Reducing 2lte egt's (1 Viewer)

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Joined
Apr 14, 2007
Threads
8
Messages
228
Location
Gibsons B.C
I have been playing around with a mechanical way of reducing egt's. Simple and effective, non electronic bleed off valve that should give years of good service. I have been testing it for month's now and seems all is OK. It's really simple and cost efficient. The threoy is to bleed off boost so that the boost psi that is sent to the boost sensor is less the the actual boost being produced by the turbo. The computer reads boost pressure through the boost sensor and adds fuel accordingly. More boost, and the computer thinking there has been no change in boost, equals lower egt's.
A short shopping list:

- A boost controller (for the turbo to increase boost)
- An air ram speed controller (that can be adjusted and lockable)
- A few vacuum tee's and vacuum hose
- A one way vacuum check valve ( I don't think it was necessary but made one anyways because the 2lte has a throttle plate and under engine braking creates vacuum.)
- cheap fuel pressure/vacuum gauge good to 15psi.

The total for the materials for me was around $100.00.
I installed my aftermarket boost gauge on the boost sensor vacuum line before the factory check valve (not a real check valve just helps to stop fluttering to the boost sensor). After the factory check valve goes the bleed off valve wit a one way check valve. The vacuum line continues to the boost sensor and right before the boost sensor i put a tee to the aux boost gauge (princess auto had a low pressure psi gauge for cheap). Now I cold see actual turbo boost pressure and the boost pressure the computer thinks I have.
A benefit to this system is that it is progressive. At 2.5 psi it is almost equal between actual boost and what the computer thinks.
at 5 psi the computer thinks it's 4psi. At 10 psi the computer thinks it is 8 psi and at full boost of 15 psi the computer thinks it's 12 psi. The bleed off valve (air air ram speed controller) can be adjusted to almost anything you want. After the system was installed, I returned the aftermarket boost sensor to the boost vacuum line right before the boost sensor. It reads less boost then what is really being made but is all relevant because if there is a problem the boost will change alerting me. On the progressive scale I have done, I have seen a drop of about 150 degrees Fahrenheit in egts. This is not the golden answer to the 2lte's problems but it sure helps.

Take care.
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did you use a manual boost controller or Electric?

pradocruzer has not been on the forums in a long time. However I'm pretty certain he was using a MBC. That's what I'm using also, and it works fine. Just buy an ebay one for $20-30 or so.
 
pradocruzer has not been on the forums in a long time. However I'm pretty certain he was using a MBC. That's what I'm using also, and it works fine. Just buy an ebay one for $20-30 or so.

Hey GTS, i don't mean to bring up a dead forum thread for you, however I'm reading some conflicting information. Thought about PMing you, but you've mentioned you like keeping technical discussions to the forums so other people can glean from them as well. My rig is currently parked, and i plan on overhauling the entire thing before it gets back on the road, going to be doing everything possible to keep EGT's down.

I found this thread through a post you made on another forum, to quote you, "The 2lte runs too rich from factory, which creates dangerous EGTs and wastes fuel. An easy way to trick the computer to add less fuel is here: http://forum.ih8mud.com/70-series-te...2lte-egts.html I've done this and it works great. My truck barely smokes and makes good power.".

This was about 9 years ago, and just by reading your posts on the 2LTE it seems like you've slowly been perfecting it, so I'm thinking that you've since learned that this isn't the case? You've mentioned on various other threads that you shouldn't be needing a bleeder valve unless you start turning up the boost significantly, and in a discussion we have had, you've stated "The bleed valve is only needed if you exceed 15 psi.".

I plan on turning up the boost to around 11-14 , without touching the fuel, as it looks like the additional pressure helps reducing EGT's. So if i was to make sense of this, a stock 2lte is already running rich from the factory, so to even out the air/fuel mixture, i could either reduce fuel consumption through the bleeder, or increase the boost?
 
I know very little about the 2LTE but I would say that without the bleed valve, 1 of 2 things will happen

1) up to a certain point, the ECU may increase fuel with increased boost. This won't reduce EGTs

2) above a certain threshold, the ECU will cut fuel thinking it is boosting beyond the factory limit.
 
Hey GTS, i don't mean to bring up a dead forum thread for you, however I'm reading some conflicting information. Thought about PMing you, but you've mentioned you like keeping technical discussions to the forums so other people can glean from them as well. My rig is currently parked, and i plan on overhauling the entire thing before it gets back on the road, going to be doing everything possible to keep EGT's down.

I found this thread through a post you made on another forum, to quote you, "The 2lte runs too rich from factory, which creates dangerous EGTs and wastes fuel. An easy way to trick the computer to add less fuel is here: http://forum.ih8mud.com/70-series-te...2lte-egts.html I've done this and it works great. My truck barely smokes and makes good power.".

This was about 9 years ago, and just by reading your posts on the 2LTE it seems like you've slowly been perfecting it, so I'm thinking that you've since learned that this isn't the case? You've mentioned on various other threads that you shouldn't be needing a bleeder valve unless you start turning up the boost significantly, and in a discussion we have had, you've stated "The bleed valve is only needed if you exceed 15 psi.".

