20+ Psi coasting

So I have one for the pros..
I've noticed after the exhaust has gone on when I'm coasting with cruse on or a pedal position just before engine braking comes on, or acceleration boost is running up to 20+ Psi. . Highest I seen was 26!!!!

When engine braking it's right down at sub 1 psi and under any sorta acceleration it's fine and maxes out at 15 as it should..

Not sure if it's the turbo over running or a faulty sensor??
Could it be not enough back pressure??

Help. I'm now worried about this weekend..
I've got 2000 road k's ahead of me!!!

Just drive the damn thing

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Originally Posted by Clunk

Just drive the damn thing

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Nek minute pin drops....

Boost wont kill it. What are egts like while this is happening?

Is your gauge absolute or is it corrected?

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Originally Posted by nissannewby

Boost wont kill it. What are egts like while this is happening?

Is your gauge absolute or is it corrected?

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Unsure on egt as yet to fit gauge..
Water temp doesn't move from the normal 88-90 though..
I can't hear the turbo spooling like I can under power.
Scangauge is reading corrected boost so you may be onto something..

What's going on here Kallen? You right for the weekend ?

blocked egr?

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Originally Posted by Chubba

What's going on here Kallen? You right for the weekend ?

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I bloody hope so!!!

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Originally Posted by trekster

blocked egr?

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Yes..
Never thrown a code

When I blocked my egr and put 3" exhaust on, without boost control, The ecu couldn't control the boost and if I was just cruising with bugger all foot down the boost would go up to like 25psi+ If I put my foot down there was no problem it would drop back, but couldn't cruise at all.... Might want to check your boost control setup assuming you have a dawes/tilix etc.

Just clean your MAF and all your issues will magically disappear ;)
Sounds like a typical 3" exhaust over boost issue, time for dowes valve I reckon.






….................... On the move

I just read this... my boost was doing exactly the same before taming it with the dawes and needle setup after getting the exhaust fitted .
It was having spasms and best description was a yoyo effect.
After Mudski helped me set it all up it was so much better to drive smooth boost curve.

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Originally Posted by trekster

When I blocked my egr and put 3" exhaust on, without boost control, The ecu couldn't control the boost and if I was just cruising with bugger all foot down the boost would go up to like 25psi+ If I put my foot down there was no problem it would drop back, but couldn't cruise at all.... Might want to check your boost control setup assuming you have a dawes/tilix etc.

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Originally Posted by Hodge

I just read this... my boost was doing exactly the same before taming it with the dawes and needle setup after getting the exhaust fitted .
It was having spasms and best description was a yoyo effect.
After Mudski helped me set it all up it was so much better to drive smooth boost curve.

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Still ecu controlled..
Bugger..
I was sorta hoping I wouldn't have to go that road..
I'm actually liking the boost smart boost actuator conversion..
Might research more..

Quick Q. Did you guys get the readings off manual gauges or did you notice boost spikes threw scangauge with corrected boost reading?

I'll swap it to the manifold pressure on the scangauge and see if it's going off chart or if it is just the scangauge miss calculating..
I can't hear any turbo spool up when is saying 20+ Psi, like I can when I sink the boot in and it hits 15..

For me both, Boost reading on torque would flash at 22psi so it couldn't go any higher, my old turbosmart gauge went to 25 and was off the chart a couple of times lol.

So I've flicked the scangauge to Manifold pressure and it's not as bad as first thought. .
At 110km/h pressures were between 25 and 33 psi..
So under full load it was 30..
So yes still a little over but not double as the corrected boost reading was..

So..
I'm thinking current exhaust is still to loud..
So I'm thinking I'll be putting a cat in the dump pipe........
That may add the little back pressure needed to control the run away spool..
If not then I guess I'll need to look at manual controls..

oh so the car is sticker material....No cat hey...what will the mrs say

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Originally Posted by Avo

oh so the car is sticker material....No cat hey...what will the mrs say

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It is it is..
She know..
She likes the exhaust.. it sings around town..
Just a touch of a pain on the open road..

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Originally Posted by Avo

oh so the car is sticker material....No cat hey...what will the mrs say

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Yeah my thoughts too. Nice fine if your caught without a cat too.

Yeah I've never understood why folk wouldn't put one back in and risk the sizeable fines, just get a hiflow jobbie so they can tell uncle plod. .... look its got one

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Originally Posted by Clunk

Yeah I've never understood why folk wouldn't put one back in and risk the sizeable fines, just get a hiflow jobbie so they can tell uncle plod. .... look its got one

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Hey it's Westy we're talking about here :)

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Originally Posted by Clunk

Yeah I've never understood why folk wouldn't put one back in and risk the sizeable fines, just get a hiflow jobbie so they can tell uncle plod. .... look its got one

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Yep I had a high flow metallic filled cat when i had the 3ltr. Seemed pretty good to me. Not sure of the power difference it would have been without the cat but it was one thing i didn't want to risk.
I got checked twice in the time i had it by the rta. In the same spot too.
Both times the first thing they looked at was under the car at the exhaust.

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Ok Cat is on its way..
200cpi stainless cat, 4" body and 3" in and out..

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Originally Posted by bigguwesty

Ok Cat is not on its way..
200cpi stainless cat, 4" body and 3" in and out..

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So why tell us if it's not coming?

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Originally Posted by bigguwesty

Unsure on egt as yet to fit gauge..
Water temp doesn't move from the normal 88-90 though..
I can't hear the turbo spooling like I can under power.
Scangauge is reading corrected boost so you may be onto something..

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I'd be fitting some gauges to monitor your EGTs etc before you start all these mods

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Originally Posted by Clunk

So why tell us if it's not coming?

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Lol. Type. Dunno how but it's on its way..

