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Deceleration Popping At Tailpipe With New Msa Premium Exhaust System


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#21 jalexquijano

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Posted 24 May 2017 - 01:06 PM

ill try this once again! i thought if i used a pertronix 1761 ignitor module, i should gap them at .035 instead of .031??



#22 scott

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Posted 24 May 2017 - 04:25 PM

i keeped bp6e with pertronix on stanard gap, done around 10000km on that setup. plug as stated looks lean but the popping sound is something you will have to live with. You need to check your O2 readings really to get the most out of it.



#23 jalexquijano

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Posted 25 May 2017 - 02:17 AM

so it does not do any effect if i gap them at .031 instead of .035?



#24 44014

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Posted 25 May 2017 - 09:09 AM

so it does not do any effect if i gap them at .031 instead of .035?

That is such a small difference you will never notice, You actually want the biggest gap you can possibly run, I would run a .5 gap.

Its only when talking high hp turbo cars that you run into issues with bigger spark gap.



#25 jalexquijano

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Posted 26 May 2017 - 12:34 AM

you mean .035 gap??? NGK BP5ES???



#26 Cozza

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Posted 26 May 2017 - 06:58 AM

I don't think plug gaps are your problem, I also don't think the gaps you are talking about (.031 & .038) will make much difference. But, the upgrade of your pertronix system over points is not the only factor in plug gap. The plug gap needs to be crossed by the spark which is generated by your coil. If your coil isn't up to the job you need to reduce your plug gap.
Plug gaps vary for a bunch of reasons but have a read of the link it is pretty well described.
http://www.gsparkplu...g-gap-settings/

With regards to your popping and stumble at idle, read all the advice already given to you again. It seems that everyone here suggests you alter your air/fuel mixture. This advice is mainly due to the colour of the plug pics you have posted.

#27 Lurch ™

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Posted 26 May 2017 - 07:16 AM

I feel this video sums up this thread adequately:



#28 Cozza

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Posted 26 May 2017 - 08:00 AM

Pretty sure that's Gav on the guitar.

#29 jalexquijano

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Posted 27 May 2017 - 07:20 AM

I don't think plug gaps are your problem, I also don't think the gaps you are talking about (.031 & .038) will make much difference. But, the upgrade of your pertronix system over points is not the only factor in plug gap. The plug gap needs to be crossed by the spark which is generated by your coil. If your coil isn't up to the job you need to reduce your plug gap.
Plug gaps vary for a bunch of reasons but have a read of the link it is pretty well described.
http://www.gsparkplu...g-gap-settings/

With regards to your popping and stumble at idle, read all the advice already given to you again. It seems that everyone here suggests you alter your air/fuel mixture. This advice is mainly due to the colour of the plug pics you have posted.

Well ill increase the gas mixture to 3.5 turns clockwise to see if there is any effect on get the plugs richer. By the way, my coil is a pertronic 1.5 ohm flamethrower coil compatible with the petronix 1761 ignitor module.



#30 Cozza

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Posted 27 May 2017 - 12:12 PM

Read my earlier post an others again.
By winding your screws down will definitely richen your mixture at idle but maybe not at cruise or wide open throttle where the mixture is critical.


I'm not suggesting the needles are worn, I'm suggesting they are not the right needle for your engine.
The needle is like the fuel jets on a Weber type carb. The taper on the needle regulates the amount of fuel that passes through the carby for a given piston/damper position.
I think your needles may be too lean for your engine setup.



#31 jalexquijano

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Posted 01 June 2017 - 07:53 AM

Which needles do you recommend?



#32 d3c0y

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Posted 01 June 2017 - 08:54 AM

I recommend taking your car to a dyno so you know what your fuel mixtures are actually doing.

#33 jalexquijano

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Posted 19 July 2017 - 11:40 AM

I just remember that i bought this car it used to have the MSA TWICE PIPES set up and it never caused any deceleration backfire popping. Now with this one whenever i reléase the gas pedal on 2nd and 3rd gear i am experiencing a pop pop pop sound at the muffler.

 

this MSA PREMIUM EXHAUST KIT  comes with an Xcelerator Turbo Muffler:

http://www.a-1perfor...rator_mufflers/

 

This is the one i had before:

http://www.thezstore...ring02a/15-6031

 

Now do this additional information can help solve the puzzle? Will adding a resonator or glasspack in the middle cancel the deceleration popping at the exhaust?

The popping is due to camshaft duration and overlap, you now have an exhaust system larger, that has less back pressure, thus allowing unburnt fuel to pas through the slightly open exhaust valves.
With back pressure, the unburnt fuel was more kept in the cylinders.
Little bit richer, on mixtures, back timing to 14 or 12 btdc, then check plug colours and run a range or two different, to decrease the plug fouling.

BTW, we visited your country last year, then a run through the Canal. Also Costa Rica, Nicaragua, great beaches, best barbeques, and amazing wildlife! Just regular tourists!






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