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Boosting a '96 Impala SS

16K views 45 replies 3 participants last post by  autowiz 
#1 ·
This car is already badass. It has I believe a 3.90 gear in the rear. It's on nitto drag radials. The owner just rebuilt his LT1 engine and it came in for some tuning work and as I'm strapping it down to the roller The customer decides he wants to boost his LT1. Nobody makes a PD blower for this engine anymore, And it has a high stall converter in it. So I think the plan is going to be to start with a 92-96 corvette procharger kit and create our own tubing and intercooler solution. But in the end the rpm dependant procharger will like the stall converter and we will see what this fresh LT1 build can do. I will take some pictures of the car and post them tomorrow. And we are waiting for the procharger to arrive before we get started. I just couldn't wait to start this thread. It's not everyday you get to chase performance in a car with such a generously sized interior.
 
#2 · (Edited)
I have two of those Impala's. One is a 525-550 HP automatic with a 3600 stall. 11.66 @ 118 and it regularly goes on long road trips. It's got a 242/248 cam with 603/612 lift. My other is a LT4 with a 6 speed. It's a lot milder with just a GMPP 845 cam, headers, 52mm TB, 30# injectors, Crane springs, roller rockers and a tune. Probably around 375 HP or so since the stock LT4 made 330. The six speed car is set up for handling and even has a 1 1/2" rear sway bar. It's a heavy sucker. It does the most predictable drift around an autocross course that you can imagine. The Hotchkiss springs, Bilstein shocks and the Z28 front sway bar probably help a bit also.

There's a company that makes a turbo kit that is Impala specific that I've been looking at. They have twin turbo kits and Procharger kits. The Corvette kit has the accessory drive on the wrong side of the engine. Impala accessory drive is on passenger side and the Vette is a driver's side thing.

Check out the link for some ideas on your project and maybe save a bit of time and trouble.

http://rmcrperformance.com/products-2/94-94-impala-ss/impala-stage-3-intercooled.html

hERE ARE THE HEADS ON MY HOT ROD
http://i118.photobucket.com/albums/o100/billburgette/afr%20heads_zpsjbe4rxcc.gif
 
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#3 ·
So here are them tires I was talking about. They should grip the roller just fine..


The car already has a nice triple gauge a pillar so adding a boost gauge will be easy. we will just swap out a gauge or two to make sure we have boost and fuel pressure..


Here is the freshly rebuilt engine..



And the car has a nice head unit maybe in the end we can get a Bluetooth obd2 adapter and link it to this head unit for more gauge display and reading/clearing fault codes and what not..


This is gonna be fun. Again we are waiting on the procharger kit to arrive before we get started on the centri supercharger install.
 
#4 ·
We have changed direction on this build and instead of a procharger we have located a vehicle specific application with a vortech supercharger. The blower is at the shop and the installation begins Tuesday morning. The kit looks pretty impressive.
 
#5 ·
Awwww man, you should have said something. There's a pretty good deal over on the Impala SS forum.

95% Complete NPR ProCharger kit. Missing the head unit and blow off valve. Everything else is there. I will even throw in a few extra intercooler piping elbows to accommodate your set up. I had this set up on my car for a few years with zero issues. Comes with fast acting IAT sensor and a 1/8" bung for meth injection. Comes with various pulleys, belts and an intercooler piping test kit. Also comes with an oil catch can. Looking to get $2300 shipped + you pay paypal.
 
#6 ·
It's alright. All that extra intercooler piping just creates lag at any price. So the vortech kit is in. It is a v-3 si trim level blower. Here is the rack of parts..


This kit is a centrifugal supercharger with an in line air to water heat exchanger. It keeps the distance between the blower and the throttle body very short. This should get into boost fast. And this piece should keep the incoming air cool..


And this is all that mounts in front of the condenser..

 
#7 ·
Hey Wiz, is that the Rocky Mountain Competitive Research kit? I've been looking at it for my Impala......if that's the one. Keep us posted on any installation tips or problems.......and save a copy of the final tune. ;). Are you going to use 60# injectors and what final numbers are you hoping for?

