Hello all. I've been around for a long time, but never signed up.
I used to mess with GM OBDI quite a bit and transitioned to OBDII when it became a more viable option.
Last week, I bought an 88 C4 Corvette. L98 (TPI) 700R4:
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And.....it's OBDI.
Normally that wouldn't be a problem, but it's been more than a decade since I've done anything with OBD. All my OBD gear has long since been sold off as I never anticipated being back at OBD, let alone ever own another GM product. But here I am.
The L98 is a good runner, no complains so far. But, I'm a "tinkerer", I just can't leave stuff alone.
I have an LT1 intake on order and plans to modify it for use on the L98. Modifying the hard parts is easy peasy for me, no trouble at all. Lathe, mill and mig spool gun plus the knowledge of how to use them is well within my repertoire. I don't anticipate actually having it ready for the car this year, maybe not even by next year. It's a slow build, all the welding and machining will be followed by painting and polishing. Probably a lot of polishing....it is a 'Vette after all. It needs to have some WOW factor when you lift that big clamshell hood. even if it is "just" a C4.
But it doesn't take a genius to see that even if it runs alright with the LT1 intake dropped on the L98, I'm still going to have to get into the calibration to get the most out of it. More so if I toss a cam in it later down the road or start porting things out.
The car isn't "raced", it's just a nice top down summer cruiser. It's never going to be a "radical" build, but pumping it up to 300 or so RWHP (so around 350-ish rank) at appox 5000-5500 rpm is a definite possibility in the future. The L98 moves it out pretty good as it is, even if there's almost too much torque down low to use it all (tires break loose any time I drop the Right foot). It cruises nicely on the highway and MPG is great for what it is, but it will run out of breath when it gets higher in the RPM when doing things like......ummm......"energetic passing"........;)
I'm trying to figure out how to go with the engine management system.
The car has a 165 ECM, so it's not that bad off. But like I mentioned, all my OBDI stuff is long gone, so I would have to re-purchase all of it. Burner, emulator, data logger, etc. All of it. That adds up pretty fast.....
But I still have all my OBDII stuff, even if it does have a pretty thick layer of dust on it (same as the "files" in my brain). Namely, I've got a couple spare 411 PCM's lying around and I have tunercatsII (roadrunnerII) and a roadrunner "guts kit" in a box somewhere just taking up shelf space. I'm also a bit more comfortable working in OBDII, even if the principles are the same as OBD. Probably because it's been more than a decade since playing around with OBD, or maybe more like 2 decades.....
I guess what I'm looking for is a bit of advice on which way to go. I'm still in the planning stages and no money has been spent, other than buying the used LT1 intake manifold (70 bucks all in).
Compounding the issues is the 88 still runs the digital dash and I'm not overly receptive to having one ECm running the gauges and another running the dash cluster. It just seems like too much "hacking things up" to be running two PCM/ECM's.
I'm also in the "tuner" category as opposed to a "programmer" category. Basically, I know my way around the tables, but any skill/interest in coding died off a long time ago and I have no real interest in getting back into that part of the hobby.
Anyone want to take a shot at some advice on which would be the best way to go (obd and 165 vs OBDII and RR equipped 411) what it would take to get there? IE;cost vs ease vs tunability, vs.....etc.
Last note: Ive used real time tuning before and I really like it! RR + RR modified 411 pcm has that capability.......
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Originally Posted by steveo
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