To my experience with Toyota cars... is has been known to mankind that a Toyota car/truck with non OEM (NGK/ND) plugs would have problems... the NGK/ND plugs is the best plug you can get for your MK2... I have seen far better improvement in changing to the double platinum NGK/ND plugs and for the price... it is a little pricy... but with the discount at TOYOTA dealer... I could get them for 5 bucks a piece instead of 8-10 regular price. and it would last longer than the regular aftermarket subtitute... as what they have said 60,000 miles
This is just another area where you really have to give the engineers at Toyota a lot of credit! The ignition system on the 83 - 86 MKII's is a well matched component system. The engineers who designed the ignition system probably calculated the electrical resistance values in such a way to include the core resistance of the Platinum plugs and also add the benefit of longer service life. Take the 82 for instance. The 82 5MGE seems to not like anything other than the conventional ND or NGK plugs. Swap the stock plugs for a set of Bosch +4's and the darn thing won't even fire or run. Please don't ask me how I know! :roll: (putting flame suit on). The aftermarket plugs would probably yield the most added benefit with an aftermarket ignition setup or modified engine with higher compression and/or cylinder pressures. Food for thought anyway as ususal. 8)
The "splitfire" design accomplishes basically the same thing as the U-groove or V-power design in that the design allows the spark to be positioned slightly away from center of the plug tip and also cause the spark to shift from side to side on the split or grooved ground electrode. This can be to some benefit on high performance engines that have very high compression and cylinder pressures, especially when combined with a hot ignition system like the capacitive discharge MSD 6A, Jacobs, Vertex magneto, etc.. Also, FWIW, in case some don't know this, MSD stands for Multiple Spark Discharge. Very useful on all out race engines!
During my recent Detonation Adventures, I walked into a Schucks Auto by where I live-A store that has a fellow MKII owner behind counter-He was not there-The person I dealt with WOULD NOT believe that I did not want to blow up another set of Bosch Plats-And said that was all they stocked-EXCEPT-They have NGK Double Plats at their overstock/No move Whse-Because of price-So Im standing by his spark plug display showing 10 Brands-I start asking him-Do you have these?-Finally-AC Delco Rapid fire/Splitfire/Bosch Plat are my choices-NO Bosch ever again-I had Ok luck with Splits in my 82-But bought Rapid Fires-So far-So good-Got some NGK plats on order-DAMN PARTS STORES!!!!!!! :roll:
Hey i work in a Toyota dealership and 90 of the problem i c are becuase ppl put junk ass spark plug that are not platinum tipped stay OEM and u wont have anyproblems, unless u turbo it then i rec NGK R @@RETC plugs
bosh plugs are renowned for not working well in most toyotas. Last time I bought plugs for a supra the NGK Iridium ones were actually cheaper then the recommend platnimum ones. So far no problems with them.
I also tried to get some power with Bosch 4s Only to kick 'em to the curb for OEM plugs...at over 10 clams each! I'm getting ready to dig deep for some Iridium plugs next, for HP, BUT YOU CAN BET those OEM plugs will be put away safely for a rainy day (at the price I payed). Toyota will tell you that the European plugs do not work well. Though I have not heard this about the splits, I would think similarly of them. I would only use platinum or iridium. I kept the bosch 4s for my 944. Cooky as it sounds nationally produced items are generally designed to work best with their own machines.