3'' vs 2 3/4'' exhaust zd30

[04SilverSTR]

guys ive done a bit of a search but itdidnt really answer my question, it seems most guys with 3'' exhausts are happy with them but are they too big for the zd30?? should we be sticking with 2 3/4''??

cheers
bryan

 

[Gonzo]

I have the 2 3/4 and couldn't be happier . I have a straight through resonator and it has a slight note but doesn't droan on the highway . And I have heard some people have a problem with the 3 inch fouling the front drive shaft. Thats my 2c worth

 

[chule]

I've got a 3" straight through exhaust. Definitely livened up the motor. Both sizes seem to work well though.

 

[charlie strayarc]

Northside 4 x4 had some dyno sheet comparisons on a thread somewhere and it seemed the 2 and 3 qtr was marginally better.
I have also heard the 3 inch lacks back pressure for engine braking when 4 wheel driving down hill.
I am undecided which way to go and look forward to comments from those that have either.

 

[rabbit-chop]

Turbo engines thrive on big straight thru exhausts, they dont need back pressure at all. That said a 3" exhaust on a pissy 110kw engine is overkill IMO and will have no real benefit compared to a decent 2.5". The most important part is a good dump pipe.
my 2c

 

[LLadnar]

Beaudesert designed the 2" 3/4 exhaust for the d40 2.5ltr originally so it's got nothing to do with 110kw. They did dyno test show there was no power benefit difference between a 2"3/4 and a 3" so why pay for a bigger pipes when it don't make no difference.

 

[Angryranga]

Yeah but the 2 3/4 is an odd size to try and get, if you are stuck in some little town somewhere. You would have a better chance of someone having 3in on stock for a repair.

 

[Lawry]

big 7L and 6L odd truck go around a 4 inch sometimes 5 inch.
cant see why a 3L would need any bigger than a 2.5
which is what i run, its not even mandrel bend and it performs perfectly.
very common size aswell

 

[MAT713]

My only concern about the beau exhaust is that it isnt actually a 2 3/4 dump pimp.

Its 2.5 and at the flex pipes opens up to 2 3/4 for the rest.

I certainly agree that cars still require back pressure on exhausts whether they be NA or turbo. But from my years playing with other nissan turbo'd cars we found the best thing is to open right up at the dump and reduce the sizing later.

this is just my theory but if I could put together the ideal set up for my D22, it would have a 3' dump pump, a flex pipe immediately after with a 3 - 2.75 reducer then that width the whole length

 

[happy john]

It's kinda 6 of one and half a dozen of the other i went for the beau due to speaking to alot in the industry have a look at the standard dump it's like trying to fart with your finger you know where.

My mate put a 3inch on his king cab d40 with standard dump results were 9hp more above 3000rpm and a a loss of a few hp in the mid and down low everybody seems to get differn't results so it's confusing for us all.

 

[4x4 ST-R]

Before I got my 3 inch exhaust I shopped around and asked the same questions. Most exhaust shops said that there's no need to go past the 2.5 inch. Chip it said that without a chip a 2.5 inch would be fine and a 3 inch without the chip could possibly lose some power, but with the chip it would perform better. So I got the 3 inch in preparation for my chip.

I have never had my Nav on the dyno so I dont have any stats for what difference it made apart from sound.

 

[happy john]

I reckon they are the same anything has to be better than stock larger exhaust is a must with a chip by the look of the feet on yours you would appreiciate the help in power mine ran 2psi more boost just going from the standard to the beau without anything also stock it would spool at 1500 now it's at 1150 when it spools 2.5 that is yours is better down low off boost nothing will help the 2.5 there.

 

[04SilverSTR]

sooo it took me an hour but i got the heat shield off the turbo tonight as i ordered a beaudesert 2 3/4 inch system today with the muffler delete. should have it here for friday and will start fitting it friday arvo/night, cant wait!!

bryan

 

[tommyhodgkin]

how much was the system, if you dont mind me asking?

 

[4x4 ST-R]

Spray every bolt and nut with WD40 now. Soak them heaps. I was spraying mine 2 weeks out before I started pulling mine apart. Made it a little easier.

 

[ekul26]

would like to know system price same as Tommy (if you dont mind me asking?)

 

[180degrees]

guys they are about $12-1300

 

[04SilverSTR]

what he said ^^^^ will know exact when i get it in the next day or so.

4x4 i have been spraying with bolt off, bloody good shit for loosening rusty tight bolts!!

bryan

 

[Tappet]

Somtimes a reduction half way down can work.
Big dump, turbo back, then maybe 2.75 or even 2.5 after the muffler. Keeps exhaust vellocity up but allowing good fast spool up of the turbo.

 

[CharlieD_03D22]

2 3/4" is an odd size, but 3" is overkill. My brother has a 4.2 patrol which turbo'd and cooled, and he made a 3" straight through exhaust for it, its a perfect match to that engine. therefore, for the 3.0 nav, i would recommend a 2 1/2" straight through, which is what I will be building for mine