100 oct over 91 oct

[dipapa]

Been contemplating getting a 2nd SCT dyno tune by Todd (A&C Performance) on the Built All Motor.

Occasionally feeding the Built All Motor with better fuel seems justified. More indicative of "true hp" rating.

There is also easy access to the 76 Station with 100oct nearby me.

The again, the motor is running so damn good right now im not so sure i want to touch anything!


Anybody have actual test results to how much more hp could likely be extracted going from 91 to 100 oct on a 10.5comp 505 cube motor?

Anybody go through higher octane testing on there All Motor Viper?

Im also not certain if 76 station 100oct advertised is actually 100oct or more like a measured 95-96 oct.

 

[ssjcreeper]

Was thinking about a 100 octane tune too, but with an otherwise stock motor (K&Ns, Mopar exhaust).

Anyone have comparisons against 91 and 93 octane tunes?

 

[97snk]

There is also easy access to the 76 Station with 100oct nearby me.

Must be nice....

 

[1fast400]

I wasn't aware a true 10.5:1 motor could run on 91 gas. I'd be surprised if you were making an actual 10.5:1

 

[dipapa]

I wasn't aware a true 10.5:1 motor could run on 91 gas. I'd be surprised if you were making an actual 10.5:1

Please elaborate as too why you are surprised?

For example, way way way back when dinosaurs existed in 2002 my then stock C5 Z06 from the factory had 10.5 Compression.

I think Motor Technology, especailly tuning have come a long way since then.

 

[dipapa]

Must be nice....

$5.99 gallon aint exactly cheap.

Then again is it "real" 100oct??? Not sure if that fuel is regulated or prone to inspector checks as the lower octanes.

 

[plumcrazy]

IMO, not worth the work for a few extra HP

 

[TowDawg]

Was thinking about a 100 octane tune too, but with an otherwise stock motor (K&Ns, Mopar exhaust).

Anyone have comparisons against 91 and 93 octane tunes?

Definitely not worth it on a stock motor. Not sure on a built one.

 

[plumcrazy]

stock motor with higher octane is a total waste

 

[Tom F&L GoR]

Anybody have actual test results to how much more hp could likely be extracted going from 91 to 100 oct on a 10.5comp 505 cube motor?

Anybody go through higher octane testing on there All Motor Viper?

Unless the 100 octane has a different BTU value, wildly different rate of combustion, or you adjust timing to take advantage of the higher octane, the answer is zero. It's not the fuel that makes the power, it's whether your engine tune can take advantage of the fuel properties.

 

[dipapa]

Well the objective was to further advance timing via SCT safely using 100oct and hopefully detering detonation increase HP and also to increase redline a bit.

On 91 the motor HP, for the most part, platued at 6000rpm so no point increasing rpm although the Built Motor could handle more.

I was hoping using 100 and further advancing timing the HP may continue to climb past 6000rpm, but none the less it be interesting to measure and see what happens. As long as its safe for motor.

 

[1fast400]

Who figured out the compression on your motor? Or are you just calling it 10.5:1 because those were the pistons used?

 

[1fast400]

Well the objective was to further advance timing via SCT safely using 100oct and hopefully detering detonation increase HP and also to increase redline a bit.

On 91 the motor HP, for the most part, platued at 6000rpm so no point increasing rpm although the Built Motor could handle more.

I was hoping using 100 and further advancing timing the HP may continue to climb past 6000rpm, but none the less it be interesting to measure and see what happens. As long as its safe for motor.

I'd be more worried about oil than fuel over 6k. I've never had my car over 6k rpms.

 

[dipapa]

I'd be more worried about oil than fuel over 6k. I've never had my car over 6k rpms.

I dont think oil pressure or oil flow is the concern here.

A bit about your motor?

 

[dipapa]

Who figured out the compression on your motor? Or are you just calling it 10.5:1 because those were the pistons used?

You cant be serious, right?

 

[1fast400]

Of course I'm serious. My father did probably 1000 motors when he had his business. We had countless people call up with their 11:1 pump gas motors that made 9:1 when properly figuring their compression. It's your motor, was just asking. As far as oil pressure, I wouldn't even risk it. Any little bit of power you'd gain at those RPM levels isn't worth risking it, IMO. How often are you actually in that RPM range anyway.

 

[dipapa]

Knowing the parts and machine shop placement specs, which i happen to have from the builder and lets get this straight, i will not disclose, not sure why so many were having trouble calculating compression ratio.

utilized online compression calculator and even checked it with my own written program to verify.

 

[dipapa]

Ok, to be frank, Im close to 10.5 could be higher could a bit lower but honestly I see no reason to publicize the exact number.

I worked this out with my builders and I have to respect certain proprietary business information I was asked to maintain and I have to be ethical about.

It is each owners responsibility to go through this with his builder when the time is right. I went through this because i trusted my builder and tuner and they delivered a good product. But sometimes engine building can be real tough and i been through hard stories too.

This query was not about my compression but about the fuel.

 

[dipapa]

Of course I'm serious. My father did probably 1000 motors when he had his business. We had countless people call up with their 11:1 pump gas motors that made 9:1 when properly figuring their compression. It's your motor, was just asking. As far as oil pressure, I wouldn't even risk it. Any little bit of power you'd gain at those RPM levels isn't worth risking it, IMO. How often are you actually in that RPM range anyway.

