Manifolds - TD42

[Maxgq]

I have recently been reading a lot of talk about manifolds, whats the deal, what are the benifits? big power increases? Put some links up please

[BigRAWesty]

Imo all wank factor imo unless your chasing 4 figure power..

Kallen Westbrook
Owner of
Westy's Accessories

[Dominator]

Are you talking about intake or exhaust manifolds?

If your talking about the intake manifold on a TD42 then the main reason people change/modify them is to get more even air flow across the 6 cylinders. Because of the design of the factory manifold cylinder no. 1 and 6 run richer than the other 4 and as we know a rich mixture in a diesel means higher exhaust temps, and high exhaust temps kill. This temp difference can be as high as 50oC. By evening out air flow you even out temps. Also a well designed manifold will allow better total air flow which will reduce spool up times and widen your torque band. It may not make a big difference to your peak power but will help drivability.

For the majority of us with less than 150HP, the gains from a modified manifold, for the expense, are questionable, but every bit helps. But when your wanting to run 20+psi I would think it could definitely be justified, if only for the insurance of not cooking your motor.

[Ben-e-boy]

Imo all wank factor imo unless your chasing 4 figure power..

Kallen Westbrook
Owner of
Westy's Accessories

Really???........ What do you base that on?

Maxgq. When I got mine I bought a spare manifold. It had oily deposits around the 4th cylinder. I assumed it was off a gu4 with an egr, thought nothing more of it. I pulled mine off (96 gq black top), it had the exact same stain with a similar amount of build up in the exact same area. I put the question to the company who built my manifold and they said that it is what happens with the standard manifold. They then showed the tops of 7 stock manifolds. Every one had the exact same stain in the exact same spot. These areas of deposits are likely caused (happy to be corrected if I am wrong) by an area of lower pressure than the carbon/oil/crap can settle on the wall of the mainfold, and once a bit has stuck there, more will stick. If these lower pressure areas or air dams? are present how can you be achieving even distribution to all 6 cylinders?

The current design of manifold which is on mine has only increases the physical volume of the plenum by about 800ml - 1L which isnt much. Where improvments have been made is its ability to distribute air evenly to every cylinder due to the spout being central to the manifold and NO square edges to cause vorticies and low pressure areas. IMO even distribution should be the main goal not volume/
You wont see a massive power increase with a plenum they will only be very slight (5-10 Kw?). I suppose you could call it optimizing (for want of a better word) what is already there?

[Ben-e-boy]

Are you talking about intake or exhaust manifolds?

If your talking about the intake manifold on a TD42 then the main reason people change/modify them is to get more even air flow across the 6 cylinders. Because of the design of the factory manifold cylinder no. 1 and 6 run richer than the other 4 and as we know a rich mixture in a diesel means higher exhaust temps, and high exhaust temps kill. This temp difference can be as high as 50oC. By evening out air flow you even out temps. Also a well designed manifold will allow better total air flow which will reduce spool up times and widen your torque band. It may not make a big difference to your peak power but will help drivability.

For the majority of us with less than 150HP, the gains from a modified manifold, for the expense, are questionable, but every bit helps. But when your wanting to run 20+psi I would think it could definitely be justified, if only for the insurance of not cooking your motor.

you beat me... dam my slow typing lmao

[nissannewby]

Dominator and Ben-e have pretty much nailed it. A well designed manifold for a TD42 can result is awesome gains in airflow and distribution. There is a very good thread about this on the other patrol forum with some very experienced people responding to it.

As dominator said for those about the 150 mark gains are minimal but its still a gain. When you starting pushing more than 150rwkw then while a manifold might be one of those 1% things the gains are really quite worth it.

[jgoose]

Hi does the td42 xhaust manifold have the same bolt pattern/ports as the tb45e x manifold?????

[Brisat]

Are you talking about intake or exhaust manifolds?

If your talking about the intake manifold on a TD42 then the main reason people change/modify them is to get more even air flow across the 6 cylinders. Because of the design of the factory manifold cylinder no. 1 and 6 run richer than the other 4 and as we know a rich mixture in a diesel means higher exhaust temps, and high exhaust temps kill. This temp difference can be as high as 50oC. By evening out air flow you even out temps. Also a well designed manifold will allow better total air flow which will reduce spool up times and widen your torque band. It may not make a big difference to your peak power but will help drivability

.

If you are talking about boosted engines the pressure will be even in all directions so it doesn't really come into it. The standard manifold will work quite well up to 18-20 lbs. Beyond this pressure some streamlining of the manifold may help with the charging of the cylinders but the pressure will do most of the work and the air charge will only back up behind the valves until it can enter the cylinder. The amount of fuel injected will have a bearing on temperature and if this is too much for the aircharge it will run "rich"
The reason most diesels have good torque is the fact that the fuel is injected over a period of time and is still burning, expanding and pushing the piston down after it is a 1/4 way down the cylinder. It doesnt just go bang up the top like petrol and scare the piston to the bottom. I have spent many hours programming Motec computers on large gas injected diesels and not got what we really wanted out of them emission wise but got a really flat torque curve from 1000 - 1100 rpm up to 2500. At the end of the day it was a bit more fuel to stop NoX which meant cutting the boost back as the manifold and a couple of feet of the exhaust were glowing a lovely red colour with temps in excess of 700 C
this is why TD & DT are not great fans of screwing fuel up too far with out having all the other parts of the equation working properly.
My 4.2 will blow a little bit of smoke when you first get going but by about 12-13 hundred RPM the turbo takes care of that and once on the move very little smoke is visible. I have no idea what the boost will go to as I very very rarely go past 2700 rpm
which is about 12-13 lbs.

[Dominator]

Yes the pressure may be even but that does not mean he flow will be. It is the lack of volume of the manifold and the shape of the inlet runners that causes turbulence which interrupts and restricts flow.
I am not talking from personal experience, I am speaking on the advice given to me from someone who had done extensive flow bench testing on the TD42 manifold.

[Gq jack]

I am having a Plazmanan TD42 inlet manilfold installed on my TD42t Gq patrol, 5" lift, 33's, 2.75" exhaust, 13PSI boost and 4" snorkel, if anyone wants to know the difference in how it drives before and after?

Also being the test 4WD for the W2A kit for GQ patrol and should have it back next month which means that I get a standard intake manifold topmount intercooler feel, new intake manifold feel and new intake manifold W2A Kit feel. I am pretty pumped to feel the difference.