So maybe I went a little overboard....

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Well I think I may have went a little overboard in the area of compression. The pistons i had made for my stang were made the to raise the compression of the engine to 10:1, I couldn't help myself, all I could think of was the potential of more HP. I think a I should have went for 9.5:1 or 9.7:1. My question is will I be able to run my engine at this level? My pistons are forged not cast. I do wonder if Ross accounted for the fact I would be using a fel-pro head gasket and not a steel shim gasket, cause that would mean my compression might be under 10:1. Well here is a list of the parts I used in my engine build up. FSPP headers, 272 cam, high capacity oil pan, roller tipped rockers, pushrods, lifters, dual roller timing chain, hipo balancer, Clifford exhaust port divider, Weber 38 carb, custom Ross Racing Pistons, Comp valve springs, Pertronix Ignitor 1, flamethrower coil, flamethrower wires, 3.03 3-speed. I have more goodies too but thoose are the main ones. . I had the block milled .040 over. I had hardened valve seats put in and a 3 angle valve job. I have everything back together now, I'm just waiting to buy a new clutch, pressure plate, and throw out bearing so I can put the engine and tranny back together and then install everything at once. If anyone can give me some guidance in what direction I should go it will be appreciated. Thanks.
 
well if this car is a daily driver, idk. But their is always C16! Some alertintive sloutions would be alchole or water injection or some sort of fuel additive.

kevin
 
See how it runs. If it pings a little, try WI or dial back the ignition. If it pings like mad, cam it up. :twisted:
 
You shouldn't have any problem. Motorcycles, sportbikes in particular typically run around 11:1 and I've never had a problem with pump gas. I always ran the highest octan available but you should be fine. Enjoy the extra horsepower!
 
But most sport bikes are desinged to run pump gas with 11:1 compression. Old engines that used to have strokes over 2 times longer than bore dia. ran as low as 5:1. There were even diesels running 10:1 to 12:1 c/r, my point being that most of our engines have a stroke that is a bit long to try 10:1 on stright pump gas. Head desing also effects this alot. Hemi heads are some of the best at preventing detonation, and most bikes use a hemi head. I know alot of racers that mix premium with 119 octane racing gas 4:1 for thier high compression cars. I have seen others that simply dial thier advance way back and keep thier foot off it when running pump gas. Of course you could always run aviation fuel if there is an airport around. Thats good stuff.
 
Well there are a couple of gas stations around where I live that sell cam 2 race fuel, which is unleaded 100 octane. Except it is like $3-$4/gallon.
 
Could I cut it running that kind of fuel or hould i look into qctane additives or maybe water injection. I'm hoping to figure this out soon before i put the motor back in.
 
Hemi heads are basically symmetrically shaped combustion chambers, like a dome, where ours are wedges. Many modern cars run hemi heads on some of their cars, Honda, Volvo, Ford...just to name a few. They aren't as uncommon as they used to be. It's not like Dodge has the only Hemi-head out there, it was just one of the first for production cars.

Slade
 
Well, as someone said before, you are going to have to do some trial and error. You may be able to use the 100 octane and cut it, or use additives in premium, but no one can really say for sure that it will work, or that you will even need it, because every engine is different.
 
If you use water injection, there will be no problem with running that compression.

If its got a 38 Weber, just use the stock water injection jets over the throttles, and connect it up. You loose a small amount of power, perhaps 2%, while under wide open throttle. The great thing is you can use low-octane gas.


If you want no loss in performance, then add 50% methonol, 1% ethel methol ketone, and the balance water. Then use the same low octane brew, and meter the set-up to suit.

Water injection is perfect when you have over compressed your engine. It's best advantage is being able to use low grade gas, with a small loss of maximum power with no loss of pistons! The mix of methonol and water is even better as you get no performance loss.

Forged pistons run cooler than cast, so I doubt you will need the water injection, but its best to be sure.

Use the Aussie Knock-sensor on the battery strap bolt at the front of the head, or run a MAP sensor to trigger it if it doesn't already have one. There are heaps of options, including microswitches to make it work.

Don't fall into the 'I won't trust a 150 buck water injection system on safegaurding my XXXX buck investment. If you want to run 105 octane and suffer the hassles, well, thats your choice.

Check with the MustangGeezer if you feel a bit worried about this.
 
Sefus, I got a race kit from P.A.W. for $700, it had the pistons w/ pins, rings, and main and rod bearings, but I dropped the bearings cause I already had a new set of bearings and they gave me new set of rods instead. Xecute I think I'm going the water injection route,

If its got a 38 Weber, just use the stock water injection jets over the throttles, and connect it up
Click to expand...

How do I set this up?

Use the Aussie Knock-sensor on the battery strap bolt at the front of the head, or run a MAP sensor to trigger it if it doesn't already have one. There are heaps of options, including microswitches to make it work.
Click to expand...

Are you saying that I could set up the water injection unit to run only when my engine started to knock?? If so that would be awesome how would set that up too? Sorry but this is my first car rebuild, I've only rebuilt the motor in my RM 250 and they are a lot easier to deal with.
 
The other thing I forgot to mention is I am seriously considering the offy tri power set up, could still run the water injection with that??
 
Try running premium fuel 1st!! If it knocks, then you can try a water injection unit. :D :D

That spearco injection unit is nice but way to expensive IMO. Try searching ebay for a obsolete holley or edelbrock vara-jection setup.

ebay search keyword "water injection" :D :D

You should be able to find somthing there for under $125.00 including shipping.

There is nothing wrong with running 9.7-10.0-10.5-11.0:1 compression on our 6's as long as its setup right!!

Later,

Doug
 
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