myke pocock
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| posted on 13/8/12 at 03:15 PM |
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x flow Tuning Question
Recently fitted a DGAV and Piper fast road cam to my 1300cc x flow engine. I had the engine rolling road tuned and it certainly made a difference
mostly. However if I punch the throttle from low reves in any gear it momentarily hesitates then pulls away. If I am gentle with the throttle it pulls
cleanly. I have a 4,2,1 exhaust manifold but the pipes from 1 and 4 are very different lengths and the tuner said that may be the problem. Eventually
I will get a better system made. Any ideas what I should look at if it isnt the manifold and if anyone has the same set-up what jets etc are you
using?
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Canada EH!
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| posted on 13/8/12 at 04:07 PM |
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Old problem, when you modify an engine you loose some of the low rpm characteristics it was designed with. Find out what the working rpm of the cam is
then get some revs up before you punch it.
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Nickp
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| posted on 13/8/12 at 04:40 PM |
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Sounds more like a jetting issue to me, perhaps the pump jets can be swapped?
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snapper
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| posted on 13/8/12 at 05:03 PM |
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Can I recomend the Turbosports forum, old school Fords they now
I eat to survive
I drink to forget
I breath to pi55 my ex wife off (and now my ex partner)
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Nickp
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| posted on 13/8/12 at 05:07 PM |
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quote:
Originally posted by snapper
Can I recomend the Turbosports forum, old school Fords they now
They've probably been down this same road 'several' times  I reckon it's momentarily running weak or rich when floored
before going back onto it's main jets.
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se7en
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| posted on 13/8/12 at 07:33 PM |
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quote:
Originally posted by Nickp
Sounds more like a jetting issue to me, perhaps the pump jets can be swapped?
+1
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chillis
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| posted on 13/8/12 at 08:45 PM |
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I agree with Nick P its a jetting problem, rolling road chap should have been able to sort that, surely.
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Chippy
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| posted on 13/8/12 at 09:56 PM |
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Isn't the DGAV fitted with an excelorator pump that squirts neat fuel in when you press the throttle, may be wrong, but if so I would look to
that as being the problem. HTH Ray
To make a car go faster, just add lightness. Colin Chapman - OR - fit a bigger engine. Chippy
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trialsman
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| posted on 13/8/12 at 10:23 PM |
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I, too, have the same carb on my 1300 (although it has the std. cam) and I have the same problem. When you get it sorted I would love to know what
internals you have in the carb. Tks Russ
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arrow-engineering
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| posted on 14/8/12 at 07:56 AM |
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i would say its either the pump jet system, or the throttle plate is too far open. both of these things should have been sorted at the rolling road.
check the diaphragm and spring in the system, take the air filter off and look to see if there is a squirt of fuel when you open the throttle quickly
by hand, dgvs only squirt down one venturi but you can get ones that squirt down both venturis at once.
the throttle plates need to be as close to shut as possible at idle, so that the progression holes are not brought into play too soon. warm up the
engine and adjust the idle mixture screw bit by bit until the engine runs at its fastest speed, then re-set the idle speed screw to correct idle
speed, keep repeating this procedure with these adjustments until you get a smooth idle with the idle speed screw as far out as possible.
give it a try and post your results.
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johnemms
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| posted on 14/8/12 at 10:00 AM |
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I had simillar issues..
turned out my 'fast road cam' needed at least 16 degrees static..
Go check your cam details from where you bought it..
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