Depending on where you look it's sometime refered to the 9.7:1 kit but its really closer to 9.8:1
I'm not trying to our rain on your parade just giving you a heads up. That motor depending on how its driven and timed will last about a year.
CK5
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Buddies buildin a 383
- Thread starter Deuling
- Start date
I'm not trying to our rain on your parade just giving you a heads up. That motor depending on how its driven and timed will last about a year.
Giving it that time frame with those heads? If he gets some better heads it would last longer?
Its not just about the gas. You have to retune the ECM. And unless you buddy knows how to do that it will cost him $200 each time. When you tune that motor it will depend on what gas you stick in it. It's not as simple as just turning the distributor to set the timing on th TBI motor is all computer controlled.
Hard to say depends on how much it detonates. Detonation can cause serious damage that makes that motor junk.
I would think 76cc TBI heads would be dirt cheap <$300 for the set. That is what I would do if I had that motor and didn't want to spend a fortune. Will run great with 76cc heads.
Ok ima have him read over this thread as all everyone has to say is that the heads need changed lol.
3MAX
1/2 ton status
Vortec heads are NOT the same as TBI heads. Vortec heads can support higher compression without detonation. Although I dont think I would have used flat tops with 64cc heads either
Could be depending on where you are your premium is actually higher then other areas. Where I am at premium is 93 octane.
I have access to both 91 & 93, but my engine shop says I'll be ok on 91. I trust these guys - they make a living building high performance engines.
Back to the original topic - Dueling, bottom line is your buddy really needs to know what he's got and what compression he's running. I would hate to see anyone put the money and effort into a nice motor and then trash it due to detonation.
here is my 383 build if he wants to check it out.
http://coloradok5.com/forums/showthread.php?t=290466
I even have a starter "tune" he might be able to use that I'd be willing to give him. But really that motor needs to be tuned for what you have on it.
Brian at tbichips.com is really knowledgeable and is capable of providing a tune.
Aight thanks guys. What all goes into checking the actual compression ratio??
Or just send me to a good thread?
Or just send me to a good thread?3MAX
1/2 ton status
Aight thanks guys. What all goes into checking the actual compression ratio??
Check out Summit's website- they have a calculator.
http://kb-silvolite.com/calc.php?action=compAight thanks guys. What all goes into checking the actual compression ratio??
Thanks dave, we will get all his stuff together sat and see what we can figure out. Ill post up results, if its way out of line for compression maybe we will have to wait to break in... But i know hes not gonna wanna wait lol
Aight thanks guys. What all goes into checking the actual compression ratio??
I wrote a calculator in excel you can download from our own forum here...
http://coloradok5.com/forums/showthread.php?t=282965
compression ratio aside, 305 tbi heads flow like crap, even compared to 350's....
it's like a beautiful fillet mignon being topped with weasel poop...
decent heads aren't THAT much coin, after buying a block and a stroker rotating imo...
it's like a beautiful fillet mignon being topped with weasel poop...
decent heads aren't THAT much coin, after buying a block and a stroker rotating imo...
Agreed, like running the engine with a choke on!
Its like restrictor plate racing...whats the point?
yup the bumpstick is the heart of a mill, the stroke is it's legs, the heads are it's lungs...
mmmmmmmmmmm, crunchy weasel poop.......
mmmmmmmmmmm, crunchy weasel poop.......
Adam, it's not just that the engine may run poorly, to high of compression with the wrong gas can destroy the engine in short order depending on the magnitude.
That's pretty high Dave, are you still running race fuel in that? (I know i could smell it at the build and greet) Have you considered switching it over to E85?
Which models are you referring too? I haven't looked at the others in quite a while, however, the one that recommends to add 15 deg to the intake closing is probably assuming you are going to use the number at .050" lift. So adding 15 deg will get it closer to the actual point where the valve is closed and it starts making compression. I think it's better to use the advertised closing number, which takes a little math if it only lists the closing points at .050". Yes, it's true that the advertised number will vary by manufacturer, I've seen that number listed at .004", .006", .015" lift, etc. However, simply adding 15 degrees is worse because cam profiles vary significantly depending on lifter style and cam applicaton.
Also, in reality its more complicated than that, because the air can start to compress at some lift number before zero lift depending on the piston speed and volume change relative to the pressure, valve size, etc.
With that said, this is just another way to guesstimate the limits of pump gas when you are selecting components, and is not an exact number anyway because of all the other variables such as ignition timing, combustion chamber shape, head material, sharp edges, temperature, RPM, etc. I believe the advertised duration number for intake closing is the most effective way to easily do that. It will get you to a much closer place in the piston stroke where you actually start compressing the gas, especially since you include the rod length in the calculation.
how do we measure deck clearance????
it's like a beautiful fillet mignon being topped with weasel poop...