I plan on turning up the boost to around 11-14 , without touching the fuel, as it looks like the additional pressure helps reducing EGT's. So if i was to make sense of this, a stock 2lte is already running rich from the factory, so to even out the air/fuel mixture, i could either reduce fuel consumption through the bleeder, or increase the boost

Hey Jemjem, I saw your other thread, and have been meaning to comment. Had a serious medical issue (not covid) and been in/out of hospital the last few days, so am a bit behind on life. Sorry to hear of your problems, and I'll take a close look at what happened to your motor and see if I have anything more to offer over what the other guys were saying.

Do you have a pyrometer on your truck, I forget?

Basically, these motors completely stock do run a bit hot/rich. I first installed my pyrometer post turbo on my engine when it was totally stock. I would see 1100F easily on a mild temp day on a mild hill not loaded or towing or anything. That is high!

So on a stock motor, an easy way to reduce those EGT's and keep things a bit safer, is raise the boost to 12psi or so, and use the bleed valve thingy to trick the ECU to add less fuel with boost. Without re-reading this whole thread, I'm pretty sure that is what pradocruzer was doing.

Now, once these motors are opened up a bit so they can breath (free flow exhaust, removal of emissions stuff and throttle plate), and an intercooler is added, things change, and the purpose of the bleed valve changes. When I did these upgrades to my motor, my EGT's dropped by at least 400F worst case. Also, the intercooler cooled the air from the turbo so much, I was able to run as much boost as I wanted.

At 17-19psi (post intercooler), I was now able to add as much fuel as I possibly could, and still run safe EGTs under even worst case conditions (for example towing my camper in summer up a long grade). The main purpose of the bleed valve at this point, is to keep the ECU from going into fuel cut. Most Toyota turbo/supercharged engine ECU's of the 90's have a drastic fuel cut around 14.7psi or so. In the case of the 2LTE, it starts reducing fuel from about 10psi even, and goes into an error mode (check engine light) fuel cut at 14.7psi. So the point of the bleed valve is to lower the boost curve just enough to trick the ECU into giving full fuel even at much higher boost.

It takes a bit to get the valve tweaked perfectly, but once it is, the motor makes great power. Like a completely different thing than it is stock. I've made up to 165hp at the flywheel (albeit with water/meth system on also). Typically it puts down about 225 ft-lb @ 2400rpm and 125 hp @ 3400rpm (to the wheels with torque converter out of lock-up!). That sort of power makes the LJ78 move great. The lighter LN130 would go awesome with the same upgrades! That power might not seem like much, but in comparison, a stock 2LTE puts about 50hp to the rear wheels. A stock 1HZ about 65hp to the wheels. Stock 1HDT about 100hp to the wheels. Etc.

Hope that helps. Feel free to ask more questions.
 
Best of wishes and I'm hoping all of your medical issues work out. Without you around to help the 2lte owners keep their rigs alive we'll be seeing a lot more blown up engines being parted out.

Yea that definitely helps me understand the system a bit more. So even with the increased air flow a RAM based snorkel, 2.5" exhaust, and 11-14psi of boost, the engine gives more than enough fuel (Even after cutting it down past 10psi) to not require a bleed valve or fuel adjustment? Once i get everything upgraded and setup, i think i might play around with it a bit and run the turbo controller and the bleed valve into the truck, and play around with different settings on the fly and see what kind of EGT's i get.

Once i figure out my tires/gearing situation, and the upgrades done, i'm inclined to get a dyno to see what kind of power i'm pushing out. You've mentioned you have used a phone app before which might work out as well.
 
Best of wishes and I'm hoping all of your medical issues work out. Without you around to help the 2lte owners keep their rigs alive we'll be seeing a lot more blown up engines being parted out.

Yea that definitely helps me understand the system a bit more. So even with the increased air flow a RAM based snorkel, 2.5" exhaust, and 11-14psi of boost, the engine gives more than enough fuel (Even after cutting it down past 10psi) to not require a bleed valve or fuel adjustment? Once i get everything upgraded and setup, i think i might play around with it a bit and run the turbo controller and the bleed valve into the truck, and play around with different settings on the fly and see what kind of EGT's i get.

Once i figure out my tires/gearing situation, and the upgrades done, i'm inclined to get a dyno to see what kind of power i'm pushing out. You've mentioned you have used a phone app before which might work out as well.

Really, each truck and engine will be a bit different. Also, your intended use will be different too. At the end of the day, it comes down to EGT's and coolant temps. Just run the engine as hard as you think is safe. Remove fuel to run cooler as required. Play around with the tuning to know your options.

As much as I'm getting out of my motor, I've actually always run it pretty conservative in terms of EGT. Max I have ever seen on the hottest day, worst case towing (9000lb total truck trailer) up the steepest hill has been 1000-1100F pre turbo. Safe IMHO. That said, I have run coolant temps up to at least 250F...haha. Evans coolant is a mixed blessing.

I used the 'perf expert' app and was quite happy with it. I also used my old school 'g-tech' thing that mounts to the windshield. I ran both to make sure the number were agreeing. Setting up perf expert is a bit of work, but necessary to have it work right. You should do a 'base line' before modifying further.
 
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Doing this mod, (with throttle plates removed and egr removed) I want the engine to be mostly stock otherwise, but running a bit leaner. I'm a mailman so I don't need top speed, just reliability and low egts
I'm asking for any opinion on the fuel economy of leaning out the system a bit as well.
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