2LT maximum turbo boost? (1 Viewer)

Joined
Mar 29, 2009
Messages
17
Hi! I'm planning to get a boost guage for my 2LT. What is the normal turbo boost of an stock 2LT (unmodified turbo)? And what is the maximum boost you can do with a 2LT? Need to decide which guage to get (15psi or 30psi)? Thanks!
 
Joined
Oct 15, 2005
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Malaysia, Kuala Lumpur
Between 7-10PSI I would not boost it any more unless you wanna break your wallet and be stuck in places you did not expect to be with a DEAD 2LT.

I would only buy a gauge to 15PSI and I would buy a EGT gauge and install that before a BOOST gauge and drive of the EGT readings.

However I may be wrong but im sure CRushers will have something to say about his favourite engine..
 

Gun Runner 5

KI4CMQ
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Oct 22, 2009
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Thomasville, GA
The previous owner of my LJ78 had the turbo rebuilt and the boost increased to approximately 16 psi without increasing the fuel imput. I personally would not do anything before I installed a good quality pyrometer. You will be shocked how hot the turbo will get when the engine is under a load. As you probably already know the 2L-TE is an engine that needs to be treated very gently. Hope that helps..............................1978HJ45
 
Joined
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Location
Alberta
Hey Marco,

I also recommend installing a pyrometer if you do not have one already before you touch the boost. Wayne actually has a post about boost on a 2LTE... I think he said 12 psi without touching the fuel.

there is a thread posted recently of step by step guide to increase boost too if you want to take a look at that.
 
Joined
Dec 8, 2009
Messages
720
Location
Kuantan, Malaysia.
Max recommended boost is 12 to 13 psi.
Use of intercooler is recommended.
Boost control.
Upgrade the spring in the fuel pump and overhaul the injectors.


To be honest I would not bother. Upgrade the engine to a 3.0 or more if you want more power.

Had a 2LT in my LJ70........should not have bothered with it, spent a load on boost etc.......6 months later chucked the 2LT.
 
Joined
Apr 14, 2007
Messages
228
Location
Gibsons B.C
The factory boost is set around 7-8lbs. If I push the boost on my 2lte past 14lbs the check engine light will come on telling the ecu that there is a over boost problem and it will feel like some one pulled on the e brake (loss of power). Once the boost is under 14lbs the light turns off and all is fine. I run 16 lbs in mine. I haven't been able to kill it by over boosting or pushing it hard. As long as you drive it by you egt's and do proper maintenance, it should last. If there is no intercooler on it I would recommend a max boost of 9-12lbs. The reason is that the more boost you create brings a very hot charge. If the charged is not cooled down you are defeating your purpose of running high boost. There seems to be misleading info on that if you increase your boost only the boost will increase, not the fuel. Completely wrong on the 2lte. The fuel trim and management is based off the boost sensors input of boost. The more boost you add the more fuel will be added until the ecu has reached it's max amount of compensation then the check engine light comes on and and there is a power loss until the boost is back within the ecu's ability to control the fuel again. I'am able to run 16 lbs of boost because my ecu thinks it's only 13lbs at max boost. This helps tons in the egt's because I am truley adding boost not fuel. If your looking for a major power increase for the 2lte, there is no such thing. Adding a few pounds of boost will wake it up a bit. This is all based on the 2lte not the 2lt. They seem to get confused a lot. For the 2lt this dose not apply.

Take Care.
 
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Joined
Apr 6, 2017
Messages
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Location
British Columbia, Canada
That kinda sounds like why mine won't run. Green light comes on starts boosting . But if u are heavy on the pedal or going up a hill it falls flat on it's face. Kinda irrelevant but can someone help me out i just bought the truck and joined the forum. Drove the truck for a hour so far. The rest of the time it's been in the shop and they haven't come up with anything besides it happens when it's hot . Tried swapping sensors and even the ecu with no chanhe
 

GTSSportCoupe

2LTE abuser
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That kinda sounds like why mine won't run. Green light comes on starts boosting . But if u are heavy on the pedal or going up a hill it falls flat on it's face. Kinda irrelevant but can someone help me out i just bought the truck and joined the forum. Drove the truck for a hour so far. The rest of the time it's been in the shop and they haven't come up with anything besides it happens when it's hot . Tried swapping sensors and even the ecu with no chanhe

Do you have a boost gauge? If so, is the turbo boosting over 14psi? If it is, this is definitely your problem. The fuel cut is very abrupt and noticeable. The behavior you described in your other post with regard to the turbo light going off and check engine light coming on makes this almost 100% certain.

