Custom Exhaust and Back Pressure?

[Duck]

Hello all.

Been a while since I last posted here, but on the plus side the old girl is slowly on her way to being what I want her to be.

So yes, my question: I'm planning to make a custom stainless exhaust system, including muffler, on my KZN130 Surf, the effect of which would obviously be a decrease in back pressure; can you tell me whether or not the ECU can compensate for this drop in back pressure or will it need manual adjustment? If anybody can enlighten me on this matter, it would be much appreciated. Cheers.

[BUSHWHACKER]

Hello all.

Been a while since I last posted here, but on the plus side the old girl is slowly on her way to being what I want her to be.

So yes, my question: I'm planning to make a custom stainless exhaust system, including muffler, on my KZN130 Surf, the effect of which would obviously be a decrease in back pressure; can you tell me whether or not the ECU can compensate for this drop in back pressure or will it need manual adjustment? If anybody can enlighten me on this matter, it would be much appreciated. Cheers.

Back pressure not an issue.

My exhaust has only one muffler (straight through type) and finishes before the rear axle, no problems with extra noise or lack of performance.

[The Lovely Boyo]

You'd probably give yourself more trouble if you go too large on the diameter of the pipe you use.

Most say going up to 2.5'' dia gives an improvement in response = better flow. I think this goes for both engines.

2.75'' dia pipe is about 20% bigger again (in terms of its area)

[surfenstein]

you will most propably find that any vehicle that has forced induction will work better without any backpressure.

[Duck]

Cheers for the replies. I don't usually deal with diesels and am not familiar with the fuel management on the surf. Finding any technical data on the ECU has proved problematic too. Does anybody know whether the ECU will up the fuel input to balance out the increase in air flow created by the loss of backpressure?

[chrisinflight]

Yep, all of the above correct. Did some research before I fitted mine and back-pressure not an issue. You will get slightly better mpg and power due to engine "breathing" better with a free-flow, besides the nice sound!

[jonogm]

With less backpressure the turbocharger should come in at lower rpm.
About how the ecu responds to the change, I don't know. But I think it does not respond to that.
I have a 3.0td 4runner with 3" all the way from the turbocharger to the back and one straight through muffler but the runner has no ecu (luckily). I think the best thing to do for you is to go for a intercooler and a low backpressure exhaust system. Although that would require a ecu chip mod to increase the fuel/air ratio. But the benefits are major