I love that show. Very informative on a lot of things. Though they do not do a lot with any modern engines which is a shame. The closest they get is a Holley efi set up.
I saw that episode too. They really beat the hell out of those headers and it still Dyno the same.
I guess we are building the same car. It will be interesting to see the results, the similarities and differences. My guess is that yours gets done first.
I guess we are building the same car. It will be interesting to see the results, the similarities and differences. My guess is that yours gets done first.
We'll see. My wife keeps tasking me as well haha. The biggest things I have left;
Finish wiring - I dove in last night. I figured out where I want to mount the ecu. Now its a matter of mounting it and re running all the wires cleanly.
Fab two engine mounts. I'm using mounts from a later c4 corvette simply because I have a bunch.
Send the MAF mount out to get 3d printed so I can attach it to the intake tube.
Then the ancillary stuff that should take me about a day. (Exhaust, fuel lines, shift cables. Etc).
I have everything, its just a matter of finding the time at this point. Hoping I'll fire it not this weekend but next. Then its rip all the body panels off so I can send to paint.
I look all the time at the local Pick a Part for these with a manual and never find them. The same goes for the G6. Never see one with a manual ever.
Keep an eye out on FB marketplace or CL. I found mine about two hours away with everything from axles to FW and all mounting stuff for $250; already pulled.
We'll see. My wife keeps tasking me as well haha. The biggest things I have left;
Finish wiring - I dove in last night. I figured out where I want to mount the ecu. Now its a matter of mounting it and re running all the wires cleanly.
Fab two engine mounts. I'm using mounts from a later c4 corvette simply because I have a bunch.
Send the MAF mount out to get 3d printed so I can attach it to the intake tube.
Then the ancillary stuff that should take me about a day. (Exhaust, fuel lines, shift cables. Etc).
I have everything, its just a matter of finding the time at this point. Hoping I'll fire it not this weekend but next. Then its rip all the body panels off so I can send to paint.
Let us know how you get it cranked.. After analyzing the wiring diagrams for the Cadillac ATS/ATSV, which uses the E36 and E92 ECUs respectively, the crank signal goes from the key/ignition to the BCM then to the ECU then to the Starter Relay. I assume you're not running the BCM. Theoretically you should be able to, with ECU power/ignition on, send the ignition signal to the starter relay like a stock fiero and the ECU should pick up the signals from the engine turning over and finish the cranking process, (PWM signals to FPCM, ignition, etc...).
If you've already figured this out, my apologies, and please share....
- The Camaro AC compressor is two wire with one of them being ground; should make that part of the swap that much easier.
The Cobalt half shafts are too large to fit through the 88's upright seals.
-Going to remove the front engine mount to make running the exhaust super simple.
-The camaro oil pressure sending unit is some god forsaken obscure thread; M16x2. The sending unit is also different than the impalas which is m14x1.5. Ordered some adapter fittings.
Hi all, I am trying to decide where to get vacuum for the brake booster. I am doing a test fit and took pictures of some possibilities. What does everyone think?
Will, This is the vacuum pump from the 2013 Impala.
That's the same pump I use in my Fiero. I have it wired to a pressure sensor that turns it on when vaccumm drops to 10 inches and stops at 15 inches. The cam is so big it doesn't make vaccum that easy!
If that pump is sufficient to run brakes on an Impala full time, why did you bother using engine vacuum at all?
It's not likely intended to do that full time. Without researching it, I'm pretty sure it's there to assist under circumstances where commanded camshaft angles produce potentially insufficient vacuum for extended periods where a situation can occur, for braking to appear frighteningly insufficient. Recall in most cases, the EGR effect is a result of the VVT, dependent upon the appropriate angles commanded. Cam angle tables can be pretty intimidating in terms of how they work in the programming, (there are at least 4 in the Bosch PCM system) and more so when it comes to figuring out which cam angle table the PCM is reading from to set the desired angles.
It's not likely intended to do that full time. Without researching it, I'm pretty sure it's there to assist under circumstances where commanded camshaft angles produce potentially insufficient vacuum for extended periods where a situation can occur, for braking to appear frighteningly insufficient. Recall in most cases, the EGR effect is a result of the VVT, dependent upon the appropriate angles commanded. Cam angle tables can be pretty intimidating in terms of how they work in the programming, (there are at least 4 in the Bosch PCM system) and more so when it comes to figuring out which cam angle table the PCM is reading from to set the desired angles.
The first part of what Joseph just said above is an accurate paraphrase of what is stated in the FSM for the Cadillac ATS with the LFX/LGX and even somewhat more so with the ATS-V LF4 TT. As a matter of fact the LF3/LF4 have an additional mechanically cam driven vacuum pump in the opposite head of the HPFP for wastegate and BOV operation.
[This message has been edited by msweldon (edited 05-31-2020).]
I am having a hard time getting a schematic of the vacuum hose routing for the 2013 Impala, and don't know where on the engine they get vacuum for the booster from. Does anyone know where I can get that info? Thanks
[This message has been edited by Daryl M (edited 06-01-2020).]
If that pump is sufficient to run brakes on an Impala full time, why did you bother using engine vacuum at all?
The pump is more than sufficient for my application. It doesn't run constantly it comes on and off on demand and keeps the vacuum right at 15inhg. When vacuum drops to 10inhg it turns on and brings the vacuum back to 15ingh. I have it wired to a relay and an adjustable pressure sensor.
