4.2 Envoy Turbo Build
- Thread starter ConeKilrAutoX
- Start date
- Dec 8, 2011
- 1,179
so far so good it throws the junk out about 5 feet from the voy. if need be I definitely will do that...thanks for the tip
Sounds very Diesel, hahaha, love it. I'd say do it, but not practical at all like that though.
Remember after you re-tune you can gain a good bit of a smoother idle and better running by simply running a colder/ smaller gapped plug. Most people find 2 stages colder is better when going from N/A to boosted, but it all depends on tune and what engine, so play around with the Gap on them to fine tune after the ecu is dialed in.
Remember after you re-tune you can gain a good bit of a smoother idle and better running by simply running a colder/ smaller gapped plug. Most people find 2 stages colder is better when going from N/A to boosted, but it all depends on tune and what engine, so play around with the Gap on them to fine tune after the ecu is dialed in.
- Dec 8, 2011
- 1,179
All my boost experience has been with 4 cyl Chevys before, haven't boosted my I6.... yet.... but from my past experience, NGK Iridiums are awesome plugs, but they don't like being gapped down too far or the electrode's internal solder joints break. But besides that the Iridium IX plugs give a very nice powerful spark that boosted engines crave.
NGK's website lists this for a Trailblazer I6........
Iridium IX
Model:LTR5IX-11
Stock#:4344
Gap:.044
And wouldn't you know its the same plug people run for a stock replacement Cavalier 2.2 L61 plug!
Yet another similarity in these 2 engines, that makes my theory that the I6 LL8 is essentially a 6 cyl. version of the 4 cyl. Ecotec L61 even more credible.
Anyways...
So drawing from my cavalier boosting experience we can deduce that if they use the same plug for a stock replacement then your plug options are as follows...
- LTR5IX-11 = Stock heat range
- LTR6IX-11 = 1 step colder
- LTR7IX-11 = 2 step colder
I'd go with the 2 step colder plugs if I were you Conekiller. Generally the rule of thumb is one step colder for S/c applications with lower boost levels, and 2 step colder for higher boost level S/C and Turbo setups.
And with a .44 gap on them from the factory that's a great spot to start with your gap, then if it needs some idle and rev smoothing after the ecu is tuned bring your gap down a bit at a time, to like .42, .40, or so, but be very gentle with them when gaping to keep the electrode from breaking.
Its so Ironic that I have all this knowledge about these engines I didn't know I had.
I picked a good vehicle to upgrade to when my cavy got totaled, and didn't even know it.:wootwoot:
NGK's website lists this for a Trailblazer I6........
Iridium IX
Model:LTR5IX-11
Stock#:4344
Gap:.044
And wouldn't you know its the same plug people run for a stock replacement Cavalier 2.2 L61 plug!
Yet another similarity in these 2 engines, that makes my theory that the I6 LL8 is essentially a 6 cyl. version of the 4 cyl. Ecotec L61 even more credible.Anyways...
So drawing from my cavalier boosting experience we can deduce that if they use the same plug for a stock replacement then your plug options are as follows...
- LTR5IX-11 = Stock heat range
- LTR6IX-11 = 1 step colder
- LTR7IX-11 = 2 step colder
I'd go with the 2 step colder plugs if I were you Conekiller. Generally the rule of thumb is one step colder for S/c applications with lower boost levels, and 2 step colder for higher boost level S/C and Turbo setups.
And with a .44 gap on them from the factory that's a great spot to start with your gap, then if it needs some idle and rev smoothing after the ecu is tuned bring your gap down a bit at a time, to like .42, .40, or so, but be very gentle with them when gaping to keep the electrode from breaking.
Its so Ironic that I have all this knowledge about these engines I didn't know I had.
I picked a good vehicle to upgrade to when my cavy got totaled, and didn't even know it.:wootwoot:
- Dec 8, 2011
- 1,179
thanks a ton for this info that is really going to be helping me out and I appreciate it! looks like Ill be purchasing these today haha. Thats crazy with the LL8 / ecotec resemblance... really does seem like the i6 is just 2 cylinders extended of the 4 cylinder.
With 93 octane those plugs should be excellent.
With 93 octane those plugs should be excellent.
limequat
Member
- Dec 8, 2011
- 520
ConeKilrAutoX said:
As scorpio was saying you definitely want to wait until the idle is nailed down before swapping them in.
