Performance Cams for 2.0L engines

[PrecisionBoost]

With lift as high as what the cams are currently, I wonder if the valve reliefs will have to be increased in depth/diameter.... but the cams were based around the X20XEV which has a stock compression of 10.8:1....... so there is a good chance we will be ok with the lower T20SED compression.

I belive that the toothed wheel on the crank is the same between all the 2.0L engines.... so the ECU's for the newer sunbird 2.0L N/A with DIS could be used (since they had the crank trigger).... where as the older versions that used the distributor did not have the crank trigger.

I want to build standalone systems that are "smarter" than the current generation of engine management systems.

The Megasquirt for example is a great system but very complex and hard to tune unless you have lots of experience.... there are so many functions it makes it hard for the average person to know what to do for all the settings.

My idea is to simply have the factory ECU harness go into my standalone.... and then have a jumper to the factory ECU.

This way it can pass through information to read the initial maps..... it can simulate all the different sensor voltages and get correspoding outputs.

Then once it's done reading map info you can unplug the factory ECU and the standalone can take over all functions.

[C20GET]

I don't want to drag this too far off the mark. lmk if this should be moved.

The 1227749 C20GET ecm works with DIS and distributor ignition. You need an ignition system which provides the correct signals and you need the right settings in the calibration. With a replaceable toothed wheel, you can use a GM DIS system more common in North America than the Bosch style system used on the 'Woo.

The ecm for the C20NE, NA PFI Sunbird, isn't "cracked" yet AFAIK. There's no information publicly available to help you recalibrate that ecm.

The idea with reading the maps is a good one. But remember that you're reading from a system even more complicated than the Megasquirt. Especially if it's OBDII. I was just talking with someone about using scantool logs to accomplish the same thing. With enough of a log and some basic understanding of such things as temperature compensation for spark advance and Power Enrichment, it's possible to get a reasonably decent starting point for a new calibration.

OE ecm's are extremely complicated, but they don't have to be. It's possible to strip much of the code out of an OE box. Although no one has done it yet (publicly), it's also possible to write completely custom code from scratch.

If we just knew someone at GM willing to hand over the calibration documents, none of this would be an issue.

[decyphex]

Find out about the hydraulic grind and the possibility of purchasing blanks. No need (or use) in saying "I'm interested" in a cam that is too big for what I want.

Regrinds often take material away from the base circle to increase lift. Regrinds are relatively cheap but are restricted to similar lobe angles as the original cam. Fresh blanks give more freedom.

If the toothed wheel on the crank is a bolt on then you're not dedicated to using the 'Woo ecu. I know that the 92+ NA Sunbird crank and at least some 2.0 and 2.2 16V engines in the US use this arrangement. Cars using GM's 4T40E trans might even be able to use an ecu from a Cavalier / Sunfire and the associated tuning software.

The ignition system used on the USA version of GM's Ecotec engines senses compression to send a cam signal. If the signal is compatible then you could use a readily available system that has published specs and troubleshooting procedures rather than a custom system with only one source in the world.

I've got a 'Woo / Delco pcm sitting here on my desk. Haven't hooked it to my laptop yet to see if I can suck a calibration out of it. That's a winter project. But I'd love to get with more people to find out what other vehicles use this same pcm.

Love to talk more about some of your ideas. I've been tuning GM pcm's for almost 10 years now. Some things can be done without making new electronic boxes. BTW, the C20GET ecm has boost control built in. I don't know why people don't try to use it.

How do you hook these pcms to a computer? Is there any software out there that can be used to tune the sunbird NA computer?

[edit]

NVM!!!! I just saw the last post from C20GET... I was looking a the first page by accident.

[decyphex]

With lift as high as what the cams are currently, I wonder if the valve reliefs will have to be increased in depth/diameter.... but the cams were based around the X20XEV which has a stock compression of 10.8:1....... so there is a good chance we will be ok with the lower T20SED compression.

Chris, can you find out about this issue? If they do not conflict, I would love to buy the set!! Even if they do, I might still be interested... And... will these cams mess with idle on an automatic? I was told they wouldn't but might mess with vacuum for the MAP sensor or something?

[kinkyllama]

Any word on this?

[PrecisionBoost]

Zero time..... Kinkyllama.....I will hand you this info on the supplier..... do with it what you want.

Chris