V8 vs V10 Compression Ratio
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V8 vs V10 Compression Ratio
OK, let me start by saying I'm not quite ready to try this, but I'm thinking....
At any rate, Ford.com lists the 5.4L V8 at 9.8:1 and the 6.8L V10 at 9.2:1. This tells me that either these motors are not exactly modular, or I could take 10 V8 slugs, shave the heads a tad, and get me a 10:1 V10! Woot!
Let me finish by adding that I'm not ready to pull the motor out, but one day, I might think about it. Especially when it's time to rebuild. I figure by then somebody will put out a computer to run the thing on it's own - without all the chassis/trans/airbags/etc./etc./etc. network of computers. There's a few (reletively) cheap computer controlled race engine specs out, and suppliers/builders. It makes sense someone will do it for the street rod market soon.
So what do you think. We take a V10 and crank up the compression, do some other work, and see what this thing can do!
At any rate, Ford.com lists the 5.4L V8 at 9.8:1 and the 6.8L V10 at 9.2:1. This tells me that either these motors are not exactly modular, or I could take 10 V8 slugs, shave the heads a tad, and get me a 10:1 V10! Woot!
Let me finish by adding that I'm not ready to pull the motor out, but one day, I might think about it. Especially when it's time to rebuild. I figure by then somebody will put out a computer to run the thing on it's own - without all the chassis/trans/airbags/etc./etc./etc. network of computers. There's a few (reletively) cheap computer controlled race engine specs out, and suppliers/builders. It makes sense someone will do it for the street rod market soon.
So what do you think. We take a V10 and crank up the compression, do some other work, and see what this thing can do!
Post Fiend
Joined: Jan 2002
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From: USA
You will not be able to shave the heads ,without changing pistons the valves are that close right now. Plus you still want to run pump gas don't you?
a change in the cam area would gain more I would think .
Rich
a change in the cam area would gain more I would think .
Rich
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I built a number of race engines (and have even more built by the pros). I'm aware shaving makes the valve clearance closer, but that's why you cut in reliefs. A bigger cams would also make the clearance closer. Yeah, I don't think pump gas would be a good idea. I'm was really just speculating on what could be done.
I'm guessing we could get over.... say 600 HP+ out of one of these motors, and still have it very streetable. I'm considering building a cobra someday, and think this setup would be a pretty sweet addition to that project. As of right now I don't think anyone is making performance parts (cams, pistons, stand alone computer, etc.).
Maybe I'll key it all into my desktop dyno (not that I believe they're very accurate).
I'm guessing we could get over.... say 600 HP+ out of one of these motors, and still have it very streetable. I'm considering building a cobra someday, and think this setup would be a pretty sweet addition to that project. As of right now I don't think anyone is making performance parts (cams, pistons, stand alone computer, etc.).
Maybe I'll key it all into my desktop dyno (not that I believe they're very accurate).
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Do it and let us know what breaks first 
Higher compression? No, I want 8:1 or lower, with a BIG blower ... with the obligatory crank-snout support bearing.
Seriously, I'm really thinking about a blower after this thing comes off of lease.
Thinks there's enough give in the timing chain setup that I can put a 1/4" thick head gasket in there? (just kidding, guys!)
Higher compression? No, I want 8:1 or lower, with a BIG blower ... with the obligatory crank-snout support bearing.
Seriously, I'm really thinking about a blower after this thing comes off of lease.
Thinks there's enough give in the timing chain setup that I can put a 1/4" thick head gasket in there? (just kidding, guys!)
Postmaster
Joined: Dec 2003
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From: Massachusetts
Does the 2006 V8 having variable cam timing have anything to do with anything. I can't imagine yes. But I have no idea how that works. To me compression is compression.
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Originally Posted by bterry
Hey Krewat, I was hoping you'd stop in! If I do this, do you think I should change the plugs??!
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Originally Posted by boxcar1974
Does the 2006 V8 having variable cam timing have anything to do with anything. I can't imagine yes. But I have no idea how that works. To me compression is compression.
I'm sure that has something to do with the difference.
Fleet Owner
Joined: Jan 2004
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From: Brentwood,CA
i thought the v10 has a .035 head gasket and the 5.4 has a .024 gasket. that may be the difference. the lower compression allows the v10 to run loaded all day long and not ping or pre detonate. just like a heavy duty truck engine should. the pistons show up as the same part number.
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Originally Posted by ford390gashog
i thought the v10 has a .035 head gasket and the 5.4 has a .024 gasket. that may be the difference. the lower compression allows the v10 to run loaded all day long and not ping or pre detonate. just like a heavy duty truck engine should. the pistons show up as the same part number.
The benefits of NOT running that high w/the V10 are obvious...
Logistics Pro
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Been building race motors of all dimensions for 30 years the diff between 9.2 and 9.8 is negligible and well withing the ability of the PCM to compensate.
There is enough room to add thicker gasket set to get under 9.0:1 and boost the hell out of her. Going the other way is a waste unless you want to spend the buck for a custom cam grind to extend the lift and overlap.
Forget about redoing the 3v V10 for any thing unless you bring a bunch of cash as the intake is your big problem. The Thermoplastic box has a variable plenum and is fairly sophisticated device. Not you daddies Edlebrock Torker of days gone by I assure you!
There is enough room to add thicker gasket set to get under 9.0:1 and boost the hell out of her. Going the other way is a waste unless you want to spend the buck for a custom cam grind to extend the lift and overlap.
Forget about redoing the 3v V10 for any thing unless you bring a bunch of cash as the intake is your big problem. The Thermoplastic box has a variable plenum and is fairly sophisticated device. Not you daddies Edlebrock Torker of days gone by I assure you!
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I just ran the gasket numbers ford390 supplied through the calc. I made a couple of assumptions to get a camber volume to start with. Piston dome and deck height set to zero (I know that's not correct, but it won't change the result I was looking for). The gaskets alone don't account for the .6 difference in compression. It only takes you to 9.45ish. Maybe the camber sizes are also alittle different.
Fredvon4, I certainly wouldn't spend the money for a custom cam grind, let alone the intake. I didn't know the 3v had a variable plenum, that's interesting. My daddy was playing with Model A's, Vic wasn't even a twinkle yet.
Personally, I love blowers. But the superchargers for these motors just don't look near as nice as a polished Weiand 671 blower. No offense meant to any of those supercharged V10 guys.
Looks like from what you guys are saying, is don't loose track of the 460 I've got out back, and use that in the (hopefully) someday Cobra project. But I still would like to see - scratch that - OWN one of these things tricked out.
Fredvon4, I certainly wouldn't spend the money for a custom cam grind, let alone the intake. I didn't know the 3v had a variable plenum, that's interesting. My daddy was playing with Model A's, Vic wasn't even a twinkle yet.
Personally, I love blowers. But the superchargers for these motors just don't look near as nice as a polished Weiand 671 blower. No offense meant to any of those supercharged V10 guys.
Looks like from what you guys are saying, is don't loose track of the 460 I've got out back, and use that in the (hopefully) someday Cobra project. But I still would like to see - scratch that - OWN one of these things tricked out.
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