The Red '96 Z26 (78K Miles)

[3X00-Modified]

Wasting your money with mid grade gas... these engines are DESIGNED to run on 87 octane... 89 is NO cleaner than 87.

We've actually seen a power drop when too high of an octane fuel is run on a race engine...

High Octane Myths – What Does That Number at the Pump Really Mean?
The truth about Regular, Plus and Super gasoline.

In the automotive world, there are many common myths, which are repeated so many times that, after a while, they eventually transform themselves into ‘facts.’ Unsurprisingly, many of these ‘facts’ have to do with gasoline, whether they be regarding fuel mileage, power possibilities or some other arcane aspect of the internal combustion engine. Gasoline can be a confusing topic, and it is easy to make assumptions about it that may seem logical, but which on closer examination, turn out not to be true. A perfect example of this practice can be seen with octane ratings.

What are octane ratings? Simply put, when you pull into the gas station and are presented with the array of different fuel grades that you can pump into your car, the numbers written above each button or nozzle indicate that particular grade’s octane rating. Typically, the range will run from 87 octane on up to 93 octane.

In the world of automobiles, it is tempting to associate higher numbers with higher quality. After all, more horsepower and more miles per gallon are a better thing, which feeds into our perception that more impressive octane ratings also equal higher performance. Gasoline companies understand this mentality and do nothing to dissuade drivers from it, labeling 87 octane gas ‘Regular,’ and 91 or 93 octane ‘Super’ in an attempt to reinforce this way of thinking. After all, since ‘Super’ is priced higher than ‘Regular,’ it’s in their best interest to convince as many people as they can that paying a bit extra means getting better quality gas.

Unfortunately, this is where the myth of what gasoline’s octane rating really means creeps into the picture. Time and again, people will be told that high octane fuel burns cleaner or more completely, and that it will give them extra power and better fuel mileage than Regular octane gasoline because it contains more ‘energy.’ These blanket statements are simply not true. In fact, the octane rating for gasoline has nothing to do with the amount of power locked inside of it – it actually relates to just how much a fuel can be compressed before igniting. The higher the number, the less likely it is to ignite under pressure.

Why would anyone want to produce a fuel that was actually harder to ignite once inside an engine? To understand the role that octane ratings and ignition pressures play in a motor, it helps to be familiar with the term ‘knock.’ Essentially, when gasoline is sprayed into a cylinder by a fuel injector and mixed with oxygen, engine designers expect it to remain there in vapor form until it is time for the sparkplug to light it up, causing the explosion that drives the piston down to generate horsepower. The timing of this explosion is critical, as gasoline that ignites too early causes ‘knock,’ which reduces engine output and efficiency and which, in worst-case scenarios, can actually physically damage an engine.

In most engines, knock is rarely an issue because the compression ratio – that is, the pressure that the air/fuel mixture is put under in the cylinder – is low enough that Regular gasoline’s octane rating is sufficient. There is absolutely no benefit to running Premium fuel in a standard motor, since it will never be able to take advantage of that gasoline’s higher knock resistance. However, more aggressive engine management schemes, especially those found in turbocharged or supercharged vehicles, can turn up the compression to a high level, requiring much higher octane gasoline to avoid knock.

How can you know whether your car actually requires Super gasoline or whether it can get by on Regular? Almost every vehicle will list the octane rating necessary to run it safely inside the owner’s manual. Some luxury or sportscars might even place a small reminder on the gas gauge itself stating ‘Premium Unleaded fuel only’ to make sure you don’t forget.

To wrap things up: no, you won’t see a power or fuel efficiency increase by running high octane fuel in an engine that has been tuned and designed for Regular gas, nor will doing so perform any extra ‘cleaning’ inside the motor. On the flip side, running low octane fuel in an engine built for Premium can increase the risk of engine damage and will certainly impact that unit’s overall performance. The next time someone tries to pass these myths off on you, you can try explaining to them how octane ratings really work – or you can just smile and nod, pay for your gas and move on.

I pay 4.27-4.39 a gallon right now because the car I'm driving is pushing 18lbs of boost... thats the only reason why I have to run 93... hell my Beretta gets 87 when I drive it on the street... I only put in 93 before I'm going to the strip and using the nitrous from the higher cylinder pressure.

[2.2H8TA]

Just hit 70k. ALMOST EXACTLY 10k miles a year! CRAZY!
Still running good and smooth, SES light remains. Been using regular gas.^^
Gonna give her some love tomorrow (Friday).
First, a good wash/wax, and interior detail, then an oil change, and it needs to be inspected in July, so more to come for sure. Tires are gonna be good (have 10k on em), but I'm not sure if anything else will be needed for inspection/emissions in July. Where I live, the only thing they check for emissions is the gas cap pressure, so the SES light shouldn't cause me any problems there.
(No the gas cap is not causing the SES light)
Brakes are good, but the left lower control arm is staring to make a bit of a clunk, so that may be an issue, whether it's bushings, or the control arm itself remains to be seen, but it all looked good last time I looked, so most likely just bushings.
Overall, this "project" is coming along MUCH SLOWER than originally anticipated, but it'll be in my possession for the foreseeable future, and will remain a DD for as long as possible. (Until I get a reliable 4cyl 5 speed beater car, which I am currently looking for )
No complaints here, just a little update of where everything stands.
Stay tuned

[Money pit Beretta]

Yeah these cars eat control arm bushings. Damn that SES light. What the hell is the code now?

