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Gday.
I have just put a 202 into my HG ute, I am running a 350 holley on it with 2 and a half inch exhaust.
The problem I am having is with the inital acceleration, I keep hitting flat spots with the revs. I have been told that this could be due to the jet size of the first stage of the carbie. Apparently the jet sizes are numbered and I can put in a smaller size jet which could help fix the problem. When you get to a higher rev, its great and goes like a rocket, its just taking off from the lights can be a painful affair at times!
I know alot of you will tell me to get rid of the 350 etc, well, thats not an option at this stage. I have to work with what I've got and hopefully there is an easy solution to this problem.
I hope you all have a great day tomorrow for christmas,
Cheers,
Tom.
Don't eat the yellow snow |
Don't eat the yellow snow |
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sounds like it needs a tune
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Rank: Member
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What the car or the carbie?
I did the timing the other day, Got new points and plugs.
Dont eat the yellow snow |
Don't eat the yellow snow |
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yep sounds like shes running rich down low,my 253 done the same
with a 308 carb
change jets and all should b sweet |
marge pass me my gun |
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The problem is not enough fuel Signal in the venturi at low rpm.
To fix it the carbie needs the bosters changing to down leg boosters and jets and air bleed changing to get the best air fuel ratio.
The accelerator pump cam and nozzel could also need changing to time the shot of fuel to when it is needed.
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2.5 exhaust is a bit big for a 202 i have found, unless it is really hot.
i have found the 2.0" ith straight thru muffler on the 202 is a better alround size.
this could explain your good top end and poor take off.
what is your diff ratio?
I normally use 65 power valve(6.5), making sure accelerator pump cam has daylight between it at idle
Jet size,..normally 59 jets on a 202
if the motor is xu-1 type spec, upgrade jets to 61.
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Old holdens brought on the spot, quick decision, cash paid. |
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Your Power valve rating is the fault.
Power valve rule 1, check your vacuum in idle, or in gear with an auto, check the Vac rate and half that is your power valve rating.
Vacuum 10 = 5 Power valve, so down to the next avail is 4.5 rating Power valve.
I had a 350 Holley on a standard 161 red motor, redline manifold to suit the carb and extractors, nothing done internally to the motor.
57 Jets and it bogged off the mark, reduced the PV to 4.5" vac, MAGIC! Never looked back.
PS; BAck fires can ruin your current power valve, if you can wind in the idle srew all the way and it still idles, your valve needs replacing.
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Interesting to read. I am running a 500 on a 186S. Yet to know what problems i will encounter.
I went on the assumption that a "Holley will always get you home"!!
Hoping so.
Best Regards Bob. |
Regards Bob Randolf. |
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I had similar problems with flat spots on initial acceleration with a new 350 Holley on my 202 years ago, however it was a dream carby on LPG. The size of the unit must complement the LPG need for a 202 very nicely. I had a handy 82KW at the rear wheels on a 202 LPG with stage 3 head, extractors, 2" system and a 350 Holley. Cam was just a stock LPG grind. http://www.ehlimo.com.au/ |
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[quote] Originally posted by Uncle Bob
Interesting to read. I am running a 500 on a 186S. Yet to know what problems i will encounter. A 500 may be too big for a 186S Bob, Id recommend the 350 up to a 202. see this link for the calculator for CFM carb size rating ; http://www.4secondsflat....arb_CFM_Calculator.html
I have now a Holley 465 Vac 4 Barrel on a mild 253, Just about perfect, still thinking of dropping the 6.5 Power valve down though to a 5.5 as it bogs a little with 60 Jets.
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