Originally posted by La fiera: The pump is more than sufficient for my application. It doesn't run constantly it comes on and off on demand and keeps the vacuum right at 15inhg. When vacuum drops to 10inhg it turns on and brings the vacuum back to 15ingh. I have it wired to a relay and an adjustable pressure sensor.
I'm not sure how often and for how long the pump is cycled on in the applications it was designed for, but my concern here would be the absence of a backup system in the event it failed to operate at some point. The funny thing about these situations, is that when there's a potential setting for something to really go wrong, it's just a matter of time before it does.
In addition to this pump in its OE arrangement, my booster also receives a vacuum signal from the intake plenum on an LLT motor. I've never bothered to trace the pump tie in. I don't recall how difficult it was to stop the Fiero without power assist, but imagine it's not an end of the world moment, however, you only need to tap the car in front of you to have your insurance company sued for a substantial amount, or worse if it involves a bit more than a tap.
I believe it's wiser to make an access point for a traditional vacuum signal and be better safe than sorry, or use two pumps.
Yes, I'm getting another pump and another source of vacuum storage because I though about the same thing. In my case is very important to have a back up I track the car more than I drive it on the street. Thank you for the reminder Joseph!
I was able to determine that the vacuum for the booster does come from two sources, the intake plenum and the electric booster pump. They use a few check valves to insure there is no bleed back from one vacuum source to another. The check valves are part of a pre-made vacuum hose . I am trying to source them individually now, but have not found them yet.
I was able to determine that the vacuum for the booster does come from two sources, the intake plenum and the electric booster pump. They use a few check valves to insure there is no bleed back from one vacuum source to another. The check valves are part of a pre-made vacuum hose . I am trying to source them individually now, but have not found them yet.
A vacuum pump probably isn't needed for your application. The main reason that the factory added one is that the new cars are set up to run at low rpm with high throttle openings for efficiency with the resultant low vacuum. That usually means less than 2000 rpm at highway speed.
A car that successfully used only manifold vacuum with a 2.8 should have no problem doing the same with a 3.6. I won't be running the vacuum pump on my Fiero track car with the LFX.
In 6th at 60mph the engine will only be at just over 1600rpm. That may call for the vacuum booster auxiliary pump.
I believe it's pretty important, especially if the OE PCM is used, currently there is a recall regarding the vacuum assist pumps used on a number of GM trucks and SUVs as a result of stopping difficulties and accidents resulting from vacuum assist pump deterioration and failure. It's a different style of pump, but none the less an assist pump. VVT coupled with direct injection apparently allows for cam manipulation that results in higher performance/emissions goals to be achieved, although with additional supporting equipment, such as the electric pump. I do not believe it is used on any of the port injected 3.6L.
I've been logging my cam angles in tables setup in HPTuners and every degree of camshaft variability available appears to be used. The cams are closest to the overlap point at low rpm, part throttle input.
I don't know what happens with vacuum on the lfx when decelerating. I think I am going to use the electric pump in addition to engine vacuum . With proper placement of check valves, it shouldn't hurt. I can monitor vacuum under normal driving conditions to see if the auxiliary pump can be removed later.
Not to change the subject, but I have been looking at options for front springs. What are thoughts on methods for lowering the front by 1-1.5 inches? Are springs available? Can stock springs be trimmed ? Thoughts?
I understand that when you're cruising at 1600 RPM at 60 mph, there might be little engine vacuum.
However, assuming that you lift the throttle before braking, won't you get back your vacuum due to the closed throttle?
That's the beauty and pain of these modern systems. The PCM makes decisions on how to apply pedal input. For starters, you may only be allowed to cruise at 1600 rpm at very low speed/gear where engine generated vacuum may not be an issue. At higher loads approaching lugging the motor in an auto, the PCM may not allow it to that extent. I've encountered this when shifting the auto manually, where an upper and lower limit is set to what I can shift to relative to rpm. Also remember there is no EGR valve, so the cams are being used to this effect quite frequently which is likely where the low vacuum conditions are most prominent. It is correct however, that at times when the PCM is in efficiency mode, it may allow a good bit of throttle input before kicking down a gear, but that falls into adaptive territory. For those not aware of this, the PCM has adaptability and can change performance characteristics based on driving habits, although I'm not sure if the feature is active in all platforms. If you drive the car aggressively, shift characteristics will change to compliment it. Much of the drivetrain performance can be changed in the tune, but the transmission parameters appear to be more complex than the engine management as far as what to change and how. The modern PCM calibrations make OBD I look like the simplest of arithmetic. It's anything but straightforward.
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Originally posted by Daryl M:
Not to change the subject, but I have been looking at options for front springs. What are thoughts on methods for lowering the front by 1-1.5 inches? Are springs available? Can stock springs be trimmed ? Thoughts?
Be very careful here in order to have a good outcome. I first tried Eibach lowering springs that were said to be 1" drop. I had 225/40R18s on the front. The car seemed to have more like a 2" drop. The bump stops had to be cut for this. The stock style shocks could not prevent the car from bottoming out which eventually ate away at my wheel well dust shields. I eventually removed them and cut about 3/4 of a coil from the stock springs and was much happier. If you can get stronger shocks you shouldn't have much of a problem, but OE grade equipment probably will not cut it. Also keep the tire size in mind using what I listed as a trouble spot for me. I had 18x8" front wheels and did not want to go to narrow on the tire so that did not help my situation with the Eibachs which were made around OE wheels and tires.
[This message has been edited by Joseph Upson (edited 06-05-2020).]
