Adam Geist

I would drain the gas tank ASAP.

Since the race gas is mixed with street gas (unleaded and lower octane), you might have a difficult time finding a racer that will take it off your hands.

When I disassembled the Elva race car, the fuel cell had 5 gallons or so of Sunoco race gas remaining. I couldn't use it in the street cars as they had cats so it ended up in the lawn tractor.

Wish I had better suggestion for you.

Adam Geist

Just checked the wiring diagram for 1989 MY and it has an intake pipe temp switch.

I'm not that familiar with the '89 MY, but both of my '86.5's have an intake pipe temp switch that runs the condenser fan with the engine shut-off if the under the hodd temps are high. You can test this circuit by jumping the switch - your fan should come on without the key in the ignition switch if it's like the pre-'87 model years.

Hopefully someone will chime in on the cooling fan system for your model year.
Adam

sweanders

If you engine is tuned for 93 octane it will not run properly on 110. Not good in any way.

As an example, a 996tt will get a CEL beacuse of misfire when running race gas. Not sure if the 928 is as sensitive.

VehiGAZ

NOTA BENE : I mixed about 13.5 gallons 110 leaded race gas with about 9 gallons of 93 unleaded pump gas, so it wasn't pure race fuel.

The engine has been running perfectly fine on it. My concern is clogging up the cats with the lead.

Does anyone know anything about the internal construction of the catalytic converter on an '89? Is the catalyst laid out in a plate or is it a honeycomb design?

Drewster67

1. Check your electric fans. Ensure they are operational - In my 88, when hot, the fans ran when I shut the key off.
2. Pressure test the coolant system
3. Replace your thermostat and expansion tank cap
4. Check the radiator fins to see if it's loaded up with road debris restricting air flow (looks like you already did)

After ensuring your fans are operational. I'd start with a coolant flush, replacing the thermostat and expansion tank cap.

Helpful hint: If your not doing this already, when you just come off the track, let the car idle and let the temp (if high) smooth to a normal level. NEVER just turn the car off right away.

VehiGAZ

Thanks for the tips Drewster!

1) I know at least one fan is operational, as I heard them running when I came to a stop, but they shut off with the engine. I will check them out to see if both fans are running or not. I searched the forums last night, but all the threads I found were about fans that wouldn't shut off.

2) & 3) I am not leaking coolant at all. But I will change the coolant, clean/flush the radiator, and replace the t-stat. What's the story with the expansion tank cap?!

4) The fins are clean and pretty much straight. Not a problem.

Re hint: That's a good idea and it did occur to me, but there was a slight incline where I was set up in the paddock, and the car would roll without brakes or leaving it in gear. It was either let the engine run and cool off with hot brakes engaged and boil my fluid, or shut the engine down, put it in gear, and let the brakes cool off, so I opted to shut off when I got to my spot.

Bill Ball

When I mentioned this recently during a get together with other 928ers, I got looks of total disbelief. They were convinced that premium provided more power in any car - and better gas mileage too! I tried to explain octane, but it was not something they wanted to hear. I lost a lot of credibility in their eyes by trying to dispell this common belief.

pcar928fan

Bill,

Some people are stupid and will stay that way till Darwin takes care to remove their genes from the pool. Pretty easy to look up too... Just sad some folks know so little and are unwilling to learn from those who know more... You have it the old college try at least! As they say, you can lead a horse to water but you can't make him drink!

Bill at least you and I know the truth. The real answer to more power is to find the LOWEST possible octane rating that your car can run on with the peddle buried and have it NOT PING and detonate...THAT will give you the most power! If you can run a mid grade fuel that would be better. My '81 runs better with the lowest grade but even at its low CR it will still ping on you in the heat of summer. You can do it in the winter...NICE power that!

Drewster67

Both fans should be running. Same as with the a/c on.

The expansion tank caps go bad after awhile as any other. It's a while your at it type of deal.

For me, I toasted as set of headgaskets in my 84S2 - so I always have that fear in the back of my mind. If I had a choice between blown HG and to rebuild some brake calipers ...I go for the brake rebuild.

Tahoe Shark

Not totally accurate! Don't forget about high compression motors. We run 12.2:1 in the Beast and the motor would destroy itself without at least 104 Unleaded. Not arguing just correcting the record.

pcar928fan

Tim,

Maybe I did not make that clear or folks don't understand what S/C's and Turbo's actually DO other than pump in more fuel...they INCREASE THE EFFECTIVE (vs. static) CR! Soooo, yea, ANY HIGH CR engine needs (or may need) higher octane fuel... A stock car like the one in question (it was not specified that it had been modified in ANY way, thus my comments phrased the way they were) would NOT benefit in any way from a race (or high octane) fuel AND if that fuel was leaded as many race fuels are it would in fact mess the cars cats up (again 1st DE for the guy, stock car, probably stock emissions)... potentially even setting the car on fire if they had a complete and total melt down...which did not happen.

Of course there is the possibility that the race fuel was UNLEADED...if that is the case then I would just keep adding pump gas (I would probably choose the lowest octane and fill the car up right now) till eventually all the race gas was gone... The problem is the NOT KNOWING if the race gas was leaded or UNLEADED...

VehiGAZ

Guys, I am aware of what octane means as well. You may recall several posts of mine discussing the pros and cons of reformulated gas. And this is why I put the 110-octane gas in my car - because it did not contain 10% ethanol dilution like all the other grades available had. I didn't buy it for the "110" rating - I bought it because I wanted more energy content for the track.

Drewster - point taken. Next time, I'll find a better spot int he paddock where I can pull in without brakes and let the engine cool off.

VehiGAZ

That's not a problem - I found out today that it was a leaded formulation.

Tahoe Shark

Yep I know that, I was only trying to clarify that if someone took your statement literally they would be wrong to assume that only Turbo and Supercharged cars that may need to run race fuel. That is my only point.

pcar928fan

GAZ,

Good for you... Glad to understand your reasoning on the choice we don't have a lot of ethanol blend down here that I am aware of. To bad about the leaded nature of the fuel though... That could have been your problem...but it still does not explain why the fans did not stay on after the car was turned off till it was cooled down... actually in my cars the I have never heard the fans stay on for more than a minute or two at most...