I've got a spare 383 LT4 in the garage. It has the Dragonslayer crank, Lunati rods, 210cc heads that could go to 227 or so if required and I believe it will hold the extra power. I so wanna do this before the Hot Rod Power Tour in about 6 months.
 
#8 ·
It sure is. We were looking for a vehicle specific kit, And then we were looking for a kit to modify and make fit, And then we found this and once I started looking at the specs and how it was setup, It was just a no brainer. This is the best possible way into boost for this car. Period. And it comes with the 60# injectors and a high flow aeromotive fuel pump, and some pretty comprehensive instructions. So far, I am loving RMCR. Oh and it comes with 2 different pulleys for the blower. a 3.7" that is pre installed and a 3.33" that is supposed to be worth 8-10psi. And it comes with an ati super damper and big fat 8 rib pulleys and dedicated belt. Something you just can't have on a corvette because of the steering rack location on the midship.

As far as tuning goes, we were instructed to download the tune file out of the car's ecu with JET DST and send them the file and they will send us back a good tune to upload as part of the kit. As a tuner myself I will use this as a starting point and log deata and make tweaks from there. Mainly to ensure no detonation. I am no fan of canned tunes.

Final numbers and a dyno video will be posted here upon completion of the job. :partyon:
 
#9 ·
Here is the mounting plate and spacers installed and ready to receive the blower..


Off to the right the kit requires a hole to be cut and this plate to be mounted that relocates the ecm and allows for fresh air for the blower for the lowest possible iat's..


And here is the blower installed. This motor is gonna get into boost fast and at a low rpm..

 
#10 ·
Wow, good work Wiz. A couple of questions come to mind that will help me if I go this way. Is his harmonic balancer keyed? Stock Impala's were not. Also, will the stock 3/16ths key hold the blower or will it need another keyway cut? There have been some blown folk that had the stock key shear from the blower drive. How many keyways are in the ATI damper that they sent you?

Since the engine is already built did he leave the compression at 10.4 or so or did he raise it. Either way, isn't that too much compression for a blower motor? Will that limit you to what......about 6 PSI? How about a blower specific cam? What's he have in there now. It's my understanding that 114-115 LSA is best for a blower with more duration on the exhaust to help get rid of the extra gasses. Most performance cams for these engines are in the 110-112 range. Where is the intake valve closing? I'm curious if 60-70 degrees ABDC would lower the cylinder pressure enough to make the blower more useful. Just curious and not judging at all.

With a NA build it appears that he's not looking for maximum power but rather something that looks and sounds cool. And that's OK too. To each his own. I know it will put out some good power at even 6 psi but with that blower isn't he leaving quite a bit on the table?

One last thing......how in the mortal Hell did he ever get those Canton valve covers to seal? Is there some magic involved. I have a set and when tightened up enough to seal they were distorting.
 
#11 ·
The kit comes with a keyed hub and a keyway for the ati super damper. 1 is enough here. 10.4:1 is low compression by my standards these days. The 69 GTO has a 10.5:1 LS6 and a 2.3L Maggie, The extremely radical C2 we are building has a 11:1 LS7 and a Magnuson Heartbeat (2.3L) supercharger. I don't know what cam is in it because I had no part in the engine being built but I am told it is to stock specs.

So the blower is installed and I am down to electrical..


This puts the air filter outside of the engine bay to ensure that you are breathing in cold air..

And the coolant reservoir and pump mount in the drivers side of the nose of the car right along with the air filter. In the below picture the radiator core support is on the left, the reservoir is mounted on the right, and front of the car is at the top of the picture..

 
#12 ·
Update on this thread. There was a big problem with the end of this build. Because it is LT it falls in between obd1 and obd2. It is it's own thing and requires its own tuning solution. HPtuners won't touch it so you have to use this JET DST tuner software which on its own is simple enough to understand. but the software is meant to work on windows xp service pack 2 and the interface has a db9 serial cable that no laptop today has. So to use this JET Dynamic Spectrum Tuner requires a serial to usb converter cable that has its own prolific chip and software drivers and then you have to run the software in compatibility mode.

