Ok,
Here's my Frankenstein.
I have a '69 Chevelle that currently has a 427 in it, soon to be "done". Painting on Sat.
Anyway I have a new 8.1 L warranty engine (perks of the job), that will be a helluva street motor in the Chevelle with little work.
I have the FI intake for the 8.1 (tall deck). I also have a FI setup for a '97 454.
I was going to steal the throttle body from the 454 (looks like it'll work) and injectors to put on the 8.1L. Then buy the fuel rails I'll need. That should get it all plumbed up.
Is it possible to use an LS1 harness and computer on this thing. It seems similar to the LS1 as far as updates. It has the LS1 firing order, LS1 shaped intake ports only BIGGER, basically a BBC LS1 as far as I can tell that seems to be what GM did to make this thing work.
Then get it all together and use LS1 Edit to get it tuned. Or maybe use LS1 edit on a 8.1 PCM.
My main concern is will the wiring harness work (stock or Painless) for an LS1 system on this thing. I can get whatever PCM is necessary.
Would I be better off using a Fast or Accel 'puter and harness?
Any thoughts?

 

Why don't you just use the 8.1 wiring & PCM set-up to ensure that it works?

 

John,
THe motor is going to be modded and not in the original chassis so I would need to be able to reprogram the PCM. If LS1-Edit would work, then it would be great but thats what I'm trying to figure out.

 

Find out if the cam/crank signals are similar to an LS1. If they are, and the firing order is the same, you can definitely use an LS1 computer with modified calibration to run it. Aftermarket stuff is still difficult at this time, FAST can be used, but would require the eDist to use the coil near plug setup. Not sure of anyone who is doing a harness to make anything aftermarket plug n play. DFI v7.0 - not sure, I hear conflicting stories everyday everywhere. Motec - I'm sure it can be made to work, but usually requires a budget with lots of zeroes at the end <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> AEM is someone else you may look at. Anything using speed-density with a wideband 02 offers great potential for performance if you have the skills to tune, or money to pay for tuning.

As far as reprogramming the 8.1L with LS1 Edit, you'll have to talk to the carputing guys about that. Since the engine is a different family, you may be SOL there.

HTH
Brian Green
89 TTA
01 Jeep TJ (to be GM powered in the fall)

 

I think it would be much MUCH easier to just buy an aftermarket system. YOu say you want to cobble together this system in order to have LS1 Edit. Well, that's $550. Plus the cost of the harness (Painless harness is like $500) and then all the sensors, etc.. I would just talk to Holley or SDS. I've heard of lots of people using SDS who were very happy with it. Completely programmable, no laptop required either. They have a pretty wide array of systems and options too. I think they start at $1k.

 

Although I have not had the opportunity to do a 8.1 yet, I think your idea may just work. I think the 8.1 is electronic throttle(?) so when you add the TB from the 454 you'll need to add wires for the IAC and TPS. At that point I think LS1 edit may do the rest. I don't follow why you need new fuel rails. I also would NOT use the injectors from the 454. I have worked with the Vortec 454 engines (I have one in a 91 Caprice station wagon), and the stock injectors are dinky! Something like 22# @ 55psi! Since the 8.1 has such good looking heads I would use the at least the stock 8.1 injectors. (I don't know what they are rated). Or at least some SVO 30 - 36 #ers. The stock 8.1 injectors are probably pretty healthy just because of the flow characteristics of the heads, and the displacement of the engine. I do believe the crank and cam scheme is the same on the LS1 and 8.1L, so I think it may work. I'm mad because I haven't gotten ahold of one yet!!!

 

