I just bought a 94 z28 and it super clean. I was talking to my buddy he told me get rid of it cause it is obd1 and non vented opti. I love the car I want to build a motor for it as well a budget build for now. my goal is to have a nice street cruiser that will rip off a 12.5 or 12.6 all day at the track. I had a 95 z28 back in 97 I put a 100 shot on it a Cai and a ignition box and thats what I was running. My question is would he be correct in telling me to do this? Or should I look for a scap engine with the obdII and newer style opti. lmk what you think and what is the most cost effective way to make the change if I need to. thanks sorry for all the babble but he got me confused a bit lol
thanks

 

I would say he dosent know what he is talking about. There are alot of OBD1 cars out there running very well. They can be made into a 11 second car with not much problem.

 

There's nothing wrong with 94s. They are unvented but you could add an MSD cap/rotor which add the vented capability to your opti.

What is your budget? To run mid 12s reliably (without nitrous) you're looking at all bolt-ons + a cam swap + tuning and all the incidentals, about $3000 or so. Add nitrous onto that combination and you'd be in the 11s easily.

Once again, your budget will be important in helping us spend your money.

 

Thats a relief thanks for that. now onto the good stuff my budget right now is about $1500. I want to start with a motor rebuild first then add boost or nitrous later to get me in the 12's. I have a beat on a 95 motor out of a z28 with a spun bearing for $200 I was thinking of getting that and building that one. So that I can continue to drive mine as the motor is being built would that be a good idea in your opinions? I just want the car to be down for as little time as possible.

 

FULL Gasket Kit
Heads checked and resurfaced (blew the head gasket)
Hotcam with springs
1.6 RR
LT Headers + Y Pipe
Opti and Harness
Pushrods
Lifters
New Radiator
New Pulley
AC delete
Belt
Most parts ordered form Summit Racing

It all set me back $1756. Tune will run me about $75 and Next month gonna be grabbing a Stall Converter. I've SEEN those setups pull mid-high 12's.

Friend just gave me his Lt1 block. And I'm gonna start rebuilding that as a 383 stroker over the next couple years

 

thanks I will definatly look into this as a option as well.

 

$1500 will get you a stock bottom end rebuild leaving very little or no room for performance goodies. As soon as you mention boost immediately add at least $7000+ to your budget so that's obviously out of the question. A common plan of action I see on the forums nowadays is "I want to build the bottom end then add boost later." Unfortunately this makes poor economic (and performance sense). If you're set on boost you need to build the bottom end for boost FIRST - then go from there.

Although if you're okay with high 12s you can get there with bolt-ons only really. This is very common.

 

The 95 engine has a vented opti on it. all you need to swap it to your motor is, 95 timing cover, 95 timing set and the vented opti,(possibily the crank hub, but not sure). might as well put a new w/p on it at the same time

This was the first upgrade i did to my 94, along with complete exhaust and 1.6 foller tips with LT4 springs. If it an auto, then throw a converter at it and maybe some 3.42s for the rear and youll have a very nice street car. i have 2.73s and a 2500 stall converter and I run 13.3's all day long

 

In order to put the 95's vented Opti on the stock 94 engine, he will also need a 95 or newer cam, with the correct diameter pilot hole in the nose for the Opti pilot shaft, and the longer dowel pin. You can drill the larger hole in the nose of the cam and install a longer dowel pin also. Then he will need the short Opti electrical harness and the vent/vacuum harness from the 95.

Shoebox covers it all (may have to scroll to bottom of page):

4th Gen LT1 F-body Tech Articles

In addition to just using the MSD vented cap, you can modify the unvented cap to accept the vent connections. There's a Corvette website with the details.

I'd be curious to know why his "buddy" feels that OBD-I is a negative? A bit harder to scan, but there is free scanning software available. Less invasive emissions diagnostics, fewer SES lights, cheaper to program, no after cat O2 sensors and EVAP vacuum detection, etc. Other than the "high stall wall" (which has been solved), there aren't many negatives.

 

Dont mean to derail the topic but very quick question:

I run 3.23 rears. I know 3.73 is the way to go for an A4 but I usually travel about 20 miles each direction to work everyday at highway speed and would like to retain SOME mpg :P But is it worth the hassle and work for me to go to 3.42? Or should I just stay 3.23?

 

The only negative ive heard is some of the dyno tuners dont mess with obd1. I actually considered converting my obd2 to a obd1 for the cheaper software for tuning and logging. You could also run the ltcc and then you only use the optical part of opti. Like Fred said it harder to get scanned but the equiptment to scan and flash is so much cheaper than my obd2. It would be about 700 plus to do the obd2 and thats getting the best prices.,......................,

 

But all the good tuners do mess with the OBD-1 PCMs.


OP.....if/when you need a PCM tune, well.....I always go to PCMforless .....but that's just me .

KW

 

Stay with the 3.23's or step up to the 3.73's.

Going up to the 3.42's.....well.....you won't hardly feel a difference unless you have a VERY sensitive butt.....and that's a bit of info we don't need to know !

KW

 

ROFL. Thats kinda what I was leaning too. Maybe when the 3.23 go bad I'll switch to a 3.73 (or get a raise to compensate for the reduced mpg lol)

Thanks

 

The OBDI's are much easier to mod than II's any day of the week.

As far as venting the opti, here's a good article on how to vent the opti without changing anything else.

venting a non vented opti