[gosutag]

I have been running 93 only since I've bought the car.

[Whitemaro6]

One thing is for certain these cars love a big breath of dry cold air!

[MuhThugga]

Originally Posted by EFI Tuning

There is on the LT1 platform. But E85 is the better option if you can get it and aren't maxing out the fuel system.

Tim

Originally Posted by EFI Tuning

Sorry... I was making an assumption that timing would be advanced beyond stock. For a stock ECM it could slow you down.

Right, you can make adjustments in the tune to get a benefit from 100 octane, but Brian was asking about just going ahead and pumping it into the tank, which will not do anything other than cost more money.

[EFI Tuning]

Originally Posted by MuhThugga

Right, you can make adjustments in the tune to get a benefit from 100 octane, but Brian was asking about just going ahead and pumping it into the tank, which will not do anything other than cost more money.

Agreed.

[Brianw36]

Thanks everyone for the great information.

[TJay74]

ok, so here is what we have found in logging data on the truck LT1 engines. The 5.3 trucks knock like crazy on 87 octane, they show to really need 91/93 octane to not knock.

The 6.2 trucks show knock events on 91, so they do benefit to have 93 octane as well. The 6.2 trucks state in the manual to only use 91 octane, you can use 87 in a pinch but it is suggested to get back to 91 ASAP.

With that the GM powertrain testing is done on 91 octane as it is available everywhere in the USA where 93 octane is not. As EFI-Tuning said, 93 wont make more power per say, it just keeps detonation from happening which will cause the ECM to drop you into the low octane table which pretty much takes 15° of timing away instantly.

Octane is a fuels ability to resist detonation. Detonation happens with timing is advanced too far and a sharp edge on the piston gets too hot. As the fuel is injected into the chamber and the piston comes up on compression stroke the hot edge in the chamber ignites the fuel charge, then the spark plug ignites the fuel charge as well.

Now instead of having one singular flame front moving across the combustion chamber, you now have 2 flame fronts. They move across the chamber and collide, that collision is what causes detonation and makes the pinging sound. The occurrence of detonation is likened with taking a ball peen hammer and smacking the top of the piston, if it happens enough or is severe enough it can damage the piston/valves and leave small marks on them.

The cooler the weather and the incoming air is, the less the chance of detonation unless the timing is just advanced way too far.

I have a station a mile from my house that carries 100 octane pure gas, I get it for $7 per gallon. I mix 6 gallons in my truck with the rest being 91 octane, brings my octane to around 93/94. I do the same thing in our Audi SQ5 as well. So far no detonation has been seen in either of them, now that it is cooler out I can run 91 and will be fine.

[My87z28]

Originally Posted by EFI Tuning

Agreed.

My first question: are you TSloper?

Second question: many of us through the country do t have much access to E85. The closest station to me is a VP station that sells C85, but is 90 miles away and doesn't deliever drums. I have a truck but feel that I'd have a very hard time getting a full 55 gal drum out of the back of it (still something I'm contemplating). *** I've seen Race Gas additive advertised quite a bit lately where you can add to 93 octane and reliably produce 100+ octane. Would it be feasible (wise within reason) to go this route, while testing each tanks octane, and have the car tuned for 100-104 octane?

[EFI Tuning]

Originally Posted by My87z28

My first question: are you TSloper?

Second question: many of us through the country do t have much access to E85. The closest station to me is a VP station that sells C85, but is 90 miles away and doesn't deliever drums. I have a truck but feel that I'd have a very hard time getting a full 55 gal drum out of the back of it (still something I'm contemplating). *** I've seen Race Gas additive advertised quite a bit lately where you can add to 93 octane and reliably produce 100+ octane. Would it be feasible (wise within reason) to go this route, while testing each tanks octane, and have the car tuned for 100-104 octane?

Yes

Technically it is feasible. However you won't net the same gains as E85. A major component of E85 is the cooling effect it has. This can't be achieved with gasoline.

Is it practically feasible? That would be up to the end user to decide are the gains worth the expense/hassle. I'd probably not opt to go this route personally until I have exhausted the hard part bolt on modifications. But that's just me.

Tim

[My87z28]

Originally Posted by EFI Tuning

Yes

Technically it is feasible. However you won't net the same gains as E85. A major component of E85 is the cooling effect it has. This can't be achieved with gasoline.

Is it practically feasible? That would be up to the end user to decide are the gains worth the expense/hassle. I'd probably not opt to go this route personally until I have exhausted the hard part bolt on modifications. But that's just me.

Tim

Thank you,

I've spoken with Pray a few times and I'm very interested in the ported intake/TB. The E85/race gas wouldn't happen for at least another year or so as I'm very hesitant on voiding the warranty for at least the first two years. If there is one, hopefully any powertrane bug will present its self within that time. What are your opinions on running the ported intake/TB and RF CAI (along with 3" exhaust already done) without doing a tune? My concerns over this is a big reason I haven't placed an order yet.

[EFI Tuning]

Originally Posted by My87z28

Thank you,

I've spoken with Pray a few times and I'm very interested in the ported intake/TB. The E85/race gas wouldn't happen for at least another year or so as I'm very hesitant on voiding the warranty for at least the first two years. If there is one, hopefully any powertrane bug will present its self within that time. What are your opinions on running the ported intake/TB and RF CAI (along with 3" exhaust already done) without doing a tune? My concerns over this is a big reason I haven't placed an order yet.

You should not have any issues with that combination and no tune.

The Rotofab unit does not affect the MAF output signal in any appreciable way which is why it is the only unit I will be selling for the Camaro 6th gen platform.

Please let me know if you have any additional questions.

Thank you,
Tim

[My87z28]

Originally Posted by EFI Tuning

You should not have any issues with that combination and no tune.

The Rotofab unit does not affect the MAF output signal in any appreciable way which is why it is the only unit I will be selling for the Camaro 6th gen platform.

Please let me know if you have any additional questions.

Thank you,
Tim

Thank you Tim

[Speedy1975]

I agree with the above and would not run that race gas additive regularly. It may be "OK" for the occasional trip to the track, but it's really the same thing as Torco. You're really better off just getting a 5 gal pail of race fuel and having a tune specifically for it on the track. I run Renegade 109 unleaded in my supercharged Challenger at the track with great results. VP makes a similar product VP109. I get 5gals for $80.

As for all the boltons and such, my advice would be supercharge and be done.

[laynlo15]

I've made all my drag passes on 93 octane, I run it on the street also. I'm planning on E85 this winter preparing for next spring. I'd like to run E98 if that will be of any benefit. I'll just buy a 55 gallon drum and use it only for drag racing.