Z-26 3.4 DOHC Turbo
Posted: Sat Nov 17, 2018 10:44 pm
Note: Okay, this will be the 'final' resting place for the info on this car, as it goes along. Most of the 'build' as it happened is in the 'General' section under 'Finally', but as this is now a 'ride' and not a 'build' or 'discussion', I felt it should come here.
So, here it is:
The car: 1995 Z-26, bought with 105k miles for $400 with the all-too-common 3100 rod-knock, courtesy of GM's typically failed LIMGs. Black Rose Metallic (BRM) with grey interior, and typically equipped for a '95 Z; A/C, Cruise, Power Windows and Doors, Cassette Radio, FE3 Suspension and the 16" Saw-Blade Z Wheels.
This was a well-liked, cared-for Z before the LIMG failure. Nice tires, the paint was kept clean and probably waxed, I would guess it was garaged for most of its' life. There are definitely flaws, but they are fewer than expected for a 23-year-old car. Even the engine-bay was kept clean (at least on the top). Virtually zero rust, except for minor surface corrosion underneath the battery.
The Engine: 1995 LQ1 3.4L DOHC V-6, also known as the 'VIN X' 24-Valve H.O. Twin Dual Cam engine. This is a full SFI engine, MAF operated fuel management. These engines were de-tuned by GM, rumors persist that it lost ~33% of its' initially design power, supposedly to keep the then-new 4T60E alive for the duration of its' warranty, and in '95 it was rated at 210 H.P. (add five more for the manual transmission models) and 215 foot-pounds of torque. The most interesting note being that the red-line was set about 1,000 RPM higher than the engine's push-rod siblings had. This was a High-Output RPM engine from the start. '95 was the last year with a lower CR (Compression Ratio) and supposedly the last year this timing-belt engine remained non-interference.
I pulled this particular example around a decade ago, intending on swapping it into a Fiero GT, but never got back to that car. The donor was a Chevy Lumina Z-34, wrecked at only ~64k miles. The engine cost me $150 at the local yard, complete from intake to oil-pan, accessories to flex-plate, even included the PCM (the W-Body Luminas placed the PCMs under the hood in '95) and wiring harness.
The Transmission: 1988 Muncie/Getrag 282, sourced from a Beretta GT. This is the oldest style of 282 -external slave-cylinder mounted on a steel bracket, and a fully housed jack-shaft. With it, I installed an LUK pressure-plate and the six-puck Stage-3 ceramic clutch disc from my GTU, replaced in that car when it got the 6-speed upgrade several years ago. This was the first clutch-disc in my GTU that didn't slip with the modified L367 3800 SC. Unfortunately, I've found that the LUK does not have sufficient clamping force for the LQ1 under boost...
Boost? Yep: The Turbocharger is a Garrett T-04, externally waste-gated unit, sourced from my '90 Turbo 'Retta -the pushrod 3.4 in that car had some troubles spooling that big turbo, so I moved it here. Before that, the turbo was brand new. The intercooler is another Blackstone unit, a very compact one that fits under the hood, where the battery usually sits. A full 3-inch mandrel-bent exhaust system runs back to a dual-out Flowmaster muffler, which then terminates in Twin Dual (see what I did there?) Z-26 exhaust-tips. A high-flowing short cone-filter keeps it fed on the 3-inch inlet side, again, still kept inside the engine-bay. A silver-faced backlit Vacuum/Boost gauge installed at an angle to the side of the instrument cluster clearly displays the 9-pounds of boost the wastegate is currently dialed in for. It will look more at home once I swap in the silver-faced electroluminescent gauge face from my other '95 Z-26...
Extras: The five-speed is rowed with an early-'90s Grand Am shifter -this uses a threaded shaft instead of the Berettas' stamped-steel arm for the shift-knob to attach to. I found a heavy Stainless Steel shift-ball I liked for a good price -it feels great and looks great with a 'Neo Chrome' finish.
While installing the clutch-pedal assemble, I swapped on a Fourth-Gen Camaro pedal pad, and matching 'ABS' brake pedal pad, both with honeycomb design.
The LQ1 is usually topped by a plastic plate that fills the spot between the intake manifold's long runners and the huge front-bank valve-cover. I have replaced this with a trimmed-down IDI top-cover from a 2.4 Twin Cam LD9. This cover also keeps the ignition cables tucked out of the way on my engine, until they head to the coil-pack placed near the right strut-tower instead of mounted to the front of the engine, as they are also on older 2.8 and 3.1 MPFI engines.
