yd25 new exhaust lacking power

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Benengel

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Christchurch, NZ
recently installed a 3inch dump into a 3inch system with a resonator.
From everything i ever read it seemed like it made the world of difference and turned her into a whole new beast...
how ever i feel like that isnt the case. 1-4th doesn't seem to bad slightly less turbo lag. how ever 5th feels like it doesn't start to pull even when your foot is planted untill 2500rpm which is already 100km/hr even then 2750 is when it seems like boost really comes on.

any ideas? already paid alot for the exhaust and don't want to be throwing alot of cash into it
any help would be appreciated
 
I've never gone 3" because I personally reckon it is to big on a small engine. I haven't changed the exhaust on the Nav, but did on my 3.0 Patrol. I chipped it first and just wasn't that impressed, so put on a 2.5" Beaudesert exhaust and it did come to life after that. I did have to limit the boost after changing it. I wouldn't have changed the exhaust without the chip.
 
I wouldnt expect noticable gains from anything other than a chip!
 
my sons D-22 with a 3 inch full system has more low end torque than my stock D-22. so there is definetly some noticeable difference.
 
A bit of extra bottom end might make the top end feel slightly less potent. As everyone has said, exhaust alone does **** all. a touch of extra bottom end. The chip is where the magic happens.
 
Basically, IMO what's happening is by opening up the exhaust that much & not adjusting the tune, is that you've made it run lean. It may rev harder, but you won't notice any more power until you have the tune adjusted with an ECU re-map, or a chip. The ECU is mapped to the factory exhaust & just putting a larger exhaust on won't change that.

I'd be interested to see the exhaust side of the pistons after you've run with that exhaust on & no re-tune for a while! Especially if you tend to rev it out between gear changes.

Please note that I am not recommending a chip, or a re-map. I like the car the way it came from the factory.
 
Yes it wouldn,t hurt to have a re - map done, atleast you know the esc etc will be in tune and the engine should run better. A friend had his Patrol re maped by nissan and it made a good difference he said.
 
Basically, IMO what's happening is by opening up the exhaust that much & not adjusting the tune, is that you've made it run lean. It may rev harder, but you won't notice any more power until you have the tune adjusted with an ECU re-map, or a chip. The ECU is mapped to the factory exhaust & just putting a larger exhaust on won't change that.

I'd be interested to see the exhaust side of the pistons after you've run with that exhaust on & no re-tune for a while! Especially if you tend to rev it out between gear changes.

Please note that I am not recommending a chip, or a re-map. I like the car the way it came from the factory.

I doubt it would affect the AFR much if at all,, unless you are seeing a significant boost increase with the new exhaust.
Even if it did run lean, ie; more air for the same amount of fuel,, in a diesel that would just mean a cleaner burn and cooler EGT's which are good things.
In reality, the turbo itself is the bottleneck in the system, at low rpm the big exhaust might help the turbo spool up better, but apart from that not much else.
 
Hey, cheers for all the info. I think it may be a placebo effect with the new exhaust feeling like there isn't much top end. I do feel like i have gain a slight increase in the bottom end.
running cooler egts is definitely a positive, can't wait to put a few bikes on the back and go up a few hills and see if there is a difference there

hopefully one day when the funds allow i'll get the chip and tune
$2300 eeeep
 
I doubt it would affect the AFR much if at all,, unless you are seeing a significant boost increase with the new exhaust.
Even if it did run lean, ie; more air for the same amount of fuel,, in a diesel that would just mean a cleaner burn and cooler EGT's which are good things.
In reality, the turbo itself is the bottleneck in the system, at low rpm the big exhaust might help the turbo spool up better, but apart from that not much else.

I have to respectfully agree to disagree.

The turbo sucks in masses of air, the injectors do their thing, the pistons compress it all & off it goes with a bang - out to the exhaust manifold.

Yes, it's a much cleaner burn. But a cleaner burn is a hotter burn, not cooler.

It's not too far different from the old high school days of using a Bunsen burner in science classes. The rich (yellow) flame was never near as hot as the lean (blue) flame. The yellow flame took forever to boil water, the blue flame did it with ease.

A lean mix in an engine fries pistons. Too much heat at the exhaust manifold.

Fattening up the mix with a re-map will avoid this, but brings with it its own set of reliability issues.
 
I have to respectfully agree to disagree.

The turbo sucks in masses of air, the injectors do their thing, the pistons compress it all & off it goes with a bang - out to the exhaust manifold.

Yes, it's a much cleaner burn. But a cleaner burn is a hotter burn, not cooler.

It's not too far different from the old high school days of using a Bunsen burner in science classes. The rich (yellow) flame was never near as hot as the lean (blue) flame. The yellow flame took forever to boil water, the blue flame did it with ease.

A lean mix in an engine fries pistons. Too much heat at the exhaust manifold.

Fattening up the mix with a re-map will avoid this, but brings with it its own set of reliability issues.

A diesel is different to a petrol engine in that there is no throttle, the engine is getting a full lungful of air at all times. It is getting a full lungful at idle, where the egt's might be about 90c, it is getting a full lungful towing a 3 ton trailer uphill at 110kmh with your foot mashed into the carpet and egt's up at 800c.
The only difference is the amount of fuel being supplied. If you could add more air to the latter scenario the egt's would come down.
Its the opposite of petrol engines when lean conditions cause high heat and/or detonation.
 
I have a 3" system, but on closer inspection, at the turbo flange, it's starts at only 2 1/2" for the first 2cm. is this normal, due to the size of the turbo outlet? so then, is it a waste to have a 3" system, after starting at 2 1/2?
 
Hey, cheers for all the info. I think it may be a placebo effect with the new exhaust feeling like there isn't much top end. I do feel like i have gain a slight increase in the bottom end.
running cooler egts is definitely a positive, can't wait to put a few bikes on the back and go up a few hills and see if there is a difference there

hopefully one day when the funds allow i'll get the chip and tune
$2300 eeeep
I dont think it would be worthwhile to spend that sort of coin on a chip n tune for a vehicle that age and value.

Have a look around you might pickup a chip around $500, or a used chip from someone selling their d22 for cheaper.
Plugit in and off you go.
 
Sorry, i just realised were talking about the yd25 not zd30.
Im not too sure which chips are the way to go here or the cost, but $2300 still sounds more than i would like to drop for a bit extra power.
 
Yeah I wouldnt fork out $2300 for a reflash. So plug'n'play modules no-go for yd25? Its all you need on a zd30.
 
heaps of info to take in, bit confused atm. are you guys all saying that 3inch could casue the rings to fry out quicker then stock?
Would you guys recommend dropping down to 2.5inch ? or just leave as is? i can definitely notice the increase in bottom but it still feels like after 110km it takes age to get up any more.
which isnt handy for long road trips at the over taking lane
For a Uni-chip in NZ the cheapest place iv found is around 1900 plus a $300 dyno tune.
 
Have you blocked the egr off too? If you haven't it might be worth doing that. Also, fit a manual boost controller. Not to wind the boost up (you won't get any more power from more boost without a chip to increase fuel) which should eliminate any wastegate creep that may be occurring.

I have a 3" on mine, straight through (no mufflers or cat), manual boost controller wound all the way off (still boosting approx 18psi as standard) and get blocked and don't have any trouble getting up over 110km/h to overtake road trains over here in WA.
 

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