88LT1Drop

Okay i was told im better off jsut getting a OBDI computer because its a bitch to tune the OBDII computer? is that true? i cant really find a OBDI computer locally besides ebay. Is there anywhere i can send my OBDII computer to get it tuned? and whats so hard about it?

Air_Adam

I assume this is for an LT1 swap, as they were the only motors to have OBD1 and II ECMs...? Neither one is really "harder" to tune than the other, but they are different, and require different programming tools. I think the early OBD1 LT1 engines had to have the chips burned, like the TPI engines, later ones could be flashed, and the OBDII stuff can be tuned on-the-fly so to speak, like the LSx. There is cheaper and more readily available tuning software available for the OBD1 stuff, but OBDII is more 'powerful' so you can more precisely datalog it and more precisely tune it as well, similar to how the LSx engines are tuned.

As for who - check with any local F-body clubs or muscle car clubs that are familiar with GM stuff, they may know of someone or a business that can do what you need. Often the best way to go is to find that one guy that most clubs have that does that kind of stuff for the bulk of the club's cars. Theres usually someone like that around. Theres one or two of them around here that everyone has do the LS1 cars, and they do a fantastic job from what I've heard. I'm sure theres someone like that around where ever you are.

Aaron91RS

iTrader: (2)

Whoever told you this. Slap them, then quit listening to them.
They both have fuel and spark tables. There's nothing easier or harder about tuning one over the other if you have the right tools.

screeminchicken

iTrader: (2)

Sorry if I am hijacking your post. and this might not make sense but........

If one gets a complete LT1 or LS1 engine for a swap.........does the OBDII connector port come with it?

Is it supposed to be part of the engine wiring harness ??

For some reason its not there , how difficult is it to add it to the harness for diagnostics and tuning ?

Air_Adam

I would think it should be part of the ECM/Engine wiring harness - When I removed the ECM and harness for my L69, the diagnostic port came out with the harness. I don't see any reason that would change with the later years?

As for adding it - check out a wiring diagram for the diagnostic port and see what wires go where, or chop one off at the junkyard and splice it into your harness.

V8Rumble

iTrader: (2)

The harness that I bought for my swap (a 2008 L92 engine) didn't come with one, so I found a suitable donor in the junkyard, & clipped off enough wire "upstream" from it to make it work.

I guess what I'm saying is "Don't count on getting it with your engine harness, since it's (often/probably) part of a different harness - inst. panel, body, whatever".

Also (FWIW), based only on my observation, it's appeared to me that people seem to get up & running more quickly (& noticeably so) w/ OBD-II. That was a major part of my decision to swap to a newer engine.

EDIT: And even if the difficulty is about the same (which sounds reasonable to me), I'd guess that there is a much-larger pool of talent on the OBD-II side, which means that issues are likely to be resolved more quickly.

88LT1Drop

k if i do end up going with a 94 or 95 pcm and plug it into my 96 harness and motor would i have to change any sensors or anything? or would it be plug and play? also if i tuned my obdII would i be able to flash my extra o2 sensors out without any problems? would taking taking the extra o2 sensors hurt my gas mileage or performance?

88LT1Drop

?

Firebat

iTrader: (7)

OBDI is far better when it comes to LT1's. Even the professional tuners can not get the OBDII LT1 to get as much horsepower gain as the OBDI setup. The OBDI LT1 setup can be tuned to get 10 more hp over a well tuned OBDII LT1 setup. As far as I know there is no monitoring software for OBDII LT1's or at least any that is cheap. Monitoring software meaning if you want to watch what your sensors and pcm are doing via a laptop. Its just easy to program, easy to monitor.

The wire harness on a 96-97 harness basically just has extra wires. There is probably a little bit more involved but I would think a 95 pcm would plug right in and maybe the underhood dash connectors and the connector wires might be different. 96-97 might have a couple extra sensors. I don't know for sure, haven't messed with 96-97 stuff much. OBDI conversions have been done and I doubt they are that hard, look around on ls1tech.com or camaroz28.com's message boards.

Other notes: 95 f-body harness/computer/engine is the easiest to swap/tune. Automatic transmissions from 95-97 are interchangable with each other, 94 auto trannys are not.

88LT1Drop

would i be able to tune out the maf sensor without any cons?

Firebat

iTrader: (7)

Cons:
1. Less MPG
2. Code thrown(can be turned off by tuning)

If the MAF is removed and the car is started, the car will automatically run in speed-density mode which has a little less MPG. There will also be a code thrown but that can be tuned out by disabling the code. The car will still run the same with the code being thrown. Shouldn't be any difference at full throttle.

