The nearest comparison to 2V perf specs I could find.

[Anonymous]

I tried to post a graph with all the specs on the forum but was unsuccessful.
The nearest comparison I could find to the 1971 2V 250 Falcon rated at 170 HP was to a 1968 XT Falcon GT rated at 230 hp in Wheels road test standing quarter mile times.
Specs in the following, both had the following, 4 speed manuals, V8 had 3.00 to 1 final drive the 2V had 2.92. the weight of the V8 was 3184 lbs the 2V was 3003 lbs (1373 kg).
The 230 hp was rated at 4800 rpm and the 2V at 4600, peak torque came in at 3800 and only 2600 for the 2V. Same tyres.
Comp 10.0 to 1 for 8 and 9.3 to 1 for 2V, the 8 had a 4 barrel the 2V had a Stromberg 2 barrel that only fowed abour 220-230 cfm.
Aussie Motor mag recorded a best time of 16.0 for 2V over standing quarter and wheels recorded a best of 16.3 for the V8. Wheels recorded an average time of 16.9 for 2V and 16.3 for V8.
Oh and another interesting point was that the article on the V8 XT GT said that the power actually dropped of slightly after 4500 rpm and pulled from below idle at 500 rpm in top gear. Cheers Tim

 

[Anonymous]

Oh and I forgot
310 lb/ft at 3800 and 250 lb/ft at 2600 in 2V

 

[xctasy]

He he he. Ford was using gross power readings at the flywheel. That 230 hp wouldn't be any more than a stock 308 Holden four-barrel. The Gross vs net figure was more than 40% different if you do the sums.

That 1968 230 hp XT Falcon GT engine was actually a very rare 1968 302 4v Mustang option..by then GTA 390'S and such were getting more sales, Shelbys were getting hotter 302's and 427/428 engine potions while the 289 was getting pensioned off. The 230 hp gross engine was no more than 163 hp to do a 16.3 second quater two up. A 1984 XF Falcon EFI x-flow weighed nearly the same, and gave 16.4 second quarters with only 120 kw (162 hp).

The 2V 250 had the same performance as the 1983-1984 EFI XE Falcon. This had only 149 hp (111 kw) and weighed about 3164 pounds...standing quarter was the same 16.9 seconds, two up, with a full tank of gas. The Weber carbed 2-bbl alloy head did 17.6 seconds with 131 hp (98 kw). Weight was 3117 pounds. (EFI's carried another 48 lb of engine and fuel tank pump weight.) So that 170 hp gross engine was really aROUND 150 hp engine, net HP at the flywheel.

And, early on, Aussie car magazine Modern Motor had a bad reputation for running cars one up, so I doubt that 250 2V figure of 16 seconds flat. A 200 HP net 351 had trouble doing 15.8 second quarters with that much in a 3196 pound 1979 XD Falcon. Unless Ford doctored the 2V 250 press car, which they sometimes did to get a good report. Ever figured why the Aussie Lazers and Telstars were always 0.5 second quicker over the quarter mile than imported 323 GT's and 626...with an engine from the same Tiwanese engine plant. Why? Because they were Doctered!!!! It was all Bill Bourkes fault...the guy drove to work in an XW Fairmont with a 375 hp gross 429 Cobra Jet. Poor expat Yank couldn't get enough hi-po grunt, and its to his credit that Ford Australia has such a rich Hi-Performance 250 six history!

 

[xt falcon]

ok what is the weight differace between a alloy head cross flow and the 250 2v. and say i had 180hp at wheels about 240 at fly? how fast should my alloy head xt falcon go down the strip with 3.23 diff and 5 speed. maybe about mid 15? and if i change the diff to 3.5 can i expect much change. sorry its a littel of topic but i have not been able to run mycar down the track yet and i am just wondering how much quicker i would go with a different ratio or would it only really change my mph thanks heaps Aaron

 

[Anonymous]

From info I have its the crossflow alloy head is 51 pounds lighter than the cast iron crossflow head I am not sure how much lighter than 2V is compared to the alloy head but a guess would say about the same difference in weight maybe a bit less. the Cross flow has a better and more even valve layout reducing hot spots in the head and improving efficiency slightly, and it is THE choice even over a 2V.
For anything else on HP figures ask Execute. I never heard from anyone who seems to have the knowledge he does on the subject. credit where credits due!

