LTCC w/non stock ECM?
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Joined: Sep 2004
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From: Boulder, Colorado
LTCC w/non stock ECM? Anyone running LTCC w/non stock ECM? I'm wanting to go with FAST or BS3 but haven't found anyone with both. I'm going to email FAST and BS3 tomorrow, but wondered if there was anyone here.
Thanks, TJ
Thanks, TJ
buddy of mine ran his LTCC with the FAST, I'll be running my stock pcm w/LTCC for awhile, probably going to use the FAST down the road so I can spin her up higher and I got used to tuning with the FAST somewhat, the wideband 02 would make the whole setup really nice for on the fly tuning.
Originally Posted by TonyJ
Anyone running LTCC w/non stock ECM? I'm wanting to go with FAST or BS3 but haven't found anyone with both. I'm going to email FAST and BS3 tomorrow, but wondered if there was anyone here.
Thanks, TJ
Thanks, TJ
Thread Starter
11 Second Club
Joined: Sep 2004
Posts: 304
Likes: 1
From: Boulder, Colorado
I've been running the LTCC for a year now. It works great. My problem is the dreaded maxed-out MAF and the weakness of the '95 pcm. I'd really love to be able to run wideband 02s and tweak the a/f for streetability and the drag strip.
Additionally, I've been struggling with a new Yank 3600 torque convertor that's giving the pcm and tranny fits. Very cool 1.5 60s then slams into the rev limiter before second. Right now I'm trying to decide between putting a fully manual valve body into the 4L60e or trying to do the job with programming. I've gone through 4 different program uploads from one of the ODB1 stall gurus to no avail.
Anyway, I've read about the ability of the BS3 to control the tranny and do all the other cool stuff, so I'm about to start diving into how it will work with my setup. Some of the stuff on my website might be out of date, but I don't think so... Click on "My Z28" in the top menu and see what you think...
Additionally, I've been struggling with a new Yank 3600 torque convertor that's giving the pcm and tranny fits. Very cool 1.5 60s then slams into the rev limiter before second. Right now I'm trying to decide between putting a fully manual valve body into the 4L60e or trying to do the job with programming. I've gone through 4 different program uploads from one of the ODB1 stall gurus to no avail.
Anyway, I've read about the ability of the BS3 to control the tranny and do all the other cool stuff, so I'm about to start diving into how it will work with my setup. Some of the stuff on my website might be out of date, but I don't think so... Click on "My Z28" in the top menu and see what you think...
Okay. The reason I asked is because if you didn't already have the LTCC, I was going to suggest looking at the LS1 version of the FAST or BS3 setups, because they're configured to handle the 8 coils straight out of the box with using only a crank trigger. You'd be saving yourself some coin by not having to buy the whole LTCC setup, and simplifying matters somewhat.
Originally Posted by thesoundandthefury
Okay. The reason I asked is because if you didn't already have the LTCC, I was going to suggest looking at the LS1 version of the FAST or BS3 setups, because they're configured to handle the 8 coils straight out of the box with using only a crank trigger. You'd be saving yourself some coin by not having to buy the whole LTCC setup, and simplifying matters somewhat.
The LTCC is designed to provide the stock PCM with the signals needed to run the motor in sequential as if it were still running the opti. But those signals cannot be used for sequential injection on aftermarket management. Im sure that DFI gen7, and both recent FAST systems will only run an opti equipped LT1 in batch fire. And with ALL of them (including BS3) you also have to run a cam trigger.
The best way I can see stepping up to BS3 or the likes, would be to get a GM cam trigger (Yes they make them, PM for part #... It looks just like the MSD cam trigger/dist. plug but cheaper)
And then somehow rig up an LS1 trigger wheel and pickup on the back of the balancer.
Then you could just get the BS3 for a LS1 and plug, play, enjoy
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Thread Starter
11 Second Club
Joined: Sep 2004
Posts: 304
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From: Boulder, Colorado
Originally Posted by Fire67
Yeah, but the crank trigger has to be an LS1 trigger and wheel setup right?
The LTCC is designed to provide the stock PCM with the signals needed to run the motor in sequential as if it were still running the opti. But those signals cannot be used for sequential injection on aftermarket management. Im sure that DFI gen7, and both recent FAST systems will only run an opti equipped LT1 in batch fire. And with ALL of them (including BS3) you also have to run a cam trigger.
The best way I can see stepping up to BS3 or the likes, would be to get a GM cam trigger (Yes they make them, PM for part #... It looks just like the MSD cam trigger/dist. plug but cheaper)
And then somehow rig up an LS1 trigger wheel and pickup on the back of the balancer.
Then you could just get the BS3 for a LS1 and plug, play, enjoy
The LTCC is designed to provide the stock PCM with the signals needed to run the motor in sequential as if it were still running the opti. But those signals cannot be used for sequential injection on aftermarket management. Im sure that DFI gen7, and both recent FAST systems will only run an opti equipped LT1 in batch fire. And with ALL of them (including BS3) you also have to run a cam trigger.
The best way I can see stepping up to BS3 or the likes, would be to get a GM cam trigger (Yes they make them, PM for part #... It looks just like the MSD cam trigger/dist. plug but cheaper)
And then somehow rig up an LS1 trigger wheel and pickup on the back of the balancer.
Then you could just get the BS3 for a LS1 and plug, play, enjoy
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Originally Posted by Fire67
Yeah, but the crank trigger has to be an LS1 trigger and wheel setup right?