What was needed: This swap has been talked about since this engine was actually hot news, that was a long time ago! There have only been a few serious attempts made that I am aware of, and nothing ever brought close to completion. This is a tough engine to fit in a Beretta, especially keeping in mind that it will need to be maintained, and possibly repaired someday. The LQ1 does use a timing-belt, but the belt is a unique design that is driven by an intermediate shaft -it does not run all the way to the crankshaft, nor does it drive the water-pump or anything else besides the four overhead cams. Therefore, the whole job can be done on it from the top, no wheel-removal necessary!
Custom engine mounts were required to position this engine in the Beretta's diminutive bay, and while harder to fab than the mounts in my GTU's 3800, they were very cheap to make.
A Big Block Mopar mount (cost was ~$3.60) and reclaimed steel plate made up the front lower mount, a stock GM bracket comprised the right rear, and a variation of the under-side transmission mount I designed for both my '90 Turbo 'Retta and my 5-speed Northstar Indy holds the transaxle in place. The stock Z-34 upper torsion mount bolts to a steel brace bolted across the entire length of the upper radiator tie-bar which in turn uses W-Body braces to bolt it to the strut-towers/strut brace (sourced from an H-Body) to keep the entire engine-bay supported and reduce body flex. The stock Z-26 torsion-brace ('Dogbone') bracket bolts right to the LQ1, but it now sits slightly rearward and lower than the stock 3100 did, so a custom Dogbone will be needed -I haven't decided if that is necessary yet. So far, the engine sits pretty solidly within the bay.
Radiator hoses were also a custom deal -I purchased a silicone hose kit for a Honda Civic, chopped one of the hoses into three pieces and installed a Toyota filler-neck/cap assembly from a 1NZ. One Civic hose is cheaper than two Beretta hoses, and will probably be easier to obtain in the future, sadly. The cooling fan is stock Beretta, but the '95 V-6 version is too thick, and would have to be installed prior to engine installation. I was able to wedge in a thinner unit, I believe it is from a '92 Quad...
Heater hoses were going to be as hacked-in as GM's original design (I am spoiled by how well the 3800's heater-hose fittings fit our cars), so I ended up with aluminum tube and a flare fitting on the engine's outlet, and a pipe and hose setup on the return. No leaks thusfar, heater works fine too. The throttle-body heater port has been plugged -I do not live in Alaska!
Wiring was what I made out of it: The LQ1 is a 60-degree V-6 at heart, and is run by the same ECM used on a 3100 SFI, so long as the 3100 came from a W-Body... It is a totally different ECM than the L-Body uses, and even retains a PROM chip in '95. But some of the sensors and accessories (especially the alternator -more on that later) are in different spots. Reflashing the Beretta's PCM and splicing in longer wires would likely work just fine, but I don't like splices. So, I totally integrated the LQ1's wiring harness with the Beretta's, keeping everything stock in the Beretta except for the tape and loom, and avoided splices everywhere except for the one-wire temperature sensor for the gauge.
The exhaust cross-over pipe had to be modified for the Turbo -but that was an optional add-on. Stock, the LQ1 is designed to exhale through 2.25-inch outlets, per bank! That is over twice the outflow given to the 3100, and matches the single 3-inch pipe I used after the turbo almost exactly. Oil supply and return lines were also made necessary for the Turbo, and I opted for a large oil-cooler to help prolong the big Garrett's lifespan.
The Clutch Line had to be altered due to the size and location of the Turbocharger. Plastic generally does not belong in an engine-bay, in my opinion, and the clutch-line is no exception. Mine is now steel, with AN (37-degree) flared fittings and adapters in place.
The Big Chill-Less, also known as the Compromise: The alternator on the LQ1 is mounted low, and to the rear of the engine. The Berettas have a frame-rail that arcs inward there, and unless I wanted the engine propped up high, the alternator wouldn't fit. So, I relocated it to the A/C compressor's spot, and deleted the A/C system. I can live with that -I also don't live in Arizona! The engine now uses a shorter belt, and while I've had concerns over the belt's contact to the water-pump which has changed due to the alternator's smaller diameter pulley, the car runs cool and consistent (according to my scan-tool, reading through the ECM).
