NewHilux.net

Hey guys! As mentioned in the topic subject, are there any pros and cons in straight piping a stock 1kd with 2.5” stainless steel exhaust system? With the intentions of running a chip in the future, not going for anything crazy but looking at 200whp.

Appreciate any and all constructive feedbacks and looking forward to hearing from everyone here! Cheers!

If I understand "Straight Piping" right, then ... Taking the muffler out of the system will drastically affect your back pressure. This will affect Power output capabilities, not to mention increase noise levels to deafening. Dunno about the rules in Malaysia, but in Australia you simply would not be allowed to do it.
That's all provided I understand your original question right?

First if you're going to chip it you need a bigger exhaust to get the heat out but before you chip it, consider an ECU remap/tune for the same dollars possibly less and it does much more than a chip.

Second if you're changing the exhaust you will definitely need a cat and muffler as they are very loud without them and as Rob says, you need some back pressure. You will lose low down torque with a bigger exhaust but the tune/chip makes up for that.

Third stainless is a total waste of money because it's a diesel, they don't rust pipes until the vehicle is very old and probably not even then

Gipsy wrote:Third stainless is a total waste of money because it's a diesel, they don't rust pipes until the vehicle is very old and probably not even then

I've noticed travelling through Asia that many Asian Country's "Call it" Stainless when in fact it's just chrome plated. The only value of Chrome plating is to "look pretty". Actual Stainless Steel, rated to various grades (304, 316 etc) under Australian Standards manufacturing ratings will also cost you big bikkies.
I think I said it all. Need another Port.

304, 316 whatever, Chrome or stainless steel is a waste of money unless you're building a hot rod or a show car with the bling on display because that's all it's good for Stainless steel is for boats and it does corrode after a while

Rob_Wood wrote:If I understand "Straight Piping" right, then ... Taking the muffler out of the system will drastically affect your back pressure. This will affect Power output capabilities, not to mention increase noise levels to deafening. Dunno about the rules in Malaysia, but in Australia you simply would not be allowed to do it.
That's all provided I understand your original question right?

Thanks Rob and everyone else, yeah I considered the noise levels as well although as long as you don’t go heavy on the right foot with authorities around then there’s not much of a problem.

About the power, I read about Cummins engines performing better with a straight pipe on another forum so I thought I’d ask here if anyone has done it with their KDs and what are the pros and cons. Are there any reasons why Cummins-powered Dodges would do better with a straight pipe?

Thanks in advance everyone!

With a straight pipe, as you put it, the 1kd is very loud even at idle. I have an x-force 3inch exhaust with cat and muffler (all low resistance) and it's quite loud when you floor it and noticeably louder than standard at idle.
I don't know why the Cummins folk say that, but naturally a straight through system provides minimal resistance to the exhaust. This does improve high end power but at the expense of low down torque because of the lower back pressure. It's your choice but I would recommend the x-force from my experience.
If you must, just try cutting out the standard muffler and put a straight pipe in and you will see what I am saying. This will be equal to a larger exhaust as there's less resistance. It will, however be less resistance than standard but also may be illegal so it's your decision.

thefatduck wrote:Thanks Rob and everyone else, yeah I considered the noise levels as well although as long as you don’t go heavy on the right foot with authorities around then there’s not much of a problem.

About the power, I read about Cummins engines performing better with a straight pipe on another forum so I thought I’d ask here if anyone has done it with their KDs and what are the pros and cons. Are there any reasons why Cummins-powered Dodges would do better with a straight pipe?

Thanks in advance everyone!

With 20 odd years working on Cummins, Detroit and others driving Generators in buildings I have not heard of this one ... even from the Cummins people we often had on site. Even pushing exhaust gases up 10, 15 or even more floors of a building, our machines still had a muffler of some sort fitted to them.
I've had too many Ports tonight to explain Torque Vs Power Outputs and how this would apply to Static Generator sets over a (much smaller) 1kd driving a vehicle.

Gipsy wrote:Gipsy

wanna play?

Ha ha, I could play Rob but I'm not sure you could understand all that theory and technical jargon
Besides, "pushing exhaust up 10 or 15 stories" would actually benefit the output... Ever noticed how heat rises Rob? And presumably the mufflers were a legal requirement subject to oh&s regulations

Muffler delete on 4 cylinder diesels sound like wet farts
Don’t do it

Gipsy wrote:Ha ha, I could play Rob but I'm not sure you could understand all that theory and technical jargon

Not if I've been on the Port, no way. Other times I'd give it a shot.

Gipsy wrote:Besides, "pushing exhaust up 10 or 15 stories" would actually benefit the output... Ever noticed how heat rises Rob?

Yeah, this is basically where I was coming from. This and how when you load up a Generator you can quite often hear the Engine "sing" a little ditty we used to call "GimmeMore". I recall one set that used to "hunt" quite violently until you loaded it up. Quite interesting to watch during startup before the load is actually switched over. Had to replace engine mounts on that unit at least once a year.

Gipsy wrote:And presumably the mufflers were a legal requirement subject to oh&s regulations

Probably??? It was Government stuff, so I imagine it woulda' been.