Wow there is some really impressive work on display in this thread. Nice to see the ol' 4.9 getting some serious attention.

My 4.9 swap

quote Originally posted by chetw77cruiser: We should start a new thread so we don't hijack this one.

I don't see an engine management discussion as a highjack, since tuning engine management is pretty essential to getting the most from any built engine.

Ok, fair enough. Now, what were we taking about?

quote Originally posted by chetw77cruiser: Looks like the LS1 cam sensor outputs a 12v signal whereas the caddy puts out a 5v signal. I do not know it that is enough for the LS1 comp to recognize. I could make a circuit that could take the 5 signal and output 12 to the pcm, but I do not know durable that is. On the other hand, the LS2/LS7 system does use a 5 volt signal. Food for thought.

i see, in addition to the 5v vs 12v, is there anything else different, perhaps number of reference points on the camshaft?

also, dont all ls2/ ls7 systems use drive by wire? if thats the case, an ls2 throttle body would need to be used instead of the lt1 or ls1 throttlebody

seems the hunt for better tuning capability on the 4.9L continues LOTS of variables to consider

the LT1 is certainly a deliverable viable solution now, as proven by Robert with this thread, AND the optispark system actually has better resolution for troubleshooting individual cylinder problems than the LS1 system, at least according to all the corvette forums...

[This message has been edited by stickpony (edited 01-14-2012).]

I would like to get an LS1 computer and harness with all the sensors and set up a bench test with it. This way I can see what works and what doesn't. In the meantime, I will have to get an LS1 cam and crank sensor and measure the output signal voltage and waveform to make sure it is a 12v square wave signal. I doubt it though based on other research. As far as a converter from 5 to 12, I have an idea that will most likely work and is simple enough. Being that there would only be a couple electronic parts, I would imagine that it would be reliable as well.

I believe that the LS1 computer can still be used with a few mods to the wiring.

quote Originally posted by Will: I don't see an engine management discussion as a highjack, since tuning engine management is pretty essential to getting the most from any built engine.

I’d agree, this thread was meant to be focused on PCM alternatives for the 4.9L since it has been the biggest hindrance to further development (IMHO). So don’t worry about posting other alternatives, I welcome them. I looked into LS based systems and even megasquirt, but being I wanted to keep the 4t60e and I really like staying with OEM components when possible I went with the LT1 PCM and associated components. An LS PCM would have taken some serious changes to run the 4t60e, at least as I could tell. (read: electronically challenged) The LT1 was plug & play after the distributor conversion, well I spliced a lot of wires to make a clean harness but no other component had to be altered to work right.

One of the big advantages to running the LT1 PCM with the LTCC (LS coil per cylinder conversion) is that the unit has built in rev limiter and timing retard for drag launches, NO2 & boost. They have several input options, so say when a Nitrous solenoid is activated the 12V signal would also be sent to the control unit and it would instantly retard timing by whatever value you set. Leaves lots of room to grow in the power department.. I nick-named it the Magic Box, here’s some pics:





(It's alot cleaner now...)

Here is a link to Bob Bailey’s site for the LTCC: www.bailey-eng.com/LTCC.html


Cheers

After conducting a bit more research, it appears that at least the earlier LS1 computers control the auto trans the same as the LT1 computer. The only difference it seems was the PC solenoid which seems to have been changed in 93 or 94. Since the 4t60e does not have a PC sloenoid, there shouldn't be a problem. Still doing research for other issues that may come up.

quote Originally posted by chetw77cruiser: After conducting a bit more research, it appears that at least the earlier LS1 computers control the auto trans the same as the LT1 computer. The only difference it seems was the PC solenoid which seems to have been changed in 93 or 94. Since the 4t60e does not have a PC sloenoid, there shouldn't be a problem. Still doing research for other issues that may come up.

LS1 came out in '97, in the C5 only as far as i know... i would look to that year as being probably the only year that might be different from the current LS engines, since Gm usually uses transition years to retain some of the older engine controls mixed with the new. let us know what you find.

[This message has been edited by stickpony (edited 01-14-2012).]