 

[Anonymous]

Execute thanks very much for above it does help explain some things.
But some others are still left answered.
I realise it is possible that there are some unknown variables involved but I still cant work the difference out in a way that makes sence to me. Unless the 250 2V (and some latter 250s) are about one of the most underrated engines there is.
Put it this way.
If all the HP and torque figures are ignored in the above and you just look at where the torque peaks 3800 in V8 and 2600 in 2V, cubic capacity of engines, comp ratio, carb selection, no of cylinders it just doesnt seem to make sence.
It begs a question if the torque peak were to come in at 3800 in the 2V and 2600 in the V8 instead of the reverse and the carb was swapped (yes you can run carb this big under right conditions). Would the 2V leave the V8 in the dust. Of course if the cubic capacity was reversed there seems to be little doupt that the 2V would smoke it for breakfast.
If this is the case then the 250 2V and latter 250s must be about one of the most underrated engines there is and some of the V8s around should be used as boat anchors? does anyone agree or have I got it all wrong. Other spec comparisons can also be used which correspond and agree with specs in the top entry.
Just reverse some or all of the specs and think about it???

 

[xctasy]

I'll be bold, and say something a little odd, with one qualification.

The qualification is that:-
Power (hp) = Torque(lb-ft)*rpm divided by 5252

The statement is:-Over a standing quarter mile, torque is irrelevent, power is everything.

You could have, say, 275 hp at 6500 rpm a 13 B RX-7 Turbo engine in a smooth, areodynamic 3160 pound car, and get a 13.7 second quarter using my formula. Torque could be a little as 245 lb-ft at 5000 rpm. But at 6500 rpm, that 275 hp is only 222 lb-ft of torque. Most of the time, the engine will be between maximum torque and maximum power, and the car will be optimised for the engine, otherwise people would write the auto maker and complain!

Car Two, is a 300 hp (SAE net) at 5800 rpm. XY Falcon GT Falcon Phase 3 with Cleveland 351 and 4-bbl 780 cfm Holley, 10.7:1 compression rah rah rah. The car weighes a little more at 3461 pounds, has the areodyanics of a brick, and a great deal of low end torque and no real desire to go past 6150 rpm because of the silly rev limiter. Still using my formula, you get a 13.7 second quarter. But the Falcon would have a torque peek of 350 lb-ft net at about 4000 rpm. So you'd think that the Falcon would have the edge. But it doesn't because the effective used rev range is only from 4000 to 6150 rpm.

Look at this:- (Asume close ratio Top Loader at 2.78:1, 1.78:1,1.29:1,1:1, and 3.25:1 diff)

Startline launch at 4000 rpm, some blue smoke from the tires skidding, then brap to 6150 rpm at 50 mph. Then drops into 2nd at 3900 rpm, goes to 78 mph at 6150 rpm, then drops into third at 4450 rpm, and hauls through the traps before shifting into top at 102 mph at 5800 rpm, right on the peak power. So all of the time, the engine was at maximum torque or maximum power.

For the RX-7, it is always at maximum power or torque too. But after a slower 60 ft time, it makes up with the lack of torque by being able to convert its megre torque into power quickly. Power is just the ablity to do work (torque) with a speed factor (ie do it fast).

I've ploted hundreds of torque verses power curves for non-turbo cars, and find that big V8's and I6's often may have 3 Nm: 1kW or 1.6 lb-ft to one hp. A Lamborghini V12 may have 0.7NM: 1kW or 0.76 lb-ft to one hp. So a rev happy engine always looses low end torque for greater high end power. On a quarter mile, sixes have some of the best 60 ft times around for there perfomance over the quarter. If a V8 does a flat 16 sec quarter, a normally aspirated Ford six doing a flat 16 sec quarter will be much, much quicker over the first 60 feet. At half track, ricers or screaming cammed engines then lift there game. Low end torque or compartive lack of torque isn't an issue over this distance.

With turbo engines, you can just dial in the boost you need to make any amount of torque...Peugot 206 rally cars behave like small block V8's with only 300 hp, but over 380 lb-ft of torque. The restrictor plate makes it gain boost, and torque, early on in its power band.

In any race between a 302/351 Cleveland and Geelong 250 2V, a six will win for the first 40 feet...no matter how hot the engine spec or cam profile is, a V8 is hampered by the need to shift gas through ports that are too big, and the higher RPM were torque comes in often causes the 302/351C's to bog until 2700 rpm. A stock cammed Falcon I6 is sweetly hauling in maximum torque from anyware from 1800 rpm (1979 XD) to 2600 (1984 XF, and 250 2V). It's something the Chrysler boys have known for years.

As I've said before, on the street, nothing your up against beats a good six from the lights. If they do, they get arrested. Simple physics of instantanous Ford Six grunt. Evo 6's, GTR Skylines, WRX's, RS Turbos...all also rans compared to my stupid Aussie auto six out from the lights! Its the most excellent fun there is!

 

[Anonymous]

Out of interest, I'm wondering about the torque curve on Alloy Head Crossflow sixes. I'm assuming Iron head cams are the same, so we'll throw them into the bunch.
For 250 Cubic Inch motors:
1976 - 1982: Stromberg 1bbl carb. Torque in at 1800rpm (295Nm Fe, 305Nm Al). 90-something kWs in at 3800rpm
1982 - 1992: Weber 34/34 ADM (320CF/M) 315Nm, Torque in at 2200rpm. 100-ish kW at 4000rpm.
1983 - 1988: Bosch LEII Jetronic / Ford EEC-IV. Varied due to fuel types, but lets call it 333Nm at 2700rpm. Slightly warmer cam. 120-ishkW(plus or minus 10kW) at 4500rpm.

