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Minimize turbo lag
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=62767		 Page 1 of 1
Author:  quebeccrd [ Thu Sep 22, 2011 10:01 am ]
Post subject:  Minimize turbo lag
Hi everyone,

i wonder if there's something to do/change/replace to minimise the important turbo lag that i experience when flooring my CRD from a complete stop...
It is not a new problem nor it's getting worst, but i was wondering if every crd owner war experiencing this as well.

does the samco's improve that?

i have the gde eco.

thanks!
Author:  Joe Romas [ Thu Sep 22, 2011 6:04 pm ]
Post subject:  Re: Minimize turbo lag
If what your talking about lasts more then one second it's not turbo lag :SOMBRERO:

After the last post asking about turbo lag I ran some errands and tested just how long it takes a properly running CRD, mine, to haul a@# :mrgreen: From a dead stop it was consistantly less then one second. My CRD has a GDE Full Torque Eco tune and a lift pump and stock exhaust.
So what is it? Most likely air in the fuel :JEEPIN:
When new mine was very sluggish off the line and the delay varied in time and it was unsafe to drive in heavy traffic. I cured that with a in tank lift pump :D
Author:  audiboy86 [ Thu Sep 22, 2011 6:43 pm ]
Post subject:  Re: Minimize turbo lag
Try a Racor filters set up first it solved my air in fuel problem. Also cheaper and easier to install and if is solves it no need to have to drop the tank and fuel lines. That is how I solved my issues.
Author:  warp2diesel [ Thu Sep 22, 2011 8:11 pm ]
Post subject:  Re: Minimize turbo lag
audiboy86 wrote:
Try a Racor filters set up first it solved my air in fuel problem. Also cheaper and easier to install and if is solves it no need to have to drop the tank and fuel lines. That is how I solved my issues.

After doing what Joe & addiboy86 recommend, open up the restrictions in the Exhaust. The flange behind the CAT that is only 2 1/8" and the crappy stock muffler is also a big restriction. Go 2 1/2" all the way back, your back pressure will drop to zero and your turbo will spool up faster.
Author:  06CRD [ Fri Sep 23, 2011 9:39 pm ]
Post subject:  Minimize turbo lag
Joe Romas wrote:
If what your talking about lasts more then one second it's not turbo lag :SOMBRERO:

After the last post asking about turbo lag I ran some errands and tested just how long it takes a properly running CRD, mine, to haul a@# :mrgreen: From a dead stop it was consistantly less then one second. My CRD has a GDE Full Torque Eco tune and a lift pump and stock exhaust.
So what is it? Most likely air in the fuel :JEEPIN:
When new mine was very sluggish off the line and the delay varied in time and it was unsafe to drive in heavy traffic. I cured that with a in tank lift pump :D


What kind of lift pump do you have? Is it necessary or useful for the hot tune to keep the rail full of fuel?
Author:  audiboy86 [ Sat Sep 24, 2011 10:28 am ]
Post subject:  Re: Minimize turbo lag
Well the fuel pump runs for a short period just to fill the filter before cutting off. The CP3 fuel pump attached to the motor acttually keeps fuel in the rail. But if there is air in the system anywhere then the CP3 pump sucks it up and the motor injects it just like it would fuel. Causing a delay in power which is probably what you are feeling.

Which brings me to my point that somewhere in your system you are getting air. It is and extremely common problem ussually starting at the heater port on the filter head. So if that is your problem a secondary fuel pump can just make it worse.
Author:  quebeccrd [ Sun Sep 25, 2011 1:09 pm ]
Post subject:  Re: Minimize turbo lag
ok thanks everyone,

maybe my turbo lag is normal...

i'll try to film an acceleration from 0 to show you so you can tell if your crd do the same...

thanks!
Author:  CATCRD [ Sun Sep 25, 2011 1:27 pm ]
Post subject:  Re: Minimize turbo lag
Turbo lag is normal. And a lift pump runs continuously as long as the engine is on, if you wired its power source to the fuel priming pump relay underhood.
Author:  geordi [ Sun Sep 25, 2011 10:15 pm ]
Post subject:  Re: Minimize turbo lag
If you don't start the engine (and you wired it to the fuel pump relay) the pump will be shut off after a few seconds of operation. I think its like 10 seconds or so.

A video would be helpful, I'd be curious if yours is behaving like my brand-new-turbo unit, which from the day I bought it, has had a very bad sticking problem. From anything at or under 20mph, if you apply throttle (doesn't matter how much)... The boost will rise slowly (maybe 2-3 seconds to get to 18psi)... And the acceleration will feel VERY sluggish. You will also be fogging the road behind you with dark smoke.

If, however, you put your foot into it and count to one... Release the pedal, and immediately go back into it - Full acceleration and no obvious smoke.

Another trick it does is similar to what I already described, but it will sometimes "magically release" once the boost gets to about 18psi and the Jeep will shoot forward while the boost spikes FAST to 26/27 psi.

I know this isn't good for the turbo, and is one of the prime reasons I believe this design is too close to its limits for our application. This behavior isn't good, but those boost spikes are beyond the safe limit of the turbo itself. That shouldn't be allowed, the design should have had a higher upper limit.
Author:  StanCRD [ Fri Sep 30, 2011 8:29 pm ]
Post subject:  Re: Minimize turbo lag
If I floor it in mine, there is serious lag. I do notice that if my fuel tank is full, the response is much better and if I want accelerate quickly from a dead stop, I have to apply progressive pressure to the throttle. So since we are only controlling fuel flow and not air I believe it is mostly a fuel delivery problem since we have to rely on vacuum.

I think installing a "lift" pump so we don't have to rely on vacuum would improve this. I'm sure lowering exhaust restriction will help too. My 2 cents based on experience and reading many articles on turbo performance.

If you are trying to race someone at a light, turn off you traction control and start spooling up the turbo while still on the brake, that should help immensely.
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