my ride vt ecotec

[vt3.8lt]

hey guys im back again i know i ask alot of questions and im sorry but i appreciate any help i can get so my latest question is i changed my heat range on my spark plugs to a 7 instead of a 6 and it killed one on a 3rd gear pull now i know theres a lot if different theorys and aplications better suited to different heat range plugs but i was just wondering what sort of recommendations you guys had for a good plug that might not die so quickly thanks dane

[Holden202T]

a colder plug is going to make any fouling worse..... normally you want a colder plug for alcohol, but if your fouling, what AFR's are you seeing at WOT ?

[vt3.8lt]

oh ok um its hovering around 11.5 ish at wot well that explains y they fouled so quickly might have to go to a 5 or something

[Holden202T]

i thought you were running E85 ?

i wouldn't go to a 5, either the stock 6 or a 7 ..... i wouldn't command 11.5 unless your running like 20psi, and even then its getting to the rich side ... probably 11.7-11.8 for 20 psi and then tapper back to 12.8 at 100kpa.....

also plug gap could be an issue, you might need to close them up a bit!

[wozza]

Hi prob a dumb answer but watch out for the brand of plugs your given, I ended up with bosh plugs once and they reverse number the heat range...see here for a cross reference chart
http://www.briskusa.com/spark_plug_cros ... ange_chart

[vt3.8lt]

yeah its on e85 and its only on 10 psi till i get it onto the dyno and tune it for more boost ive just street tuned it for the time being so i opted for the richer side of things to be a bit safer ill have to look at getting it to around those afrs when i put it on the dyno the plugs im using are ngk and i gap them down to .8mm witch seems to be fine for them untill they die definatly going to have to look into going to a 5 or back to the 6 heat range

[Dylan]

Thinking 11afr might be a bit lean for E85?

[Gareth]

I know it is...

What exactly happens to these spark plugs that "kills" them? Any photos of those plugs?

[VL400]

I think he would be using the petrol equiv by using a kinjflow botched petrol tune rather than making the AFR numbers that of E85. E85 at a real 11:1 AFR at idle would run pretty badly let alone under 10psi load!

[Holden202T]

yeah 9.7 at stoich (14.7 petrol), probably 9.2 at idle (14 petrol) and about 7-7.3 on full boost (10.6-11 petrol)

plenty of E85 tunes around though so getting the right info int there shouldn't be too hard.