ford crossflow

[daniele]

1700cc
1.3 pistons
234
stage 3 head
2x40 dcoe with 34 venturi
50f8
125-F11-160
35 pump - .40 discharge hole
bestek distributor



just dynoed on 4th gear:



corrected are 140hp at flywheel
on paper seems ok, but not very fast imo

[Graham]

fast? well i suppose that depends on what your comparing it to.

what diff ratio you running?

[daniele]

good q:
not remember but it is original koln so I suppose around 3.6x?
at 6.7k rpm engine stop to breath
cam is timed 3/5 inlet 2/5 exh, with smaller valves clearences 0.4 inlet and 0.45 exh

[Miniliteman]

Daniele,

what is the difference between P/Nomin. and P/Mot?

Leon.

[daniele]

Hi Leon, P-power motor(e) is the true measured power in that session. Nominal is that same power mathematically calculated in relation at std Din 70020 conditions (at certain air pressure, temp and humidity).
tomorrow, time permitting, I 'll post the print of the previous curve made with just 10 points diff in air corrector. It is quite amazing to me. Never thought that a simple 10 step in air corrector can does a so big difference on the whole tq curve.

[daniele]

ok, here is
this is the first run.
emulsion tube was F16 tried at first. However mixture was a bit on the lean side on full load from 4k rpm upward

peak torque is higher as value (+17Nm) and higher in the band (near to 5000 rpm)
this confirmed (and the dynoman confirmed it too) that F16 are better to suit a high revving engine capable of reach at least 8000 rpm.


this is the run made with F11, 125 main and 165 air corrector

respect to previous print, it is obvious the way the engine changed.
much better to suit a road engine like mine.
But mixture was still too lean at full revs, so we decided to reduce the air corrector to 155.
Final result is the first print shown on this topic.
I lost something, a lot of torque and around 1000 rpm, even if with only a couple of KW lost.
We tried to gain the losses increasing the main jet (with 165 corrector again), but the only result was a too fat mixture at medium revs.
Now I'm waiting a set of 160 air correctors. I'll try and see what happens
As said before, never thought air corrector is so important even at low revs!

this is the induction

the airbox is coming from - I suppose - a H120 holbay hunter. Air filter is a BMC item. Carbs trumpets are the longer I'm been able to fit, 60mm.
we tried the final run with and without the BMC filter and luckily it shown no differences at all
Trying to reduce the induction noise down, I reduced the inlet of the BMC filter (65mm opening) with a trumpet with a 45mm diameter mouth. 3KW lost was the result, so I discharge it. Noise was lower btw.
Anyway, to avoid that possible vaacum condition in the airbox can mismatch my mixture, I copied the vented jet covers as found on my 34-35 dcoe. This helped me to keep the jets sizes lower than needed with "sealed" covers. Simple dhla transformation.

[Miniliteman]

Hi,

will study those graphs in detail tomorrow.
But, a very small change in airjet cannot lead to such a big change.
Also, the last graph you posted is what it should be like:good torque from 2500-6000 rpm.
A correction of 11-12 kW for corrected (Nominal) power is somewhat big I think.

[racing escort]

Have you tried without airbox also ?

[daniele]

yes, no difference at all.
tried to run with 160 air corrector but without special results

[daniele]

anyway I would love to be able to fit a decent header like those Mass (?), much better than the shortened Ashley I have

[caprimentle]

34mm chokes in twin 40's on a crossflow seems large

[mexicotait]

Still good power hopefully my engine will do similar power if i ever get round to doing it
You couldnt get much more in the engine bay

[daniele]

thank you Mexicotait
caprimentle, I tried 30, 32 and ended with 34. I asked to both Vulcan and Fastroadcars (ebay) and they confirmed for 34. I remember that some of you already told me 34 are a bit big. But I tried to get those 7k rpm 234 cam promised, with partial success.

[Escort TC]

The plot may not be correct so I think. The atmospheric pressure is 905 mbar. I think this is not a normal air pressure for Italy at 21C degrees. The normal air pressure would be perhaps about 1000 mbar. Can you explain, maybe.
If the air pressure is higher, the Power would be lower.
Comparison of the values ​​in my RR Software
161 HP / 175nM @ 1002 mbar 30C degrees (that's my XFlow)
when I change the values for the correction calculation
176 HP / 191nM @ 905 mbar 21C degree (That would be a dream)

That's a very big difference

[daniele]

hello
dyno is on a sort of mountain, so altitude is different and so air pressure.
In fact I had 90.5Kw recorded as true, 101 are corrected kw's-
sorry, but lower air pressure means less hp's! This is the way a turbo engine works, you pump air to increase the pressure.