high octane gas

Putting 100 octane into a Mondial is like throwing $5 bills into the East River. Once again using higher octane than an engine was designed to run on will do nothing but waste $.

 

I agree, waste of money. A QV engine will run perfectly on 87 octane....unless of course you've add a turbo / blower or changed pistons to get the CR up into the 11 or 12:1 range.

 

With out higher static compression you will loose performance and waste you'r money.

 

waste of money...no direct link between high octane and increased performance...

 

with 100 (ron+mon)/2, don't forget to buy the "gas saving Intake Tornado".

I agree (and search this topic for much more great information previously posted here on FC), the engine must be designed for the fuel to take proper advantage of it.

However, that said, I have run 100 unleaded in 348/355/360 Challenge race cars, but this is because I wanted consistent fuel quality while traveling across the country and had no need for cold-start capabilities. It just removed one variable out of the performance/reliability equation.

It did not 'add' any power, but was insurance against potentially poor quality local pump fuel.

Best regards,

Rob Schermerhorn

 

I can certainly notice the difference between 95 and 98 Ron here in the UK - the 98RON is Shell Optimax. The car feels a touch quicker and 'ticks over' smoother.

 

Some cars with computer controlled engine management systems will allow more advance until the engine just knocks which may increase performance slightly. Of course this would depend on the software. But, for the most part, I would say that it is like throwing money away...

 

Tried Union 76 Racing gas in our Vette, V12 jag, 5.0 Mustang. The ONLY car that was better was the Vette. Engine ran cooler with a better bottom. The only way to inprove the 5.SLOW mustang was PUSH IT OFF A CLIFF!.
IMHO I WASTED about $100.00 on fuel for those cars.
Take Care
George P.

 

100 octain may not be of any help if your timing is not advanced. More advance requires more octaine to prevent predetination. Another option os a boost to about 95 octaine with toluline. Search the archives for a great article "Rocket Fuel". Try that first, it works.

 

What is an adequate octane rating for a 328 running primarily at sea-level?

 

What ever the manual says should be fine.

 

Was tracking the 328 at Roebling Road over the weekend. I bought some 100 octane gas at the track (at $5.50/gallon - felt like I was in friggin' europe!).

Noticed a bit better performance due to less weight in my wallet.

 

Anyone consider saving the money over $4.50-$5.50 a gallon and just buy the highest grade (in California, ranges 91-93 octane) and add octane boost? It's definitely cheaper.

 

I certainly notice the difference using Shell Optimax in the UK vs the standard 95 Ron fuels.

There was of course the other time when I ran out of fuel at the end of a track day event. There was a racing team there who allowed me to fill up with their 'standard' fuel so that the car could get me to the next petrol station. I didn't drive off immediately but as soon as I left the track, the car was absolutely flying I raced back to the track to see if they were still there so I could offer to buy a tank full but no luck ... they had left

There must be some merit to filling up with 100 Octane. This was in my 308QV rather than the 355 so maybe the ECU regulated later cars adjust to negate the effects

 

If you noticed an improvement in a QV by switching to race gas, it most likely means that your mixture was not set correctly. The specific gravities of fuels vary and do effect mixture, that a big part of the reason races like to pick a brand, preferably one they can buy at the track, and stick with it. Also, many racing fuels are also oxygenated, so you need to put more in than normal gas. If you pore that in the tank without retuning for it, you will be very lean.

 

It is my understanding that octane values are computed differently in the UK than in the U.S. but I do not know the difference. (Meaning, 93 octane in the U.S. would be different than 93 octane in Europe, but I don't know which is "higher").

I run 89 octane in my 77 GTB only because the 89 tends to have better detergents than the el cheapo 87 "bottom of the barrel" stuff and runs cleaner. The difference in price is about $1.00 a fill up. I can afford it, big spender that I am. With the compression ratios of standard 308's, there is no reason to put in anything higher than 87 in terms of knock control.

Ironically, my little Honda Civic with a little inline 4 requires 89 octane minimum and definitely prefers 91-93 for heavy highway trips with a lot of crap in the car. The compression ratio is considerably higher than the Ferrari!

Birdman

 

As I understand it, 93 in Europe is higher than US 93.

The 100 octane is probably intended for the new generation of heavily turbo boosted ricers. The stock EVO runs a massive 19.0 psi of boost. The STi, in particular, (at 14.5psi) has been experiencing problems with 91 octane (max avaiil in CA), especially when its top-mounted intercooler gets heat soaked. (The EVO's I/C is front mounted. And it doesn't stay on boost long -- by the time the EVO gets full boost, it's time to shift. )

A US model QV, if memory serves, only runs 8.6:1 compression. 93 should be more than sufficient for that mill.

 

"A US model QV, if memory serves, only runs 8.6:1 compression. 93 should be more than sufficient for that mill"

I run mine on 93.....now that I turned the supercharger up to 22 psi, it ran fine on 87 before that

 

Another point to remember ----- Even if your cat(s) was replaced by a test pipe----the O2 sensor can also be killed by leaded gas. Trust me, I know.