quote Originally posted by 1BadGT: I think I had to choose the Megasquirt because I still require the stock caddy ECM for the 4t60e tranny.

Have you considered just switching to a 4t60 non electronic shift trans? You can find them in any 90 caddy. Then you could do away with the stock 4.9 PCM and throttle body/ISC motor. Might be worth looking into. A good starting tune already exists for using a 7730 ECM on a 4.9 turbo.

[This message has been edited by Fieroseverywhere (edited 09-29-2009).]

quote Originally posted by Fieroseverywhere: Stock programmed redline on the 4.9 is 5252 (fuel cut off). The limiting factor in a stock 4.9 is the 4t60e shift points set up in the PCM. They don't allow the motor to rev above 5000 (actually 4800 IIRC). However the 4.9 can rev to 6000 on stock valve train with the fuel cut off limit moved. In stock form they just don't make much power up there so without the other mods there really is no point. They do a little better with a cam re-grind. Adding a turbo though... Going higher then 6k requires valvetrain mods which most 4.9 guys know don't exist in a bolt on form. There are options out there but require a good amount of custom head work which is pretty cost prohibitive unless you can do it yourself. New valve springs, cam and possibly rockers are in order at the very least. Mine currently revs to 5600 easily and makes decent power there with only a mild cam.

That's some very helpful info concerning another issue I've been having with the car. Do you have build thread or the like with some detailed info on that? I always suspected it was possible to milk quite a bit more out of the engine, but I wasn't planning on doing anything until this engine needed a rebuild (hence the turbo )

That's one major showstopper for my 4.9L right now is the stock tranny/ECM making making the car bounce off the limiter at WOT on shift points. I had talked to Rockcrawl long ago about fixing that but I never kept up with him to see if he (or anyone) worked a way around that in the stock ECM. It sounds like you may have a way...

I'm definitely intending to see how far I can take this engine (or another 4.9L or two after it). I'm still searching for a 4.5L Allante to steal some stuff off that (intake, rocker arm supports, valve springs) and those will go on the car as soon as I find them regardless where I am in the turbo project. IF anyone has said items available please let me know.

I might be of more help then.

First off let get you all the Allante stuff you could ever need...
http://www.allantesource.com/contactus.htm
Give Dick a call. He can get you anything you need when it comes to the Allante and has almost everything in stock. He's got the best prices also and thats counting shipping from Florida. If you order all the allante intake stuff try to get a PCM also. They use different idle control motors and it seems no one has the files for the allante motor in particular. StickPony here on the forum has been looking for them. I think the 7730 ECM will also run it and the knock sensor really is key.

Now you may or may not know this already, Tunercat now has definition files for the caddy 2240 PCM and a couple others that were used for the 4.5 & 4.9PFI's. I haven't looked into it fully but they may have everything needed to be the first 4.9 to run a turbo on the stock PCM. It could really help open the door to an easier 4.9 turbo. Wouldn't that be cool. The only drawback that I've seen so far is it appears there is no provision for a knock sensor on the 2240. Let us know what you find if you look into it.
http://www.tunercat.com/tnr...cm_sup.html#cadillac

For the rev limit bouncing there should be an easy fix. Either the shift points can be adjusted or you could raise the rev limit to keep from hitting it. Either way is possible as far as I know. Don't take my word for it though, I'm not really an auto guy and haven't played with the "E" ones at all. I do wonder if the internals are the same for the 4t60 non and electric shift? Might give yet another option if they are.

One of the major bonuses to the 7730 ECM is the fact that you can get a harness for a 305 camaro from painless and basically have a plug and play setup. I pretty sure it even includes a knock sensor connector.

I don't mind the soft shift for my setup. Thats a manual thing though. Without it its not hard for the motor to stall when pushing the clutch. The 4.9 rpms just drop really fast, even without an aluminum flywheel. I can see how it would seriously suck for an auto though. Again though, this can be adjusted in the PCM either by shift points or the "desired idle" setting. I may not be calling it the right thing. On my scanner it says "desired idle". Basically its the RPM the ISC holds until the speed goes below 5mph.

Thanks for the Allante site; I'd passed by it real quick and wasn't sure if they'd be able to help. I'll give them a call soon. All I'm looking at getting for is the Upper/Lower intake manifolds (off an '89-'92, good-bye EGR) and fuel rails. If he can pull the valve springs and steel rocker arm support, I'll take those too.

I've been doing a lot of research on Megasquirt and it looks like I can do everything with it, MAP, knock, AND electronic shifting. So it looks like I'm going to go with that.

I spent a good bit of time researching the different ECM options and none appear to work for me. I really would have liked to get into the chips and make this a bit easier for anyone else dreaming of turboing their 4.9L, but it just can't happen with my setup. I'd have to use both the 16132240 and the 1227730 or 1227749 to keep all my features. Still, I found a pretty cheap kit for datalogging, burning and emulating ECMs...so I might do that one day.

Sorry it took me so long to respond...I just got home today from a 3 month deployment so it took a bit to get settled in.