Does adding more fuel increase detonation?

[2005 1m]

In the past I've run a RKT high compression head with a speedwerx y & single and SLP can on my 900 EFI King. That was using the stock airbox with no modifications. This year I've decided to open up the airbox with a snorkel to the old tach hole. I may also try pods at some point.

So my question is, I'll need to add more fuel to the cylinder to make up for the added air. Will this increase the likelihood of detonation? I've never had a problem before with 91 octane at 8-12k ft. I'd like to keep running 91 if possible. Or do I need to mix in a little race gas?

Does the added fuel & air in the cylinder increase my chances of det? Thanks in advance for any help.

 

[mmsports]

Pre det

Pre detention is from low octane for compression you would be best off to run a gallon of race per with it.

 

[WyoBoy1000]

Pre detention is from low octane for compression you would be best off to run a gallon of race per with it.

timing also plays a part in deto.


More fuel usually reduces deto, at that elevation I think you should be fine but if you ever hear a tingy sound like a exhaust spring is rattling all over the pipe it might be to late.

 

[markoo]

Pre detention is from low octane for compression you would be best off to run a gallon of race per with it.

Why would he have to run race fuel. He isn't changing timing or compression. As long as he adds enough fuel so it doesn't run lean it should be ok with what he was using. 91.

 

[1Mike900]

Markoo my sentiments exactly! If nothing changes compression or timing wise you should be able to add more fuel? But if the fuel has up to 10% alcohol on occasion this may present a problem? It is the consistency of the fuel you are depending on?

Mike

 

[WyoBoy1000]

Adding anything that produces more hp (the bigger air box) increases the rate of compression and could cause deto, the faster or higher it spins the more compression. but I don't think it will be a prob at 8-12k.

If it doesn't make sense then put a full pipe on a m1000 and run it at sea level with 87 octane and see what happens. BOOM

 

[Rixster]

How are you planning on adding fuel ?
If you are looking for a "LITTLE" fuel just unplug the ethanol wire. It richens the mixture 2 %

 

[2005 1m]

Thanks for the responses guys.

I knew that low octane can lead to detonation but I wasn't sure if an argument like Wyo made would come into play. That is more what my question was geared towards.

Rixster - have a pure logic controller. Already have the ethanol wire unplugged and it runs great with my current mods. Figure that with opening up the airbox it will need more fuel naturally - hence the new addition of the pure logic controller.

 

[Rixster]

Thanks for the responses guys.

I knew that low octane can lead to detonation but I wasn't sure if an argument like Wyo made would come into play. That is more what my question was geared towards.

Rixster - have a pure logic controller. Already have the ethanol wire unplugged and it runs great with my current mods. Figure that with opening up the airbox it will need more fuel naturally - hence the new addition of the pure logic controller.

Make sure your pure logic box is grounded GOOD !!! I fried a ECU in about 3 seconds of motor running because the box wasn't grounded

 

[2005 1m]

yikes!

Make sure your pure logic box is grounded GOOD !!! I fried a ECU in about 3 seconds of motor running because the box wasn't grounded

That's a little scary!!!! I have it grounded on the recoil where many of the rest of the instruments are grounded from the factory. That would suck if it fried the ECU!!!!

 

[fishtank]

I didnt realise opening up the airbox would affect performance like that. I was going to block off the air intakes on the inside of the engine bay so as to only allow the airbox to draw cold air from the footwells and the snorkel setup I have.

I also noticed that the airbox has some random holes drilled into the side of it that I cannot see what they are used for (other than drawing in warm air from under the hood). I was going to block these off as well but now Im not so sure...

Should I be leaving mine how it is? It seems to run fine as far as I can tell.

 

[mmsports]

RKT head ON 900

That is the only reason I recommended some octane boost in years past just seen some pre det issues and it is very cheap insurance.

 

[WyoBoy1000]

Air box mods are always a guess, I've seen some have a benefit and some that lost power, you will just have to test it and find out. I usually do them based on other mods or weight loss.