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Turbo LS, 4l80E being replaced by Dual Clutch, 4 link
It's time for a build thread.
I've built lots of fast turbo cars before (Dodge), but with only half the cylinders. The goal for my first 8 cyl american muscle car is car that can really cruise the streets comfortably as well as race at the strip, somewhere in the 10s.
It's going to look stock, not with some huge hood bulge, or open headers poking out of the nose. I'm keeping the heater and the retractable headlamps. As most of you who have worked with C3s before know, it's tight for turbo and stock appearance.
I like to do things a little different from most, so I'm not just dropping in some bolt ons. It's also a platform for me to test out some of my crazy ideas.
In my opinion, 4l80E fits the bill for a street/strip car since it has overdrive and huge power capabilities.
After I get most everything mocked up and tested, I'm going to tear it all down and send the chassis out for powder coating.
For mid 10s, gotta have the roll bar. I think I can get by with 5 point with hinged drivers side arm bar, so I can comfortably street the car.
Picked up a 2002 5.3 and 4l60e from a 12,000 mile wreck for $400 from JY. But water got into the engine while it sat in the Tahoe for 13 years and needed a rebuild. Sold the 4l60E for $350 which paid for the re-bore and new pistons and rings. I'm keeping this engine's internals stock for starters, but expect at some point to replace it with a forged 6.0.
Last edited by DblTrbl; 04-18-2023 at 08:28 AM.
Reason: update
Sounds interesting. Keep us posted.
Where in central Jersey are you?
In Middletown. I see the raceway park building behind your vette. Hope to see you in the lanes sometime in the future for side by side C3 action. Although Lebanon is close to Island, don't get there too often nowadays.
Needed to make room for all the turbo stuff, so I removed all the vacuum headlamp stuff and bought linear servos from Ebay for about $30. Made adjustable mounts using screws so I can tweek the open and closed height. Works perfectly, but these servos are not as fast as vacuum operated ones (on the rare occasions when they actually worked) but now there's a whole lot of room. Ebay has different speed servos available.
All is takes is a relay and they open automatically when the headlamps are turned on and close automatically when the lights are turned off.
Did research as to what it would cost to beef up the rear end and decided it to build a 4 link instead. I'm using a for 8.8 rear with 9 inch internals, 31 spline. Found a Ford F150 rear with nearby for $100. I didn't go with a kit for the 4 link because my rear end had 3.25 tubes and the kit is designed for 3 inch tubes, so i sourced components instead.
I narrowed it and welded Big Ford Ends. The rear came with a 4.10 ratio and a posi.
I had it bored .020 over to remove the rust after it sat for 13 years in the wreck. Put back stock style .020 over pistons. Ring gap .025. Cleaned up the head and refreshed valve seats. Changed springs to higher spring rate.
Chassis ready for the new motor.
And the fun begins:
ended up moving the engine 3/4 inch forward of where the stock adapter locations were. It was just too close to the firewall.
Built brackets and idlers to bring the alternator down so it will fit in stock hood. No way I can see to fit an AC compressor. Really wanted to keep that.
Built a beefy turbo support. I see lots of unsupported turbos nowadays and it scares me.
Started by locating the turbo first, then the turbo collector and building the manifold back from there while trying to keep clearance for suspension and frame components.
Radiator and Intercooler install. Instead of hanging the Radiaor from the body, I'm supporting the radiator and intercooler from the frame. This way I can slide the body on and off to insure everything fits.
I built a fan shroud out of fiberglass, that supports a 14 inch and a 10 inch fan. The intercooler has two 12 inch fans.
The radiator return hose is temporary. I'm going to replace that black section (borrowed from a BMW E30) with a stainless 90 degree tube.
Fuel supply line is 8 AN. It has a Y before the fuel rail. Both left and right sides are fed directly from the 8 AN feed line. There is another Y on the other side of the fuel rail that goes to the 6 AN return line. So both left and right fuel rails are fed in parallel instead of in series. I'm planning on having this car run on any mix of gasoline and E85. Maximum boost will be limited automatically by the percentage of E85 to gasoline. With E85, you need about 30% more fuel than gasoline, so the parallel setup will insure the last cylinder is not fuel starved.
The injectors are 80# Siemens.
Twin Wallbro 255HP pumps are connected in parallel as well. One fuel pump will come on when the engine starts and the second will come on as some preset boost value.
I built the fuel system this way in case I decide to up the horsepower somewhere down the line. That would require a bigger turbo and injectors, maybe also a change of fuel pumps.
I drilled some holes in the chassis on the passenger side and will snake the fuel feed and return lines through the chassis.
I added an offloader circuit into the wiring harness. What it does is turn off all heavy electrical loads while the engine is cranking. This leaves more battery for the starter.
It's just a 4 pole relay that is normally closed. 1 pole for the radiator fans, 1 for the headlights, 1 for the intercooler fans, one for the heater fan.
when the starter gets power, this relay opens all of these electrical loads.
Upside... 8 direct injectors. 8 direct GM coils, throttle by wire, some canbus support, internal and external logging, built in wideband and, got a smoking deal on a new unit. lots of extra inputs and outputs, all programmable, small, waterproof, huge amount of flexibility (maybe too much).
Downside I've seen so far... not as many GM users, would like to see better support. No auto tuning. No built in transmission control. I wouldn't suggest it for newbs, but it's got all the bells and whistles.
I've had good results with previous generations of AEM controllers, we'll see how this one works out.
One of the features I'm really counting on is the ability to blend the E85 and gasoline maps. E85 is not as easily obtainable as I'd like around here, so the tank will usually contain a mix of gas and E85. The percentage of E85, the more boost I can run. AEM connects directly to the E85 sensor which I'm going to plum into the return line.
I used the connectors that came with what was left of the junk yard harness to build a new harness for the AEM.
08-10-2016, 02:33 PM
Turbo LS, 4l80E being replaced by Dual Clutch, 4 link
. The goal for my first 8 cyl american muscle car is car that can really cruise the streets comfortably as well as race at the strip, somewhere in the 10s.