So once finally connected I make some changes and while writing the ecu the very first time, I get this windows message show up that jet dst encountered a error and needs to close. And then it just closes like that. In the middle of flashing the ecu. And that was the end of the ecu. And the big problem is I don't know why it encountered an error. I got no details. This experience will be our last with jet dst. So we felt we had no choice but to get a mail order pcm. It worked. We went back and forth a few time. The car made good power but had troubles in areas that as a tuner I know damn well I can fix but because of the controller I can't do a damn thing about. So shamefully we had to deliver the car. It is good it runs it makes power but it is not to our standards of what should be expected of a shop with a resident tuner and in house dyno. The thing runs so rich it slowly fouls out the spark plugs.

So here is where I get to make all this right. This car is now getting an ls engine controller and harness and efi connection kit. Then once I can tune it myself with HPtuners it will go back on the roller and we will get to finally put things right. The job is currently waiting on parts delivery.
 
#14 ·
We have decided the best way to make this go down is to just pull the engine and prep it on a stand. So here is the last time anyone will see this engine with an optispark attached to it..


Once out and on a stand we can see that someone disabled but didn't remove all of the egr components..


So we made a proper block off plate for the egr valve and removed the blockoff for exhaust inlet and just tapped the hole for a pipe plug..


The new reluctor for the crank gets sandwiched between the timing sprocket and the harmonic balancer. The reluctor for the cam is also in place and the new timing cover is ready to go on..


This looks beautiful to me. a cam and a crank position sensor and no optical sensors near places that are prone to leaking..


And here the motor is all back together and ready to go back in the car..


 
#15 ·
Before we toss the engine back in the car we really want to get the new harness installed..


Unfortunately this vehicle does not have a dedicated engine harness. The Antilock brakes, transmission and some emissions and other stuff all pass through this main harness that is also the engine harness. So we must deconstruct the harness to separate the engine stuff from everything else..


Once we have the harness separated we can identify the attaching wires left and chop this engine harness out..


Now we can lay the 2 harnesses side by side and get a better idea of the needed modifications to the new harness to make it correct for this application..

 
#16 ·
I spent the entire day today modifying the standalone harness to be right for this application..


The standalone harness just comes with the minimum mandatory to get the engine running. For all the features that this car had we need to add a bunch of circuits to the pcm connectors, and spend time with a shop database(shopkey pro) sifting through diagrams for both a 1996 impala ss and also a 2000 Camaro z28. There is a factory anti theft system that we would like to keep in tact. There is cruise control that we would like to keep. We really want the ecu to control the a/c compressor because this way we can have it cut out the a/c compressor at wide open throttle and also so we can drive the fans off of a/c state and pressures. This requires a fistful of circuits on its own as there are 2 wires for ac request and control but also 3 wires for a/c pressure transducer. For the fuel tank emissions to be correct we are adding a fuel tank vent solenoid and pressure sensor so the 0411 pcm can drive the purge solenoid correctly and watch them fuel tank pressures. And we are trying desperately to find a way to make the uart communicating abs module work with the class 2 communicating pcm. This might well end in a ebcm conversion to keep anti lock brakes with this conversion.
 
#17 ·
Something else that needs to happen here is we really want to try to create a stiffer connection between the engine and the car. As the power and rear gear have gone up the engine really wants to twist in the engine bay. Here is where the motor sits..



On the bench we drill out the rivets and break down the motor mount..



And then we replace the inserts and bolt the mounts back together..



Now these inserts were not made for the '96 impala SS. In fact they were made for a F body. So there was some modifications that had to happen to make these work in this car. While they fit in the clamshells, they were too wide and I had to grind metal off one end on both inserts. Also the spacing between the bolt hole and alignment pin on the inserts was different. To resolve this I notched the motor mount brackets on the engine..

 
#18 ·
So the engine is back in it's place and urethane motor and trans mounts are all in and done and water under the bridge..



