ok my car was cuting out unless i had it to the floor .it would cut out around 3 or 4 thousand rpms if i didnt have it floored .so i took it in .and they said it was the spark plugs. proably cause i was boosting so they said. they just put better spark plugs in it .so it ran just fine .but then today i was out running it kinda hard and it started again .why is this so ?what is happing to my poor spark plugs .?
I’m still learning about turbos but…
sounds to me like maybe your boost is too high/or your injectors aren’t spitting out enough fuel???
Because before 3 or 4 I would think the turbo wouldn’t be engaged,
So after that if there was too much air and not enough fuel
that would bog it down…
Maybe a mis-diagnosis by the shop?
Are they familair with turbo?
How long have you had it “turboed” for?
As far as spark plugs for your application, my opinion would be to get : NGK BCPR7ES (gapped at 28). Double check your gapping and make sure your plug wires are in good shape.
As for cutting out: it may be just your fuel filter needing replacement. HTH
it ran fine after the new plugs were put in for like 3 or 4 days i have ngk in there now i just dont know i have been boosting 4 maybe like 4months only (6psi) i just dont know whats going on i guess ill take it to the shop again monday.
Did you get colder spark plugs? When you go turbo it is necessary to get spark plugs that are one step colder than stock. If you are boosting a lot, you may even go two or three steps colder. What boost are you running, and what is your fuel set-up? We can’t help you if we don’t know what your set-up looks like.
ok i am really not the brightest when it comes to cars as you can tell. but im trying to learn so can some one explain on this hole colder spark plug thing. and why you need it and what not thanks alot .
From Maximum Boost, by Corky Bell. Chapter 9: “Events In The Chamber” pages 111 & 112.
"The choice of a spark plug for a turbo engine application is relatively easy. The heat range of the plug is the key factor to get right. Classifying plugs by their heat range has nothing to do with when or how they manage to get the fire going. 'Heat range' means no more or less than how the features of the plug are configured to conduct heat away from the electrode. Presume for a moment that it is desirable to have the materials of all spark plugs operate at about the same temperature, regardless of load conditions imposed by the engine. Then the spark plug of a low-speed, low-load, low-compression engine would need to conduct heat away from its electrode slowly, or else the plug would operate too cool. This is called a hot plug. An engine of our liking, clearly, must have plugs that conduct lots of heat away from the electrode. This plug, then, will be referred to as a cold plug. The balance to acheive is to keep the plug hot enoughto continuously burn the soot and deposits off yet cool enough to keep the materials from rapid deterioration. [b]A plug that operates at too high a temperature can also serve as an ignition source that actually starts the fire prior to the spark. This is pre-ignition, and it can lead to detonation.[/b]
In the actual selection of a plug for a high-pressure turbo engine, the choice should start with a plug about two ranges colder than stock equipment. If the plug deteriorates rapidly or fractures in any way, try a third range colder. Should the plug get dirty and acquire too much resistance to fire, back up one range hotter.
Installation technique will contribute to the plugs' consistency and durability. Certainly all threads and washer seats must be thoroughly cleaned. A proper spark plug lube, like Never-Seize or molysulfide, should be lightly applied to the threads and between the washer and plug. Top this off with tightening the plug to the manufacture's suggested torque, and you will have done all you can toward good spark plug performance. Torque specs are usually between 10 and 14 ft-lb for aluminum heads and 16 to 18 for iron."
Basically, a hot plug retains heat longer than a cold plug. Since turbo engines are doing more work with more compression than stock, you need a colder plug (one that disappates heat faster). Hope this helps. I am going to try to draw a picture for you in paint.
Okay look, I drew this picture for you. See how the cold plug has more material for the heat to travel into? Everyone who has studied physics knows that the more of a medium there is for heat to travel into, the faster it will go. A good example is water. If you have two different sized pots of water, the larger one will take longer to boil because it can absorb and hold more heat than the smaller pot. So in the case of spark plugs, the cold plug with more material will take heat away from the electrode more effectively than the hot plug with less material to absorb heat. Understand now?
Also, did you read the part where he said that hotter plugs can cause pre-ignition, which can easily lead to detonation? I think I’ll go back and bold that part for everyone.
Originally posted by Projecteg unsolvedriddle: What is the exact model of ngk spark plugs you are using?
ok guys if it’s a spark plug problem try NGK 7525 you don’t need to adjust anything just pop them in. I have a B18 A turbo running at 10psi with stock internals… just waiting to blow up my engine so that I can do a ls/v-tec set up.
haberdasher, my NGK plugs i got are BCPR6E-11, i belive stock NGK plugs is BCPR5E-11 correct? someone told me that one number higher means one step colder? true? then the ones i have are one step colder right? are your plugs two step colder? stock gap for the BCPR6E-11 are 40. what would be the best gap for 6 or 7psi on the onestep plugs? and also, do you think its a good idea to use the BCPR6E-11 for 6 or 7psi?