Andrew's 1989 325i Project

[5Toes]

The little car that could!

What a wonderful drive it was to Naches, although we encountered a detour along Hwy 7 before White Pass. The pass was closed with up to two hour delays, so my Mom and I didn't wait and took SR123 North to SR410. WHAT A DRIVE!!! No cars in front of me the whole way, beautiful views, snow to play in (and do donuts :)). Also there is a short tunnel, which I popped the car into neautral and bounced off the redline... fun time.

http://en.wikipedia.org/wiki/Washington_State_Route_123

SR410 through Chinook Pass is also amazing drive. All in all it was 235 miles from my home to my friends.. and the car got 24.22 MPG. Excellent considering its an auto and I pushed it fairly hard... We did 70/75 most of the way on HWY 7, and 65 most of the way on SR410, but not through the top of the pass of course.

Its a great drive, I recommend it. I didn't see but one cop the whole way there.. except for one coming from the opposite direction on 7. Great pavement the whole way too, we took SR410 the whole way home and after the pass it turns to shit pavement. Ick

Also took my car up a forest road and got sideways... sort of. Haha I took some great pictures up there. Ill post them tomorrow afternoon.

[5Toes]

Leaving on my trip soon. Should be fun.

Been drooling over these.

[5Toes]

Roadtrip! Taking a roatrip to my buddy's in Eastern WA. He lives in Naches... 190 mile drive one way.. should be fun. Leaving Tuesday morning (fuck that store). While there I will be travelling some of the 350 miles of desert gravel roads within 20 miles of his house. Awwww ya. Getting sideways.

Also, trying to decide what stickers I want to get some extra power.

Im thinking Sö Good atleast (any word on who is selling these besides eBay?)

[5Toes]

Will make note for when I pull them out.

.40 is what I read on one plug that came out. Like I said I gapped mine to .30 the best I could

[KenC]

Good read.

Our track car has nothing but wipers, and a defogger as far as accessories go (and a gauge cluster obviously). Perhaps more juice from the alternator is free for the ignition?

In any case, we run a hair under .40 and have no misfires with a bone stock M20 ignition system that is pretty stressed.

[Sagaris]

Bought some Bosch Supers from Mike O'Hara in Portland, and he swore up and down that the Bentley spec was too tight and that .36-.40 was ideal for them. He's owned his independent BMW shop since 1981, and definitely knows his way around M20s. Any local PNW guys will know who he is... local old Bimmer guru.

We've always ran our copper cores at .40 in our track car and have had zero issues with them even after hours and hours of 4500-7000rpms during endurance races.

:up: cool. good info. I was hesitant to push mine past 0.034" but I think I will have to give 0.039" a shot now. Thanks for the info!

Andrew, heres some info from NGK's site about gap size:

"Since the gap size has a direct affect on the spark plug's tip temperature
and on the voltage necessary to ionize (light) the air/fuel mixture, careful attention is required. While it is a popular misconception that plugs are pre-gapped from the factory, the fact remains that the gap must be adjusted for the vehicle that the spark plug is intended for. Those with modified engines must remember that a modified engine with higher compression or forced induction will typically require a smaller gap settings (to ensure ignitability
in these denser air/fuel mixtures). As a rule, the more power you are making, the smaller the gap you will need.

A spark plug's voltage requirement is directly proportionate to the gap size. The larger the gap, the more voltage is needed to bridge the gap. Most experienced tuners know that opening gaps up to present a larger spark to the air/fuel mixture maximizes burn efficiency. It is for this reason that most racers add high power ignition systems. The added power allows them to open the gap yet still provide a strong spark.

With this mind, many think the larger the gap the better. In fact, some aftermarket ignition systems boast that their systems can tolerate gaps that are extreme. Be wary of such claims. In most cases, the largest gap you can run may still be smaller than you think."


Cliffs notes: smaller gap = requires less energy to jump the gap, more reliable, less chance of a misfire
wider gap = requires more energy to jump the gap, more power, more chance of misfire

[5Toes]

Whats wrong with a hotter spark though (smaller gap)?!?

[5Toes]

Hmm... well when I pull them out in 1000 miles or so, I will gap to .38

[KenC]

Mr. KenC, I am curious as to what your source is on the gap being 0.035"? I am not claiming that you are wrong, I am just interested in where you got this number or what kind of experimentation you have done to be able to make this statement?

Bought some Bosch Supers from Mike O'Hara in Portland, and he swore up and down that the Bentley spec was too tight and that .36-.40 was ideal for them. He's owned his independent BMW shop since 1981, and definitely knows his way around M20s. Any local PNW guys will know who he is... local old Bimmer guru.

We've always ran our copper cores at .40 in our track car and have had zero issues with them even after hours and hours of 4500-7000rpms during endurance races.

[Sagaris]

Mr. KenC, I am curious as to what your source is on the gap being 0.035"? I am not claiming that you are wrong, I am just interested in where you got this number or what kind of experimentation you have done to be able to make this statement?

[KenC]

Should be at least .35 for a good spark.

Copper cores are right though.

[5Toes]

NGK's are indeed copper core. ZGR5A

Pelican and another sourc both said .027. Website I read said .028 to .032. So I gapped to a .030

[KenC]

The gaps were way off though. $15 for ew plugs after tax and everything is fine by me.

You can always re-gap them.

What do you have them at now? They should be .35-.40 for an M20.

Are those NGKs copper core?

[5Toes]

The gaps were way off though. $15 for ew plugs after tax and everything is fine by me.

[Kershaw]

old plugs didnt look so bad.