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Originally Posted by threedogs

I'd be fitting some gauges to monitor your EGTs etc before you start all these mods

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Yes should have.. But got to keen. Lol..
Cats going in and gauges too..
All on the way..
Exhaust is done.

Hey did you end up fitting a Dawes or anything to fix your boosting issues or hoping the cat will fix it?


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Originally Posted by Bacho86

Hey did you end up fitting a Dawes or anything to fix your boosting issues or hoping the cat will fix it?


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Hoping the cat will fix the issue..

The cat wont fix your issue. I dont see 20 psi as an issue aswell. If it were 10psi i would.

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Originally Posted by mudski

The cat wont fix your issue. I dont see 20 psi as an issue aswell. If it were 10psi i would.

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It's not really an issue no, but it's not wanted.. happy with stock.
But the cat will assist the lack off back pressure and that has to be only reason why it's over spooling while coasting..
Not sure if it'll fix it or not.. I'm hoping it does but if not then it'll be valves to take control..

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Originally Posted by bigguwesty

It's not really an issue no, but it's not wanted.. happy with stock.
But the cat will assist the lack off back pressure and that has to be only reason why it's over spooling while coasting..
Not sure if it'll fix it or not.. I'm hoping it does but if not then it'll be valves to take control..

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All rite, interested to hear how you go.

Did you ever consider just doing the 2.75" exhaust upgrade?

People seem to have a lot less issues with this on the CRD, but I think only Beaudesert sell them at around $1200, which is close to double what you pay for a eBay 3" exhaust...


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Was there an outcome to this As mine (2012 CRD ) does the same boost climbs to 25 PSI

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Originally Posted by Bacho86

All rite, interested to hear how you go.

Did you ever consider just doing the 2.75" exhaust upgrade?

People seem to have a lot less issues with this on the CRD, but I think only Beaudesert sell them at around $1200, which is close to double what you pay for a eBay 3" exhaust...


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Sorry for the belated reply. I did read it with good intentions but then got side tracked..
No never did consider the 2.75" system purely for the reason you mentioned. .
In my eyes my old td42 had 25 years and over half a million k's on the stock zinc exhaust..
We run oil burners.. so unless your in the salty drink often I can't see the need for stainless..
So yea went the Playtime 3" system.

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Originally Posted by Getaboutabit

Was there an outcome to this As mine (2012 CRD ) does the same boost climbs to 25 PSI

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Yes and no mate..
I have fitted the 200cpi stainless cat which is higher cpi than what Dea and Playtime fit. They only fit 100 cpi ceramic core cats.
But unfortunately it hasn't resolved the issue.. It's made an improvement, I'm only seeing over spool to 20 ish psi not 26 psi. That's on the scangauge reading calculated readings.
But Tillix is on its way soon to rid the issue..

Ok so bit of closure on this. .
Tillix kit was installed to tackle the over boost issue..
Great bit of kit.
Have have completely done away with the stock ecu control but if you wanted to keep it you could simply put the tillix in and 'T' it into the vac line just before the actuator..
Then if you do get the over spool it'll only ever reach the max tillix setting and hold..

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Originally Posted by nissannewby

Boost wont kill it. What are egts like while this is happening?

Is your gauge absolute or is it corrected?

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What does this mean ^^^

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Originally Posted by [IMG

http://www.nissanpatrol.com.au/forums/images/misc/quote_icon.png[/IMG] Originally Posted by nissannewby http://www.nissanpatrol.com.au/forum...post-right.png Boost wont kill it. What are egts like while this is happening?

Is your gauge absolute or is it corrected?


growler2058;695262]What does this mean ^^^

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Absolute refers to MAP (Manifold Absolute Pressure) which is the total pressure in the manifold. This includes the air pressure + the boost. For instance here in Adelaide when I start up the scangauge which is set on MAP it normally displays 14.? psi without the turbo spooling. This is the barometric pressure on the day and can be affected by temp, humidity and altitude so it varies. When I drive off it adds the boost from the turbo and you get the number. Example: Barometric pressure is 14.5psi and turbo is creating 15.5psi the gauge will show 30psi or MAP.

Corrected is the value obtained by removing the barometric pressure and displaying only the pressure supplied by the turbo. A scangauge will show both but the MAP is more accurate as you have to tell it what the barometric pressure is and it just uses that value all the time regardless of altitude, high/low weather patterns etc.

What he said...

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Originally Posted by Rock Trol

Absolute refers to MAP (Manifold Absolute Pressure) which is the total pressure in the manifold. This includes the air pressure + the boost. For instance here in Adelaide when I start up the scangauge which is set on MAP it normally displays 14.? psi without the turbo spooling. This is the barometric pressure on the day and can be affected by temp, humidity and altitude so it varies. When I drive off it adds the boost from the turbo and you get the number. Example: Barometric pressure is 14.5psi and turbo is creating 15.5psi the gauge will show 30psi or MAP.

Corrected is the value obtained by removing the barometric pressure and displaying only the pressure supplied by the turbo. A scangauge will show both but the MAP is more accurate as you have to tell it what the barometric pressure is and it just uses that value all the time regardless of altitude, high/low weather patterns etc.

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Brilliant explanation.
Since having the stand alone boost gauge fitted I have found out the calculated reading can be off by a few psi..
So yes I still had an issue, but it may not have been so bad as originally thought..

So currently my MAP maxes out at 28.9. We'll see what happens when the new exhaust is on

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Originally Posted by growler2058

So currently my MAP maxes out at 28.9. We'll see what happens when the new exhaust is on

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That's 15 psi boost as per stock..
Take it for a cruze mate.
Under power and engine breaking it'll be fine.. But watch the coasting...