Offroad-Express

Hi all I have had a bit of a search on the net about a aftermarket turbo manifold to suit the td42 engine I have been looking on trade me at these: http://www.trademe.co.nz/motors/car-parts-accessories/tools-repair-kits/other/auction-612947525.htm and this one http://www.trademe.co.nz/motors/car-parts-accessories/performance/turbos/auction-611829956.htm. One is the tube style manifold and the other is the log style. I'm not going for all out performance but want reliability so what do u guys reckon? Any help would be appreciated.

For the small difference in price, I would go for the tube. I understand the best design for best performance is to have each of the pipes from head to flange, the same length.

You want a log type manifold but needs to be split between port 4 & 5 as this is where all the twist happens. AXT have done the maths and that is why they make theirs that way.

Reece

Like above you want a log type manifold but I would get a better quality than the ones on Trade me.

Interested in the reasons for the log style??

I did a good bit of research to look at building mine, and all the drag racing guys I know said the best design for their turbo is the extractor style, but each pipe must be exactly the same length.

EDIT: Well mine is a TD27, but basically the same head, just missing 2 ports

On a Petrol you want the equal length runners extractor style,

On a Diesel you want short runners to keep the exhaust gas as hot as possible to help spool the turbo because of the limited rev range.

nismo26 wrote:On a Petrol you want the equal length runners extractor style,

On a Diesel you want short runners to keep the exhaust gas as hot as possible to help spool the turbo because of the limited rev range.

Cheers, good to know.

SV1K wrote:You want a log type manifold but needs to be split between port 4 & 5 as this is where all the twist happens. AXT have done the maths and that is why they make theirs that way.

Reece

Wow thanks for the fast replys!!
So it should be the log type where would I find a ATX manifold do they have a web site? if I have to spend a little bit more for a quality product I would rather do so.

When u say twist happens do u mean the manifold twists?

theres a really good discussion on log vers tuned manifold design on patrol4x4.
long length pipes give to much room which slows and cools the exhaust gases. diesels got lower egt's than petrol, you can't afford to waste any.
also the extra volume requires refilling on gear changes etc which makes it slower responding. plus pulse tuning is limited with a diesels rpm range.

tweake wrote:theres a really good discussion on log vers tuned manifold design on patrol4x4.
long length pipes give to much room which slows and cools the exhaust gases. diesels got lower egt's than petrol, you can't afford to waste any.
also the extra volume requires refilling on gear changes etc which makes it slower responding. plus pulse tuning is limited with a diesels rpm range.

Didn't know that. Makes perfect sense when you think about it. How do the converging exhaust "wave fronts" affect the flow in the manifolds? Does this create backpressure issues or do the rules change with diesels?

SV1K wrote:You want a log type manifold but needs to be split between port 4 & 5 as this is where all the twist happens. AXT have done the maths and that is why they make theirs that way.

Reece

Axt who now use chines crap in there cores that fail after 1000km ,

I wouldnt go off anything axt use , there turbos are utter shit , do you want some of the chinese wheels in my scrap metal bin ?

And yes they did use to be quality untill they swapped garrett for 10 year old slave labour components

Trundle wrote:And yes they did use to be quality untill they swapped garrett for 10 year old slave labour components

Well I guess I wont be looking at a ATX then lol everyone is coming up with some real interesting things to consider

Heath wrote:Didn't know that. Makes perfect sense when you think about it. How do the converging exhaust "wave fronts" affect the flow in the manifolds? Does this create backpressure issues or do the rules change with diesels?

i would take a good guess that flow would be effected.
not only due to gas having to do a couple of tight 90 degree turns, but hitting flow from the other ports will also impeded flow.
however i'm told that a bit of extra back pressure on the motor won't hurt it anywhere near as much as a few lbs lost of boost.

cam timing on a diesel is more tolerable to backpressure than a petrol. less overlap means less gas left behind.

end of the day log manifolds flow like crap so paying attention to small details can pay off.

with 4cyl you can do a few tricks like putting the turbo opposite an exhaust port so it gets max drive off one port.

edit: i forgot. toyota 2lte has a short extractor style. cyl's 1 and 4 are paired, as are 2 and 3. but pipes are short rather than long tuned style.

