Hey Guys

After about 4000 miles on this built motor (intermediate load/intensity driving), I decided to replace the plugs (had misfire codes), and while I was at it, did a compression test as well (with fingers crossed behind my back).

OK here are the results:

Cyl 1: 170 psi
Cyl 2: 170 psi
Cyl 3: 167 psi
Cyl 4: 170 psi
Cyl 5: 175 psi
Cyl 6: 170 psi

Here is what ALL of the plugs looked like:



I used two bottled of MMT-containing octane booster (NOS Racing formula), and I think this is why there is a red residue on them (and they smelled like gas). I had pulled the plugs for an inspection right before, and they did NOT look red. This I am not worried about, more of an FYI thing.

Here is what they looked like before, each one of them:

Cyl 1


Cyl 2


Cyl 3
[url]http://www.gurgen.com/G35Pics/Spark%20Plugs/Cyl%203.jpg[/IMG]

Cyl 4


Cyl 5


Cyl 6


Here is the real question. Would the plugs look like this (any of the two cases above, before and after octane booster use) if I had a water (head gasket) leak? Last time I did, that plug looked completely "washed out", almost like bleached look.

Any comments whatsover would be appreciated. I am just tryign to see if I still have an issue with these sleeves. Thanks

 

I just noticed #4 and #6 last 2 on drivers side right ? look like they run leaner . When I did the rebuild , the cyl. them selves looked the same . Does the #4 and #6 get less fuel or more air ?

 

I think it gets more air. That was also (for most of the plu's life) the results with a stock plenum. Put the spacer in a couple of hundrer miles before the check.

On the last check, the 'red' plug look above, ALL of the plugs looked IDENTICAL.

Will pull them in a couple of weeks for another check.

 

i'm definately not an "expert" but those plugs look pretty damn normal to me!!!
my compression numbers were all lower...possibly because my larger piston to wall clearances..or some other factor...did you do you compression test immediately after driving?...i believe my numbers were all in the 130's or so

TODD

 

Hey Todd,

no this was on a stone cold (well, around 70 deg F) engine. NOT before driving. So, with the engine warmed up, the numbers should be even better. Will do that next time.

 

how many times the ambient compression was compressed to get the given number at 5500ft altitude:

we'll do the following arithmitic in inches of mercury conversions (because Gurgen didn't know the psi numbers off hand) normal atmospheric pressure..drop of one inch of mercury for every thousand feet elevation...5.5 inches dropped....minus 29.92 (14.7psi)

29.92-5.5= 24.42 atmospheric pressure in inches of mercury at 5500ft

24.42/29.92 = percent of air at this altitude compared to sea level: .82%

given 82%... convert to psi

.82*14.7 = 12.0psi (this is the amount of atmpsoheric pressure at 5500ft altitude)

compression test here was in 130psi ballpark...to see what these numbers would have been at sea level: 130/12= 10.83 (compression ratio for compression testing purposes--not CR of piston)

14.7 * 10.83= 159.2 ---> that would be MY compression at sea level

leave the other variances to difference in piston to wall clearences, accuracy of the compression gauges, etc..

*** this entire math lesson was brought to you by a conversation with physics/math master Gurgen***

owe, my head hurts!

 

octane boosters have alot of crap in them, definately could turn the plugs red or orangeish in color. don't remember what it is exactly, but i believe it is lead. but octane boosters really are crap. if you read the fine print on the bottles. they claim "7 points octane raise" in reality it is only 7/10ths of one full point!!! not a full 7 numerical digits. octane boosters are not good for the motor at all because of the deposits they leave behind also, like you have shown here.
comp #'s look good though. what is the comp ratio you are running in that motor. it actually sounds kinda high for a 9.0-1 or less motor. the stock Z spec at 10.3-1 is 185lbs max.

 

if you want an inexpensive way to get higher octane fuel, look into toluene. can be had at paint supply stores in 55 gal drums (and usually 5 gal containers). natural R+M/2 octane is ~120 I believe. So add 9 gal of 93, 1 gal of toluene (assume 120) == 95.7 octane. This is basically what the 80's turbo f1 cars ran as fuel. it is actually (in a small percentage) part of 'normal' pump gas. it is completely compatible with all fuel system parts (at least in the 10-20% mix), and is by far the cheapest way to get high octane yum yums. downside is keeping what is, in essence, 55 gallons of gasoline in the garage, which many won't/can't do.

skip the '108 boost' crap on the store shelves. you'd have to add so much to make any meaningful difference it doesn't pay (especially at $5/bottle or more).

ahm

 

more like $7 a gallon...anything but inexpensive!!!

i tried this route...did the math AFTER i had tracked down a five gallon drum of toulene...the yield of mixing 91 and 110(toulen---some sources say 114oct)...at the ratio that woul dmake it cost prohibitive...would give you 101 octane for about 2 cents less than buying it at the pump for $4.68/gallon...

