Turbo Lag.

[Steve4wdin]

What can be done to reduce turbo lag in 3lt crd? I have put a 3" s/s turbo back exhaust and dieselsmart module. The turbo doesn`t spool up till 2200rpm and that is a pain when starting off. The other day I was coming home with camper trailer in tow, and had to put the snail/trol in low range to get up a hill on bitchaman.

[threedogs]

I've fitted a DAWES valve and Needle valve ,found it a touch nippier off the mark, forever leaving traffic behind.
You may need to fit guages EGTs and boost to allow you to adjust things and know whats happening.
Even a EGR blanking plate?


Somethings not right

[Steve4wdin]

I've fitted a DAWES valve and Needle valve ,found it a touch nippier off the mark, forever leaving traffic behind.
You may need to fit guages EGTs and boost to allow you to adjust things and know whats happening.
Even a EGR blanking plate?


Somethings not right

Thanks 3D, with the module it has a boost control within it that limits the boost whitch is the same as a dawes and needle. Can it be wastgate issues?

[nipagu7]

HI steve4wdin . I think the boost control on your module only works on the car computer whereas a dawes and needle valve takes control of boost away from the computer and allows you to control it manually . I don,t think you have a wastegate their normally found on petrol engines . Did you fit the exhaust and module your self or have it fitted , I think you probbably need to have the car dynoed to tune the module to your engine and exhaust properly.

[Steve4wdin]

HI steve4wdin . I think the boost control on your module only works on the car computer whereas a dawes and needle valve takes control of boost away from the computer and allows you to control it manually . I don,t think you have a wastegate their normally found on petrol engines . Did you fit the exhaust and module your self or have it fitted , I think you probbably need to have the car dynoed to tune the module to your engine and exhaust properly.

Thanks, I thought wastegates were only on petrols but a mate said different. No stupid blow off valves on diesels. The boost control is incorperated in the module not the ecu. Yes the trol has been dynoed 3 times now.

[nipagu7]

This seems odd as normally when a car has larger exhaust and module fitted the turbo spools up earlier and this should have been seen on the dyno when being tuned , and the problem diagnosed at the time . do you have dyno readouts . if so it should obvious at what rpm,s the turbo spooled up.

[nissannewby]

All turbos have a waste gate whether petrol or diesel. It can be done but you wont see blow off valves on a turbo diesel very often at all. There maybe an adjustment for your vnt or you could possibly have a leak on the control circuit for you vnt which can cause issues

[the evil twin]

All turbos have a waste gate whether petrol or diesel.

Nah, not quite right there, Cobber.

If you can show me the waste gate on a VNT turbo (as fitted to the ZD30's factory) I'll buy the first carton if you let me help drink it

[nissannewby]

You are correct. The VNT (VGT) turbos are still controlled by the exhaust and dont have a wastegate. By going on how the VNT works its as if your turbo isnt working correctly its as if the variable fins are wide open all the time meaning you are getting down low boost.

[boots]

Steve what intercooler do you have fitted mate ? factory or aftermarket ? cause if its leaking that may be your issue . not turbo lag as such . just a thought .

[Steve4wdin]

Guys, appreciate your help, The trol is a 2011 3lt crd with 10000ks on it. The only thing I have done to it is 3" exhaust and module. From 2200rpm when turbo spools up it is a weapon especially with the module. Highway and towing is great. Just low revs it frustrates the sh.t out of me. Could it be to big an exhaust? Have I taken away all the back presure?

[Robo]

Is it possible mufflers are blocked? one idea stopping spool up.
Faulty waste gate another

It sound slow to spool as you say, I'm no expert on diesel so I'll stay out of that.
Waste gate is for the exhaust system do rid it self of un wanted pressure on the turbo and allow it to dump exhaust when you lift the go peddle.
Blow off valve (bov) is the same idea for the air intake system (after turbo), not only does it relief inlet pressure , it also reduces back pressure on the turbo and allows it to keep spinning freely it has many advantages over no bov.
Low "turbo" pressure diesel motors may not benefit alot from a bov , but up the pressure and they would and its not all that expensive to do.

[Steve4wdin]

I have had fitted high flow cat with the exhaust, and new muffler. It can`t be that. Is 3" exhaust to big?

