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  #31  
Old 29-08-2017, 03:33 PM
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Mr Ex Jnr Mr Ex Jnr is offline
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Hmm ino I spoke to warbie on Monday and told him there guy in Stockport that's good not far for me so am gunna get a jet kit and get him to re jet it and get running sweat
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  #32  
Old 29-08-2017, 03:36 PM
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Carb Flooding

Quote:
Originally Posted by Farmer42 View Post
I think you can get a pair of HS6 carbs from Burlen. They always say stuff is out of stock because they manufacture to order. Having said that, there will be a lot of fettling to do on the HS6 as the throttle linkage is different and I am not sure they bolt straight onto a nissan balance tube.



The best bet is to go to Z Therapy in the States. They do the proper job and are not too expensive (at least until the shipping costs are added). Still cheaper than Webers & Injection kits. They also do full rebuild kits.



Ali (Smileyinside) has used ZTherapy so he may be able to give some perspective.


Yup as Mr Farmer said the ZTherapy carbs are as good as new; if not better given their sealed throttle shaft bearings and SM needles. They totally transformed my car and at c.500 worth every penny if you are not chasing high displacement, big BHP and 8K RPM.

The SM needles do run a little rich on a stock engine but half the fun is fiddling to get them set up right (which is easy). I had the benefit of the very interested MOT guy with rollers and an oxygen sensor helping me. So it was even easier!
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  #33  
Old 29-08-2017, 04:02 PM
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johnymd johnymd is offline
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The engine old on my blue car was a 2.8 with "nice" head and triple 40's. It went really well and delivered low to mid 30's to the gallon on our trip to Le Mans in 2010. We were taking things easy though and rarely went over 80mph. The car was re-jetted on a rolling road just before we went and a lot of time was spent getting it as close as possible to correct. Carbs are never perfect but if you can get in the ball park then fuel consumption shouldn't be that bad. Aim for 14:1 AFR on cruising and there's no reason why you should use loads of fuel. Cruising and transition fuelling is something most rolling roads really don't want to do as its so time consuming but that were the economy is found.
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'72 240z RHD (4BOA) Painted and waiting assembly.
'72 240z LHD Silver "Rat look" daily runaround.
'76 280z ExLHD Red v8 Lexus powered restomod.
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  #34  
Old 29-08-2017, 04:05 PM
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Right cruising around 80mph it does 13 to 15 i deffo need it re jetting for next year show season just need to look for a webber kit
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  #35  
Old 29-08-2017, 04:18 PM
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If your interested in seeing how good or bad the fuelling is then invest in a lamda sensor and gauge. Over a short period of time you will start to notice were it is rich and from that work out which jets will require changing.
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Drives:

'73 240z 1JZ-GTE. Was pretty quick. 11.10@132.5mph
'72 240z RHD (4BOA) Painted and waiting assembly.
'72 240z LHD Silver "Rat look" daily runaround.
'76 280z ExLHD Red v8 Lexus powered restomod.
'74 260z LHD Restomod just started.
'71 240z LHD zg arched. Still in California.

Go to: www.240z.me.uk to checkout the cars.
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  #36  
Old 29-08-2017, 04:19 PM
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Mr Ex Jnr Mr Ex Jnr is offline
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Thats interesting am gunna look in to it and get it sorted for next year
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  #37  
Old 29-08-2017, 04:47 PM
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I dunno how much of a difference it would make on my fuel having no air filters on the webbers
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  #38  
Old 29-08-2017, 05:36 PM
SKiddell SKiddell is offline
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Correct Stoichiometric ratio is around 14.7:1 for complete combustion.......irrespective of induction choice....carbs, FI or aunt Daisy's turkey basting spoon

This ratio will be tweaked around driving conditions (acceleration or idling) but generally its a golden number

In short, to make X amount of power, Y amount of air and Z amount of fuel is required in that ratios.....independent to the induction choice and /or aunt daisy's cutlery

