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4.2 petrol carby options

Tech Talk for Nissan owners.

Moderators: toaddog, V8Patrol

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Posts: 3
Joined: Tue Nov 23, 2010 11:22 am

4.2 petrol carby options

Post by Quigga »

Heya guys,

New to these forums but been around on others for a while.
Just need some quick suggestions to get some more beans from the carby motor without spending big, So far i have have come up with a few ideas but nothing really in concrete, for now it has to stay carby and internally stock (may port head if the time comes) for class rules but may efi/turbo later

retain stock carb but take out restriction plates and rebuild and rejet to suit a meth/tolulene mix

use a holley or webber downdraft carb (dont know sizes that would suit though) also will use a fuel mix there too

upgrade to electronic ignition with beefier coil and leads (possibly petronix )

any links or guidance would be appreciated
Posts: 3
Joined: Tue Nov 23, 2010 11:22 am

Re: 4.2 petrol carby options

Post by Quigga »

bump it up

any suggestions guys
Posts: 470
Joined: Wed Jan 24, 2007 12:21 pm
Location: Australia

Re: 4.2 petrol carby options

Post by 351ciofgrunt »

What class rules says it needs to stay internally stock?

To get some decent power out of a normal atmo TB42 will take alot of money, it's a very heavy rotating assembly, with a tiny cam and no compression.

Save your money and go down the efi & turbo path, very impressive power
GQ Patrol Wagon, 6 point roll cage
351 cleveland, CHI heads, solid cam, Funnelweb single plane, 750 HP DP
Posts: 1258
Joined: Wed Mar 21, 2007 7:49 pm
Location: Mornington/ Victoria

Re: 4.2 petrol carby options

Post by PGS 4WD »

Quigga wrote:Heya guys,

New to these forums but been around on others for a while.
Just need some quick suggestions to get some more beans from the carby motor without spending big, So far i have have come up with a few ideas but nothing really in concrete, for now it has to stay carby and internally stock (may port head if the time comes) for class rules but may efi/turbo later

retain stock carb but take out restriction plates and rebuild and rejet to suit a meth/tolulene mix

use a holley or webber downdraft carb (dont know sizes that would suit though) also will use a fuel mix there too

upgrade to electronic ignition with beefier coil and leads (possibly petronix )

any links or guidance would be appreciated
Do the ignition, good intake, extractors and exhaust. A dynotune with premium and some cary adjustment can get from about 75 to 85-90 rwkW in a manual.
-Pre trip inspections/ servicing
-Suspension/ custom modifications
-4wd Dyno & tuning
-Qualified mechanics
Posts: 3
Joined: Tue Nov 23, 2010 11:22 am

Re: 4.2 petrol carby options

Post by Quigga »

ok appreciate the help so far but im assuming there isnt or is very few who have actually tried to develop this motor so it looks like ill have to just trial and error it :lol: ill do a write up of sorts anyway so the next person isnt greeted with the usual stuff
intake, zuast, ign, tune
it must stay internally stock for the class rules (it says so in the cams licence for the class all parts are to be engraved and pics taken prior to installation) the turbo route may happen next year but with a 4.6 later anyway if we move up a class (or 2) with some tricks i know from building 25/30's and 26/30's it should be making around 500-600hp with like well over 1000+ torque

btw ive already changed to some 3inch extractors and made a custom pipe to dump behind the diff (so far biggest gain)
made a custom intake and snorkel setup (response and bay temps went down)
got a petronix on order

oh and im gonna use the stock carby, it has restrictor plates and fairly small jets so ima change it accordingly and run it on a 10-15% meth mix to run a whack more timing which the petronix with help with(so far with the math its looking at an extra 50-90hp just with the carb so much more with the juice)

anyway still welcoming ideas as it can never hurt
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