%20Injectors%20Base%20DC%20-%20RPM%20vs.%20MAP%20chip6.jpg

Cheers

Marcus

Marcus,

u r right they r to big

but with almost twice the size turbo it spools

in higher rpm just like the secondary injectors

and gets rich only on higher rpm

than back to normal

I also use red line oil and change it @ around 1500 miles

to be safe

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I put some iridiums in my Esprit and knocked like crazy!

Artie

Art

knocking according to freescan

or were there symptoms?


chris

90SE

just because I don't CARE doesn't mean I don't UNDERDSTAND

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Tony,

If I understand you correctly ...

- you have modified engine with a huge turbo

- your engine runs fine but with high rpm it runs overly rich

- to prevent your pistons and liners from getting washed out (= oil gets removed from too much fuel and the risk of piston/liner damage) you are changeing your engine-oil every 1500 miles

Sorry Tony, but this all looks exactly like too big secondaries. You should put in something in the 300+cc range.

Your engine will run much better with high rpm/boost/load (because overly rich mixture will kill power) and you dont have the risk of damaging your piston liners. And you can safe on engine oil ;o)

IMHO, you should get this tuned correctly as soon as possible.

Cheers

Marcus

Marcus,

u r right they r to big

but with almost twice the size turbo it spools

in higher rpm just like the secondary injectors

and gets rich only on higher rpm

than back to normal

I also use red line oil and change it @ around 1500 miles

to be safe


Marcus

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Marcus,

I had this setup for few years,

car run perfect,

this is at low boost 14psi,

Hope you can understand

these few words :)

Cheers

Tony

I apologize guys

I got off the spark plug topic

Edited by Tony94S4

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Tony,

Yes I can understand your words quite well .... :)

According to your dyno-sheet it looks perfectly like I was assuming ...

The A/F curve does not look homogen at all ... :)

Up to 3500rpm it runs too lean. I would suggest to put in highher flow primary injectors. Something around 370-400cc.

Then your secondaries kick in (from 3500 and up) and the A/F becomes way too low (= rich). It even drops below 10.

IMHO, your setup would be much better if you put in bigger primaries and smaller secondaries.

Marcus

Marcus,

I had this setup for few years,

car run perfect,

this is at low boost 14psi,

Hope you can understand

these few words :)

Cheers

Tony


Marcus

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that was the first thing I did fitted larger primaries

but could not get it to run and idle good,

that was the last dyno I did but I made the mistake

of putting my battery in Before the run so didn't give

much chance to the ecu to learn

cant find my other sheets I remember at 1.25 bar I was leaning

out @ high rpm I think

the good part is I decided to put the 910 engine back in

as soon as I decide what I want to do with the clutch

then I hope u will build me a custom chip for my

setup

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Tony,

If your primaries were chosen too large then you will get problems at idle and/or with partial throttle/load conditions.

This has to do with the ECU's ability to adjust the fuel within a certain range (you can monitor this by looking at the "integrator" value via Freescan)

Can you remember the injector size you were trying first ?

Yes of course, I would be happy to do a custom chip for your future setup.

Marcus

that was the first thing I did fitted larger primaries

but could not get it to run and idle good,

that was the last dyno I did but I made the mistake

of putting my battery in Before the run so didn't give

much chance to the ecu to learn

cant find my other sheets I remember at 1.25 bar I was leaning

out @ high rpm I think

the good part is I decided to put the 910 engine back in

as soon as I decide what I want to do with the clutch

then I hope u will build me a custom chip for my

setup

Edited by Paula&Marcus

Marcus

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Yes they were to large & exact problems as u described,

I thought if I drop the fuel pressure on idle will fix that

but could not get it right

Could not find anything back then in between 370cc and 550cc,

so I went with 550cc

bad choice

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Tony,

Oh no no no no, lowering the fuel pressure is not the right way !!!

You should keep the fuel pressure like it is or maybe rise it a little bit (but not much if you get a "bit-too-lean" problem), but never drop it !

Once again ...

stock injector sizes are:

4x 370cc + 2x 190cc

For an engine like yours I would take something around:

4x 400+cc + 2x 300+cc

what you did: 4x 370cc + 2x 550cc is giving an unbalanced result like you can see on your A/F graph.

Can't you remember the size of the bigger primaries you tried first ? I'm just curious.

Cheers

Marcus

Yes they were to large & exact problems as u described,

I thought if I drop the fuel pressure on idle will fix that

but could not get it right

Could not find anything back then in between 370cc and 550cc,

so I went with 550cc

bad choice

Edited by Paula&Marcus

Marcus

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Ha !

550cc primaries ? :lol:

You should not be astonished why it did not run well ... thats too big, indeed.

Marcus

550 primaries, stock secondaries

Marcus

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since the ecu could not control the primary 550s and was running rich,

I tried to lower the fuel pressure on idle,

and then on boost I used fmu to raise the pressure more than usual 1 to 1 ratio,

some dyno time and checking the spark plugs could not set it up right,

maybe its doable if I had a wide band reader vich I plan to purchase

I know with stock primary's its a big no no to drop the pressure,

but you think it can be dropped with larger primaries?

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Tony,

NOOOOOOOOOOOOOO ! Dont lower the fuel pressure. Never - ever !

Please, do it right, or restore it back to stock.

I'm sorry for this, but what you did is simply "turning the wrong knobs" in the wrong direction.

You simply have a wrong setup now, and doing something else also wrong will not cure it ... please believe me.

Marcus

since the ecu could not control the primary 550s and was running rich,

I tried to lower the fuel pressure on idle,

and then on boost I used fmu to raise the pressure more than usual 1 to 1 ratio,

some dyno time and checking the spark plugs could not set it up right,

maybe its doable if I had a wide band reader vich I plan to purchase

I know with stock primary's its a big no no to drop the pressure,

but you think it can be dropped with larger primaries?

Edited by Paula&Marcus

Marcus

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