The next step is to figure out a way and place to mount 8 ignition coils to this motor. I have already created a mockup for this effort and figured out where I want to put them so from here we just need to build something strong that matches and looks ok sitting atop those huge aluminum valve covers. So we start with a a length of Stainless steel all thread chopped down into quarters..



Next we need some hardware..



And now we have 2 coil packs..



I want them centered on the valve covers maybe using just the 2 center bolts of the valve covers to secure them..



So I got a length of aluminum angle again chopped it into quarters and now I have my new coil brackets..



They make a nice fit..



Up next is some light electrical work..

 
#19 ·
Now that the engine and coils are in place I can remove the engine harness for one last round of modifications before permanent install..



Along with the electrical as we build this back up there are some further changes that we want to make to help in the generation of boost. Or rather keep from loosing pressure. And the way we do that is by removing the pcv system from the intake manifold. Later on we will take the pcv valve and tee it into the fresh air hose that goes into the valve cover and then run a hose to the air filter.- No need for a catch can with them huge canton valve covers, we shouldn't be picking up any oil. So we removed the fitting under the throttle body in the intake manifold where the pcv valve gets plumbed to and replaced it with a pipe plug. We then remove the plate on top of the throttle body and do this..



There is a rubber vacuum cap pushed down the hole so nothing can pass through into the engine and the pile of right stuff on top is to keep the vacuum cap from pushing out when the intake gets into positive pressure. There is a really nice new cover plate for the throttle body that came from efi connection. It is a nice piece and looks good on the motor..

 
#20 ·
Got the blower and exhaust back in and brought all harnesses up to the ecu..



We also supposed to find more power aside from correcting driveability issues with this conversion. One thing that is going to help that end in a big way is moving away from that restricted 3.5" screened maf. we are switching to a card style maf and sticking it in a larger 4" tube just so the maf is not causing any type of a restriction up high..




And from underneath the LT looks very different without the optispark and ignition wires..



This car should be running and on the dyno before the week is over.
 
#21 ·
On the subject of the card style mass air flow sensor..



We need to wire in the connector for it but we need to make a quick change to the connector first. Here is our 5 wire pigtail..



We need to convert this to a 3 wire. Because we would rather be measuring inlet air temps downstream of the power adder and heat exchanger. So we open the connector and remove the 2 pins for the iat sensor..



And here is our 3 wire card style maf all wired in and ready to go..

 
#22 ·
#24 ·
Finally got started on the Impala today. First up on our list is to do something about high intake air temps. The heat exchanger that came with the power adder we feel is an inefficient design. It is our opinion that this heat exchanger is too thick making it harder for air to pass through it and also we fell it is too far in front of the condenser to have meaningful air pulled through it and also we don't like how the heat exchanger mounts directly behind the front bumper. In this picture the heat exchanger is on the right..



So we took a heat exchanger from a Magnuson supercharger kit for a C6 Corvette. This part has a generous surface area and is no more than 1" thick allowing air to easily flow through it. And then we made it fit..



That is about as good as we are gonna get here without dumping the air to water stuff and mounting a real intercooler.
 
#25 ·
Now you're getting somewhere.:D Check out the cool intercooler setup starting at 1:04 in the video. It looks badass and probably is. I'll bet the owner of the Impy would think it's cute too.

Be careful that the block doesn't break in two. I read this post somewhere.:laughing: You're on borrowed time.
Grumpy Rated all Factory Small Block Chevies Blocks good to 360 HP.
That's It.
Anymore is on Borrowed Time.
 
#26 · (Edited)
Now you're getting somewhere.:D Check out the cool intercooler setup starting at 1:04 in the video. It looks badass and probably is. I'll bet the owner of the Impy would think it's cute too.

Be careful that the block doesn't break in two. I read this post somewhere.:laughing: You're on borrowed time.


https://www.youtube.com/watch?v=dkTMkg1P7yE

Those guys can not even do 3rd grade Math.
775 HP at the rear wheels.
T56 Trans with a GM 8.5.
775 +100 = 875 at the Flywheel . Far from 1000 HP.
 
