So a while ago I was reading on NASIOC and one of the big time subaru tuners was talking about how colder plugs on e85 can make less power.

He explained how e85 already runs cooler EGT's and running colder plugs just make it harder to ignite things off.

I know we are talking about completely two different engines so I thought I would see if this had the same affect with 4G63's.

Does colder plugs affect power at all with e85?

Whats the best heat range for EVO 8's and EVO 9's?

 

When using E85, most of the guys I know have found that you need to move to at least one range "hotter" plugs than you would if you were using gas. Here in Colorado, Lucas Gaines mentioned that to me last week, and so did Jake L., who was tuning my car at Lucas's Superflow dyno, and who has been running E85 on a 750+ HP 4g63 2G road race car for quite some time...

 

I have been having a ton of misfire issues on e85 at 25ish psi even with a Dyna ARC2 and I use BR8ES plugs. I might switch back to stockies and see how that works.

 

I'm running stock plugs (actually 37,000 miles on the stock plugs) on E-85 30 psi (stock turbo, stock ignition) with no issues.

 

Well I hate you I have been having soo many ignition problems it isnt funny. What is the gap on your plugs?

 

Stock gap (never measured...whatever the stock iridiums come gapped as). I took them out once to check them and they looked fine.

I do plan to change them out for another set of stockers due to the mileage, but everything seems to be working fine.

 

Interesting; I had never thought of that or read that anywhere. I just recently switched to the Denso IKH24 plugs (one step colder than stock) after running the stock iridium plugs for 21K miles. So far I haven't noticed any ill effects running 32psi on an FP Red, but this will have to be something to keep in mind.

 

Stock plugs on e85 here, no problems for three years.

 

We tested the 1 step colder plus on E85 30psi on a stock block 35r and found that it would constently missfire at the top end switched the car back to the stock plugs and problem solved

 

7s at .020 work for misfire free operation at 45psi on a 4202.

 

Good to know... so stock IX plugs are fine, yes?

 

All we use

The IX plug is still a heatrange 7 and the gap is the same as the VIII and 1G that we run the BPR7EIX at, that was what I was referring to. The ILR7H is the same except that it is 1/4" longer or so than the BPR7.

 

Good stuff to know!

 

i was told to go with the NGK bp8