I'm willing to state that over the above's various different induction types, the Falcon Crossflow motor would have a reasonably flat torque curve of at least 300Nm from 1800Nm up to something like 3000rpm. Probably more RPMs, but that'd be pushing the envelope. Anyone care to add comments?

 

[xctasy]

Would you believe that I have a leaded XF EFI pwer/torque curve to DIN net form a Wheels article.

Have to pop down into my basement and grab it. It compares with the earlier XE engine.

I'll get back to ya on it, disco' ol' pal.

 

[MustangSix]

Here are some other possibilities:

Let's say they overrated the 302 4bbl by as much as 20 hp. That brings you to 210. 25% drivetrain loss gives you ~157 RWHP.

Let's say they may have underrated the six for marketing purposes. After all, why spend more for a V8 if the six is as powerful? Let's say that it's under by as much as 15 hp, bringing you up to 185. That's 139 RWHP.

Plug the weight and power figures into any 1/4 mile calculator and you'll find the cars to be very close.

The lesson is that published hp numbers are meaningless. The marketing mavens manipulate those to "place" the engines in certain markets. The Boss 302 was deliberately underated at 290 hp to meet insurance targets. So was their 500 hp 7 Liter monster. Chevy did the same. A ZL1 427 was probably closer to 675 hp than the advertised 500hp. The Chevy Z28 at 290 hp? Not likely it was that low.

The only was to really determine the answers you seek are on the track or on the dyno. Either way, it's a moot point. We already know how good the six really is!

On the subject of torque, I can testify to my Crossflow's very flat curve. The engine pulls very strongly from just above idle all the way to redline and is really very nice to drive because of that. Peak torque is high, but the curve is very flat. I'd guess that I have at least 90% of peak available from 1500 to 4800 (where I usually shift) with redline held to 5500. The engine will rev to 6000, but it stops accelerating hard at about 5000, so what's the point - just shift at a lower rpm.

 

[Anonymous]

Thanks for the info Im impressed

Just a question though. Ive noticed a lot of V8s advertise a torque curve that peaks at around 2600 the same as the 250 2V. A 302 Cleveland is an example. Isnt the 2600 faily high for a six to peak and wouldnt it make it faily close to a Clev 302 over the start. Or do the exhaust ports still play a role as you said in above.
Im starting to wonder, thats all, because I just had my exhaust in my 2V ported by 1.5 mm on all sides all the way along the runners and believe that their is some depate that the inlet on a 2V is verging on being to large. Thought Id even up the score by porting the exhaust but what I gain up high I might lose down low negating the sixes major advantage. Is this the case and is this something a lot of those seeking perfomance from a six forget with selection of cam ect.
Im inclined to think increase youre natural advantage dont lessen it. Oh and beat em at the start before they gain and then just criuse HA Ha. What they dont know will hurt em. Im not nice am I.

 

[Anonymous]

I looked at my info which records times over quarter from 0 to 40, 0 to 50, 0 to 60 mph ect. its seems that for approx half of the quarter the V8s were behind and then made up all the lost ground in the last quarter. This must means that the 8 would have to excellerate past the six before it was finished the quarter for them to both to get fairly even times.
Id love to see this happen in the rear view mirror of my 250 2V and wave good bye with a satisfied smile to the fast approaching bigger V8 as it passed with its desperate driver at the wheel???

 

[Anonymous]

Jack
Sounds like a great cam what is it?

 

[xctasy]

Tim, MustangSix. As you well know, that's what any 250 has got, irrespective of head.....bag loads of torque from go to whoa!

You really can't make a mistake with a long stroke, short rod engine. I think you could cam it up with a 310 degree solid lifter job and port the head to an inch within its life, and still have it haul off line like a clydesdale.

I may post a jpeg of the 250 EFI cross flow power and torque figures...but they are all in metric Jack!. Most poeple get confused over graphs even if they are in imperial...then adding metrics would just munt them up real big.


I hate metrics, they suck!

 

[Anonymous]

Settled then! Anything else you have to say on the matter Id be pleased to hear from you.

Thanks Tim

 

[xctasy]

Yes, there was just one thing that you really need to know. You need a Taz avatar...

.

Go to Profile, select avatar (in gallery C-d), and go left 3 rows, and down 9 cells. Treat yourself!

Any guy who reserches his questions like you has the tenacity of a Tasmanian Devil. :wow: z:


Then we need to work on Discokin6...a dude like him needs an avatar like this