If the car is only getting 13 miles / gallon then outside of the lead foot effect, one or more of the following are happening

1. The larger carbs (higher air/fuel flow potential) are unleashing huge amounts of additional power

2. They are running rich ...

3. Fuel is leaking the entire length of the A5.....

Maybe thats why people fit those crude fuel catching trays over the exhaust.
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  #39  
Old 29-08-2017, 05:46 PM
franky franky is offline
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Quote:
Originally Posted by SKiddell View Post
Correct Stoichiometric ratio is around 14.7:1 for complete combustion.......irrespective of induction choice....carbs, FI or aunt Daisy's turkey basting spoon

This ratio will be tweaked around driving conditions (acceleration or idling) but generally its a golden number

In short, to make X amount of power, Y amount of air and Z amount of fuel is required in that ratios.....independent to the induction choice and /or aunt daisy's cutlery

If the car is only getting 13 miles / gallon then outside of the lead foot effect, one or more of the following are happening

1. The larger carbs (higher air/fuel flow potential) are unleashing huge amounts of additional power

2. They are running rich ...

3. Fuel is leaking the entire length of the A5.....

Maybe thats why people fit those crude fuel catching trays over the exhaust.
I did follow a guy in a 240z a few weeks ago, his car was running that rich that i could smell fuel in my car at 60mph.

How did you find the transition from carbs to FI? For ultimate performance I agree FI yealds easier to get results etc.
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  #40  
Old 29-08-2017, 05:56 PM
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I doesn't **** out seeps a little bit av only noticed that recently after getting to oulton it's always run rich but never seeped.

Wat am saying tho is I don't run it with air filter just trumpets so air be going in quicker would that make it use more fuel.

Wud it use less if I had air filters on
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  #41  
Old 29-08-2017, 06:02 PM
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I only noticed it seeping when I got to oulton Saturday always run bit rich like but never seeped quite a few fresh petrol marks. But even when Allan my dad run it he sed needed rolling road re jetting

Does it make a difference as I run it with no air filters

Would it use more petrol as it getting air in quicker

Why do race cars run just run trumpets with no air filters

Why dont race cars use k and n filters as most of u zedders use k and n

Most samuri if seen run just trumpets

Wonder way johnny 260z like on petrol he runs air filters on his

Last edited by Mr Ex Jnr; 29-08-2017 at 07:32 PM..
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  #42  
Old 29-08-2017, 07:58 PM
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Air filters make a difference but they don't need to be restrictive - one of the thing a rolling road may try is a run without filters if they think they're restrictive - but if well chosen they won't be.
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  #43  
Old 29-08-2017, 09:14 PM
Pilot1002010 Pilot1002010 is offline
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I ditched the SU's in favour of triple 40 Webers, would never use anything else the increase in performance is mind blowing 😄😄😄😄
Adjustment is simple with an airflow meter and a screwdriver 🏁🏁🏁🏁
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  #44  
Old 29-08-2017, 09:15 PM
SKiddell SKiddell is offline
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Running open trumpets on an L series can be bad due to drawing in dirty air full of dust, dust sticks to cylinder wall and makes and excellent grinding paste

Open trumpets also mean that your pulling in very hot air (in excess of 80 degrees) hot air into an engine is undesirable (its less dense and can promote detonation)

In tests (back to back dyno) we found an increase of 17 HP in some parts of the curve when using an airbox versus open trumpets....reflected pulses anyone !!!!! no, didnt thnk so.

And most Samuri's use open trumpets because that was the thinking of the time.....back before the asteroid strike when dinosaurs built engines

Oh and they sound good
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  #45  
Old 29-08-2017, 09:28 PM
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Mr Ex Jnr Mr Ex Jnr is offline
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Right so would you sugest getting filters for them or a open air box with one filter at the front some where

Or keep it period the engine been like this all my life so I dunno what to do

Also my dad took the choke off it aswell runs nice without it just bit of a thirsty zed but I fort webbers were

I am thinking of 're building carbs for a start
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