Overall, this was one of the harder swaps I've done, but that was partially because I wanted it to be one of the cleanest too, regarding the general condition of the car. It took a long time to complete (months!) and I felt like the progress was constantly being stalled -but I also performed a five-speed conversion, and a Turbo installation too, which was not initially planned on being done right away.
So, here it is:
The car: 1995 Z-26, bought with 105k miles for $400 with the all-too-common 3100 rod-knock, courtesy of GM's typically failed LIMGs. Black Rose Metallic (BRM) with grey interior, and typically equipped for a '95 Z; A/C, Cruise, Power Windows and Doors, Cassette Radio, FE3 Suspension and the 16" Saw-Blade Z Wheels.
This was a well-liked, cared-for Z before the LIMG failure. Nice tires, the paint was kept clean and probably waxed, I would guess it was garaged for most of its' life. There are definitely flaws, but they are fewer than expected for a 23-year-old car. Even the engine-bay was kept clean (at least on the top). Virtually zero rust, except for minor surface corrosion underneath the battery.
The Engine: 1995 LQ1 3.4L DOHC V-6, also known as the 'VIN X' 24-Valve H.O. Twin Dual Cam engine. This is a full SFI engine, MAF operated fuel management. These engines were de-tuned by GM, rumors persist that it lost ~33% of its' initially design power, supposedly to keep the then-new 4T60E alive for the duration of its' warranty, and in '95 it was rated at 210 H.P. (add five more for the manual transmission models) and 215 foot-pounds of torque. The most interesting note being that the red-line was set about 1,000 RPM higher than the engine's push-rod siblings had. This was a High-Output RPM engine from the start. '95 was the last year with a lower CR (Compression Ratio) and supposedly the last year this timing-belt engine remained non-interference.
I pulled this particular example around a decade ago, intending on swapping it into a Fiero GT, but never got back to that car. The donor was a Chevy Lumina Z-34, wrecked at only ~64k miles. The engine cost me $150 at the local yard, complete from intake to oil-pan, accessories to flex-plate, even included the PCM (the W-Body Luminas placed the PCMs under the hood in '95) and wiring harness.
The Transmission: 1988 Muncie/Getrag 282, sourced from a Beretta GT. This is the oldest style of 282 -external slave-cylinder mounted on a steel bracket, and a fully housed jack-shaft. With it, I installed an LUK pressure-plate and the six-puck Stage-3 ceramic clutch disc from my GTU, replaced in that car when it got the 6-speed upgrade several years ago. This was the first clutch-disc in my GTU that didn't slip with the modified L367 3800 SC. Unfortunately, I've found that the LUK does not have sufficient clamping force for the LQ1 under boost...
Boost? Yep: The Turbocharger is a Garrett T-04, externally waste-gated unit, sourced from my '90 Turbo 'Retta -the pushrod 3.4 in that car had some troubles spooling that big turbo, so I moved it here. Before that, the turbo was brand new. The intercooler is another Blackstone unit, a very compact one that fits under the hood, where the battery usually sits. A full 3-inch mandrel-bent exhaust system runs back to a dual-out Flowmaster muffler, which then terminates in Twin Dual (see what I did there?) Z-26 exhaust-tips. A high-flowing short cone-filter keeps it fed on the 3-inch inlet side, again, still kept inside the engine-bay. A silver-faced backlit Vacuum/Boost gauge installed at an angle to the side of the instrument cluster clearly displays the 9-pounds of boost the wastegate is currently dialed in for. It will look more at home once I swap in the silver-faced electroluminescent gauge face from my other '95 Z-26...
Extras: The five-speed is rowed with an early-'90s Grand Am shifter -this uses a threaded shaft instead of the Berettas' stamped-steel arm for the shift-knob to attach to. I found a heavy Stainless Steel shift-ball I liked for a good price -it feels great and looks great with a 'Neo Chrome' finish.
While installing the clutch-pedal assemble, I swapped on a Fourth-Gen Camaro pedal pad, and matching 'ABS' brake pedal pad, both with honeycomb design.
The LQ1 is usually topped by a plastic plate that fills the spot between the intake manifold's long runners and the huge front-bank valve-cover. I have replaced this with a trimmed-down IDI top-cover from a 2.4 Twin Cam LD9. This cover also keeps the ignition cables tucked out of the way on my engine, until they head to the coil-pack placed near the right strut-tower instead of mounted to the front of the engine, as they are also on older 2.8 and 3.1 MPFI engines.
