I have read the tech section showing std coil packs should have a resistance of 0.7 Ohms between the middle and the left pin of the coil connector plug (looking from the side of the engine). Mine are reading 1.0 on most and 1.1 on #3 Is this out of range? My plugs are breaking down ONLY after changing gear after reving to 6500 It runs on maybe 4-5 cylinders for maybe 10-20sec under no load then comes good again I will be changing the plugs shortly but thought I'd get some opinions on whether the coil packs are out of resistance range and are the cause for dropping a few cylinders Splitfires or replacing with oem style might be the answer Has anyone else had this issue?
Cheers Rollin, that makes sense I have only just changed the top end mixtures to 11.5- used to be 10.5 Plugs are probably buggered from early days tuning as well I'll change plugs before needing to ask about the coil pack resistance
thanks man. good to know. Even at idle I cannot get the car to idle smooth with std af mixtures Since the build on low comp pistons it seams to need the extra fuel! At 25psi I am a little scared to lean it out further. I found the oil cooler was leaking last weekend so changing the pkugs can wait another week I'll check the running of motor after plugs then take on board ur suggestion on 12 to 1 af Cheers mate
I was running 1.1 and the plugs looked perfect but thought I was getting blow out so reduced to .7mm. Ran horrible especially low revs. Changed to .8mm ran a kittle better but still the odd miss at low revs. Might go to .9 or1.0mm on the new plugs as they are still looking too black. When I ran 1.1mm the plugs were a perfect colour for 98 premium. Might be worth mentioning I am not a beleiver of $20 plugs. I run NGK R Bcpr6es.
What do u class as decent plugs All the drag guys and drifters report anything more than 5 bucks per plug is just performance tax
Have you asked them what sort of lifespan they get from their cooper plugs? It may or may not be the cause of your problem but you've increased boost significantly over stock and also running a fairly rich tune (I get that it's for safety, no problem there), and at the same time you've downgraded your plugs (compared to stock). Try denso iridium plugs gapped to .8 or even .6
Try increasing your Ignition Dwell Duty...... in the higher rpm register. If you're going to run 25psi , I would stick to 11.5 afr (fuel is cheap, motors aren't)
agreed with rob on the plugs 25psi is kinda sketchy on 98, even with low comp pistons how low did you go ?
I'll go with robs idea to rule out plugs As much as it's a pain in the arse to change, at least the tune is good enough to not kill the plugs like the 1st set. I'll play with the gaps to see what runs best. Obviously gaps depend on what work is done to the motor but I'll report back my findings 25psi on 98 is not bothering the motor at all. I am surprised a little as well but then again the brand and quality of the parts supports the work that has gone into the machining of the build. The internals have all been built to handle 40psi on e85 and 28-30psi on 98 So far the sensors have been reading safe
I'd suggest possibly using PFR6B-11B which is the standard extended reach plug for a TT in the USA and moves the combustion a little further down in to the cylinder. At high boost though spark blow out can be a problem at 1.1mm gap. My personal suggestion based on experience would be running ZFR7F which are copper but also extended reach like the PFR6B-11B and pre-gapped to around 0.8-0.9mm which in a lot of peoples experience is good for higher boost applications. -ltd