Here's a pic of Autoroc's plugs after 55k miles. This is a 414 RWHP 4.2. Not too shabby, and no misfiring problems.
http://www.vortec4200.com/forum1/viewtopic.php?f=10&t=798&start=90#p15125
- Dec 8, 2011
- 1,179
limequat said:
haha DEFINITELY after the idle is nailed down
Just wanted to order them while I still had enough money
ScarabEpic22
Member
- Nov 20, 2011
- 728
Scorpio...you cant re-gap Iridium plugs and not have them fail prematurely. As soon as you try to gap them, they're pretty much junk. Notice how all of the stock AC Delco iridium plugs for the I6 come pre-gapped at the right gap? Some people have had luck doing it, I wouldnt recommend it though. Id start with a 6 heat range and see what happens, not going to be pushing tons of boost through a stock engine (6-8 psi max) without it going boom.
The I6 shares some with the other 4 cylinders, especially when it comes to the PCM (if you look at the code, they're very similar). Moreso with the I4/I5 Atlas engines though, they're almost identical to the I6 minus a cylinder or 2.
The I6 shares some with the other 4 cylinders, especially when it comes to the PCM (if you look at the code, they're very similar). Moreso with the I4/I5 Atlas engines though, they're almost identical to the I6 minus a cylinder or 2.
- Dec 8, 2011
- 1,179
well I havent ordered them yet. Whats the consensus then you guys think? ngk or ac delco ? pre gapped? adjust the gap at all?
Just curious I wont be buying them until I get the idle taken care of. max boost 7ish psi min boost 3 psi
Just curious I wont be buying them until I get the idle taken care of. max boost 7ish psi min boost 3 psi
limequat
Member
- Dec 8, 2011
- 520
ConeKilrAutoX said:
Colder are plugs are a good idea for boost, but I've also heard a lot of horror stories about NOTHING other than stock plugs working right. I'm planning on switching to colder plugs eventually on the supra, but it's pretty low down on the priority list.
- Dec 8, 2011
- 1,179
ok thanks and thats what I heard to.. it will be lower on my list too then... pcm is on its way lol
Its funny every where you go you hear just don't GAP Iridium plugs, and don't use any thing but AC delco.
I worried about the Gap issue when I ordered my one stage colder for my S/C L61 build. To be sure, I emailed NGK, they told me to not Gap them either direction very far, like no farther than .5 to .75 or so as it could damage the internal solder joint and give you misfire conditions and the related bad things (engine boom, lol).
Add to that the numerous Ecotec cavalier guys running these gapped down with no issues.
So you can Gap these exact line of plugs, not sure about the others, but like I have said 3 times now, don't Gap them very far.
As far as not using anything but AC Delcos, no idea on the LL8, haven't changed mine yet as I haven't needed to yet... but I've never had any issue with NGK plugs designed as a stock replacement on any of my boosted cars, chevy or otherwise.
The biggest thing with the ecotec plugs was the weird shoulder to tip length and design of the threads positioning/ housing, other companies sell "stock replacement" plugs based on length only, not taking this design into consideration, and they don't seat properly in the head, making the spark path too high up, and causing some arcing in the head, and misfiring. So take all my experience with the eco in account, I know its not the same engine but it uses the same plugs so it just may be very similar in nature.
That said, here's hoping she runs awesome at .44 gap so you don't need to re-gap them, and Scarab just may be right, Ive always just ran 2 stage colder when turbo, but depending on your boost level you may want to start with the one stage colder and go down from there after you turn up the boost later, or when you do, I should say.
I worried about the Gap issue when I ordered my one stage colder for my S/C L61 build. To be sure, I emailed NGK, they told me to not Gap them either direction very far, like no farther than .5 to .75 or so as it could damage the internal solder joint and give you misfire conditions and the related bad things (engine boom, lol).
Add to that the numerous Ecotec cavalier guys running these gapped down with no issues.
So you can Gap these exact line of plugs, not sure about the others, but like I have said 3 times now, don't Gap them very far.
As far as not using anything but AC Delcos, no idea on the LL8, haven't changed mine yet as I haven't needed to yet... but I've never had any issue with NGK plugs designed as a stock replacement on any of my boosted cars, chevy or otherwise.
The biggest thing with the ecotec plugs was the weird shoulder to tip length and design of the threads positioning/ housing, other companies sell "stock replacement" plugs based on length only, not taking this design into consideration, and they don't seat properly in the head, making the spark path too high up, and causing some arcing in the head, and misfiring. So take all my experience with the eco in account, I know its not the same engine but it uses the same plugs so it just may be very similar in nature.
That said, here's hoping she runs awesome at .44 gap so you don't need to re-gap them, and Scarab just may be right, Ive always just ran 2 stage colder when turbo, but depending on your boost level you may want to start with the one stage colder and go down from there after you turn up the boost later, or when you do, I should say.
watching the video, assuming all else is right mechanically I would guess it just needs tuned. your gonna be swapping out the running several times before it's right in my experience, keep scanning it and tweaking it, you'll get there.