Fast355

iTrader: (2)

The OBDII stuff works better plain and simple. The most powerful production LTx ran OBDII. Can we say LT4 people. Both systems tuned identically there is NO WAY you are going to get 10+ HP from the OBDI setup over the OBDII. The OBDII stuff typically has better coding for even the basic engine operation. This means the engine will idle smoother, have quicker throttle response, better transmission shifting, the list goes on. I am switching my TPI engine from OBDI to an 0411 LS1 PCM running the fullsize Express van tune for the L31 350 Vortec. The "Black box" 1997 PCM runs my factory L31 in my Express van GREAT and runs even harder after being re-programmed. I doubt I will see much peak HP/TQ by swapping from my OBDI to the OBDII stuff, but the ability to run a modern 4L60E and the improved driveability and mileage are a great plus.

Firebat

iTrader: (7)

From one of the top LTx/LSx tuner's website about the advantages of LT1 obd1 over Lt1 Obd2:

http://www.madtuner.com/index.php?op...=31#question18

On madtuner's site didn't say 10 hp but it does say a few. I'm talking about LT1 obd1 vs Lt1 Obd2. LS1 obd2 is a different story, along with running coil packs in a LS1 Obd2 setup.


This LT1 obd1 vs LT1 obd2 has been discussed on other boards such as ls1tech.com:

http://www.ls1tech.com/forums/showth...bdi+conversion

Fast355

iTrader: (2)

The OBDI processors are still slower, even on the LT1. The OBDII stuff will run better. Equally tuned there will be NO HP difference between the PCMs, PERIOD. Its just not going to happen. Now if some parameter is altered between them and not tweaked, you might see a slight, negligable difference. My favorite normal LT1 to drive was always a 1997 Camaro SS. 305 HP vs. 285 of the normal LT1 and it responded easily to modifications and tuning. The highest "Factory" NA rating of the LT1 was the 1994 Firehawk, I've driven two of them and both ran GREAT.

Firebat

iTrader: (7)

PCMforLESS says 5-7 HP gain. Programmed OBD1 vs Programmed OBD2.

http://www.pcmforless.com/index.php?...temid=78#faq10


I'll agree that the 96-97s had higher HP ratings from the factory but that was mostly because they had dual cats.

If there is proof that a programmed OBD2 LT1 pcm makes more HP than a programmed LT1 OBD1 PCM in the same car then I would like to see it.

Fast355

iTrader: (2)

Thats just because they must not know what they are doing with all functions of the PCM. I would like to see dyno sheets proving the 5-7 RWHP gain. If there was such a gain, there would be physical PROOF in the form of a dyno sheet. I would also want to see 3 runs of each PCM averaged togather on the same dyno, same day, same engine temperatures, on a very controlled environement. I've seen the same car dyno 5-10 WHP difference over the course of 3 dyno pulls.

88 350 tpi formula

iTrader: (9)

they should be identical as far as HP. perhaps it is more of a MAF delete that is showing the slight hp increase and not the ecm

Klortho

Consdiering Bryan at PCM4Less is probably the best tuner out there for LT1s, this statement is not correct. Alot of the guys running Impala SS are ditching the OBDII to go with OBDI for better tuning.

Fast355

iTrader: (2)

That statement IS correct. There are other tuners out there much better than PCM4less. I wouldn't touch mail order with a 10 foot pole. I can do the same stuff they do in about 10 minutes with a stock calibration. I am my own tuner and the OBDII stuff just runs better in general. I just dyno'd my Vortec 350 after getting ahold of a Tunercat II software and reflashing the stock Black Box (same OBDII PCM as your LT1s) and gained 30 RWHP @ 4,000 and 40 ft/lbs @ 2,400 and have seamless driveability. I am making more HP and torque than most stock tuned B/D-body LT1s with a lower compression Vortec truck engine.

evilstuie

sorry to bring back an old post, but i'm getting ready to do a l98 upgrade to obd2 setup and was wondering if there's anywhere to download tunes/maps from?
I have a 290/300hp non-roller 350 chev sbc motor which is a very common crate motor and was wondering if anyone would already have a tune for this motor i can start with.
I'll eventually be putting a l31 450hp motor into the T/A but don't want to have to pay for 2 sets of long dyno sessions getting it tuned. At $80/hr and avg 10hrs to tune its not something i want to through a lot of cash at.