I have an 87 300E. I am considering the 13953 Bosch because I do not want to pay $120. One thread mentioned NTK put out a cleaner signal and had a faster response. Anyone know if NTK/NGK is better?
Any opinions NGK TR5 spark plugs vs H9DCO?
Thanks.

True, NTK is a very good O 2 sensor, but I would not pay a whole lot more money for it than a Bosch.
On the plugs, I believe you have a very " plug-sensitive " engine, so I would stay with the Bosch ( and always verify the gap before installing ).
Btw. if I remember my numbers correctly, the NGK you mentioned are resistor plugs.

__________________
2007 C 230 Sport.

The NGK TR5 is the same geometry and heat range as the Bosch H9DC or H9DC0, but it is a RESISTOR plug as indicated by the "R" in the designation. The Bosch equivalent is HR9DC. I use TR5s in my Cosworth Vega and they are also a good replacement for the platinum plugs in Corvette LS-V8s.

For various and sundry reasons, Mercedes use NON-RESISTOR plugs and can exhibit problems if resistor plugs are used. Lots of discussion in the archives if you are a non-believer.

Use either the Bosch H9DC or the HD electrode H9DC0. Personally I prefer the H9DC.

Duke

I was thinking the same thing! I believe the "R" in "TR5" refers to resistor, and you want to stay away from them in this older, lower output ignition system. With resistors in the end caps on the ignition wires, and possibly elsewhere - read about one being in the rotor and in each distributor cap terminal - you don't need to introduce another in the circuit. Mercedes does not recommend plugs with resistors because resistors are already in the system. In addition, Mercedes does not recommend platinum plugs because the resistance of platinum is higher than that of copper and along with the resistor found in platinum plugs may provide a weaker spark - especially at higher RPMs. In our older cars, the coil is probably putting out between 40-45,000 volts max., compared with up to 80,000 volts in high energy ignition systems found on slightly newer cars.

Yes, the "R" indicates a resistor. Look at the NGK catalog.

Modern OE ignition systems don't generate more than about 35KV open circuit voltage. It only takes 5-10 KV to break down the gap resistance. Excessively high open circuit coil voltage just helps breakdown the secondary ignition components if there is an open circuit. What's important is ignition ENERGY (which usually measured in millijoules), and higher energy creates a longer duration spark, which is what is necessary to prevent misfires.

Modern OE igntion systems are HIGH ENERGY, not high voltage.

Advertised "coil voltage" is just marketing BS.

Duke

will avoid TR5s. I usu buy H9DCs for $1.09 each. Bought some H9DCOs mail order to try. A local shade tree style independant mentioned TR5s.

On O2 sensors , the Bosch 13953( needs soldering in)I mentioned is $42+tax and the NTK(needs soldering too) is $29 plus $10 shipping. Prices are similar so is NTK better quality?

The prices are similar so is NTK better than Bosch and are thee any data? Thanks