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Since I have seen so many threads about improving power in the 60*, maybe I can offer some tips on helping these engines perform better.
First, some factory specs:
2.8 V6 (RWD 82-85) RPO: LR2 VIN: B
Engine Description (LB6) 2.8L 60 degree V6 (Carbureted)
Horsepower ([email protected]) [email protected]
Torque ([email protected]) [email protected]
Block Cast Iron
Heads Iron
Valves 12
Displacement 2.8L (2800cc, 173ci)
Bore 89mm (3.503")
Stroke 76mm (2.992")
Compression Ratio 8.5:1
Intake / Exhaust valves 1.60" / 1.30."
Valve lift .347" / .394"
2.8 V6 (RWD 85-93) RPO: LL2 VIN: R
Engine Description (LB6) 2.8L 60 degree V6 (TBI)
Horsepower ([email protected]) [email protected]
Torque ([email protected]) [email protected]
Block Cast Iron
Heads Cast Iron
Valves 12
Displacement 2.8L (2800cc, 173ci)
Bore 89mm (3.503")
Stroke 76mm (2.992")
Compression Ratio 8.9:1
Intake / Exhaust valves 1.725" / 1.425."
Valve lift .393" / .410"
Cam specs on 2.8 TBI pushrod motors:
Stock Cam:
Centerline ATDC = 109* on both sides
Duration at .50 = Intake -196* exhaust – 203*
Max lobe lift at .50 = intake -.263* exhaust -.273*
Rocker ratio = 1.5
Gross lift = intake .395” exhaust -.410”
Lobe separation =109*
The first issue is the factory camshaft in all of the S10 2.8s is JUNK (as far as performance is concerned). The lift and duration are so weak it produces a poor power band and doesn't help when power adders are installed. (One of the best things you can do to these engines gets an aftermarket or GM performance cam. The stock cam duration is concise for low-end power but doesn't allow the engine to breathe well)
Some key points:
1. Intake: The intake manifold of TBI motors is very restrictive. It is best to improve your intake before your exhaust. Although it is more expensive than exhaust, it is easier to design your information to accommodate future exhaust upgrades than to create your exhaust for future intake upgrades. There aren't many aftermarket manifolds available, but a longer duration cam makes ALOT of difference in intake flow. The throttle body should also be on the list of upgrades. Holley made a 400 CFM TBI in place of the Stock 235CFM TBI, and of course, the 4.3 TBI and boring the manifold is the best TBI improvement.
The Holley 390 CFM /Edelbrock intake is another good option. There are a few others, but they
require more creativity.
2. Exhaust: The stock exhaust is restrictive. The less restriction, the easier it is for the exhaust to expel itself, and it makes the motor work much less to push the exhaust out. This is why headers make such an improvement over manifolds. Manifolds usually only have 2-4 inch runners. The exhaust gas slams into the manifold's abrupt enlargement or "log" and, in turn, cause quite a restriction. There are a few companies that make headers for the 60* engine.
Free and cheap mods:
Adding a little timing advance can add some torque in the bottom end, sacrificing very little in the top. The theoretical hot spot of a 2.8 is 14* advance at base timing for low-end torque and HP. Higher than that will remove the upper RPMs and may cause detonation (ping).
EGR, of course, puts inert gas into your cylinders. This effectively reduces detonation and NOX emissions. The bad thing is it also effectively reduces your engine's performance.
Summary- Get rid of it if you can.
A cold air intake will improve combustion.
GM TBI Specs:
Flow is lbs/hr @ 13psi
GM Part # / Engine / Flow / TBI bore
5235430 / 2.8L / 33 / 35mm
5235203 / 4.3L / 45 / 43mm
5235279 / 5.0L / 40 / 43mm
5235206 / 5.7L PU / 55 / 43mm
17084327 / 5.7L Police / 65 / 43mm
1708430 / Late BB PU / 80 / 51mm
5235231 / Early BB PU / 90 / 51mm
2.8/3.1/3.4 Power improvements:
Stage 1
A. Build a cold air intake. Parts are available on eBay for small pesos.
B. Bore the intake openings and install a larger TBI assembly. You can also install a manual fuel pressure regulator for increased pressure.
C. Advance timing to approximately 12* to 14* base timing. If the engine detonates, retard accordingly, although I think 14* will be fine.
D. Make sure there are no restrictions in the exhaust system – particularly the cat.
E. Install an electric fan and controller.
F. Check that all tune-up components are at peak efficiency. Change your oil @ 3K miles.
G. Make sure your tires are correctly inflated – I run 30F and 35R.
Stage 2
A. Install a more extensive cat-back exhaust system. 2 ¼" to 2 ½" is good. The larger will give the top end, the smaller for lower/mid-range power. There are many systems available for these trucks through Jegs and Summit.