Thanks for your opinion & concern Fast. I understand its good for all of us to be continuously made aware of important factors. I always try searching this forum for more information and it bugs me if its just not here or I cant find it. But then again i dont have countless hrs to read cars. Im sure that goes for most of us.

 

[1fast400]

Hahahahaha, you're acting like your motor is some super secret motor that has set the world on fire. I hate to inform you, it's a motor. There is nothing crazy about building a motor these days for these cars. You are an interesting bird .

As others have pointed out, if you aren't tuned for 100, putting it in there is of no value. I doubt you'd see a huge difference even if tuned to be honest.

 

[dipapa]

Hahahahaha, you're acting like your motor is some super secret motor that has set the world on fire. I hate to inform you, it's a motor. There is nothing crazy about building a motor these days for these cars. You are an interesting bird .

As others have pointed out, if you aren't tuned for 100, putting it in there is of no value. I doubt you'd see a huge difference even if tuned to be honest.

Nope your mistaken. Its out of repect to the builders. Its their work, not mine, I just paid the bill, big deal. Im sorry, Im not into disclosing too much business work of friends or close business ties.

And of course im not tuned for 100...

the post was intended to begin a query on SCT tuning for 100oct and its potential HP gain after the tune is performed.

I went this far on the motor already might as well tune it for better fuel and find out

 

[1fast400]

Well no offense, but if your putting so much value in your tuner, you should ask him since he's the only person allowed to know the exact details of your car. You're not going to tune it anyway, correct? Your tuner will? If that is the case, asking a message board is worthless.

 

[dipapa]

Well no offense, but if your putting so much value in your tuner, you should ask him since he's the only person allowed to know the exact details of your car. You're not going to tune it anyway, correct? Your tuner will? If that is the case, asking a message board is worthless.

Well, thats not my call. He's the boss and as long as he does a great job maybe i should not be concerend about details.

Probably like 2-3% HP increase max.

Im sure somebody has tried higher octane tune with an Built All Motor and im sure a few here been through enough cars to know

I will post the 91 & 100 dyno change, whether up or down, when i get the 2nd tune just to post more data.

 

[ssjcreeper]

If you can post some comparisons - that would be appreciated. I have to believe there's a few ponies out there with advancing the timing. Question is - how many ponies? 1 rwhp or 10 rwhp?

Probably like 2-3% HP increase max.

Im sure somebody has tried higher octane tune with an Built All Motor and im sure a few here been through enough cars to know

I will post the 91 & 100 dyno change, whether up or down, when i get the 2nd tune just to post more data.

 

[ACPERFORMANCE]

Just a quick short reply. The motor is simply just a well put together, well tuned setup, with excellent quality parts. Compression is actually a little under 10.4. Head CC"s, head gasket thickness, piston dimensions, deck height, so on and so on.

Truth is is the VP or other race fuels burn slower, helps higher compression motors, forced induction big boost, etc.. run without detonation. With no other changes, adding it to your tank will NOT make any more power. If the engine wants more timing, I'd feel safer pushing the envelope with some good fuel in the tank versus the crap at the pump.

If we decide to push for a number, maybe will try 50% U4 or MR9 fuel. It WILL make more power as it is a much more oxygenated fuel. But it has been know for killing fuel pumps due to it's lack of lubrication if left in the tank for long periods of time. Most times when mixing though it's never a problem.

Todd

 

[Tom F&L GoR]

Peak power is made when the maximum cylinder pressure is produced at the most advantageous combination of crank and con rod angle. Spark timing is adjusted to reach this, so if fuel octane is the limit, then the engine falls short of the best configuration. If the octane is high enough, then spark timing will allow peak power. If the fuel burns slow, then the engine loses power, since cylinder pressure isn't building quickly. It's therefore odd to think that "race fuels" burn slower; they should burn faster. The overall best case is high octane, fast burn for peak pressure at the theoretical 14 degrees or so ATDC.

An oxygenated fuel (a gasoline containing alcohols or ethers) means the gasoline octane has been raised with the methanol, ethanol, MTBE. Each of these has an octane blending value well over 100. The energy needed for evaporation leads to a more dense mixture in the cylinder, which may produce more power. By itself, an alcohol or ether isn't a power aid since it has fewer BTU/gal.

The CCWS and IRL have used fuel lubricity additives (Klotz brand comes to mind) to save injection pumps and nozzles. Of course, they also flushed back to gasoline when not using the engine.

 

[tucker]

Todd, any other pictures of the car in your avatar?

 

[viper k]

93 Oct Is The Best For Stock

 

[FastestBusaAround]

Higher octane = less power. Unless you have a specific need for a higher octane gas, like a detonation problem....you're wasting money and losing power. Do the research - some of the top race gasolines are only 87...

 

[Camfab]

I ran 100 octane Trick unleaded in mine and it ran like crap. I'm sure it may have run better with a tune for that fuel, but with my present tune and close to 600rwhp the Trick fuel test was a no go for me. 91 octane works just fine and is a heck of alot cheaper and readily available.