NGK irridium plug too cold ?

[Schulmann]

Here is my setup: Roe supercharger, 8psi, methanol and some other staff.
This car has to run long distances on highway and has to be in top shape for Targa race class and sometimes for fun: drag racing.

In recent weeks I have done a LOT of testing on spark plugs for HIGHWAY/CITY use. My most recent finding: NGK BKR5EIX irridium plug. This plug seem to be very cold for highway/city use. Much colder that the regular NGK FR5 plug that I use for racing. Likely for racing this irridium plug has top qualities.

Any body has tried the NGK BKR4EIX irridium plug ? How much hotter is it ?
Until now the best plug that I found for highway/city use is NGK FR4 (a little too hot for the front cylinders).

 

[carl B]

I really need the WBC calibration for the VEC2

Can you help please?

Carl

 

[Bob D]

Is the higher number colder ? I've been running BKR6EIX and overall they are a bit cold. I think I'll try a 5 or maybe a 4 if it's not too hot.

Bob

 

[Schulmann]

Carl B: I just posted the instructions to calibrate VEC2.

Bob D: Yes higher numbers are colder in the NGK brand. Depending what you do with your car you select the plugs. BKR6EIX is likely a good plug for racing but might generate a lot of carbon on long highway trips in certain modified engins. I had this trouble ....

Long time ago I even programmed an abnormal ignition curve without knowing that it was due to the carbon in the combustion chamber. Since I am very careful.

 

[Russ M]

Schulmann,

An NGK 5 is a fairly hot plug, I think you need to be running more like a 7. What are you using for a reading which is making you decide that a 5 is too cold?

 

[Schulmann]

What is the number of the NGK plug that you talk about when saying "5" ? An NGK FR5 is much hotter that an NGK BKR5EIX. So even within the NGK brand there are differences.

What makes me feel that an FR4 or FR5 is good for me ?
I check the carbon on the plugs and the electrode to see what heat range I need. When accelerating with too cold plug I have misses. Again I am looking for a plug for highway use: cruising under vacuum and some short and light acceleration.

 

[Russ M]

When say NGK says their plug is a 5, that means that all the plugs in their lineup with the number 5 are the same heat range.

Carbon has nothing to do with the heat range, that is all in the tune/oil burn.

You should be checking your plugs by the heat on the threads, you want your car to be pulling 3-4 threads. Meaning that 3-4 threads on the plug should be discolored, if that makes any sense.

Misses are probably due to lack of spark, the reason the FR5 works better for you is probably because it has less resistance/Gap which means a better spark.

Your car with the 8psi and the **** injection should be running 7 heat range maybe even 8. Call ROE and ask, unless you want to hurt your motor.

 

[Schulmann]

According to the tests that I have done an FR5 is much hotter than an irridium 5. Its a fact I have tested it. But I can be wrong.

Sean provides a Bosch FR8DC with the supercharger (this is the hotest Bosch plug). Its heat range is close to the NGK irridium 5. Now, in the past I had troubles with carbon in my engin. But since I am using FR4 (highway) and FR5 (racing) my Viper runs MUCH better.

Now check this:
Bosch FR8DC <=> NGK FR4

However FR4 seems to provide a better combustion compared to Bosch. I would even say that NGK is a little too hot. But for highway cruise NGK FR4 has great qualities that I love.

I have a friend who runs NOS with NGK 8 plugs. His car has terrible misses when accelerating on highway without NOS. I told him to run with hotter plugs on highway and change his plugs for racing. I hope he will do that.

 

[mntngts99]

Now check this:
Bosch FR8DC <=> NGK FR4

So is the NGK FR5 colder then the Bosch FR8DC

 

[Schulmann]

Actually both FR4 and FR5 are much hotter than Bosch FR8DC.
The books say that FR4 <=> FR8DC.
In real world on my Viper it is not the case.