err no.
its not a petrol. equal/tuned length extractors don't work well for diesels especially when hauling around 2+ ton of ute.
YD25 Compound Turbo
- Thread starter dilmah
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its not a petrol. equal/tuned length extractors don't work well for diesels especially when hauling around 2+ ton of ute.
I thought that you would rather have the exhaust pulses equally hitting the turbo? Could be wrong. On the 300hp nav on club frontier used them.
blue navaras is also auto which helps and he was chasing out right power rather than usable torque range most 4x4's go for.
the problem with tuned length is there is to much room for expansion so you loose drive on the turbo, which makes it laggy and loose power in the low rpm.
diesels have colder exhaust gas than petrols so can't get away with having large volume exhaust manifolds.
you can go semi tuned style, extractor style but unequal length. instead of making the two center ports full length, having them short and go straight to the turbo reduces manifold volume and gets maximum punch from those ports, but at the expense a few hp in the top end due to not being tuned length.
I don't think Ill run more than 30psi, otherwise Ill kill the engine pretty quick, you need to remember that this is now a comp truck. it only gets driven once or twice a month so I can push the engine harder than a daily
camo.b
Member
What is considered a good daily HP limit for a YD25?
I was thinking about a new manifold for mine after i get the new turbo sorted out...mabee ill just keep the adapted standard log manifold and run with that....
Dilmah yours is still the stock log one right?
I was thinking about a new manifold for mine after i get the new turbo sorted out...mabee ill just keep the adapted standard log manifold and run with that....
Dilmah yours is still the stock log one right?
Yeah still stock manifold. I've got 2 mate who have build custom manifolds for a 1HZ and TD42 but its a lot of work as you have to make them out of Ally and I cannot weld it yet. Other option is to pay someone to do it which will be expensive. For the Hp gain is it really worth it? I know the stock design is pretty bad and making a custom manifold is tricky as you are limited for space due to injectors and tiny engine bay.
Id consider a YD25 with a 3rd gen chip, emmisions controls removed or blocked 3" exhaust, upgraded intercooler making about 130 rwkw on 32's to be the limit of a daily. After that you are looking at aftermarket turbos, big W2A setups, custom chips or remapping, water meth injection, the list goes on
Id consider a YD25 with a 3rd gen chip, emmisions controls removed or blocked 3" exhaust, upgraded intercooler making about 130 rwkw on 32's to be the limit of a daily. After that you are looking at aftermarket turbos, big W2A setups, custom chips or remapping, water meth injection, the list goes on
camo.b
Member
None of the documented over 300hp yd25s have changed the inlet manifold.id almost say its not important...ive never seen any of the asian tuners running custom inlets also and those guys are crazy and will make anything. Ive seen toyota d4d inlets and dmax ones tho.
The main area I will struggle with is fuel supply, atm im running out of fuel when I get to 23 - 25psi the AFR's are leaning out to 25 - 26:1. Im hoping with the Unichip, a lift pump and bigger injectors I wont have this issue
camo.b
Member
Heard back about the injectors yet?i couldnt get baileys to ring me back....must say i rate my water meth kit.my mid to top end is nothing without the meth.i doest stop pulling till 4500.but ive got a very smokey 2600-3000 range with the injector chip and chipit turned on..without the meth i cant seem to get the top end fueled up enough with either chips......p.s im only going off smoke and egts for AFRs.
camo.b
Member
I think Im more excited to hear how yours goes with final fitup and tuning than mine
You need to be thinking in pressure ratios, not gauge pressures.
Final tune is at least a month off. I need at least a grand to get it tuned properly. It will be on the dyno all day @150/hr. Dion I must have my maths wrong if you don't think it works just by adding the primary to secondary. Can you post the correct formula I should be using
you need to do the math in absolute pressure (add roughly 15psi to gauge).
the rough math afaik......
prim turbo at 18 psi gauge (33 psi absolute). 33 psiA divided by 15psiA(atmo) gives drive ratio of 2.2 . increase primary inlet pressure by 5psi (15psiA + 5spi= 20psiA), so 20psiA times pressure ratio 2.2 giving 44psiA out of primary turbo, which is 29 psi gauge pressure.
i hope thats right.
that doesn't factor in air temps or mass flow. overall efficiency is roughly efficiency of turbo times efficiency of turbo 2. so if both are at 80% its 80%x80%=64% (bs numbers, its just to give an idea of the math)
the rough math afaik......
prim turbo at 18 psi gauge (33 psi absolute). 33 psiA divided by 15psiA(atmo) gives drive ratio of 2.2 . increase primary inlet pressure by 5psi (15psiA + 5spi= 20psiA), so 20psiA times pressure ratio 2.2 giving 44psiA out of primary turbo, which is 29 psi gauge pressure.
i hope thats right.
that doesn't factor in air temps or mass flow. overall efficiency is roughly efficiency of turbo times efficiency of turbo 2. so if both are at 80% its 80%x80%=64% (bs numbers, its just to give an idea of the math)
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Yer ok, Ill set the secondary at 12psi and adjust the primary to suit until I'm hitting around 25psi at full noise. Ive got manual boost controllers on both so there will be a bit of playing around to get it to boost right
Here's some reading for you. Dougal seems to know his shit ( he's also the only other person that remapped a navara and wrote about it ).http://www.4btswaps.com/forum/showt...Compounds-HX30W-WH1C&highlight=compound+turbo
http://www.4btswaps.com/forum/showthread.php?66417-larger-compounds-for-4bt&highlight=compound+turbo
http://www.4btswaps.com/forum/showthread.php?66417-larger-compounds-for-4bt&highlight=compound+turbo
i would do it the other way around.
set you small turbo as planned, then set the big one low and work up until overall boost hits 25psi.
if you set big one and adjust small one i think you would see boost increase rapidly with minor adjustment as turbo's are multipliers.
but then again with gauges and controllers on both you can play with it all day long.
HJ22
Member
I say let Dylan try this setup before the negativity, nobody else can do it.
Rabbid-chop
Member
Why isnt anyone listening to tweakes? He is the only one in this thread who has his head around the concept.
i don't know about that. i have some rough idea but the devil is in the detail.
i looked at this years ago but with supercharger feeding small turbo.
compounding is certainly interesting. its very complicated and i don't know half of it.
very interested to see how the project goes.
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