Wiki page has good info. Octane rating - Wikipedia I've considered adding a dash of toluene as an octane booster, although I think it's supposed to cause serious neurological damage. I guess I shouldn't have put my hands in all that paint thinners. "Toluene can be used as an octane booster in gasoline fuels for internal combustion engines as well as jet fuel. Toluene at 86% by volume fuelled all the turbocharged engines in Formula One during the 1980s, first pioneered by the Honda team. The remaining 14% was a "filler" of n-heptane, to reduce the octane to meet Formula One fuel restrictions. Toluene at 100% can be used as a fuel for both two-stroke and four-stroke engines; however, due to the density of the fuel and other factors, the fuel does not vaporize easily unless preheated to 70 °C (158 °F). Honda solved this problem in their Formula One cars by routing the fuel lines through a heat exchanger, drawing energy from the water in the cooling system to heat the fuel.[22] In Australia in 2003, toluene was found to have been illegally combined with petrol in fuel outlets for sale as standard vehicular fuel. Toluene incurs no fuel excise tax, while other fuels are taxed at more than 40%, providing a greater profit margin for fuel suppliers. The extent of toluene substitution has not been determined.[23][24]"
Thank you the explanation regarding octane ratings. As an aside, I questioned an industrial chemist once regarding using paint thinner and he said it would destroy seals and it evaporates too quickly.
I'm running 10 lbs boost from my 6-71. 8:1 TRW pistons, .040 over 350 sbc. Have run 91 pump gas for 25 years with no problems.
My dream engine runs on E96. The same dream includes living in a community where there is a small distillery making the stuff from local regenerative farmers' organic sorghum rotations.
It might be worth getting some way to know when it's detonating, like a knock sensor, and doing some experimenting. Or do some experimenting without bothering with the knock sensor. If you get it to ping under any conditions, then you'll at least know that you're on the edge under those conditions, and you can work from there. Maybe run some 87 in it and do some short pulls, and listen...see what you hear. It does take more than a few short rattles to blow up the motor. I did this accidentally on my blown 427...there was something loose in the distributor, it advanced itself 20 degrees on a long road trip. I heard it ping under relatively light load conditions on 87, and finally realized just how low octane it really needed.
you might also want to explore the dynamic compression ratio, with the cam timing you have. Might be that swapping the cam could allow you to run more boost, perhaps at the sacrifice of some low end torque. But with the gearing in those cars, they spin pretty high, so that shouldn't be much of an issue.
There was a thread awhile ago on knock sensors I was interested in but it never went anywhere. as I recall. I'm very hard of hearing and would love a simple knock sensor kit.
That would be nice. Change the carbon cycle from an unsustainable multimillion-year one, to a multi-month one.
Does your ignition system have a knock sensor? Programmable ignition system and methanol backup for HARD driving is the safest way.
I don't currently have knock detection. I have been thinking of getting a safeguard system that gives you individual cylinder knock detection and active dwell. The programmable ignition is on my list as well. As I want to keep a period correct look I am going with a CB performance Black Box as opposed to an EDIS setup. The Black Box for the ignition map and the Safegaurd to control knock under boost. I am running a Snow Performance Stage 1 water/meth injection set to start at 4 PSI. The set up works great but I plan to install a Stromberg WW carb that will double the CFM from the YH side draft that is currently installed. I'm sure running 91-93 octane will be fine in this engine. The reason I have run 100 octane is I have easy access to it and with the chamber design of the heads I thought it would give me added peace of mind. When I get the car out in the spring it will have the above upgrades, and be tuned for pump gas. Thanks for the comments guys
Damn, I thought about going the blown route while my motor is apart but it seems it makes a guy cranky and crabby and by the questions, answers, and general conversation its way to complicated for the street. Maybe its breathing the fumes ????? LOL
heh....it's dirt simple, and works good and lasts a long time. If you do your homework first. I've been running a 6-71 on the street and strip for thirty years....
Hey guys, It's been said that I should man up and that is exactly what I'm going to do. My attitude wasn't conducive to any meaningful exchange of info last night. I enjoy the exchange of info on our cars and don't want to create barriers to accomplishing that. Mike and Squirrel, I hope you accept my apology. As for my cam selection- I went with a 260 tb grind to help with low end torque before getting up on boost. Being that the motor is 170CI I need all the help I can get in the lower RPM and cam replacement in a Corvair requires a complete engine teardown.
61 - Funny, I just wrote a comment that was sorta...well, never mind. I wrote it before I read your comment above. So, I deleted it as you can see, no more funny business. All is fine on my side. Peace. Mike
You might wish to be careful here. Stromberg type WW's were made in a few different internal venturii sizes. The very largest type WW would flow approximately 33 percent more than the type YH Carter. The smaller common versions of the WW would flow approximately 20 percent LESS than the YH. To get twice as much, you will need to use the larger WWC Stromberg. The WW is a size two carburetor, the WWC is a size three. Jon.
Thanks Jon, I am aware of this. I was planning on using the carb that would normally be installed on a 318. I have the model # in my notes. I have heard that finding jets for the carb may be difficult as well. If I run into alot of road blocks with the Stromberg I will change my focus to a weber DCOE 40 or 45. If I go this route it will require modification as well. I would have it built to act as a progressive 2brl. It's a proven mod with Spyder motors. Many have had problems getting the fine tuning right, but with a wide band O2 I should be able to get the A/F ratio in happy land with either carb. Speed always equals money and time. NORM
Jon, As I get all the parts together for this project I'm sure I will need more advice as carbs can be a PITA. If you have any recommendations on witch carb you would use for this application I would love to hear them. Thanks
Norm - you are out of my area of expertise on which carb to select for a blower application. With the exception of the Carter AFB's and YH's, and haystack Holleys, I have little experience with blower carburetors. Would rather defer to those with more experience than give you a wrong answer. As to parts: Virtually any part is available mail order for the Carter AFB, Carter YH, or any of the Stromberg WW's (as well as the larger WWC). I can also suggest modifications, if using a blow-through application. As far as the Webers are concerned, not my favorite carb. If you call, I will relate a really long story. The short version is, that after spending more than $1500. in parts alone a few years ago, neither myself nor several "Weber experts" could make supposedly the "hot setup" 44 IDA be as competitive on a Ford 4 cylinder race engine, as I did with a $5. junkyard Autolite 2100! Jon
I hear ya Jon, that's why I thought the Stromberg would be a good choice. The Webers as you said are an awful lot of money. I had a friend that was running a DCOE45 on his turbo engine and it did develop wood power but was very temperamental off idle. I don't think he ever got it sorted.
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