Zorst Decisions - 2.8L N/A Diesel

[RockyF75]

ATM, my entire zorst is pretty shabby. Stoopid thing only has 2 mounting brackets so it rattles around heaps and as such it breaks the flange at the Manifold end. So that needs fixin. From the muffler back, the pipe needs replacing cause i squashed it offroad and its about to fall off. And needs a new mount near the G/box to prevent the aforementioned flange problems re-occuring.

As it stands I can prolly get new pipe from muffler back, new flange, and new mount for around the $150 mark.. i think. But can get whole new straight through system for about 100 more.. Q is, Will straight through give me any more power and/or economy? Or just make it noisey Noise aint a huge issue, so long as I get power/economy, i'm happy to compromise on it. And what size? 2", 2 1/2"? 3"??? And what about extractors... are they a worthwile? What sort of pipe size would i go with them?
And could you's please post up guestimates/past experience with what you have/would expect to pay for what you suggest.

Thanks in advance

[The Rocky]

iv got 2" zorst and extractors on for $650 in newy

[RockyF75]

straight thru?

[HotFourOk]

Straight through only refers to the rear muffler type.
It gives better flow characteristics, but a touch noisier.
It's mainly a perforated tube inside the muffler, whereas the other types can have expansion chambers, flow directors etc to restrict flow and reduce noise.

It won't make all that much difference, you're not turboed or anything
But really, just get a well known brand and it should be ok.
Get 2" piping also ... PS Kane's sounds mad I'd go for extractors too

Around the $600 mark is the going rate... Just go get it done

Normal Offset type muffler



Straight through type:

[ausyota]

You can get offset straight though mufflers too. The inlet and outlet dont have to be in line.
I have a centre - offset 3" straight through that I am fitting to my 2.8 lux with a turbo.

[RockyF75]

can u have too much flow, i was leaning towards 2 1/2", and getting extractors later on.

[EXHAUSTFIX]

ATM, my entire zorst is pretty shabby. Stoopid thing only has 2 mounting brackets so it rattles around heaps and as such it breaks the flange at the Manifold end. So that needs fixin. From the muffler back, the pipe needs replacing cause i squashed it offroad and its about to fall off. And needs a new mount near the G/box to prevent the aforementioned flange problems re-occuring.

As it stands I can prolly get new pipe from muffler back, new flange, and new mount for around the $150 mark.. i think. But can get whole new straight through system for about 100 more.. Q is, Will straight through give me any more power and/or economy? Or just make it noisey Noise aint a huge issue, so long as I get power/economy, i'm happy to compromise on it. And what size? 2", 2 1/2"? 3"??? And what about extractors... are they a worthwile? What sort of pipe size would i go with them?
And could you's please post up guestimates/past experience with what you have/would expect to pay for what you suggest.

Thanks in advance

ok you where all pretty much on the right track

what u need is a set of extractors and dont go for the mandrell ones this is only a small engine so use press bent ones u want a bit of ristriction to keep your torque in the right area of your rev range

if your going 2.25" use the largest body muffler u can possiably fit under your car i would go for a centre/center muffler with purf tube inside (no expansion chamber

do not go any bigger as you will loose torque and low down power

good luck

ross

[HotFourOk]

can u have too much flow, i was leaning towards 2 1/2", and getting extractors later on.

I think 2.5" is too big Nath, you would lose too much torque... and that's all diesels have Hence your economy will be shot too

As Ross said, 2" or 2 1/4" max with a hiflow muffler should be ok.

[tweak'e]

do not go any bigger as you will loose torque and low down power

don't mean to criticize but whats this business about to big makes less torque business?

the old racing rule of thumb was "no such thing as too big an exhaust after a turbo or extractors". if your putting restriction in to gain torque then that sounds like poorly designed extractors, which is not uncommon, as they are often designed for max power which is what sells.

i remember a certain sports car a Aussie firm designed extractors for, they made more torque but less hp than the American made ones (which where the only ones available at the time). the car with the Aussie ones was the quicker of the two.

also especially with carby race cars if the tuning of the extractors was good it would suck a lot of air/fuel out the exhaust on the low revs, so the trick was to off tune the extractors which stops the low down suction and helps keep the air/fuel in the motor making more power down low. restricting the exhaust will effectively do the same thing.

with diesels and their minimal rev range i doubt they will running a lot of overlap for that to occur, which makes me thing its a poor extractor design or cam timing is a bit out. does anyone make adjustable cam pulleys for those motors ??

[HotFourOk]

"no such thing as too big an exhaust after a turbo or extractors"

It is true that you can put a much larger size pipe on a turbo setup, but it is also to a certain degree. One simple reason is that the engine is creating more power, hence creating more exhaust gases. Also, the scavenging effect occurs before the turbine, so changing the pipe size does not affect this as much as a n/a setup. This allows the turbo to spool up faster too.
Turbo systems are also quieter due to the turbo reducing exhaust noise.

In a n/a setup, gas scavenging from the cylinders needs to occur effectively and helps in removing the exhaust more quickly. Extractors help with this, as they are usually a tuned length, so the pulses of exhaust gas improve this scavenging, allowing the engine to perform at its optimum.
If you use a pipe size which is too large, the gas will cool down and travel more slowly, hence reducing performance.

[chunderlicious]

mates 351 with custom made extractors, port matched heads and 3 inch collectors into twin 3 inch mandrell systems, is noticable when only running the extractors. when the full exhaust is on the car chirps taking the foot off the break, when the exhaust is off the fast pedal needs to be pressed.


twin 3's is alot of flow and still works better than just his extractors....