So If I throw a z6 head on a a6 block will I still be able to run 87 octane? My father-in-law just picked up a 89 crx si for comuting to work. Here is the deal he need to get good mpg, but the drive to work has alot of slow driving loging trucks and people who like to drive 10 under the speed limit and stare at rocks and trees and ----, So he needs a little umpfff to get past them on the short straightaways. So is it worth it to do the swap, or just do a heade, exhaust,r cai, and a cam? I know i will chip it and do the one wire vtak and all that ----, but I will end up chipping it anyway and probably do a little tunning to possably lean it out on the freeway to get a little better mpg.

 

Lemme put this in perspective for you...leaning out for highway driving and 87 octane are a bad mix, especially under load. Depending on the HG you run will also depend on what your c/r will be, which will determine what your timing will run at and what octane rating you should use. Hell, even if you do fill it with hi-test it's still only going to run about $20 to fill that tank lol.

 

But I would only lean it out when it dosent have a load on it. I have been running my a6 an the freeway leaned out for a 1 1/2 years and haven had a problem. Im running about 3400rpms at cruse, 18-15 in on vac, 7-15% on tps, and afrs sit around 14.9-15.3 and it runs ------- ****. On the last tank of freeway driving that i did, I averaged about 42 mpg. But Im running 92 octane and im turboed. But Like I said Ive had no problems, but Thats why im asking, Ive never leaned out a na a6 on the. So if I ran a little colder plugs would it help or is the whole thing hopeless?

 

---- 42 mpg is hella good

 

I was happy as ----, At first I thought I was running a little lean, But I said ---- it, I dont realy care about this motor much. But its still happy 1 1/2 years later. And when im in town I rape my car daily, I avarage about 24-26 mpg.

 

I have those same results on my car but i'm running a vafc

 

Its alll about keeping it simple.

 

 

In your personal case you can get away with that, just due to the fact under low load you're still going to sit at an effective c/r of around 9:1. On a mini-me your c/r will be higher all the time, though only a few points higher. If it was a load based ecu system you can get away with it, but I don't know how well it would work with honda's speed density setups. I'd talk to Bone about the lean situation, IIRC he's got a monster of a d15 running somewhere in the 15 afr's and seems to do quite well.

 

I had nothing but problems running lean partial throttle maps