[WogsRus]

WOW, mine makes full boost at 1400rpm, that is 15psi as stock, no mods what so ever. 18 psi is only seen while cruseing

[Lieney]

I agree that petrol engine turbo's have a waste gate; however, disagree that all turbo's do. VNT exempt
In my case I have seen several turbo's on various diesel engines over past 15 years that do not have a waste gate at all.
If ya got a chip and 3" pipe it should spool quicker.
Mine (although not CRD) kicked in about 2000-2200, now about 1300ish with the addition of a 3".
I found the vanes or actuator sticking and causing issues, along with oil leaks. New turbo solved that issue and was smooth.
I illiminated my lag today, that has been $hitting me to tears since I bought the car.
I used a cable-tie to keep the butterfly open that sits in the inlet manifold. This aparently helps in overboosting. Also as I found out, caused me a lot of lag.
I also dropped my boost to 15psi and found a dramatic difference immediately.
Although I have zip-tied this butterfly valve, I did this for other reasons, but I go the result I was after and my car is running sweeeet and no overboosting as dawes valve
I would not advise using a zip-tie to keep the butterfly open if you have no decent boost limiting device.
Get an EGT & boost gauge if you fiddle, as it could cost ya

[Robo]

Think you can rule out the exhaust being the problem if its all new.
Turbo's need flow and that comes with little as possible restriction.
To big as you put it is only going to help turbo spin up.
Small pipes restrict flow and turbo as well
Agree, no not all turbo's including petrol have a waste gate built into them.
There are quit a few external waste gate turbo on the market, but getting side tracked.
Something is defiantly hobbling your engine.
Sorry I cant help more.

[BigRAWesty]

Is it simple a faulty turbo?
Maybe it could be replaced under warranty..


Sent from a device which doesn't always agree with my thumbs...

[Robo]

I take it new cat was after new exhaust ? .
Trying to fix the spooling problem.
Question
How was it before the new exhaust was fitted ?.

[mudski]

Do you have a snorkel fitted? Sound to me a flow issue. Take the air filter out and take the car for a quick spin to see if there is a difference. This might tell you if its an intake problem. Also check all you hoses, vacuum and boost. 3inch is not too big IMO, plus you don't want back pressure, you want a free flowing exhaust. Well, a free flowing system from intake to exhaust...

[WogsRus]

CORRECTION, Nissan patrol 3.0L DID or CRD turbos so not run a wast-gate, never have and never will. Boost is controlled via a VNT adjustment as for 99% of diesels.

[Steve200b]

Boost leak poor flowing exhaust? I would drop the exhaust off before the cat and take it for a run to eliminate that then check for a boost leak.

[Steve4wdin]

Hi guys thanks for all your input and help. I have a snorkel fitted by ARB, The exhaust from turbo back is brand new, including high flow cat and new muffler. I`m sure its not the intake or exhaust so it is either hose leak or turbo. When I find some thing I`ll pass on.
Regards Steve

[Steve200b]

I have had a cat block in two weeks from a poor tune

[kingy]

For shits and giggles can you turn off/remove the chip your turbo I would of thought would spool earlier I have DI and with the 3" exhaust it actually caused mine to spool a couple of hundred RPM earlier went about 1700 ish to 1500 ish and impreove low torque and having to engage low range to get up a hill should not happen.

Cheers

[Robo]

I know I wrote your new system may not be the prob.
I was thinking you would've looked into this.
in hindsight maybe not, so here goes.

Some mufflers design & construction can still restrict a system.
Had this myself on new larger/improved system,(non turbo).
system had miss-matched pipes from extractors back 2 1/4 and 2 1/2 pipes.
had this all replaced with new 2 1/2 from extractors back
Suddenly lost torque across the entire rev range.
Proberly a drop off of at-least 20%.
Ended up being Hobbled by the new muffler.
What a disappointment going backwards.

[Steve4wdin]

Well I think I have finally resolved the turbo lag. Long story short or maybe not??? I adjusted the screw on the turbo to the vacumm. I turned it 1/3 of a turn out. I also found some body has fiddled with this. One of the oem nuts that hold the vacumm bowl in place was sitting on the frame wedged in a pipe and a normal nut fitted in its place. Hose clamps going to intercoller have been damaged and were loose. Bloody Nissan. But why? Any way, I have now got low down torque and use less pedal. It seems smooth right from start, and will pull from 1200rpm. I am 1000rpm better off. Can't wait to hook the camper trailer up and test on a couple of hills.
Thanks everyone for your help. A great forum for sure. I hope this makes sense.
Steve