In a message dated 27/04/2010 20:03:38 GMT Daylight Time,
WeslakeMonza1330@aol.com writes:
Hi John,
Jetting data from dyno testing on its way to you 'For Your Eyes Only' (I'm
ex military!).
I'm not certain if some UK A-series racers use a 48 DCO (48 DCOE is
obsolete) with 42mm chokes. If you can find a 48 DCOE it can be choked down
to
40mm.
One very respected UK racer had done some machining work so he could get
42mm chokes into a DCOE 45.
What I don't see much of is the use of Full Radius rams which make a big
difference on how the DOCE pulls from low rpm. I also don't see many CV
exhaust systems on road cars.
I drive slower than I used to. The current engine is particularly strong
from 5000 to 5500 rpm which on 3.9 diff and a five speed is 100 - to about
112mph. If I'm driving at 4000rpm which is about 80mph in 5th and need to
change to the outside lane to over take I EXPECT to accelerate to 4,500 rpm
and 90mph pretty much straightaway and without changing down to 4th.
The engine will pull smoothly from about 2000 rpm in 4th (on a 3.9 diff)
even if the throttle is floored and I think I showed Frank this when he was
in the UK though it may have been slightly higher rpm (2300?) as that engine
was near the end of its life (though managed to haul the car to 105mph+
the week before I pulled it to fit the new engine).
With a controlled vortex manifold from Janspeed and Full Radius rams on
any Spridget with a DCOE, and especially a street car you'd soon be on the
phone ordering some bigger rams as the engine would pull like a train but feel
asthmatic going through 6000rpm.
In early days of ownership my Sprite had a 4.5 diff and a 4 speed so
110mph was 7,500rpm and seen on a regular basis on weekends. I was much
younger
then.
Regards
Weslake-Monza 1330
In a message dated 27/04/2010 19:43:34 GMT Daylight Time,
fastvee@yahoo.com writes:
I know that different size choke tubes can be made to work in the same
carb body with different jetting combinations, but many 1275 race engines use
smaller venturis than that, so I am surprised. Our definition of road going
must be vastly different, and your choice would not be the best choice for
my street driving. I drive fast, but for me road going means 2000-5000
rpm, with much more time under 4500 than above it, and where mixture quality
and smooth transition from idling to the main circuit trumps the last bit of
airflow any day. I would be interested to see your dyno sheets.
John
Fogelsville, PA
_______________________________________________
Donate: http://www.team.net/donate.html
Suggested annual donation $12.75
Archive: http://www.team.net/archive
Forums: http://www.team.net/forums
|