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Discussion Starter #1
plugs foul easily….

It is on the race car.

It seems that if it almost does not catch first time, then the plugs get very wet and require cleaning and drying. Once that has been done then it will generally kick into life.

Anyone suggest a remedy for this. (possibly been done before)

Could it be wrong plugs as they were the original race engine plugs still in there. Something else perhaps?? Any ideas before I go trying things that are a waste of time? :)
 

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Change the plugs.
 

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Discussion Starter #6
Plugs are NGK's BCPR6ET

Just pulled one out to check make and model - and although dry it was a bit sooty.

The car is running standard 16v injection with standard fuel pump and regulator - although the ECU has been 'chipped'. The car is running 98ron with the wire connector correctly swapped (as far as I can tell) in the little connector block near the fuel relay - to tell the ECU is it running 98RON petrol with no cat.

Any suggestions - I was wondering if these plugs were 'hot'??? ones more suited to a race car - so something??

Anyone know. Open to ideas. Do I just need to dump these plugs - or is there something I should check in the set up first??
 

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What chip is it using?

one of those ebay specials that just make the car run over rich as if on choke all the time?
if so dump it, its doing you more harm than good.
 

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Hi,

If the plugs remain sooty after 25-30 minutes of fully warmed up engine operation that may mean that
the plugs are not reaching their self cleaning temperature, they rated to more hot engine operation.

Startup problems apart from the shortcircuit caused by the soot, may result of over enriched mixture
during cranking and/or too retarded ignition timing @ cranking RPM, or weak spark during cranking.
Ignition timing and start enrichment is determined by the ECU, the MAP may need to be fine tuned.
 

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Agree with all above. Not sure obout those plugs though. I would go for NGK B7ES or better still Bosch super 4.
Ed.. be careful with plugs. The scope for disaster is monumentally high.

NGK plugs are numbered with the higher number signifying a harder/"colder" plug. This is the other way round to Champion for instance.

If you had a super-tuned engine running on Nitro-methane and making 500bhp, you would probably have a "9" NGK plug in there. If you only ran to the shops and back, you would use a "5"... so your plug is at the "hot" end already (i.e. for a sustained rpm running/racing engine it's biggest problem is that it is likely to over-heat).

The standard NGK numbers for road cars are 6 or 7... so your plugs are not causing your particular problem. I'd speculate that someone put the "6" in there to try and cure the issues you're having. If the car is fouling plugs then a hotter plug (a plug with a lower number in NGK speak) is theoretically better at burning the soot off. A "6" is what you'd put in there if you had your problem and found that a "7" plug was fitted.

I think you're fouling plugs because you're over-fuelling it. Either your injectors are worn or your map needs a look at. I'd try a standard map and new plugs to start with. Until you solve the problem, another set of BCPR6ET will be cool... or hotter actually. Do you see what I did there? :D

You may be able to use BCPR7ET later.. (hotter runng i.e. colder plugs) when the beast is running properly... but one thing at a time. :)

Note that you need a projecting nose electrode by the sound of it.. (the "P" part of the NGK code). Make sure you use these if they're what the car needs.. otherwise your spark is taking place too close to the top of the combustion chamber and that won't help.

However... never fit projecting nose electrode plugs into an engine not designed for them.. they project further into the cylinder.. so your pistons have to be designed for the plugs to be jutting out. Obviously immense metal-carnage awaits if the piston is expecting a normal plug.

If you want to use 98-RON later too... then you can get a remap from someone who knoes what they're doing but anyway I'd revert to standard setup first and get the beast running properly.

Note that Bosch Super-4 (and the standard Golden Lodge plugs) are not hugely improved from a standard single-electrode plug. All that happens is that the spark jumps to the nearest electrode.. you sadly don't get 4 simultaneous sparks all happening at once, regardless of what the packet shows you. It helps the plug find a spark because there's 4 electrodes to choose from... but if your car was running right, you wouldn't really notice a difference with multi-electrode plugs on a race engine.


Ralf S.
 

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Discussion Starter #12
That is very, very interesting.

I had another theory explained to me as well. A friend said that the water temperature sensor in the near side throttle body is the one that the ECU uses to sense water (and therefore engine) temperature. If this sensor is not working then the ECU will think that the engine is cold (start up) all the time and over fuel much like an electronic choke. I have recently changed over the sensor for a new (but used one) to see if this does make any difference.

I haven't whipped out a plug since doing this, but the engine was run up nice and hot yesterday and does seem to start better. May well whip out a plug this afternoon and report back.

As you all say - get back to basics and see if I can achieve normal running etc. So, trying to make sure that all of the ECU sensors are working probably is a good starting point.

Just about to buy an Omex system for the race car - that will be handy as with the laptop I will be able to see if the ECU is receiving a signal from each sensor. Happy days!
 

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Have to agree with what's said above Bosch super 4 are nothing fancy really.

The spark just takes the shortest path to earth so moves around all the time as each electrode wears down.
Yes they last longer but they don't give you any performance advantage over the correct spec and grade of plug
 

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I used NGK 7BES in an 8v racer, I found the Bosch super4 '6' rated plug would only last a few races before needing replacement.

I noted a difference in low rev engine response between the NGK an Bosch, slightly better on Bosch .
 

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Discussion Starter #16
it is so nice for now to just pull a plug out and it not to be covered in soot! :)

I have found a good cleaning technique - but all the same - it is better if the engine cleans itself.

It is so nice when the car just fires up on its own, without having to wonder if it will indeed catch.
 

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Hi I also used as veesix75. Not for racing though. Dave at MTECH tuned our 33 on the NGK and that is what he used when he raced. The BOSCH I put in purely for the low rev stuff. But it is essential as everybody has said about getting all other tune stuff correct.

I am no expert just like to learn.
 
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