Perhaps someone put a boost controller on your turbocharger to increase the boost? If not, it could be that your waste gate has failed, is not connected, has been modified, etc. The waste gate is what controls the turbo boost level by allowing exhaust gases to bypass the turbine.

Post a picture of your engine bay; specifically the area on the turbo side of your engine, and we can help identify if there are any obvious problems.

I recommend you install a boost gauge regardless if you don't have one. T in to the vacuum line that comes out below the throttle body, as this will give you accurate manifold pressure.

It will happen more often when hot, because hot air produces higher boost (air expands when hot).

It really surprises me how much difficulty auto shops have dealing with these motors. They are very simple really. Checking for an over boosting condition on a turbo engine should be dead easy for a shop.

Where are you located? BC is a big place.... there are lots of us around the province, maybe someone local to you can give you some more ideas.
 
Last edited:
Joined
Apr 6, 2017
Messages
19
Location
British Columbia, Canada
Do you have a boost gauge? If so, is the turbo boosting over 14psi? If it is, this is definitely your problem. The fuel cut is very abrupt and noticeable. The behavior you described in your other post with regard to the turbo light going off and check engine light coming on makes this almost 100% certain.

Perhaps someone put a boost controller on your turbocharger to increase the boost? If not, it could be that your waste gate has failed, is not connected, has been modified, etc. The waste gate is what controls the turbo boost level by allowing exhaust gases to bypass the turbine.

Post a picture of your engine bay; specifically the area on the turbo side of your engine, and we can help identify if there are any obvious problems.

I recommend you install a boost gauge regardless if you don't have one. T in to the vacuum line that comes out below the throttle body, as this will give you accurate manifold pressure.

It will happen more often when hot, because hot air produces higher boost (air expands when hot).

It really surprises me how much difficulty auto shops have dealing with these motors. They are very simple really. Checking for an over boosting condition on a turbo engine should be dead easy for a shop.

Where are you located? BC is a big place.... there are lots of us around the province, maybe someone local to you can give you some more ideas.

Just got the truck back today will take pics tomorrow. He had a boost gauge hooked up on test drives and said it was making 10psi then dropping off under load. I was also wondering if the cts is supposed to have the same plug as the crank sensor .square hole with a notch . I went to lordco with the part number I got from the mechanic and it came up with a completely different looking plug. With 2 prongs. Is it possible to have them switched?
I'll have to take a look tomorrow. I'm also on Vancouver island
 

GTSSportCoupe

2LTE abuser
Joined
Mar 23, 2012
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Victoria, BC, Canada
Just got the truck back today will take pics tomorrow. He had a boost gauge hooked up on test drives and said it was making 10psi then dropping off under load. I was also wondering if the cts is supposed to have the same plug as the crank sensor .square hole with a notch . I went to lordco with the part number I got from the mechanic and it came up with a completely different looking plug. With 2 prongs. Is it possible to have them switched?
I'll have to take a look tomorrow. I'm also on Vancouver island

I'm not sure which sensor you mean by CTS.

Good that he was using a boost gauge. I guess the problem is not so simple then.

Have you guys pulled the codes out of the computer? Any time a check engine light comes on, it stores a code identifying the problem. It is possible to pull these codes by putting a jumper in the diagnostic connector and watching the check engine LED blink a pattern.

If you are in Victoria I can help you with this part. (Assuming the mechanic doesn't know how...). Or if you are somewhere else on VI, then I can describe the procedure to you.
 
Joined
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British Columbia, Canada
I'm not sure which sensor you mean by CTS.

Good that he was using a boost gauge. I guess the problem is not so simple then.

Have you guys pulled the codes out of the computer? Any time a check engine light comes on, it stores a code identifying the problem. It is possible to pull these codes by putting a jumper in the diagnostic connector and watching the check engine LED blink a pattern.

If you are in Victoria I can help you with this part. (Assuming the mechanic doesn't know how...). Or if you are somewhere else on VI, then I can describe the procedure to you.
I'm in Duncan so I can try and get the codes off of it i found a plug not connected that comes off the sensor he told me yo check. But it's got a plastic cover that it's plugged into but not anything else I'll see if I can post a picture

14916732744131087520543.jpg
 
Joined
Apr 6, 2017
Messages
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Location
British Columbia, Canada
This is the plug he said was the coolant temp sensor. But part number came up as a different looking sensor. And by matching it by what it looks like it is the same as the crank sensor

14916737567531938161289.jpg
 

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