(did not include math because i am hungry and tired,...and have food waiting for me downstairs, take my word...it is not inexpensive!!!)

 

Hey gurgen did you make sure an gap the sprak plugs by tapping them on a hard metal surface

-George

 

LOL.... I swear i remembered yu when I was doing this.... I was as cereful as humanly possible...NO tapping.

This particular booster was tested by a magazine or such independent group. Showed that in the recommended ratio (and I went OVER this), this booster raised the octane by 2.5 points. Can't remember the link (guys on bobistheoilguy.com linked me). The "outlaw" brand, with the less potent booster (not MMT), raised it by 0.7-0.8 points, and here i am referencing REAL points.

I spoke with todd about octane boosters at length, there has GOT to be a chaeper source for toluene... Maybe a chemical supply company.. I'll try to research this.

Todd.... glad I could help...hehe.
Gosh I wish the 100 octane stuff was $4.68 per gallon, as you saw on your recent trip it's $5.95 out here... Well let's just pretend we are in Europe...

 

Can't believe I forgot to mention it...

It's 9.3:1 compression...so I think the numbers, are quite good.

The possible water leak was more of my concern.

 

The article to which Gurgen refers is the July 2005 issue of Sport Compact Car. It's also the issue with Randy's Vortech'ed G35 in it. Can't seem to create a hyperlink to that particular atricle but it's in www.sportcompactcarweb.com.

George & Gurgen - a ball peen hammer also works as a gapping tool!!

 

I belive that was Sport Z mag not SCC.

 

Yep it was SportZ, but that's not where the octane test was undertaken. Here is tha articl, enjoy:

http://europeancarweb.com/tech/0503ec_techboost/

 

OK, so I was HALF correct!! I just picked the wrong Vortech'ed G - the SCC issue had John Ngo's G coupe with the NX Intercooler. Randy's WAS is Sport Z - oops!!

 

Except I'm not interested in getting to 101 octane. Tune with 93 pump, then mix to get 95-96 safety margin for track time.

Its all about what your needs are. I have no intention of needing >93 day-to-day, especially because there is almost no where to get 101 locally.

ahm

 

ok...so say you want to get to 95-96 octane
figure the 93 costs $3.00/gallon...maybe less, let's assume $2.90

so based on a 16 gallon fill-up, if you used 14 gallons of 93 and two gallons of toulene, the price for the fill-up would be approx: $54.60 ($2.90*14 + $7.00*2)...this would yield a fuel with an octane rating of approx: 95.625 ({93*14 + 114*2}/16)

Vs the scenario of filling up with 93 pump: $46.40 ($2.90*16) and buying an octane booster like the one that Gurgen was talking about that raises the octane level 2.5 points (estimated cost $7.00)...giving you a grand total of $53.40 for 95.5 octane fuel... an almost identicle gain for $1.20 less!!!

The point is...you DO NOT SAVE MONEY BY MIXING YOUR OWN FUEL WITH TOULENE, no matter what your octane goals are...101 or 96...i thought i had stubled onto a secret too, then i purchased the materials, did the math, and laughed at myself for wasting 2 hrs of my day finding the toulene and only saving 2 cents a gallon to mix my own fuel vs...buy it at the pump...(unless you can find toulene for much cheaper if purchased in bulk, but then do you want to store 50+gallons of highly flammable fluid in your garage? )

So, even if 101 is not readily available, I would look into the octane booster that Gurgen was talking about.

TODD

 

a math major i was not methinks the man might be on to something here...

my understanding was that 55 gal drums could drive the price down to just $2-3/gal. after reading the article, i'm a little stumped however - they talk about 99% pure toluene vs paint store toluene, although never mention what its 'purity' is. since it was a racing fuels company doing the talking about that, i'm reticent to believe that as anything other than salesmanship. still, i'm going to call a paint store and chemical supply house to see what kind of prices turn up.

all that being said, this is the first 'octane in a bottle' product i've ever seen actually throw off worthwhile gains from *1* bottle.

kudos to NOS for not selling snake oil, and thanks for doing the math Todd!

ahm

 

http://www.mkiv.com/techarticles/read_plug/plugdiag.jpg