GU Turbo thingey

Hi all,

Now I’ve had the new bus (09 GU) a couple of months I’m starting to learn how to drive it. Bit of a change from a GQ TB42E auto to the 3L turbo manual. These gear change things catch me out every now and then :). Been re-introduced to the bunny hop and had a few stalls here and there… Like I’m on my L plates all over again!

Just got a couple of Q’s regarding other ppls 3L’s out there…

Wondering on how early the turbo should spool up. I’m not feeling it come in until about 2500 rpm, and getting good boost at about 3k. This seems too high. Changing gear at 3k plus doesn’t seem right for a diesel. I thought these things were good for low end grunt without revving the t*ts off it !

I’ve got the NADS gear fitted. Haven’t played with anything there yet, but I feel some adjustment needs to happen. Freeway driving at 100km in 5th gear, EGT sits pretty stable at around 500 deg, with around 8-10psi boost. (with 4 adults, 2 small kids and 3 light suitcases on the roof rack). This seems high as well, reading other guys specs. The highest I saw it was just below 600deg, on an incline. Boost generally doesn’t go over about 15-16PSI. Low rev’s are just painful in any gear except first.

Can anyone offer any opinion on whether that’s all normal. Am I expecting too much from it?

My Missus has a 2l turbo diesel in her Hyundai IX35, auto of course, but the take-off in that is instantaneous and the thing goes like a rocket from go to whoa, no turbo lag at all. Of course there are size and weight differences between the 2 vehicles, but I feel like I should get more out of the patrol. Clearly it ain’t no race car and I accept that as well..

Any opinions/discussion welcome :)

Cheers and have a happy father’s day all
Simon

Simon,

How low do you call low, in terms of Revs .....

Even my old Turbo 4.2 Diesel didn't particularly like taking off from 800 Revs in Top Gear after dribbling through town ( although it would do it )

The Auto would never ever let the engine get so low, so you don't notice in the Auto....

My CRD is good from around 1800 rpm usually. I roughly drive in the 1500 - 3300 rev band ... no need to go more or less to get where you need if you are in the right gear

I'd try winding in your needle valve a little bit until your boost is 10-12psi at 100

Put a few more psi of boost in it as your EGTs suggest not enough.
Do you have a needle valve fitted.
Also you could go and get a dyno to sort it out

Hey mate, ive only re ently fitted the nads kit to my 08 patrol. Goes heaps better egts at 100ks are 400 and ery stable. Full boost on mine is at 2200 rpm and max is 16 psi. It pulls hard from low down in the rev range. Took a little bit of fiddling of the needle valve to get it spot on.

Thanks Happy,

I'd expect similar performance to your CRD I would think. Do you 'feel' the turbo coming onto boost or do you have a smooth power delivery through that rev range ?
I'd be happier to have more power/pickup at 1800 RPM than 2800...

I wouldn't even try to pull away at 800 RPM in 5th. I'm sure it would do it eventually, but EGT would go through the roof and I reckon I'd run out of road first :)

Simon

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Originally Posted by happygu

Simon,

How low do you call low, in terms of Revs .....

Even my old Turbo 4.2 Diesel didn't particularly like taking off from 800 Revs in Top Gear after dribbling through town ( although it would do it )

The Auto would never ever let the engine get so low, so you don't notice in the Auto....

My CRD is good from around 1800 rpm usually. I roughly drive in the 1500 - 3300 rev band ... no need to go more or less to get where you need if you are in the right gear

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Thanks Telstra,

Looks like a bit of fiddling is due :) Your specs are more what I'd be expecting...

I've got a Needle valve under the bonnet and I think a Dawes valve adjustment in the cabin. All NADS stuff was already installed when I bought the vehicle. (Catch can, dawes & needle valve, EGT & Boost guages, EGR blank)
I understand the Dawes valve (If I am naming it correctly) controls max boost, and the needle valve controls turbo spool up rate ?

I'll have to get out and have a look.
Dyno is certainly an attractive option.
Does anyone know of a reputable 'Patrol whisperer' on the north side of Perth anywhere ?

Cheers for the replies all.

Simon

Quote:

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Originally Posted by Ex telstra truck

Hey mate, ive only re ently fitted the nads kit to my 08 patrol. Goes heaps better egts at 100ks are 400 and ery stable. Full boost on mine is at 2200 rpm and max is 16 psi. It pulls hard from low down in the rev range. Took a little bit of fiddling of the needle valve to get it spot on.

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Quote:

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Originally Posted by Lambroast

Thanks Happy,

I'd expect similar performance to your CRD I would think. Do you 'feel' the turbo coming onto boost or do you have a smooth power delivery through that rev range ?
I'd be happier to have more power/pickup at 1800 RPM than 2800...

I wouldn't even try to pull away at 800 RPM in 5th. I'm sure it would do it eventually, but EGT would go through the roof and I reckon I'd run out of road first :)

Simon

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Simon,

Yes, yours should be the same. I have now had 2 CRD's, and both have been identical.

You don't really feel the Turbo 'hit' at 1800 - it is more that the power feeds on smoothly. I guess the best way to describe it, is that under that at 1200prm, you push the accelerator pedal, and it can take off slowly or in a manner that is not entirely predictable ( sometimes slower than others due to load, incline, temperature, etc - sometimes faster like a V8:wink:), but when it gets to 1800, it is then always fairly predicable, and will take off with the same acceleration curve, as it is then in its best power range for the engine

Mic

If you have a valve inside the cab i would have thought it would be the needle valve rather than the dawes.

Simon,'

I just took mine out for a drive, and actually had a careful look at what I was doing, and I only use 1800 - 3300 rpm for acceleration away from the lights....

For the rest of the time I was cruising along at around 1400 - 1500 rpm and the truck would cruise along just fine at those revs, even in fifth gear, at 60 K's

Mic

Needle valve would be in the cab, not the dawes. I would increase your max boost more via dawes, and then wind in the needle valve a little more to increase spool up. Just remember. If you raise the dawes pressure and dont adjust the needle valve to suit your spool up will be slower. The two adjustments are relative to each other.

Awesome replies guys, thanks very much.

I'm away at work at the moment so can't play with the car till Saturday.
Will have a bit of a fiddle then.
Still learning the new beast and looks like I will be for a while yet :)

Cheers

Simon

Ive got mine set for a smooth power delivery pulls quite hard for a big heavy truck. My boost is at 15 psi at 2200.and by 3000 it has hit 16psi. Every car is different. You will know when you get the sweet spot. When i was setting it up it was adjust and drive. I found setting the dawes valve for max boost 1st, got that set and then just keep opening up the needle valve in small increments at 80ks my egts are at 220 and on long climbs it gets to 420 and thats under full boost. I do ha e a 3" exhaust and a snorkel and fuel consumption is around 13lph. Hope this helps