B. Install a high-flow cat at least 2 ½" in/out. For the two ¼", use reducers at both ends. You can eliminate the cat, but I don't recommend it due to emission laws.
Stage 3
A. Install a set of headers and run a large Y merge pipe for the exit unless you run dual exhaust.
Two ¼" pipes from the headers to a Y pipe into the cat is the trick.
Stage 4
A. It's cam time! Select an aftermarket cam with about .480 lift and .285 duration with a 10* or 12* lobe separation. You will also need new lifters. You can go with less lift/ duration, but this is about right for a good power punch. Install a TRUE ROLLER double-timing chain. Close makes them for this application. Note how stretched the old chain was. The new unit will not pull as quickly.
Stage 5
A. Install a set of roller rocker arms. These are not cheap, but it's the last bolt-on that you can do. They come in 2 varieties. 1.6 and 1.5 ratios (stock). The 1.6 will give more lift and a little more power.
If you do all these stages, expect to spend close to $2K. I shopped on eBay, Summit and Jeg's, and IIRC this is approximately what I spent on my 3.4.
The result will be a 2.8 that puts out approximately 155 to 165 horsepower. This also applies to 3.1 and 3.4, resulting in more power due to larger displacements.
You can go completely wild and do internal mods (pistons, balance, porting, bigger cam etc.), but that is not the intent of this thread. This will give a healthy 2.8 that will pull up hills easily. Your fuel mileage around town will suffer somewhat, but on the highway, it will be ok.
I may have missed some of the minor mods that can be done; if anyone feels I have missed something, please feel free to add on.
Notes:
I have not covered any ignition systems; the ECU controls that with the TBI system.
If you go with a carb option, I am running a non-stock Mallory mechanical advance dizzy. There are other options also.
If you run a TBI system, you will never see optimum performance unless you do a 'tune' to the ECM. This involves running the truck on a dynamometer and adjusting the air/fuel ratio and timing for optimum performance. This procedure is somewhat complicated and requires hardware and software to interface the onboard ECU with a laptop computer.
If you are really creative, you can install a multi-port injection system from a Camaro/Firebird. This is probably the best option for performance. A good tune and has all of the five stages; I wouldn't be surprised if you could get 180 HP from a 2.8.
Thanks to s10planet.com, where I plagiarized some information.
And you know that Confucius has to say:
Man, with a good 2.8, go up hill easily...
First, some factory specs:
2.8 V6 (RWD 82-85) RPO: LR2 VIN: B
Engine Description (LB6) 2.8L 60 degree V6 (Carbureted)
Horsepower ([email protected]) [email protected]
Torque ([email protected]) [email protected]
Block Cast Iron
Heads Iron
Valves 12
Displacement 2.8L (2800cc, 173ci)
Bore 89mm (3.503")
Stroke 76mm (2.992")
Compression Ratio 8.5:1
Intake / Exhaust valves 1.60" / 1.30."
Valve lift .347" / .394"
2.8 V6 (RWD 85-93) RPO: LL2 VIN: R
Engine Description (LB6) 2.8L 60 degree V6 (TBI)
Horsepower ([email protected]) [email protected]
Torque ([email protected]) [email protected]
Block Cast Iron
Heads Cast Iron
Valves 12
Displacement 2.8L (2800cc, 173ci)
Bore 89mm (3.503")
Stroke 76mm (2.992")
Compression Ratio 8.9:1
Intake / Exhaust valves 1.725" / 1.425."
Valve lift .393" / .410"
Cam specs on 2.8 TBI pushrod motors:
Stock Cam:
Centerline ATDC = 109* on both sides
Duration at .50 = Intake -196* exhaust – 203*
Max lobe lift at .50 = intake -.263* exhaust -.273*
Rocker ratio = 1.5
Gross lift = intake .395” exhaust -.410”
Lobe separation =109*
The first issue is the factory camshaft in all of the S10 2.8s is JUNK (as far as performance is concerned). The lift and duration are so weak it produces a poor power band and doesn't help when power adders are installed. (One of the best things you can do to these engines gets an aftermarket or GM performance cam. The stock cam duration is concise for low-end power but doesn't allow the engine to breathe well)
Some key points:
1. Intake: The intake manifold of TBI motors is very restrictive. It is best to improve your intake before your exhaust. Although it is more expensive than exhaust, it is easier to design your information to accommodate future exhaust upgrades than to create your exhaust for future intake upgrades. There aren't many aftermarket manifolds available, but a longer duration cam makes ALOT of difference in intake flow. The throttle body should also be on the list of upgrades. Holley made a 400 CFM TBI in place of the Stock 235CFM TBI, and of course, the 4.3 TBI and boring the manifold is the best TBI improvement.
