250/2V flow numbers

[rickwrench]

I did a search of the forum and found reference to 175 cfm on the intake @ .50" lift. I believe the pressure drop was 25". Are there any benchmark numbers for a stock 250/2V head, intake and exhaust, at various lifts?

Rick(wrench)

 

[addo]

The only ones I've seen as a more complete set came from Az, IIRC.

Here, SOTP and dead reckoning from experience are often the building blocks. I had a fellow look at a head chamber; he said straight up "that's about 49cc". I measured it, and he was right. Next time this fellow wanted to talk porting, I listened.

I've noted too many "sixth sense" engine builders, to trust numbers alone. It's a bit like at the pleb hardware stores, the boxes have bright labels and state excitedly, all the features and benefits. The trade items have tags that simply say stuff like "Colour: Orange / Qty: 100"...

Plus that Aussie gambling streak likes a punt on the unknown. Ever seen The Life of Brian? It's a British movie but the skinny gladiator at the beginning, well mirrors the larrikin spirit of Oz racing drivers and engine builders.

 

[rickwrench]

"Wait! -I'M- Brian!"

Flow numbers are just another data point, yes. But they do tell you quite a bit about a head/engine's potential performance.
175 cfm @ .50" lift translates to about 233 hp potential at 80% VE. I was trying to find low lift numbers as they will give clues of the actual VE of the head/engine. Then there are chamber dynamics, quench, valve and seat shape, etc.

I bought LaGrasta's 250/2V head and intake to put on the Squire's next engine (US 200). It looks like the days of 15 second 0-60mph times are soon going away, and the wife heartily approves. She says the Squire is "WAY too slow", having been completely spoiled by the other cars (see sig...). Also soon-to-be-gone are 33mpg averages, but I haven't mentioned that part to the wife. Although, with the 26 gallon tank, she probably won't even notice.
Rick (wrench)

 

[addo]

Why not get hold of Leroy Poll and see what he's doing with the other 221 shortblock? I know there were enough Toploader Oz bells to make one adapt up to a T-5. 10% extra cubes, negligible extra weight (18 pounds).

Is the Alfa done? I couldn't see an update on your website.

 

[rickwrench]

The Alfa was on the road for about five days a couple months ago. It is now pulled apart again for a new steering solution. Not in a thousand pieces, maybe only five hundred.
This next steering system should work much better - I think. Using first gen honda civic rack and ends, and custom steering arms. The civic rack has a geometry very similar to the Alfa's linkage. The "old" fiat rack did not have the required travel, and seemed very... weak. There were some unforseen bump steer issues as well. Not what I wanted in car that will likely be capable of running in the 11s. The car weighs right around 2250lbs with me and gas in it, and the engine is likely producing -at least- 300hp at the flywheel. I've run simulations on several programs that show 305 hp and 325 torque with my particular setup and head flow. In the past three or four years, every engine I've built has been right on the money, or up, on the dyno 2000 software estimates. Once I get the 4x dcoe weber crossram manifold built, and the 180 degree headers installed, I should pick up another 10-15 ft-lbs of torque. Not to mention a wonderful exhaust note. All I need is time.
As far as the power and acceleration of the first driving experience... all I can say is "SPEC-TAC-ULAR". Handling was not so spectacular, and I'd go so far as to say "poor". I definitely need a much thicker bar up front, I'm looking for a shankle race bar, there is one on evil bay now, we'll see. If I don't get it, I'll slice and sheath the stock bar.
Speaking of flow numbers vs the real world, I've found the 64 300 heads produce much more power than the simulations show, which are primarily based on flow numbers, with just mild bowl and guide work (Buick always had the best engineers). Seems to be very well (lucky) designed runners.
Yeah... the website. C'mon I just did an update last ... August? I'll try to get some pics up. I think my wife took a couple when I backed out of the driveway. You may have noticed my documentation goes something like this:
Outline idea,
take pics of parts at start,
one or two more pics right at the beginning of the project,
then - nothing.
I get into project mode and that's that.