Heath wrote:

tweake wrote:theres a really good discussion on log vers tuned manifold design on patrol4x4.
long length pipes give to much room which slows and cools the exhaust gases. diesels got lower egt's than petrol, you can't afford to waste any.
also the extra volume requires refilling on gear changes etc which makes it slower responding. plus pulse tuning is limited with a diesels rpm range.

Didn't know that. Makes perfect sense when you think about it. How do the converging exhaust "wave fronts" affect the flow in the manifolds? Does this create backpressure issues or do the rules change with diesels?

That's a good point u have there when u look into some turbo manifolds there is a divider in the flange what is that intended for?? strength or to divert opposing wave fronts?

pajero1983 wrote:That's a good point u have there when u look into some turbo manifolds there is a divider in the flange what is that intended for?? strength or to divert opposing wave fronts?

see my edit above.

Trundle wrote:

SV1K wrote:You want a log type manifold but needs to be split between port 4 & 5 as this is where all the twist happens. AXT have done the maths and that is why they make theirs that way.

Reece

Axt who now use chines crap in there cores that fail after 1000km ,

I wouldnt go off anything axt use , there turbos are utter shit , do you want some of the chinese wheels in my scrap metal bin ?

Well then I guess I have a non Chinese one, coz I have done more than 1000 km and still no issue... maybe you have a bad unit from them.

Remember that the money you put into it you are not going to get it back when you sell it, so its a long haul investment... also the H/P increase wont be extremely high, just more stamina from the motor...

Reece

a log style is easy to make, i'm sure someone on here could make one if you put out a request, probably cheaper than buying one. i'm going to have a go at making one out of steam pipe bends and tees sort of like this

Liking the short steam pipe.

So going by what everyone has mentioned, the best design would be a mixture of this steam pipe, nice, thick and short to retain the heat.
You could probably get a good flow by placing a split/divided collector in the middle, that has a nice short smooth bend to help the flow up and out the flange. This would help stop the flows from opposite sides colliding.

Well then I guess I have a non Chinese one, coz I have done more than 1000 km and still no issue... maybe you have a bad unit from them.



Axt use to use quality cores , i ran one on my gq at 28 psi for years , but after the last kit i imported failed on a customers vehicle at 12psi i sent it to Steve murch to see why it fell to bits and he confirmed it was all chinese shit and the exhaust wheel was faulty , turns out most diesel specialists in nz wont touch there stuff anymore as its just crap now ,
Needles to say after fitting oem components to there housings it is now fine

y60 safari driver wrote:a log style is easy to make, i'm sure someone on here could make one if you put out a request, probably cheaper than buying one. i'm going to have a go at making one out of steam pipe bends and tees sort of like this

i'm not a big fan of those.
one is the pipe size, log part should be sized up depending on how many ports are feeding into it. ie no1 is smallest, no2 is bigger, no3 bigger again etc.
the other is using T joins. nice curves for gas flow but its both ways. you really want to make it flow down the log but not back into the other cylinders.
ie on port 2 have curve from 2-3 but not on the 2-1 side.
thats to slow down the gas going from port 2 back into port 1.

but when price is an issue i've seen worse ways to do it

you want to try and find a log type manifold that has each port runner turned slightly so it merges with the flow. kinda like an on rap for the motorway. The old dsr cast manifolds were quite good for this.
Will you be turboing the truck yourself ? If handy with the tools then you can quite easily do the install yourself. Turbo wise go garrett Gt2860 or imo the best one is the tdo5 16g small wheel. Really expensive brand new but you can pick up a good second hand one and put a good quality bush/seal kit in for half new price.
That's what I've done and has worked really well for me.

crazyclark31 wrote:you want to try and find a log type manifold that has each port runner turned slightly so it merges with the flow. kinda like an on ramp for the motorway.........

nice way of putting it

I get what you are saying but once you have a good size collector in the middle the pressure difference would keep if flowing anyway wouldn't it? like water in a pipe joining the current flow. i'm sure it would cause a slight resistance but not enough to worry about if you not running huge boost/power

i don't know what the power difference would be. probably find one of the patrol tuning guys have tested it.
i would not expect the difference to be big but it more about driveablility. eg boost comes on a bit earlier, it chokes a bit later, wider torque curve etc. nothing big but it makes it better to drive.

if your going to the expense and hassle of making one, do it the best you can.