Looking for a LT4 log with SCIAP Vacuum and Pressure in the channel list.

[Ben Charles]

Greg, excellent info.. I compared ls3/lsa map pin outs and they match (makes sense due to the ls9/lsa map sensor is direct swap)

So yes, I should have stuck to my guns and would been right… I need to swap 1-3

Have ti do family time today, and car is at my shop 2 hours away, so be next weekend before I can revisit

[will_974]

You need to request the SCIAP linear and offset from Hptuners.
The SCIAP pressure log should not be 0, when voltage is at ~4 volts.

[Ben Charles]

You need to request the SCIAP linear and offset from Hptuners.
The SCIAP pressure log should not be 0, when voltage is at ~4 volts.

You have a pic of these tables?? I’m fairly certain they’re already there. This is a 15 vette

[GHuggins]

You need to request the SCIAP linear and offset from Hptuners.
The SCIAP pressure log should not be 0, when voltage is at ~4 volts.

Are they all "pre-filled" with 0's from factory? If you don't mind me asking what should they be? They should be 128 and -.3ish if regular 1.5 bar settings. I would have to request a lt4 and the one I'm working on to know the factory settings otherwise...

Guess once it's wired correctly we need to verify it's reading baro with koeo to know if it's set from factory, which sounds like it won't be.

[will_974]

I can not speak to vettes default values. But I assume it is 0 and 0 from the factory.
The values should match the pressure sensor you wire to it.
128 and -.3 are correct for a LT4 motor.

Screenshot 2023-06-11 145931.png

[GHuggins]

I can not speak to vettes default values. But I assume it is 0 and 0 from the factory.
The values should match the pressure sensor you wire to it.
128 and -.3 are correct for a LT4 motor.

Screenshot 2023-06-11 145931.png

I know I'm asking a lot with this one, but you wouldn't happen to know the addresses to be able to use user defined parameters to enter them in would you - just to make things go quicker in the future

Thanks Again for all of this.

[will_974]

I know I'm asking a lot with this one, but you wouldn't happen to know the addresses to be able to use user defined parameters to enter them in would you - just to make things go quicker in the future

Thanks Again for all of this.

I poked around today, and i was able to find the SCIAP Linear for the 2015 Corvette File provided.
I am 90% sure i found the SCIAP Offset, but can't be sure without decompiling and checking the source
PM me with your email, and i will send the xdf file

[GHuggins]

PM Sent.

FWIW Bill, I had my customer swap those two pins in his pcmofnc kit and now his sensor's reading is changing so progress being made. Before it was fixed like yours. Hopefully Alvin can get the wiring corrected in them. Now we just have to get the settings fixed and should be good to go

I'm also having him wire in the temperature sensor for the lt4 map as that should be what the ecm is now using to make it's timing corrections with the supercharger settings being enabled. I don't know what map you're using or if it will default to another temperature sensor for pulling timing or not with the calibration being set up like that???

[GHuggins]

Posting this just in case anyone needs it too. This is for the temperature sensor wire in from the lt4's map sensor. A lot of it's repeated from the earlier post, but will hopefully help someone.

[Ben Charles]

[QUOTE=GHuggins;733748]PM Sent.

FWIW Bill, I had my customer swap those two pins in his pcmofnc kit and now his sensor's reading is changing so progress being made. Before it was fixed like yours. Hopefully Alvin can get the wiring corrected in them. Now we just have to get the settings fixed and should be good to go
]

Great news, I’ll adjust mine this coming weekend and report

[GHuggins]

Found out something else interesting from Will. Apparently the trucks - at least the majority of them I guess - are already set up for the linear and offset settings. The cars however, are pretty much all zeroed - so if you're doing this to a car you have to request those tables and if a truck you might get lucky???

Guess it just goes further to illustrate the different programming teams.

[Ben Charles]

Thanks Greg for the info and you as well Will!! I’ll send the file and request to Support!!

[GHuggins]

Yes, thank you Will and Ben both on this. I've been going in circles just assuming this one gentleman's kit was wired right since he got it from a big name supplier and there were several saying that the readings weren't changing, but their vehicles were acting differently - I just assumed this was how it was. It was Ben mentioning the pins that got me to purchase access to GM's site and do some digging as I couldn't find any lt4 schematics anywhere. In doing so we confirmed wiring and got the thing to working right. Funny enough the guy's tune is requiring the opposite changes I was making. Now I'm having to add into the DD table in the higher speeds and take out a lot in the lower speeds. I had his somewhat close with just regular DD and torque model adjustments, but it would still randomly go wot with 30% cruising pedal especially in the higher speeds. I've never had one this big of a pita to tune a blower on before.