What was needed: This swap has been talked about since this engine was actually hot news, that was a long time ago! There have only been a few serious attempts made that I am aware of, and nothing ever brought close to completion. This is a tough engine to fit in a Beretta, especially keeping in mind that it will need to be maintained, and possibly repaired someday. The LQ1 does use a timing-belt, but the belt is a unique design that is driven by an intermediate shaft -it does not run all the way to the crankshaft, nor does it drive the water-pump or anything else besides the four overhead cams. Therefore, the whole job can be done on it from the top, no wheel-removal necessary!
Custom engine mounts were required to position this engine in the Beretta's diminutive bay, and while harder to fab than the mounts in my GTU's 3800, they were very cheap to make.
A Big Block Mopar mount (cost was ~$3.60) and reclaimed steel plate made up the front lower mount, a stock GM bracket comprised the right rear, and a variation of the under-side transmission mount I designed for both my '90 Turbo 'Retta and my 5-speed Northstar Indy holds the transaxle in place. The stock Z-34 upper torsion mount bolts to a steel brace bolted across the entire length of the upper radiator tie-bar which in turn uses W-Body braces to bolt it to the strut-towers/strut brace (sourced from an H-Body) to keep the entire engine-bay supported and reduce body flex. The stock Z-26 torsion-brace ('Dogbone') bracket bolts right to the LQ1, but it now sits slightly rearward and lower than the stock 3100 did, so a custom Dogbone will be needed -I haven't decided if that is necessary yet. So far, the engine sits pretty solidly within the bay.
Radiator hoses were also a custom deal -I purchased a silicone hose kit for a Honda Civic, chopped one of the hoses into three pieces and installed a Toyota filler-neck/cap assembly from a 1NZ. One Civic hose is cheaper than two Beretta hoses, and will probably be easier to obtain in the future, sadly. The cooling fan is stock Beretta, but the '95 V-6 version is too thick, and would have to be installed prior to engine installation. I was able to wedge in a thinner unit, I believe it is from a '92 Quad...
Heater hoses were going to be as hacked-in as GM's original design (I am spoiled by how well the 3800's heater-hose fittings fit our cars), so I ended up with aluminum tube and a flare fitting on the engine's outlet, and a pipe and hose setup on the return. No leaks thusfar, heater works fine too. The throttle-body heater port has been plugged -I do not live in Alaska!
Wiring was what I made out of it: The LQ1 is a 60-degree V-6 at heart, and is run by the same ECM used on a 3100 SFI, so long as the 3100 came from a W-Body... It is a totally different ECM than the L-Body uses, and even retains a PROM chip in '95. But some of the sensors and accessories (especially the alternator -more on that later) are in different spots. Reflashing the Beretta's PCM and splicing in longer wires would likely work just fine, but I don't like splices. So, I totally integrated the LQ1's wiring harness with the Beretta's, keeping everything stock in the Beretta except for the tape and loom, and avoided splices everywhere except for the one-wire temperature sensor for the gauge.
The exhaust cross-over pipe had to be modified for the Turbo -but that was an optional add-on. Stock, the LQ1 is designed to exhale through 2.25-inch outlets, per bank! That is over twice the outflow given to the 3100, and matches the single 3-inch pipe I used after the turbo almost exactly. Oil supply and return lines were also made necessary for the Turbo, and I opted for a large oil-cooler to help prolong the big Garrett's lifespan.
The Clutch Line had to be altered due to the size and location of the Turbocharger. Plastic generally does not belong in an engine-bay, in my opinion, and the clutch-line is no exception. Mine is now steel, with AN (37-degree) flared fittings and adapters in place.
The Big Chill-Less, also known as the Compromise: The alternator on the LQ1 is mounted low, and to the rear of the engine. The Berettas have a frame-rail that arcs inward there, and unless I wanted the engine propped up high, the alternator wouldn't fit. So, I relocated it to the A/C compressor's spot, and deleted the A/C system. I can live with that -I also don't live in Arizona! The engine now uses a shorter belt, and while I've had concerns over the belt's contact to the water-pump which has changed due to the alternator's smaller diameter pulley, the car runs cool and consistent (according to my scan-tool, reading through the ECM).
Overall, this was one of the harder swaps I've done, but that was partially because I wanted it to be one of the cleanest too, regarding the general condition of the car. It took a long time to complete (months!) and I felt like the progress was constantly being stalled -but I also performed a five-speed conversion, and a Turbo installation too, which was not initially planned on being done right away.