Near as I can tell there wasn't much of a change in regard to the transmission control connections. Based on what I have read, the LS1 comp could even control the 4t65e, but no guarantee on that. If this is going to work with the 4t60e, there is going to have to be some major tuning changes in the ls1 code. Unfortunately I do not have the equipment to program the LSX series of computers so I am no help there. That is why I am going a different route with my engine and trans control, if I go with an auto that is.

[This message has been edited by chetw77cruiser (edited 01-14-2012).]

Here's what I was thinking of:
http://www.eficonnection.co...iconnection/24x.aspx

The 24x trigger wheel allows the use of the LS1 computer on an LT1 or traditional SBC. I'm trying to convince my dad to mill out a custom sensor mount to go in the mechanical fuel pump location on the Caddy 500 and read one of these trigger wheels.

The resolution on the LT1 wheel essentially doesn't matter because there's so much "monkey motion" between it and the crankshaft: timing chain/drive harmonics, varying valvetrain drag, oil pump drag and surges, backlash in the distributor drive, etc.

The LS1 wheel reads the crankshaft directly.

The issue of crank sensor resolution is vastly overblown anyway. I calc'd a while back that a 4 cylinder using a 1 trigger pulse per ignition event (worst possible case for timing error) was going to have <0.1 degrees of timing error at 1000 RPM per second acceleration rate.

Also, the LS1 computer can be tuned with HP Tuners and EFI Live. It's not the same as LS2, etc. with drive by wire (I think all the DBW apps except the very early LS4 use the 58x trigger wheel anyway).

[This message has been edited by Will (edited 01-15-2012).]

quote Originally posted by Will: Here's what I was thinking of: http://www.eficonnection.co...iconnection/24x.aspx The 24x trigger wheel allows the use of the LS1 computer on an LT1 or traditional SBC. I'm trying to convince my dad to mill out a custom sensor mount to go in the mechanical fuel pump location on the Caddy 500 and read one of these trigger wheels. The resolution on the LT1 wheel essentially doesn't matter because there's so much "monkey motion" between it and the crankshaft: timing chain/drive harmonics, varying valvetrain drag, oil pump drag and surges, backlash in the distributor drive, etc. The LS1 wheel reads the crankshaft directly. The issue of crank sensor resolution is vastly overblown anyway. I calc'd a while back that a 4 cylinder using a 1 trigger pulse per ignition event (worst possible case for timing error) was going to have <0.1 degrees of timing error at 1000 RPM per second acceleration rate. Also, the LS1 computer can be tuned with HP Tuners and EFI Live. It's not the same as LS2, etc. with drive by wire (I think all the DBW apps except the very early LS4 use the 58x trigger wheel anyway).

I look forward to seeing your results with the caddy 500 LS1 conversion. the fab work on adding a crank sensor and reluctor wheel seems to be a reasonably fun challenge

[This message has been edited by stickpony (edited 01-15-2012).]

I'm interested if you guys come up with anything - I looked into all the reluctor wheels and such to use an LS1 PCM, but in the end decided stabing a dizzy was easiest option.

Particularly interested in the Caddy 500 build, I got one sitting the garage I'd like to use some day.

Since I posted about the LTCC, here’s some pics of the coil per cylinder conversion. The bracket I fab’d up won’t win any beauty contest but it did exactly what I wanted with being hidden and tilting the coils forward.

Nice build! Looks like quite a lot of work.

Any reason for not going stand-alone? I was going to coil-on(or near)-plug my 4.9 but, the coils were a bit more than I was looking to spend. It just looks like a lot of fabrication to get it to jive with some other stock electronics. Fabrication that you really did a nice install on! I megasquirted mine because I was too lazy to trick the stock stuff in working.

Best of luck on your project.

quote Originally posted by IceRacer: Nice build! Looks like quite a lot of work. Any reason for not going stand-alone? I was going to coil-on(or near)-plug my 4.9 but, the coils were a bit more than I was looking to spend. It just looks like a lot of fabrication to get it to jive with some other stock electronics. Fabrication that you really did a nice install on! I megasquirted mine because I was too lazy to trick the stock stuff in working. Best of luck on your project.

Thanx!