Thanks so much for the answers guys,
I am a Master Tech at a huge GM dealership so I have access to Tech 2 and other scanners, so would this eliminate the need for any other programs?
I also have a laptop that I could use for tuning.
I'm VERY familiar with the operating parameters of a FI system but have never done any 'puter tuning but have extensive experience tuning carbed applications. So I know rich from lean, etc..
I do a lot of driveabiltey and emissions repairs in my job everyday, unfortunately I just don't get to go in and edit the GM tuning <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />
I sure would like to though...
The PCM for the 8.1 is only ~$120 my cost new, I will check and see if maybe it is the same PCM as an LS1.
I bought the 8.1 as a warranty core it had excessive oil consumption, got it CHEAP, perks of the job.
It is missing the fuel rails, throttle body, injectors, but has the intake, valve covers, coils, most sensors, etc..
I have a Vortec 454 FI setup too so figured I could steal the injectors to make it run, but since you mentioneed they are that small I'll get what I need.
I have looked at some of the aftermarket controllers because I was thinking the same thing about cost of PCM, Harness, software, sensors, etc.. But it looks like it would still be cheapert to go the stock route.
Holley Commander 950 system has to use a DIS controller that is $1200 plus the cost of the $900 Commander controller and harness.
Looking at about $2300 for the FAST with harness by itself, don't know if it needs an additional controller.
This 8.1 is pretty neat, LS1 shaped intake ports, same config but BIGGER.
Would make a nice powerplant for my '69 Chevelle that currently has a 427 in it.
Keep the answers coming.
I can compare part numbers at the dealership for PCM's, sensors etc..
So I'll do some checking.
So a stock LS1 PCM and harness could probably work.
Maybe I can scrounge a good harness and PCM from the wrecking yard.
I've done a V8 FI conversion on a 4x4 S10 so am pretty familiar with all the basics and the wiring is fairly easy for me (troubleshooot it all the time) but am not quite as familiar with the LS1 stuff.
Theoretically the PCM will not notice a huge difference in the engines CID if the injectors are properly sized, i.e 8.1 is ~40%larger than 5.7 so injectors sized approx 40% larger will result in similar pulse width, etc.. Obviously MAF readings will be different <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
But I could probably get close enough to tune from.
My plans for this thing are to possibly drop into my Chevelle, use existing headers, stock 8.1 heads, injection, etc.. Use custom grind cam around 236 degrees at .050, and other than that about stock.
Should be a smooth idling, 600+ lb ft of torque to 5000-5200 setup. Street killer.
I work on these things occasionally and they are the smoothest idling BBC I have ever messed with.
I guess the new firing order really helps.

 

If you use the LS1 harness you can use the car injectors but, if you use the 8.1L harness you'll have to use the 8.1 injectors. The car and truck injectors have different connectors.

Of course if your doing custom stuff to the harness you could always just put on whatever connectors you wanted. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

I would definately try to use the LS1 injector connectors though because you have alot more options on injector size.

Good luck

John

<small>[ July 20, 2002, 12:06 AM: Message edited by: XLR8NSS ]</small>

 

Yeah if I am not mistaken I read somewhere that the 8.1 has 28 lb injectors, but either way that will be awesome when it is finished. IMO though I think you should just go ahead and use a truck 6.0 harness and switch out the injector plugs if you want to use ls1 style injectors, because most if not all of the other connectors will match right up to your 8.1.

Remington

 

watch the cam close, i installed a ZZ502 crate engien cam The duration at .050" is 224/234; and the lift is (intake/exhaust) is 527/544. Lobe separation is 110 degrees. I'm pretty sure that it caused piston to valve contact and caused my #5 piston to come apart, sending two rods out the oil pan. all other pistons showed signs of valve contact on the Intake valve, 527 lift 224 @50 The pistons are about .006 out of the whole, no deck clearance, and the intake valve is large! check your clearance very close if you change cams. i've also read the pistons are very weak in these motors.

I did an 8100 swap into my 67 shortbed, view my website below for some information.

I used a Do-It-Your self EFI system called Megasquirt. www.megasquirt.info
I too got a warranty 8100 for oil consumption, which never used any oil when i ran it. I also started out using vortec 454 injectors. they are taller, then the 8100's but you can space the fuel rail with a spacer and longer bolts, it should work fine.

anyways. i'm pretty sure the crank signal is different. i've looked at the crank reluctor wheel on both my 8100 and a LQ4 6.0L and they are different, so i'd figure they would generate a different signal. I have been working on hooking the crank sensor up to a scope and see exactly what the signal looks like. I'm trying to get the stock crank sensor to feed directly into my EFI controller to run the spark. I added an external crank trigger wheel and a sensor to run a ford EDIS-8 ignition module, and fire wasted spark ignition coils on my swap. my DIY efi controller controls the edis-8 module for timing.

i have well under $1000 in my entire swap into my 67 chevy pickup. including the engine! I started out with a set of vortec 454 injectors, not knowing the injector size, i guessed at 22 lbs. watching my o2 sensors at WOT i never saw them dip below 900mv. I had fuel cut set at 5200, so i think the vortec454 injectors should be large enough, just keep an eye on your o2s. i built a cheap o2 sensor monitor with 8 led readout, lean has 2 or fewer led's on, and rich shows 6 or more. easy to monitor at WOT tests.

 

HI: Check out Arizona speed and machine on this site I Think they sell a harness that lets you operate An 8.1 truck motor on a modified Fbody computer. Also S and P has some stuff for these motors.

 

We also make the 8.1 harnesses and program the computers. We've made several of these harness/computer packages now. We even keep an 8.1 engine here to test the stuff on.