308 V12 conversion begins

No need to move any studs. I will need to use a longer stud for the top, but the position is fine....or at least it will do.

 

Thanks.

No turbos, no superchargers on this one. Maybe the next one, but this one will be NA becasue I want to here engine sounds not turbo sounds.

I was talking a bit about a clear plenum when I realized how cool the ducati TBs look.....I may come to my sences though and return to the stock looking plan.

 

Hans, this car is going to weigh about 3000 lbs....well that is unless I throw the whole thing out and start over in carbon fiber....hmmmm.....

 

Errr... yes of course. I meant 2850 lbs. Sorry, lbs don't mean much to me, I'm thinking metrics...

Still, you'll get Veyron kind of power to weight values...

 

See, I thought you were just trying to trick me into building a carbon fiber 308

 

That would be a remarkable project. Now to find a giant oven....

 

Maybe that will be the next project. It would be pretty cool but I guess at some point it stops being a ferrari and that might a tad past that point.

 

I know of a couple of very large ones in Japan. used to cook up 787 fuselage sections, largest in the world.

 

Just use an upper and lower pan, attach the upper pan to the hood (with flexible ducting to the air intake or make it mate up when the hood is closed) and voila, you get to see the TB's every time you open the hood. Or, just put bug catchers on them and change the oil more often...Clear plenum just doesn't seem right for this project as you've gone to pretty great lengths to keep it 'stock' looking.

 

I think you are right....plus I can't even imagine trying to keep a clear plenum clean.

 

I cut the seats quickly tonight and gained .....nothing for flow. I guess I've gotten pretty good at eyeballing what the seat should look like. It looks like the cut I'm using would like the valve to be a bit bigger to leave the full profile with the seat ID I have, I'll have to think that. A valve change without a seat ID change doesn't harm velocity at all provided the valve head itself isn't getting too close to stuff to become a restriction....maybe

I've got to spend some more time checking may port area al the way out and generally fine tuning to port it looks like, it will only make 750hp the way it is now and we can't have that.

edit - I should have said cutting the seat profile because there aren't actually more left of the seats at this point. Once I get the port working and all the welding done I'll cut the head to accept new seat to work with whatever size valves I end up with
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Nothing photo worthy tonight. I played with the position on the manifold on the head and settled on a .400" moved up to get the top of the manifold making a straighter run at the top of ther port. The top of the manifold is very short, maybe an inch or a little less so there is very little room to play with blending. The bottom is 4-5 inches long though and in that length I could make almost anything blend....so align the top and blend the bottom, but I didn't get the blending part finished to get it on the flow bench.

The seat cutting not real helping the other night has me thinking it's more likely that I have a problem up around the guides then is is I'm just a seat balling god and no machine could do better then me. after I get the manifold fixed I'll have a look at that. I've got the velocity up to 190 ft/s (at 10" H2O) which is pretty darn good so it wouldn't be the end of the world to put in bigger valves.....but I sure would like to see 195 ft/s and not need bigger valves......

 

I think I'm going to demonstrate that a little knowledge is a dangerous thing here, but is the surface texture (rough or polished) a significant factor when it comes to final flow numbers? Also, at the port velocity you're looking at is boundary layer behaviour a significant factor in the flow of a port, and is turbulence desired to aid compression turbulence? Or am I over thinking things?

I'll go back to lurking at a safe distance now.... To say this is a great project is a massive understatement, when you finally finish it will be a bitter sweet moment as I'll miss the daily antics, (I might even be forced into actually getting some work done) - keep up the good work!

 

I'm glad your enjoying it.....and don't worry about it being finished any time soon

Those are good questions and if you ask 100 people you will get at least 200 different answers. So what I'm giving an answer is my opinion which may or may not be right and could be swayed by a completing argument.

Surface finish, boundary layer and turbulence all matter and are all related. I'll start with turbulence….I hate it in the port because it consumes energy that could otherwise be used to fill the cylinder. I try very hard to minimized turbulence in the port, then let the inevitable turbulence off the intake valves and a .030-.050 squish zone around the combustion chamber to cause turbulence in the combustion camber itself. The problem with this strategy it keeping the fuel suspended until it gets the final mix in the cylinder and combustion chamber. I'll be dealing with this problem with the seemingly over complicated injector strategy of 12 injectors low in the port and 12 shower injectors above the port. This will allow me to keep the duty cycles short so I'm only spraying fuel when the air is moving, allows me to use the turbulence off the butterfly and valve to mix the fuel better, lets me shut down the shower injector at low power when it would be spraying on a mostly closed butterfly while also giving me good control of the mixture due to the much reduced injector flow rate with the large (it will be about 2/3 the total fuel flow) shower injector shut down….I think.

Surface finish and boundary layer are very closely lined with a smoother finish resulting in the thinner boundary layer. I'll finish the port to a pretty smooth surface finish…not polished but close because I'm too lazy to polish and it doesn't (I don’t think) add much improvement over just a pretty smooth 400-600 grit finish. This gives the smallest volume port that will have adequate flow. There are exceptions though You I grind a touch too much in an area and the flow goes down, simply roughing the surface a usually will being the flow back up because the boundary layer will get thicker and has a similar effect as putting the material back. The other exception is the insider edge of a tight radius sometime want a rougher surface because it helps prevent or reduce flow separation (which causes turbulence).

Again, these are my thoughts….but I'm not in any way calling them facts.

 

Thanks for the explanation!

With the shower injector, if it's good enough for F1, then I guess it'll do.

http://www.youtube.com/watch?v=Eo-9Io41bt8 (A thing of beauty)

Mounting all 12 shower injectors centrally between the intakes would complete the look nicely but I guess you don't have the room


How are you with clearance to the top of the airbox with this setup - I seem to remember that you get issues if the roof is too close to your ports...?

 

A friend of mine sent me a similar Renault F1 dyno video back when I first started thinking about the injectors...which got mo to look in to it to begin with.

I am thinking about making or buying new velocity stacks and doing a central mount for the injectors. I'd like to use the ducati pieces if I can becasue there nice and they are already made, but it's not as neat as a central system would be. That might go on the future upgrade list.

I'm not sure about the space for all this cool stuff under the hood. Once I get the maniflod the way I like it I'll do another test fit in the car. I'd like to leave the hood stock...but I've been thinking I'd like a composite (carbon or glass fiber) hood for some time so if I find I need more room I guess that will be the time. The other V12 cars out there all had hood work I think, but I thought since I was lowering the engine I might get away with the stock hood....we'll see.
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TR style lid and yer all set.

 

I could probably save myself a lot of time and money with this.......

http://www.thebestemployee.com/forum/vbclassified.php?do=ad&id=245
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yup

 

That looks like a Katrina engine.

 

It does look rough....but it's in Saudi Arabia so probably not a huricane. Still, at $10K it seems like a great deal.

 

Mmmm, whats worse, water or sand?

 

I don't know...moot point though as I'm WAY to stubborn to shift gears at this point.


Maybe somebody else want to have the first 550 powered 308? (or course my version of a "550" engine will still kick your butt )

On a different note, the manifold/port is looking pretty good with the new position. Maybe tomorrwo I'll have a chance to get it on the flow bench.

 

Mark- I am really looking forward to hearing this engine run. Should be one mean-sounding mother.

Taz
Terry Phillips

 

The engine you are building will be 10 fold more interesting (and more powerful) than if it had a vanilla 550 engine stuffed into it. I can't imagine any auto journalist not wanting to get their mits on it once you are all done!