Nissan Patrol 4x4 (Africa)

Cedric -- F Y I the power increase om Boezman from "boxed" to 63mm straight was BIG -- that 16 valve ZD 30 LOVES luuuuvvvvvv to breathe.
As I said, VIPER has done their research on the performance aspect an Abel says: 76 mm down pipe, into 63mm at the flange [and then for bottom bottom end torque, small box -- but in Boezman i mos sommer ran it straight out all the way.

Ask WIMPIE O what he thinks of Boezman's performance :-)

I think on a hardbody, at about 1.8 odd tons, that free breathing ZD30 pulls like a steam train, but on a 2.8 - 3 ton Patrol, with 2 solid front axles, and the aerodynamics of a block of flats..... the extra grunt may not be felt as much. But yes you are probably correct, there could well be more power.

Tony, is yours the 3.0 or the 4.2? ( on the 4.2 there are also 6 cylinders and this motor is not very " revvy") the 4.2 at 3500 rpm sounds like the pistons are going to fly out the block....

Now that is where I feel the most need for a little more grunt! I hate revving an engine and always battle with pull offs and low rev situations - when I chipped my motor, I was hoping it would help in that rpm range .... it did'nt, and then I fitted 75 profile tyres - and guess what happened !!! Anyway I would'nt change my Trollie for anything else, ever. Thanks Cedric.

Sorry Cedric, 3.0 Turbo 4 cyl - and I cannot believe I am complaining, coming from a 1990 one tonner 2.4 petrol that was so pap, and I still drove her for sixteen years and thought she was great. This TD is an absolue gem, cheers.

Uncle Mac, You would be amazed at how that Boezman will perform with 3 inches. My old 2.7 does way better than before with the bigger straight pipe, but is a bit noisy. I had to make a plan to take the pipe past the body where the noise would not get trapped under the car or behind bumpers. But that produced a few other problems I am still working on.

I was playing the other day and from 130 upward with foot planted to the floor, the diesel motor breathes so well that you it just can't get the EGT up into the red. Even the water temp seems to be more stable. The only gauge that is really affected by foot flat is the fuel gauge .. Seems I drop from around 9.5KM/L to around 8

Dis wat OOmpie se Davy -- Boezman HET 'n straight pyp op [63 mm = mos 3 duim .. dan nie?]
Vra maar vir Wimpie -- hy beiindruk met Boezman

Oompie Mac, 2.5" = 63mm en 3" = 76mm.

Ek het die hele storie ding met Chuck ook gedoen: 3" pyp al die pad vanaf die turbo en geen enkele silencer meer in die pad nie.

Die resultaat is 'n klein bietjie van 'n dreun by lae revs (klink eintlik baie mooi!), maar sodra die turbo aan die spin gaan is alles net so stil soos met 'n kleiner pyp & silencers.

Chuck se EGTs sukkel om oor 500 grade te kom, maar ek dink lae EGTs het meer te doen met 'n goeie tune & optimale fueling as met die skezors se grootte. Die warm lug kom mos vanaf die enjin, nie vanaf die uitlaatpyp nie?

Volgens VIPER Engineering is optimum 'n 76mm "down pipe" na die fklange en vanaf die flange tot agter uit 'n straight 63mm pyp met geen bokse in nie
Daai bikki "back pressure' wat die 76 into 63 jou gee is daai low low low very low end torque wat die diesel so goed is mee ..

EN dit haal ook die turbo lag se doodsheid uit jou lorri uit ..
as ek nou lieg, het Abel vir my gelieg :-)

Maybe Abel's getting bored explaining exhaust theory to all his customers after all these years?

1. Why exhaust velocity is aim for normally aspirated engines: Back pressure: The myth and why it's wrong

"One of the most misunderstood concepts in exhaust theory is back pressure. People talk about it with no real understanding of what it is and what it's consequences are. I'm sure many of you have heard or read the phrase "Engines need back pressure" when discussing exhaust upgrades. Sadly, that phrase is completely inaccurate and a wholly misguided notion."

2. Why turbo engines need as little back-pressure as possible: Turbo Exhaust Theory

"As most of you know, the design of turbo exhaust systems runs counter to exhaust design for n/a vehicles. N/A cars utilize exhaust velocity (not backpressure) in the collector to aid in scavenging other cylinders during the blowdown process. For turbo cars, you throw all that out the window.

You want the exhaust velocity to be high upstream of the turbine (i.e. in the header). The idea is to get the exhaust velocity up quickly, to get the turbo spooling as early as possible. Here, getting the boost up early is a much more effective way to torque than playing with tuned primary lengths and scavenging. You have a turbo; you want boost.

Downstream of the turbine (aka the turboback exhaust), you want the least backpressure possible. No ifs, ands, or buts. Stick a Hoover on the tailpipe if you can. The general rule of "larger is better" (to the point of diminishing returns) of turboback exhausts is valid."

PS: The Z's now got dual 63mm pipes with only about half the backpressure of the original factory system. Guess what I'm saving up for?

Kagiso II wrote:Volgens VIPER Engineering is optimum 'n 76mm "down pipe" na die fklange en vanaf die flange tot agter uit 'n straight 63mm pyp met geen bokse in nie
Daai bikki "back pressure' wat die 76 into 63 jou gee is daai low low low very low end torque wat die diesel so goed is mee ..

EN dit haal ook die turbo lag se doodsheid uit jou lorri uit ..
as ek nou lieg, het Abel vir my gelieg :-)

Maybe a small 3lt needs that, but on real trucks a straight through pipe is the best. 76 mm from turbo to the back with great torque from down under. Fueling will give you more torque on the bottom end and definely not a box.