New Caprice - Discussion forums

Once the supercharger was in place and the heat exchanger was installed, it was time to take care of a bunch of little things, like the intercooler reservoir, intercooler pump, pulleys, wiring up relays, etc. This ate up some time, but was actually an enjoyable part of the build. You'll notice in the pictures that the power steering reservoir is mounted close to its original location. I just cut the mounting bracket off and welded it higher up on the bracket that attaches it to the head so it would clear the s/c snout. I also had to cut a relief behind the s/c tensioner in order to let the wiring harness pass behind it in that location.

Here is my chosen location for the intercooler pump. Most people put it on the passenger side, but I mounted mine on the drivers side where it could draw straight from the reservoir, push the fluid down through the heat exchanger, and then up into the intercooler in the s/c lid, and then of course back into the reservoir.


I put the pump relay on its own circuit. The main power for the pump is running straight from the main battery post on the fuse box. I did take switched power for the relay from the closest pink wire that I could find. If anyone knows what this circuit is or if it cannot handle the extra 0.8 amps required to open the relay, please let me know and I will reconfigure it, but with such a small load, I figured I was okay taking switched power from just about anywhere.

And finally, here is the "almost finished product". In this picture, you can still see some of the relay wiring, which will be cleaned up as well as a few other things. Seems like there are hoses and wires going everywhere. For the evap purge solenoid, I used the stock plastic line but I had to bend it to fit its new location on the supercharger. I did this by taking the largest diameter wire that would fit inside the line, gently heating it up with a propane torch and bending it to fit. It didn't take much heat, and having the wire inside kept it from collapsing while I bent it into place. I would have just eliminated the system altogether, but I want this build to be completely emissions legal, cats and all.

The intercooler reservoir is from a Saturn ion. I just went to the junkyard, searched around until I saw an expansion tank that was just the right size, and brought my prize home to install it on my caprice. You'll notice that I have the return line running into the vent tube instead of the intended return port as it was much too small for my liking. I also modified the lid so it let the coolant pass easily back into the tank with no extra resistance. The whole intercooler system seems to flow very well. Time will tell if my intake air temps stay withing reason.
I scheduled an appointment with my dyno tuner and he is booked until the middle of August, so it'll be a while before I get the car dialed in just right. In the meantime, if anyone knows any good dyno tuners in Utah that will work on GM cars, please let me know.

id move the heater hoses so they run along the brake lines , less heat going into the s/c lid

and also look into a roto-fab , or doing a custom 4" intake and put the filter into the bumper area ahead of the tire

I've gotta do something. I took it out for a drive today and my IAT's were between 140-150 degrees. This is my first supercharged build, so I'm not sure what's normal, but that seems pretty high. I am taking the temperature from the sensor in the lid instead of at the maf so that I can get an idea of the air temps just before they go into the engine. Also, I am getting a code for a lean condition. I took the fuel tables from a guy who loaded his G8 tune onto the tune repository at HP tuners. His car had bigger injectors, smaller s/c pulley and headers. Any ideas on which tables I need to adjust to richen it up a bit? I am a tuning newb as you might be able to tell. It's a 20 mile drive to the tuner and I don't want to hurt the engine.

that is about normal , but not ideal which is to get it down to ambient temp

which is why i suggest moving the heater hoses , and using a different intake set up that blocks out the under hood temp from the filter , which the roto-fab for the 14-17 SS will do , or making a custom one to move the filter into the bumper area , i would fix these before getting a tune

you are reading the IAT in the correct place

a good friend of mine is using a custom 4 1/2" that was made for a CTS-V in his 09 G8 GXP

if the tune file you used had bigger injectors , then you should be on the rich side if your injectors are smaller than he was using

STOP DRIVING YOUR CAR. I only see one G8 tune for the LSA in the repository. If it is the one I just looked at, it is for a car with 2.55" pulley and using ID850 injectors and the tune is scaled by about 50-60% due to the older gen E38 ECU hard code limit to 64 lb/hr injectors. If you have smaller injectors it will run lean all over the place. Log your VE LTFT, MAF LTFT, KR, Retard, fuel pressure and INJ duty cycle at least. If you are running a blower and are also not logging AFR or Lambda and commanded AFR vs actual AFR error, you need to asap! Also please check the spark tables. I looked at it quickly and it's pulling timing down to 13 degrees right after peak torque just as the PD blower is running out of steam so I bet his car falls pretty flat at high RPM.

If you are talking about another tune, then never mind.

What year is your PPV?

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2014 Chevrolet Caprice PPV
2014 Chevrolet Stingray Z51
2016 Cadillac ATS-V
2015 BMW X5 iDrive 50i

Yeah that's the one. Since I really have no idea exactly which tables to copy, I just copied them all. I was hoping that his tune would serve as a good base that would at least get me to the tuner's shop, but it sounds like I'd better reconsider. My car is a 2012.

Heater lines are relocated. Hooray for zip ties I had to shorten both lines by a surprising amount to run them this way. Cutting the heat shrink tubing off of the heater lines was kind of a pain, but worth it to accomplish the goal.


Time to start designing a cold air intake cover. Maybe I can zip tie that on too

Ya I wouldn't recommend just copying that tune blindly. You might end up in a bad place. Since it looks like you already have HPTUNERS, look up Dave Steck, Jeremy Formoto, and Shane Hinds. I'm not endorsing any one tuner but they are some of the best in the business. Shane has probably done more remote tunes of 6.0L and 6.2L LSA blower conversions than most. Any of them will get you running quickly and will fine tune your file over several logs that you will take.

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2014 Chevrolet Caprice PPV
2014 Chevrolet Stingray Z51
2016 Cadillac ATS-V
2015 BMW X5 iDrive 50i

looks much better

Thanks for the lead on some guys that can help me with my tune. I'll look them up.