I wanted to stay with an OEM option - $125 for LT1 PCM and wiring harness, or could have pulled on from the local yard for @ $75. I got the coils off eBay, brand new Gen III (hottest coils to date) for $199. With the LTCC ($399), everything was plug & play = spent more time doing the wire harness than fabricating. Added bonus is the built in timing retard if/ when I go turbo or NOS. Using stock PCM makes it easy to datalog and tune as well..

Got pics of your megasquirt setup?

Cheers

Sorry,

I don't really have any pictures of the install... well maybe a short video...
http://www.youtube.com/watc...VvMQ&feature=related
That just after I did the upgrade from MS2 to MS3. The bad throttle response was having the sequential injector phasing out by 360 degrees... It barks better now...

It was a quick and dirty install (as you can see)... I basically jammed the stock harness into the trunk, cut out the bottom of the trunk to fit the straight exhaust and wired it to the megasquirt. I did replace that ratchet strap engine mount with an angle bracket and some threaded rod. By no means a legit road car install!

It will still do launch control/2 step/3 step, flat shift, anti-lag, traction control, full timing and fuel, didn't bother with the knock sensor but could do that too.... Electronic boost control I had running on my MR2... Fully sequential ignition and fuel...
It will basically run any trigger wheel combination (including the crazy 3 tooth grand national stuff!) and pretty much any coil setup, though it requires additional high current drivers for multiple non-logic level controlled coils.
The ms3 was around $400 bucks... but I end up switching them around cars. I've probably done 7 different MS's now... I just find it easier.

That is what I am going to use on one of my project cars, probably with the 3.4 DOHC with MAF/MAP blending. I have done 29 MSII/III swaps, with and without MS3X, and find that it is a great way to go. Will just about work with anything, other than the kitchen sink. I am sure someday that will be taken care of as well.

Simple solution here....take everything with wires off and slap on a carburetor.

I am completely kidding...

Kidding aside, there are times where a carb is the way to go. I have kept my back country FJ60 Landcruiser non-efi and kept the transistorized ignition. Much simpler and you can't argue the reliability, especially after 278k miles with no problems.

I wonder how well or how not well a 4.9 would work with a carb on it using a 4.5 port injection intake.

quote Originally posted by mattwa: I wonder how well or how not well a 4.9 would work with a carb on it using a 4.5 port injection intake.

Try searching the archives, I know someone did a carb 4.9 - used an olds distributor and an adapter plate if I recall.

Carbed 4.9 may have been with the early 4.1/4.5 TBI intake also...

Bubbajoe's early swaps used a carb and the Olds distributor.

81 4.9L X-11, I sent you a PM earlier if you didn't get it.

Replied,

Cheers

Here's some pics of the throttlebody adapter I made to use the LT1 throttlebody on the Allante intake. I put it at an angle to clear the master cylinder, not that anyone doing it in a Fiero would have to worry about it.

I traced gaskets from both the LT1 & Allante throttlebody's and had them drawn in autocad, then had 10mm aluminum plates laser cut. This allowed me to build the side with 1/8" aluminum plate. Works very well !!
















Time for a little porting....

Can't wait till you get this dialed in with that LT1 PCM, and then dynoed so all can see the real power and TQ potential of the caddy 4.9L maxed out without a turbo, nobody has ever built it up like this and then actually fine-tuned it afterwards. Rick Stewart did a build almost as radical as yours Rob, but he just fell way short when it came to tuning. His car just loaded up pig rich and he was getting 12-15mpg, before he sold it.... anybody know where the vehicle's new owner is? he might want to check out this thread!

Dyno results?

Sorry, no dyno yet - no good excuse, just been busy. I'm doing a ridiculous LS4 build and I need to adjust the lifter preload & relocate the wideband O2 bung on the 4.9 so they are competing for garage space (need new build out of garage). I'm hoping to get it sorted and dyno'd by end of June.

Let's see if I can make this video of the autocross at SuperChevy work..

Guess, not here's a link: http://www.youtube.com/watch?v=7KP8qhlT0n4


Cheers

[This message has been edited by 81 4.9L X-11 (edited 04-14-2012).]