Now that the SCIAP is working it's not going wot in the higher speeds anymore, but has started gong 70% throttle in the lower speeds. Should be able to tune it in now though.

I did make an edit to my earlier comment on what has to be activated. Only the top two pressure sensor settings need to be enabled. If all 3 are it will start setting baro codes as the lt4 does use a different baro setup...

Thank you for the information and help Will and Smoke and thank you Ben, for questioning it in the first place

[Alvin]

PM Sent.

FWIW Bill, I had my customer swap those two pins in his pcmofnc kit and now his sensor's reading is changing so progress being made. Before it was fixed like yours. Hopefully Alvin can get the wiring corrected in them. Now we just have to get the settings fixed and should be good to go

I'm also having him wire in the temperature sensor for the lt4 map as that should be what the ecm is now using to make it's timing corrections with the supercharger settings being enabled. I don't know what map you're using or if it will default to another temperature sensor for pulling timing or not with the calibration being set up like that???

That's very interesting. There must be two different pinouts maybe OS dependent or something out there because we've done a good handful personally in the shop and watching SCIAP pressure and voltage change is how we know it's OK and its good to proceed with tuning.

So we install, Check scanner for activity, OK good to go. I had one in the beginning not move but we were trying to use some other map sensor and assumed back then AAP 1, 2, or 3 was the SCIAP. it isn't.

I guess we need to know next which applications are how we have the instructions written and which application needs it like this.


I can look up the local installs I've done.. I can't remember the year ranges but there were 3 magnacharged trucks and 1 edelbrock LT1 C7. My employees(mechanics) do the installs with the same instructions we print for customers... I strongly suspect we might dealing with two different pinout/application.

[GHuggins]

Anything's possible with these things I just matched the pin outs to the lt4 since they all used the same ecm's with the same internals. Mine's a 17 silverado. I know at 16' things changed - shoot prior to 16 you could tune these without the sciap no problem - after that it's VERY hit and miss, but should still have the same pin outs.

[Alvin]

I just triple checked my instructions and they are showing correct with above diagram. I even found the schematic I used when I made the kit/ wrote the instructions.

Its very possible the customer made a mistake. Its easy to do moving wires around.. and while this is easy to do it would also be easy to make a mistake.

Here is the schematic I used when I wrote it.. I back to suspecting only 1 pinout for GEN 5 until proven otherwise.


SCIAP.pdf


The schematic is easy to write instructions for because the LT4 pinouts are listed right where the LT1 pinouts are + add the pinout for sciap. This sorta dates our kit too.. I got that diagram in 9/2022. All of the PD blowers done here since then have gotten the kits (4 I think) and have all worked out like we expect. The only time I had it not work is when I tried to use a GEN 3 1 bar map sensor as a SCIAP because the vacuum nipple they use would have been easier to use mechanically than the bolt in style MAP sensors that have that o-ring nipple.




Side note.. we also sell plug and play fan kits. Weekly we deal with people who installed it "correctly" and "triple checked wiring" and spoiler alert.. its always the installer making a mistake.

[GHuggins]

Trust me I know that better than anyone

He said all he did was swap the "brown and green" wires. Not sure where those are supposed to go in your kit?

I know if you go by what was originally posted on the forum they are indeed backwards. This may be how it got wired up backwards if he looked at those instructions instead.

All I know is it's working now and we can proceed and good to know the instructions are correct in your kits, cause I already told some others to order them and then if I see this again I know what to look for... I did learn some things about the settings and everything else from this from different individuals, so not a complete loss.

[Alvin]

Heads up about the settings..

AAP1, 2, and 3 are not the SCIAP sensor. I don't think they are even the baro but my notes/memory are foggy on this now.

[Ben Charles]

Heads up about the settings..

AAP1, 2, and 3 are not the SCIAP sensor. I don't think they are even the baro but my notes/memory are foggy on this now.

Correct, the SCIAP are in the “background” Will sent me up a file with the SCIAP settings correctly done that I plan to test this weekend along with flipping pins 1 and 3 (slots 4 and 5)

[Ben Charles]

SUCCESS!!!!

Swapped pins 4 and 5 and loaded the File that Will sent me that turned on the SCIAP portion (Thank YOU again)

Below is a log of it working.

I also want to add, watching this can tell you how much restriction you have pre rotor, this is a great method for determing if your inlet/snout, CAI, filter is costing you power. Many LT4 setups I tune I see the pressure roughly 100 KPA below 4000 rpms and sometimes as low as 92 KPA near Peak redline, that of course is restriction..

SCIAP success.hpl