RoeDao
Isuzu Junior
If you notice this notice, you will notice that this notice is not worth noticing
Posts: 52
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Post by RoeDao on Oct 21, 2005 16:54:21 GMT 11
I have my vehicle in bits at the moment (see signature) i decided to bid on a new turbo/turbos on ebay...... one turbo is stuffed, but the other is in good condition.... i was considering twin turbos (side by side) basically for something to do..... the engine will be LPG injected once it is up and running again.... and i think the 2.8 can produce enough exhaust to spool them up........ but i would not be able to use all the boost available to me.... the original turbo without any holdback devices  produces about 10.5 psi (mine did anyway before i "made" it run at 12psi) I suffered very little to no lag with it.....i was wondering about using these 2 turbos, and running them inline..... so the small turbo would spool up first, and as it was running out of breath, the bigger one would start working...... anybody think that running them that way would work? i'm not up with turbo tech.... i am thinking run the exhaust in series into the small turbo, from there into the bigger one..... and the same with the compressed air...... small turbo to big turbo and so on....... any thoughts that you have would be appreciated  here's the turbos.........  |
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Post by Jimmu on Oct 21, 2005 20:11:22 GMT 11
My thoughts...
Running them in parallel is going to be very inefficient and you will have massive lag.
A sequential turbo setup can provide an excellent combination of spool up time and top end boost. But they are generally very difficult to set up and expensive for the performance returns. (Most people swap the setups from the factory to one larger turbo)
Upgrading the single turbo to something bigger however will certainly open up some opportunities for more power at a worthwhile cost.
Let me know how you go as I will be upgrading my turbo sooner rather than later.
Jimmy.
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Post by maletimaru on Oct 22, 2005 16:54:22 GMT 11
Wasting your time
The only way to get better performance in the 4JB1-T is to get it spooling quicker (leave boost as is) and increase size of turbo and exhaust pipe size too. If you fitted an anti-lag system and launch control to it (like in drag cars) you would notice considerably more power, efficiency and economy.
The basic set up you are suggesting sounds great in theory but in practise it does not work - hence why the subys that use the sequential turbos have their primary turbo "you know what" itself early on in its life
You are better off going for one larger turbo and reducing the lag time
Reduction in lag = turbo doing the work for you - not the engine!
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Post by superturbocompound on May 8, 2006 1:30:21 GMT 11
RoeDao i am pleased to hear that they are a few people willing to go the distance in performance tuning,about that twinturbo set up,most high performance trucks in america have the turbo lay out in series,big turbo(low pressure) blow into a small turbo(high pressure),i am doing some research on that lay out,you can too,check out TURBOCHARGERS BY HUGH MACINNES BOOK, new bmw 535tdi opel antera diesel twin turbo www.bd-power.com/ram/product.php?pn=BD+Super+B+Twin+Turbos&tt=ramwww.piersdiesel.com/DodgeTwins.htm |
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Post by roscoe46956 on May 8, 2006 18:36:03 GMT 11
I remember working on and driving a truck with a Cummins twin turbo set up years ago and it it was a pig with bad lag and narrow torque bands as each turbo spooled up but once the second turbo finally got wound up it was awesome for its day.
Caterpillar have just gone to a twin turbo set up with their latest truck engines but, they are completely under computor mangement for emission control.
Remember, the bigger the turbo, the slower it will spool up due to a larger rotating mass.
This new "greenie" thing that is coming out about smokey diesels is something to consider
too, get the set up wrong and the smoke nazis might start goose steeping towards your vehicle.
Impco use to do a LPG mixer that was designed for a Turbo system so that may be worth some follow up.
good Luck with it anyway.
Roscoe
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Post by dani4JB1T on May 22, 2006 12:07:19 GMT 11
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Post by dani4JB1T on May 22, 2006 12:40:13 GMT 11
if is fitted 2 turbos inline will be necessary get reinforced head bolts??....what about pistons and and bearings ??
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Post by superturbocompound on Jun 23, 2006 1:59:34 GMT 11
the reasons for having 2 turbo in series is achieve high boost pressure,in access of 30psi or more,but i doubt you're heading that way right???anyway just to answer your Q ,4jb1's is tough so reinforcing on the bolts are not required,pistons are okay too but tunning plays an important part('egt' key factor)bearings that i am not to sure.based on friends who drag these engines the #1 enemy is revs(broken camshaft,crankshaft,oil pump gears,rods flying out the block etc)
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produces about 10.5 psi (mine did anyway before 