#31 ·
Look around for a Used Little M.
The Fast Guys use them.
I can't use a Little M block. My heads won't fit. AFR #1039 are close to $2500 not counting the custom porting by Tony Mamo. He was the top dog head designer for AFR and he "massaged" my heads. He took them from 195cc to 205 cc. I don't need or want the 227 cc heads. I need the torque that smaller ports give me. I have looked at it in the past. I'm fast enough for me. Lots of Impala guys are in the high 9's and low 10's on stock blocks. Some guys do a partial fill while others don't. No one has split their blocks in two yet. 2 bolt mains and the block machined to accept splayed caps are what me and most guys are doing. I'm mid 11's and pretty near 120 MPH and that's close enough for me. I'm getting too old to be in that big of a rush.:laughing: I sure seem to surprise a lot of Mustangs and other quick cars with my great big ole' 4 door Impala.......Not that I'd ever street race. Now a little red light Grand Prix might be another story.

I know that you will never understand but reliability and comfort trumps speed for me. 383 are enough cubic inches for me although I may go to 396 on my next build.......maybe. But maybe not. Cranks are a lot of money and probably not worth it for 13 more cubic inches.

I believe that my bottom end will support a lot more power than I make and I'd not even worry a little bit around 800 HP or so. I do like the looks and performance of that twin turbo setup. That would mean about 800 bucks for some new pistons and I'd be ready for turbos. Cranks and rods are fine. I can get a turbo kit for around 6 grand. With all due respect to the Chevy engineers 360 horsepower is just BS. Hell the 327 fuelie made what.....375 on a stock block. Maybe a bit more nickel in the old blocks but I'm fine.

No matter how fast you think you are there will always be someone just a little bit faster. That's not a game that I wish to pursue at this point. Heck, my Spring project is to put about $5000-7000 worth of stereo in the old girl That's going to ADD a hundred pounds or so and slow me down. The parts are in my closet waiting on me to crank open the woodworking area in the garage. I'm more excited about a great sounding sound quality system than the turbos.
 
#33 ·
Those are some impressive numbers and you should be damn proud, sir.
Well it was 11.67 and 118. I exaggerated a bit for effect. That time was on a borrowed set of 27" drag radials with my big tires on the front and 4350#'s. Not really much of a drag racer. One of the serious racers said that I must be making around 550 HP. This guy had a weather station with him for God's sake. He had more equipment than the National Weather Service. I had no idea it was that complicated.:laughing: I have no idea how I went that fast. I would have thought that my block would have blown in two and the 4L60E would have made like a hand grenade.

That's the automatic car not the 6-speed. 3.73 gears, 3600 stall converter 400# Eaton posi and a built transmission that does shift a bit harshly on the street. Maybe it was all the weight savings from the aluminum driveshaft. The driveshaft is from the police package in a Ford Crown Vic. Just a wee bit longer than the Impala driveshaft and I used some funky u-joints that are Ford on one pair of cups and Chevy on the other. Spicer stuff.

The engine does seem to make some real good torque. With all that weight I needed it. Smallish intake ports that flow around 312 CFM on the intake and 1 3/4" headers. I'd love to get the ole' gurl dyno tuned. Do you do OBD1 stuff or just the newer OBD2 stuff? I'm always up for a road trip. I drive to Buffalo, NY for chicken wings and Wells, Maine for lobster. Baltimore is for crab cakes and I'll be going to Houston for some barbeque and New Orleans for some Royal Red shrimp this spring. Might as well stop in Florida to get a tune.:thumbsup:
 
#34 · (Edited)
It was a Nitrous Power Adder Pass you made 12 years ago on Corvette Forum with your SS Impala.
No 4.56 gears in yet.
3-series.
No 90 /10 50/50 shocks.
No Moroso Trick Coil springs.

Did the Race math.
Made way more N/A power possible from your combo specs times.
More advanced than 3rd grade math.
 
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