got a good one for you guys.

i know i can run 6psi and see no KR with pump gas, i added a 35shot on top of that and during my testing i used xylene to get me to 100octane, i saw 0 KR.

if i continue to use the nitrous at a 35 or 50 or even a 75 shot and do not see any KR with pump gas would there be any benifit to running an addative or race gas? i will not run the nitrous without activly monitoring for KR and letting of at the first sign.

got another one for you, why is the truck section the best place to ask questions, i have asked fuel/injector/compresion/cam questions in other areas and always get the best responce in here. <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" /> , i think we have the best forum.

 

I have read that you only want to run enough octane to prevent detonation because the more octane you run, the harder it is to burn. That is what I have read, so I am sure someone else will chime in on whether or not that is correct.

kent

I have also noticed that in the other sections. Seems like if you don't have a F-body, people don't answer your questions.

<small>[ March 06, 2003, 10:35 PM: Message edited by: 1999stepside ]</small>

 

I was about to say the same thing. If you have 0 KR, there is no need for more octane.

If I remember correctly, higher octane is less combustable which makes it resist detonation, but also makes it less explosive. You only want to run enough octane to prevent knock, no more.

 

As for the first part of your two part question.

If you are runing boost with N2O and not seeing any KR on pump gas. I would still recomend higher octane just incase. There are a lot of reasons to or not to, but what if you run lean just in case. Beter safe than sorry.

As for part two.

Not to take anything away from are cousin the F-body. F-bodys are for going really fast. And thats it. Our truck however come in many forms form an bag'd ground scraper, to a lightning killing 1/4 burner, to going really slow climing up really big rocks. Thats a lot of diferent ways to make your truck 'perform' beter.

 

The old "use only enough octane to avoid detonation" does not apply when you are talking forced induction and or spray and or high compression. Just ask the head gaskets on my 12.5 compression Buick with a 350 shot and 100 octane. Better safe than sorry. Naturally aspirated is a different story.

 

seems we have a diference of oponion here <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> , i don't plan on going lean though, got a bigger fuel pump, fire hose injectors, fuel presure gauge, wide band and atap to monitor, lets just assume i will not ever go lean. does that change your vote?

the next time i do some runs i am leaning towards not puting in the good gas till i see a hint of KR, might be able to save a few bucks. any one else got a view on this?

 

BigTex is right about not using more than you need but, it only takes one time detonating to send the piston into the oil pan. <img border="0" title="" alt="[Frown]" src="gr_sad.gif" />

Other than using the race gas as a safety margin I don't think there is a whole lot of benefit to using it if your not seeing any knock on pump gas.

This may be a benefit but, I really don't know much about it. I think race gas may burn cooler and definately burns slower which may help keep peak cylinder pressures down. It might also help keep hot areas on the piston and cylinder head cooler. Like I said though that's all just speculation on my part. I was just thinking about it like using different powders for reloading bullets and the effects they have on pressure.

Maybe you should ask in the fueling section. <img border="0" title="" alt="[Razz]" src="gr_images/icons/tongue.gif" /> <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

John

PS - Don't forget to pull some timing before you try just pump gas. Better to sneak up on the right tune. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

<small>[ March 07, 2003, 01:46 PM: Message edited by: XLR8NSS ]</small>

 

I agree with Kent and Richard. Higher octane makes the fuel burn slower, thus reducing detnotation. So in actuallity using a higher octane rating than you need to prevent detonation will actually hinder performance and economy due to incomplete combustion. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

 

Back in the day when we were runnin 12/1 compression they were sellin 102 at the pumps. High compression needs high octane, low compression will drown on it.

 

Parish you have avoided the problem by adding more fuel. More fuel will cool the motor and cut down on det. These motors with 7to 9 psi should not need high octane, and the 50 or 70 shot should not carry it to the level where you need octane either. Don't forget now that you are adding Naz to the equation you are cooling the intake air dramatically and taking away more of the possibility of det. Many people run small 70 hp shots on blower motors to help cool it along with extra fuel...In my yrs of fun you should be more than Ok....Good luck and glad to see you hauling some *** too.....Its so much fun dragging sports cars...lol