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x flow Tuning Question
myke pocock - 13/8/12 at 03:15 PM

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?


Canada EH! - 13/8/12 at 04:07 PM

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.


Nickp - 13/8/12 at 04:40 PM

Sounds more like a jetting issue to me, perhaps the pump jets can be swapped?


snapper - 13/8/12 at 05:03 PM

Can I recomend the Turbosports forum, old school Fords they now


Nickp - 13/8/12 at 05:07 PM

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.


se7en - 13/8/12 at 07:33 PM

quote:
Originally posted by Nickp
Sounds more like a jetting issue to me, perhaps the pump jets can be swapped?


+1


chillis - 13/8/12 at 08:45 PM

I agree with Nick P its a jetting problem, rolling road chap should have been able to sort that, surely.


Chippy - 13/8/12 at 09:56 PM

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


trialsman - 13/8/12 at 10:23 PM

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


arrow-engineering - 14/8/12 at 07:56 AM

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.


johnemms - 14/8/12 at 10:00 AM

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..