4jb1t rocker ration mod

[superturbocompound]

hello fellow 4jb1t owners

i have been looking for a forum that does mod on this engines to share my experiences,
i have done loads of mods to the car(2.8 turbo diesel twin cab) and one of them is the rocker arm ratio,its a bit of a back yard work but it does work,fortunatly i have all the necessary means to,(own a fab shop)
1)here goes, the original rocker where the nut to adjust the valve clearance was welded up to make a new hole 1.5 mm closer to the fulkrum(rocker shaft) after having done that i installed it and presto!!! high lift cams.i noticed that the boost was delayed but a hill that i go through to work every day showed that with a lower boost i was producing the same power,and also the engine reved easier.
2)LONG DISTANCE FUEL SAVING,there is another mod i did to the waste gate system,it works like this:the turbo will only have boost when accelarating,when cruising there is no boost,the waste gate opens and no back pressure,i find that in crusing mode the engine is quiter and use less fuel because i have to lift off the acc pedal to maintain a constant speed.the waste gate has a booost feed and a vacuum feed so during cruising the vacuum opens up the waste gate.
3)CURRENT PROJECT.i am working on a super turbo compounding 4jb1t.supercharger off a toyota 1ggze and a vatn turbogt3571klv.i will post pictures soon if there is anyone interested to see it

[superturbocompound]

forgot to mention when doing the aluminium welding on the rocker arm,must no apply too much heat or the rocker arm would not fit into the shaft.the hole that the shaft goes through might warp

[dani4JB1T]

im more than interested....please put some pics

cheers

[dani4JB1T]

did you take it to a dynotest to check the new power/torque figures ??

[superturbocompound]

unfortunatly here in borneo(sabah,malaysia) we do not have a dyno machine,but we do lot of drag racing on this engine,some of the guys here have the fuel modified to rev to 6000rpm but extremely unreliable,usually blow up oil pump,i think the practical limit here is about 5000rpm but don't quote me on that.

[dani4JB1T]

interesting mate...only 4J race tunned engine i know is this: www.takasaki.ne.jp/mu/index4.html...problems is how to translate it to english.

we don`t have dynotests here too...()
6000 RPMs !!!!!..... how long that engines lives before that...geeez

please tell us more of what are you doing with these engine over there in malaysia...and link us to some pics/vids

cheers

[superturbocompound]

i see from the pic u drive a rodeo too,i know that the front suspension of the rodeo does not have much travel,i have the same car as you,i improved mine by using a big horn suspension,the arms are longer and you get more travel,even better if you can get a lotus edition because the anti roll bar(anti sway bar) is bigger and is more stable but mods are quite extensive,just do brief you what i have done to my truck,front suspension big horn lotus edition,front mounted intercooler & oil cooler,remote oil filter mount(underneath driver behind front wheel),aluminium radiator with electric fan(no vicious fan)not advisable,will fry alternator,fix by using big horn alternator.special waste gate with vacuum and boost function.nissan ball bearing turbo and ceramic turbine wheel(stock item on nissan rb20)boost controller etc

[dani4JB1T]

mmmhhh....good tip, thanks...im going to ask a wrecker for a bighorn lotus edition.

I think you must post your other mods too. Somebody here wants to put a remote oil filter mount. I also intersted in the front mounted I/C, oil cooler mods.

[dani4JB1T]

forget to ask what bighorn version...the early or the latest one ??

[superturbocompound]

just for your info why don't you have a look in here,these are my products(ariasher store):-
list.lelong.com.my/Auc/List/List.asp?DA=A&TheKeyword=intercooler&CategoryID=

[superturbocompound]

i am not too sure which big horn but i did use back my manual lock hubs,didn't like auto lock hubs ,the ones i used(big horn) were the type which do not have a button to engaged to 4wd,i think pre 4jx1 models can be used.

[superturbocompound]

some pics of the rocker arm ratio being altered

[Jimmu]

Did you use the whole turbo from a RB20? Or just the compressor wheel?

Jimmy

Oh and

try babelfish.altavista.com/babelfish/tr

Jap to eng

[superturbocompound]

well i did use the whole unit once and the low end was good,i still managed to get 1 bar climbing a hill on 3rd,however i changed the compressor wheel and housing to an rb25(nissan 45v) and i experienced some surge in the early part of the rpm(boost needle shaking) although it did improve my 4th gear top end.my guess is that if it does a lot of city driving the rb20 would be better...turbos i've tried rb20,rb25(turbine housing too big)rb20 turbine/rb25 compressor wheel,housing(only good top end),honda wing turbo vatn(good all rounder,cannot boost more then 1 bar),current:supercharger from 1g-gze/ turbo garett gt3571klv (will'll see...)

[superturbocompound]

just installed modified rockers arm on inlet side on two isuzus,a rodeo and a big horn 4jg2,feed back is very good top end,low end and midrange not much improvement.