Rick(wrench)

 

[LaGrasta]

Rick, I'm after high mpg in my 63, even willing to sacrifice performance for it. 33mpg? What are doing correct? I've done everything I can think of to increase mine with no real luck. High teens is all I can gather. Nothing better then I get form my Astro van (4.3, v6).
I just bought a C4, but I don't expect it to give me anymore since the final drive will still be the same as my 2 speed. I am going to sell off the high stall converter it came with (2500) to get a stock version. That should help a little.

 

[rickwrench]

Hi Anthony,
Highway mileage is what I was bragging about. I drive to Sacto and Santa Rosa all the time, so I get to check the highway mileage fairly often. Around town I get mid 20s.
As the US 200 motor sits now:
I'm running a DSII with the plugs gapped at .050".
A high energy coil, brand forgotten (it's chromed).
8mm plug wires.
A Holley 1946 off a late 70s (80s?) fairmont, with just a good rebuild, although I now have the choke disabled.
Idles at 550-600rpm.
195* T-stat which, with the jumbo rad, is where the car runs, always (this makes a difference).
The timing is 7-8 degrees initial advanced.
An old 35 amp alternator (low amp = low drag).
Sanden 508 compressor (-2-3mpg when A/C is on).
The engine is old, well maintained, essentially bone stock, just well tuned. I suppose after 145,000 miles, I also have "low tension" rings.
Starting to use a -little- oil now, so the new engine should be ready by summer.

The biggest factor in the mileage, by far, was the T5 conversion.

Before my ford-o exploded I was getting about 24mpg on the highway, after the T5, 30+.
I didn't notice a drop going from the 3.50/1 7.25" to the 3.40/1 8" rear. I did lose a couple mpg going from 3.40/1 to 3.00/1 8" chunks. Wierd?
The tires are 205/70-14 and I keep them at about 38 psi.
Also, I drive like an old man.

 

[LaGrasta]

Thanks for the overview. For a second, I thought you were describing my car. We have almost everything identical except mine is a 170, Pertronix, 65 amp alt, 25° advance, 3:00 chunk, and a lot less miles. I know my advance sounds crazy, but I did it by the number and by ear and where it's at now is teh place it runs best. And no I didn't jump a tooth. If you ask around liek I did, there are a lot of us advnaced that high. I suppose that could account for some of the loss mpg.

 

[addo]

The larger plug gap has in my experience been pretty handy for economy. Plus, LOM vs DS-II is apples vs oranges.

Anthony - have you tried the Bowling and Grippo calculator for best rear ratio?

While we're so cheerfully heading on a tangent, I need to blame Rick for more recent lustful glances at a 1300 Junior (not a Z, one before that) that's "just sitting". Not bad in the rust department.

 

[LaGrasta]

I have th esame plug gap and I haven't tried that calculator. I do have a 2:79 pumpkin in the garage. Mayeb it's time I pull it out.
As far as the Alfa goes, I too have lusted after them, almost buying an Alfetta GT years back. Silver and black... it was so sweet. Now, I'd want an early 60s red and black.

 

[rickwrench]

Alfas were great little cars. I've wanted to put an aluminum V8 into a 105 GTV since high school (25 years ago). Alfa leased the rust concept from Mr. Porsche though.
Addo, if it's just sitting there, doing nothing, it -clearly- needs rescue.
It could sit covered up in your sideyard, waiting it's turn (but in your possession), just as easily as someone elses. There are some great restoration companies for Alfas down there, where it's summer right now, I've bought some stuff.
This 69 is my second Alfa. After I got badly T-boned in my first (picture firemen extracting big ol' ketchup coated Rick from a seriously stomped on soda-pop can), it took a long while before I could picture myself in one again. Of course my next car was a 61 caddy.
Anyway, this thread has turned left, eh?
Airflow numbers through a 250/2V, that's what all this is about!
Rick(wrench)