You're correct about needing both a cam and a crank signal to run sequential injection. Here's the bottom line about sequential injection:
Timed vs. Batch
Sequential is a bit of a misnomer. Technically, all EFI systems are sequential in that once all cylinders have been injected, the sequence starts from the beginning again. A better term would be timed, implying that the starting and finishing of the injection pulse is timed with the intake valve opening. The idea behind this is to spray fuel only when airflow in the intake runner is established. This is supposed to mix fuel and air better and reduce manifold wall wetting. The other injection strategy is batch fired where several injectors are triggered simultaneously and not timed to the intake valve open period. In effect, the fuel sits in the runner for a short period of time before the valve opens and the airflow carries the mixture into the cylinder. Some people are dismayed that anyone would use the batch fired method however, there were tens of millions of Bosch and Bosch derivative systems sold in the '60s, '70s, and '80s which worked just fine using batch firing. It is a very well proven concept indeed. The SDS is also a batch fired system. The timed concept was developed mainly for tougher emission laws and EPA cycle testing where much of the cycle is run at low rpm and part throttle, where the time available to inject is long and the injector pulse is short.
Performance Applications
Performance applications are somewhat different from stock applications. Rpms are generally much higher, fuel flow rates are much higher and emissions usually take a back seat to power output. As rpm increases, the amount of time available to inject the fuel decreases. This is true whether the system is timed to valve opening or batch fired. The batch fired system has the advantage of being able to inject fuel for the entire period of crankshaft rotation whereas the timed system technically only has the time available that the air is flowing in the intake runner. This is determined mainly by the camshaft characteristics. On an average performance cam having 220 degrees of intake duration measured at .050 valve lift, the sequential system has only 61% of the time to inject the fuel as the batch fired system. As such, true, timed, sequential systems must have larger injectors fitted for a given hp. It should be remembered that there is little airflow and velocity in the port and runner until the valve is open a fairly significant amount. Starting the injection sequence early and finishing late, partially negates the supposed advantages of timed injection. On a high revving engine, there are only a few milliseconds available to inject before the next cycle begins. On the other side of the coin, with batch fired injection, the amount of time that the fuel sits in the port shortens as rpm increases. In the end, there are no significant differences in top end, wide open throttle, horsepower between batch fired and timed systems. We have also not seen any significant differences in fuel economy between the two strategies. Emissions at part throttle are likely to be better with timed injection as this is what it was developed for. On performance applications, emissions are often not an issue and most engines not equipped with a catalyst will not pass a modern emissions standard anyway.
Complication and Expense
Batch fired EFI systems are far less complicated from a software and hardware standpoint so it stands to reason that they will be less expensive to purchase and easier to program. Timed systems require camshaft timing information for the ECU either derived from a camshaft sensor or a multiple input signal from the crankshaft sensor. Timed systems also require a drive transistor for each injector, a separate trigger wire for each injector, cam timing specs, injector response time specs, cylinder firing order and the software to process the information. The person programming also requires a lot more knowledge on how all these aspects inter-relate to each other and the wiring for the injectors becomes much more complicated. If any of these steps are omitted or misunderstood, the timed system is no longer timed. Additionally, there are some aspects about intake port flow that very few people would have a clue about. You'd really be taking a bunch of guesses about when to start injecting and stop injecting the fuel. Is all this worth the trouble on the average performance/race application for little or no gain in hp? Would YOU understand how to hook up and program a sequential/timed system? I think those questions have already been answered. The batch fired system merely requires a tach frequency. Generally, for each ignition pulse, there is a fuel pulse. There are less wires to run and no complicated timing software to figure out. Very simple and it works very well.
http://72.14.207.104/search?q=cache:...s&ct=clnk&cd=1
I'm not intending for this to become a "batch vs. sequential" debate, but I wanted to offer an explanation about what the true differences between both systems are so that the thread poster has a little better idea of what he's getting into and can make an informed decision. If he decides that he wants to go with a sequential setup, then the cam trigger sensors mentioned by Fire67 would be a necessity in addition to a crank trigger wheel. As far as installing them: the intake would have to have a hole drilled in the location that a normal HEI type distributor would reside.
Does anyone know if the Delteq can be run w/ the FAST? Seeing how it still reads off the opti it should work in there, right? Just wondering if anyone knows off hand as I've been told 2 different things. Waiting on my harness and I have the XFI so I'll be the 1st guinea pig to find out if it does or doesn't. 
I just came across this from the company that makes the "Dynaspark" Opti. It looks like their new upcoming GenIII model is designed specifically for running an LTCC setup. Here's the description on their web page:
"Development Pending – The Gen III is designed to work with the LTCC coil pack system offered for the LT1. This is a rotorless system with a billet aluminum cap. We plan to offer this as an upgrade from your current dynaspark as well as purchased new. Check back often for updates"
http://www.dynaspark.net/gen3.htm
Judging by how things sound in this description, this would appear to be the simplest solution to running the LTCC setup with an aftermarket PCM without having to mess with custom fabricating provisions for a cam position sensor. By keeping an Opti signal in the equation, you could just go with an LT1 FAST setup, since that PCM is designed to read the signals from the Opti which makes it kind've exclusive in that regard. With this, you could keep everything at the bolt-on level. Might be worth investigating.
"Development Pending – The Gen III is designed to work with the LTCC coil pack system offered for the LT1. This is a rotorless system with a billet aluminum cap. We plan to offer this as an upgrade from your current dynaspark as well as purchased new. Check back often for updates"
http://www.dynaspark.net/gen3.htm
Judging by how things sound in this description, this would appear to be the simplest solution to running the LTCC setup with an aftermarket PCM without having to mess with custom fabricating provisions for a cam position sensor. By keeping an Opti signal in the equation, you could just go with an LT1 FAST setup, since that PCM is designed to read the signals from the Opti which makes it kind've exclusive in that regard. With this, you could keep everything at the bolt-on level. Might be worth investigating.
