3" Exhausts and low RPMs

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As your trying to promote your own business and products, I don't think it matters what anyone else says your going to disagree unless it is to your favour.
eg, If your making and selling 2.5" exhausts then of course your going to say they perform better than say a Taipan 3" and vice versa.

So to continue the thread is pointless IMO.

Why don't you start your own thread showing all these dyno runs your claiming to have done. Lets see the EGT graphs on a stock D22 with nothing changed other than exhaust from factory to 2.5" to 3".

3" is generally better. however there may be a reason this particular engine is dropping low down power. quiet possibly the ecu is detecting to much boost early on and is reducing fuel or its having trouble controlling turbo.
it could be something thats fixable, or use smaller exhaust to get around the problem.

what doesn't help is some of the early variable turbo engines had poor control systems. when you fitted a big exhaust the turbo overboosted causing problems. so exhaust crowds will not fit big exhausts to them. hence the "smaller is better" line is born.

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tweak'e said:

3" is generally better. however there may be a reason this particular engine is dropping low down power. quiet possibly the ecu is detecting to much boost early on and is reducing fuel or its having trouble controlling turbo.
it could be something thats fixable, or use smaller exhaust to get around the problem.

what doesn't help is some of the early variable turbo engines had poor control systems. when you fitted a big exhaust the turbo overboosted causing problems. so exhaust crowds will not fit big exhausts to them. hence the "smaller is better" line is born.

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Actually the "Smaller is better" bit has been going around for a lot longer than VNT turbos, it has been kicking around for cars since 4.1L Falcons had exhausts that would be better suited to a 120Y.

I would agree however that early VNT control systems were pretty ordinary. Not sure how well the YD25 copes with changes but the early (NON CRD) Patrols were poor. They had a simple system that appears to base all control on assumptions, change something that is assumed and boost control problems follow as a matter of course. Not sure if the early YD25 VNT was controlled closed loop or open loop, but the 140KW version has a totally different actuator on the turbo, it looks to be a stepper motor where the old ones were vacuum/pressure actuated, so hopefully that indicates at least the new ones have proper closed loop boost control.

the_bluester said:

Actually the "Smaller is better" bit has been going around for a lot longer than VNT turbos, it has been kicking around for cars since 4.1L Falcons had exhausts that would be better suited to a 120Y.

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yeah all that is from atmo engines which can be true when dealing with the tuning section of the exhaust. however downstream of the tuned section it can't be to big.

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Do you have a stock graph for the D40? Interesting torque curve on that one, pretty flat for an oiler I reckon with 60% of its peak available right up the top end of the useful rev range. A pity that I don't reckon my 05 model is like that, it falls off noticeably through the midrange.

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I suppose an obvious question is "how much is a Unichip" ?

Some of the testing you guys have done is fantastic, but it might not be so easy for a competing firm to get someone to pop a D40 on a dyno that quickly and put up results like you've shown us. I'm sure they have the basic graphs but taking boost pressures, EGTs and more is probably not the norm.

Maybe it should be, since these specific things are so important.

Well done on the testing.

But dont bag out the competition.

Well you keep the customers happy and word gets around. The business keeps flowing.

Re: 3" Exhausts and low RPMs

Dave said:

Well done on the testing.

But dont bag out the competition.

Well you keep the customers happy and word gets around. The business keeps flowing.

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Agree with Dave. Bagging out the competition won't make me buy a products. Showing me how a product is better then another ( which you have ) will make me buy it.

docta.phipps said:

Agree with Dave. Bagging out the competition won't make me buy a products. Showing me how a product is better then another ( which you have ) will make me buy it.

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This is true, but the sellers attitude would turn me away and make me go elsewhere.

Northside 4x4, not really related to this conversation but can I ask, are the 2.5" and 3.0" systems you have tested on the Navaras both mandrel bent and close to identical in layout?

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Northside 4x4 said:

Leprechaun, Chipit, Anyone?
Where are the comments on the graphs, and responses to them?
Everyone is quick to play the slam down game, until results are actually posted for once.
And then what? No response, just like I anticipated.

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Mate I'm not telling you how to run your business, but seriously, talking to potential customers like that? Do you expect us to buy from you?