Starting to Learn on 95 G30 5.7 for Towing

[Fast355]

Thanks for the heads up. The converter has been changed to a recent 3" but it has a few goobers stuck to the bed. It may get left off for now, to be replaced in the future. No bathtub pistons, the standard ones that all light duty vans have. No ridge and very little carbon build up. My van is 800 lbs short of the heavy duty GVW. I found it has a replacement passenger side exhaust manifold made in China. The front port has the entire top half blocked off with some excess iron.

I just read back all 5 pages. I forgot you mentioned that the cat had been replaced. That exhaust manifold sounds like a junky dorman replacement. I am not a fan of having those cast iron heat sinks dumping heat into my cylinder heads but they are simple and usually reliable. You might be able to port out the casted shut part without hurting the integrity of the manifold. With the standard pistons you should be in the 9.3 to 9.5 range when you use the thin gasket.

[donf]

Out with the flat tappet, in with the roller.

[donf]

So new vortec heads will be here in a week via slow UPS from Jegs. They have some house brand castings that are made in the USA. I don't know a lot about them but they should be good enough for this mild engine.

[donf]

I have looked a lot on here the last few days and this place has a lot of information, but no where that I looked was a simple list of what to change for a starting bin when vortec heads and a mild roller cam are added. Here is what I think needed changed, this is not a tune, just a basic changes to fire the engine and prep for wide band logging.

1. Scalar: Change Engine Constants - Injector Flow Rate from 61 to 74 to compensate for 18 psi spring
2. Scalar: Temperature for EGR On changed from 74.8 C (0x99) to 149.8 C (0xFD)
3. Scalar: Initial Spark Advance changed from 0.0 deg (0x00) to 9.8 deg (0x1C).
4. Table: Change both open and closed throttle Main Spark Table vs. MAP vs. RPM to base 1998 truck vortec timing table. zero out all negative numbers, smooth slightly.
5. Table: Desired EGR vs. RPM vs. Vacuum changed to 0.
6. Table: EGR Fuel Reduction vs. RPM vs. Vacuum changed to 0.
7. Flag: Code 32 EGR Failure changed from Set to Not Set.
8. Flag: Linear EGR/EVRV EGR changed from Not Set to Set.
9. Flag: Backpressure EGR changed from Set to Not Set

The idea is to let the computer know that the injectors now flow more fuel. Get the initial timing to 10 from 0 and load the most conservative vortec timing table. The Egr changes were made according to the instructions for the WBO2 zip and I increased the temp for EGR On to make sure it was off as I have it blocked. Any other suggestions? This is not a tune or even a complete list of what has been changed on my Bin, just some basics to build on and get the engine fired when switching to higher flow heads and a small cam on a TBI. There are a few thread where people lose 10 degrees of timing when messing with the scalars for timing so I just changed the one and will check to make sure its working as intended by setting the timing tables to all one number and reflashing as a quick test with a timing light.

[Fast355]

I have looked a lot on here the last few days and this place has a lot of information, but no where that I looked was a simple list of what to change for a starting bin when vortec heads and a mild roller cam are added. Here is what I think needed changed, this is not a tune, just a basic changes to fire the engine and prep for wide band logging.

1. Scalar: Change Engine Constants - Injector Flow Rate from 61 to 74 to compensate for 18 psi spring
2. Scalar: Temperature for EGR On changed from 74.8 C (0x99) to 149.8 C (0xFD)
3. Scalar: Initial Spark Advance changed from 0.0 deg (0x00) to 9.8 deg (0x1C).
4. Table: Change both open and closed throttle Main Spark Table vs. MAP vs. RPM to base 1998 truck vortec timing table. zero out all negative numbers, smooth slightly.
5. Table: Desired EGR vs. RPM vs. Vacuum changed to 0.
6. Table: EGR Fuel Reduction vs. RPM vs. Vacuum changed to 0.
7. Flag: Code 32 EGR Failure changed from Set to Not Set.
8. Flag: Linear EGR/EVRV EGR changed from Not Set to Set.
9. Flag: Backpressure EGR changed from Set to Not Set

The idea is to let the computer know that the injectors now flow more fuel. Get the initial timing to 10 from 0 and load the most conservative vortec timing table. The Egr changes were made according to the instructions for the WBO2 zip and I increased the temp for EGR On to make sure it was off as I have it blocked. Any other suggestions? This is not a tune or even a complete list of what has been changed on my Bin, just some basics to build on and get the engine fired when switching to higher flow heads and a small cam on a TBI. There are a few thread where people lose 10 degrees of timing when messing with the scalars for timing so I just changed the one and will check to make sure its working as intended by setting the timing tables to all one number and reflashing as a quick test with a timing light.

In no way shape or form would I use the stock Vortec timing map especially with a bigger cam than the Vortecs cam with.

I would start with the one I attached. Pull about 6° across the whole map if you are running 87 octane then creep up 1° at a time on the dyno until you find the best power or experience knock retard.

I run the same timing tables in Idle and Off-Idle tables. It helps keep the throttle response and transition back to idle from being jumpy.

I would on enable the linear EGR valve if I were using its input for a wideband.

In case anyone wonders the ignition timing map is more or less a computer version of the GMPP HEI distributor that comes in the HO and ZZ series of GM crate engines.

[donf]

Cool, thank you for looking at this. Yes they linear egr input was changed from not set to set, I am thinking that turns it on for the wideband. I think that turns that input on. I will edit the timing map match the one you recommended and pull some out for starters.

[Fast355]

Cool, thank you for looking at this. Yes they linear egr input was changed from not set to set, I am thinking that turns it on for the wideband. I think that turns that input on. I will edit the timing map match the one you recommended and pull some out for starters.

Hey Donf,

Just checking in and curious if you had made any headway on this swap.