[2.2H8TA]

As far as I know the SES light remains due to the evap canister, or a vacuum line leaking somewhere. It's kinda hard to inspect the lines, so whenever I get the chance, most likely before inspection in July, I will have this all looked into, and replace what is needed.
Yes HUGE PITA!
Oh and I know about them eating the control arm bushings, I had to replace them multiple times on the old 95 2.2, and the 90 I had also. What brand bushings would you recommend using? I think I always just went with the cheepest, but now I actually care, cuz it's a Z. LOL

[Money pit Beretta]

If I remember what Weba said right there is a stiffer bushing that is used stock on a Z. Other than that Moogs or GM's will work, your choice. I like to think of it this way: the stock ones on my car went 150k and I'm not sure the car will out last another set.
Yeah I know how bad it is when testing lines. I have a hand held vacuum pump, but finding the end and pluging it is a pain(when the lines get long). The EVAP lines are short and easy to test. Also the trans line is easy. I replaced the "T" on that just incase.

Do you have an adjustable vacuum modulator for the trans? They are great and help the shifts be more firm.

[2.2H8TA]

I had this puppy serviced a bit this weekend. Oil and filter change with high mileage non synthetic valvoline, tire rotation, and just an overall check-up on some things. I had the codes cleared, and now the SES light is no longer on! I also had the TB cleaned out, along with a new air filter. I had the muffler support replaced, so it's back to hanging where it's supposed to, and no longer rattling around back there. Then I gave it a bath, and cleaned up the wheels real nice. After being serviced it runs alot better, more power, and it's much more responsive. Ihad the front end checked out, and it's all nice and tight still, the control arms, and bushings are still good, so I'm thinking the noise is the struts. They will be next on the list. I'm gonna try to get some new pics while it's still all nice and shiny, but I just started a new job, so not much free time. This was my fathers day gift to dad.

[Money pit Beretta]

Where are those pics? Good to hear that the front end is in good shape. Alot of money can go into replacing front end parts.

[2.2H8TA]

I seem to have a slow coolant leak just below the water pump. I went out today and found a small puddle near, and under the pass. side front tire. The coolant level is still good. The car did not get run at all yesterday. Anyone have any ideas on what the problem could be?

[Money pit Beretta]

If it's coming out of the weep hole it's time for a new pump. Anyway you are just going to have to take a look around. Check for a loose clamp too.

[2.2H8TA]

I originally thought it was coming out of that weep hole, but after running it, and backing it in to the parking place, it looks to be slowly leaking from a small line on the pass. side of the oil pan. It got driven to the store last night with no leaking at all. This was at maybe 9pm. I checked it at about midnight, and it did not leak. I got up today, and looked, and there is a small puddle, and it seems to be slowly dripping from a small covered line just to the pass. side of the oil pan. Is this a line to the trans?

[Money pit Beretta]

If it is coolant it has nothing to do with the trans. Covered by a plastic mesh?

[2.2H8TA]

Ok, I guess that was a dumb question. Yes the line looks to be covered in the plastic mesh. I really can't even tell if it's dripping from the line, or somewhere else. It is an extremely slow leak, and it seemed to take hours for it to start after the car was ran.

[Money pit Beretta]

Hey, take a look and see if the stock clamps are still on there. Also check to see if the hose looks new. If someone replaced the hose and used the stock clamps that could be where the leak is coming from.

[2.2H8TA]

Has not leaked any coolant for over 24 hours. It did not lose much, and most of what it did leak I cought in a plastic cup. On another note, I got 13 gal. of gas for $30 today! (Supermarket discount made it like $2.25 a gal.) After I filled the tank, I drove about 10 mi. on the highway. I then shut the car off for maybe an hour. When I started it back up the SES light re-appeared for the first time sense I had the codes cleared last Saturday. I drove it probably about 30 more mi. turning it off and back on again atleast 5 times. During this time it got heated up pretty good, due to alot of sitting and idling. It only got to a little over the half way point on the temp gauge, and the fan kicked, and did it's job. It then got about a 3 hour break, ran for like 2 mi. and shut back off again. All this time the SES light was on. It then sat for another hour, and when I turned it back on NO SES light! WTF? It has been on and off 3-4 times now and driven maybe 10 more mi. and no SES light.

[Money pit Beretta]

I'm thinking O2 or EGR. Can you pull the code?