The Holley 390 CFM /Edelbrock intake is another good option. There are a few others, but they
require more creativity.
2. Exhaust: The stock exhaust is restrictive. The less restriction, the easier it is for the exhaust to expel itself, and it makes the motor work much less to push the exhaust out. This is why headers make such an improvement over manifolds. Manifolds usually only have 2-4 inch runners. The exhaust gas slams into the manifold's abrupt enlargement or "log" and, in turn, cause quite a restriction. There are a few companies that make headers for the 60* engine.
Free and cheap mods:
Adding a little timing advance can add some torque in the bottom end, sacrificing very little in the top. The theoretical hot spot of a 2.8 is 14* advance at base timing for low-end torque and HP. Higher than that will remove the upper RPMs and may cause detonation (ping).
EGR, of course, puts inert gas into your cylinders. This effectively reduces detonation and NOX emissions. The bad thing is it also effectively reduces your engine's performance.
Summary- Get rid of it if you can.
A cold air intake will improve combustion.
GM TBI Specs:
Flow is lbs/hr @ 13psi
GM Part # / Engine / Flow / TBI bore
5235430 / 2.8L / 33 / 35mm
5235203 / 4.3L / 45 / 43mm
5235279 / 5.0L / 40 / 43mm
5235206 / 5.7L PU / 55 / 43mm
17084327 / 5.7L Police / 65 / 43mm
1708430 / Late BB PU / 80 / 51mm
5235231 / Early BB PU / 90 / 51mm
2.8/3.1/3.4 Power improvements:
Stage 1
A. Build a cold air intake. Parts are available on eBay for small pesos.
B. Bore the intake openings and install a larger TBI assembly. You can also install a manual fuel pressure regulator for increased pressure.
C. Advance timing to approximately 12* to 14* base timing. If the engine detonates, retard accordingly, although I think 14* will be fine.
D. Make sure there are no restrictions in the exhaust system – particularly the cat.
E. Install an electric fan and controller.
F. Check that all tune-up components are at peak efficiency. Change your oil @ 3K miles.
G. Make sure your tires are correctly inflated – I run 30F and 35R.
Stage 2
A. Install a more extensive cat-back exhaust system. 2 ¼" to 2 ½" is good. The larger will give the top end, the smaller for lower/mid-range power. There are many systems available for these trucks through Jegs and Summit.
B. Install a high-flow cat at least 2 ½" in/out. For the two ¼", use reducers at both ends. You can eliminate the cat, but I don't recommend it due to emission laws.
Stage 3
A. Install a set of headers and run a large Y merge pipe for the exit unless you run dual exhaust.
Two ¼" pipes from the headers to a Y pipe into the cat is the trick.
Stage 4
A. It's cam time! Select an aftermarket cam with about .480 lift and .285 duration with a 10* or 12* lobe separation. You will also need new lifters. You can go with less lift/ duration, but this is about right for a good power punch. Install a TRUE ROLLER double-timing chain. Close makes them for this application. Note how stretched the old chain was. The new unit will not pull as quickly.
Stage 5
A. Install a set of roller rocker arms. These are not cheap, but it's the last bolt-on that you can do. They come in 2 varieties. 1.6 and 1.5 ratios (stock). The 1.6 will give more lift and a little more power.
If you do all these stages, expect to spend close to $2K. I shopped on eBay, Summit and Jeg's, and IIRC this is approximately what I spent on my 3.4.
The result will be a 2.8 that puts out approximately 155 to 165 horsepower. This also applies to 3.1 and 3.4, resulting in more power due to larger displacements.
You can go completely wild and do internal mods (pistons, balance, porting, bigger cam etc.), but that is not the intent of this thread. This will give a healthy 2.8 that will pull up hills easily. Your fuel mileage around town will suffer somewhat, but on the highway, it will be ok.
I may have missed some of the minor mods that can be done; if anyone feels I have missed something, please feel free to add on.
Notes:
I have not covered any ignition systems; the ECU controls that with the TBI system.
If you go with a carb option, I am running a non-stock Mallory mechanical advance dizzy. There are other options also.
If you run a TBI system, you will never see optimum performance unless you do a 'tune' to the ECM. This involves running the truck on a dynamometer and adjusting the air/fuel ratio and timing for optimum performance. This procedure is somewhat complicated and requires hardware and software to interface the onboard ECU with a laptop computer.
If you are really creative, you can install a multi-port injection system from a Camaro/Firebird. This is probably the best option for performance. A good tune and has all of the five stages; I wouldn't be surprised if you could get 180 HP from a 2.8.
Thanks to s10planet.com, where I plagiarized some information.
And you know that Confucius has to say:
Man, with a good 2.8, go up hill easily...