- Dec 8, 2011
- 1,179
hey sorry not too many updates to report. still troubleshooting the bad idle/running. it will get there. everything else for the turbo is done and ready to bolt in once it idles/runs correctly!!! did some led mods in rear he mean time (pics when finished will be in led thread) thanks for all the support guys!!!
- Dec 8, 2011
- 1,179
I did put all new plugs in and new 93 octane as well which can only help out the situation. but todays my birthday and im in pitt at a rock concert so no car work today haha
- Dec 8, 2011
- 1,179
Ryda55555 said:I was expecting a great photo of your turbo build when i saw that you posted something in here but was greatly dissapointed..... So i guess i'll just have to say happy birthday.....JK! HOPE ITS GREAT!
hahahaha thanks man. hopefully in the next few weeks I can post an up and running video
gmcman
Member
- Dec 12, 2011
- 4,656
ConeKilrAutoX said:
Just an observation since you posted this, I assume your tune is set for atmospheric pressure at minimum and 3 PSI is what you will be expecting at part throttle correct? Not that you would have 3 PSI at the bottom of the MAP values correct? I haven't tuned an EFI motor so I'm talking out of my arse but just wanted to ask since you were having idle issues.
- Dec 8, 2011
- 1,179
gmcman said:
Hi. Thanks for the question and concern I appreciate any suggestions and help. I believe my tune is set atmospheric and the MAF sensor (when the turbo is installed) will pick up higher than atmospheric psi and will inject fuel accordingly based on the tables limquat has set up for me. After a scan I should hopefully have an idea of what is causing the problem.
- Dec 8, 2011
- 1,179
gmcman said:
the idle was bouncing from stalling to 1500 the entire time. it can hold steady at 3000 but just sounds like its missing. I dont know about 1500-2000 I will try that today as well as trying to have it run and I will pull each coil connector one at a time and see if theres a difference when I pull one of them
- Dec 8, 2011
- 1,179
- Dec 8, 2011
- 1,179
should I try 60's?
limequat and autoroc have had success with 80's though :/ I wouldnt mind 60's if it would run
limequat and autoroc have had success with 80's though :/ I wouldnt mind 60's if it would run
- Dec 8, 2011
- 1,179
- Dec 8, 2011
- 1,179
no luck. I tried unplugging each coil one at a time while it was sputtering and there was no change whatsoever for any coil. hmmm... and the idle bounced between 500-1500 irratically. no vacuum leaks either. I swiped my fingers across the inside of the throttle body plate (engine side) and it was dripping wet with gas. I keep having to clean the throttle body every start up and unplug the battery and that whole procedure.
Any suggestions for what to try next?
Any suggestions for what to try next?
gmcman
Member
- Dec 12, 2011
- 4,656
ConeKilrAutoX said:
Why is it wet that far from the nozzles? Not sure what type of DMM you have but can you measure the pulse width of the injectors? Can you find out what the tune is calling for?
How limited are the stock injectors for 7-8 PSI of boost?
Just a hunch but it sounds like you need to cut the pulse width way down for these high flow injectors if they are functioning properly.
Is your FPR functioning properly?
- Dec 8, 2011
- 1,179
I am unsure about the tune as I do not own a scanner and linequat has been helping me out by doing all the tuning (has been very helpful.. definitely cpuldnt have got this far without his help)
the fuel pressure regulator is what I am concerned about could a bad fpr cause this much issue? I have it hooked up to the vacuum port on the intake manifold directly via the vacuum distribution block I had bought. no leaks but is that hooked up correctly?
the fuel pressure regulator is what I am concerned about could a bad fpr cause this much issue? I have it hooked up to the vacuum port on the intake manifold directly via the vacuum distribution block I had bought. no leaks but is that hooked up correctly?
gmcman
Member
- Dec 12, 2011
- 4,656
Sorry for the multiple posts but I went out and looked at mine and from what I can see, the FPR should be ported vacuum. You need a vacuum line on the intake plumbing before the TB. In my understanding, when the vacuum drops the FPR gives more fuel, so if yours has more vacuum then it should be giving less fuel. 
So why do you have fuel all over the place? I would check to see if the FPR is leaking first, then check the vacuum. The fact you have fuel behind the throttle plate leads me to think it's leaking.
So why do you have fuel all over the place? I would check to see if the FPR is leaking first, then check the vacuum. The fact you have fuel behind the throttle plate leads me to think it's leaking.
gmcman said:
FPR should have manifold vacuum the way you have it as far as i know. The point of it is to keep constant rail pressure relative to manifold pressure( differential pressure across the injector stays the same). So at idle it should show about 30 ish. At wot or with the vacuum line disconnected it should show about 43 if that is what you have it set at.