Hello everyone,

I need Corvette lovers and experts' help. I am on the verge of buying a mint 1990 Corvette with the ZF 6 speed, only 46,000 miles, one owner, driven in summer only from Vancouver, Canada (USD 11K). But, there is a but and that's where your help would be greatly appreciated

I am normally a person who like cars stock with no mods. In his case, he installed a Z Industries performance chip back in 1999, stainless steel headers, throttle body replacement, good plug wires etc. This chip enables to shift at higher RPM which is already a concern as he mentioned this engine being able to rev until 7-8k as, Corvette Specialties shop told him. However he says he never exceeds 5200. That's already one thing.

Second, even though he really loves his car (I repeat it is mint), I asked him how he serviced it. Answer, last coolant change back in 2006 and 40,000 miles, brake fluid in 2013, engine oil change every 5k miles or 3 years.

During winter, full tank of gas, starting the car once every 2 weeks until warm, until beginning of spring. Concern here is old gas (several months) used in a car with a perfomance chip that probably needs good gas (when he resumes driving it after winter time).

SOOO, my questions are, is this car possibly very clean in and out but with potential undetectable wear due to chip tuning and laid back servicing? (and potentially misunderstanding of the actual RPM that this engine is safe to be driven).

OR, am I worrying too much for nothing and I should buy it?

Help needed... Thank you very much

 

Well a 1990 with a TPI can't really rev much beyond 5200rpm. The intake won't let it get anywhere near 7000, and the fuel cutoff is over 10,000 rpm (essentially unreachable) so I'm not sure exactly what he's been told, the chip aint doing **** for that.

About the most the chip is doing is adjusting the timing curve, he may be running more advance, or leaving the injectors open longer. Given its an off the shelf chip, probably just advanced timing. I would not be concerned on that topic.

He's not driving enough for me to be overly concerned with anything except the oil changes and fuel. You should change oil yearly whether its a garage queen or not, and fuel should not be allowed to remain in there that long. 6K miles since 2006 means he may not even be running one full tank out a year. I would ask if he's at least running it empty after storage each spring, or if he's draining the tank and refilling otherwise.

Otherwise It seems like the car should be fine.

 

Car sounds solid, regardless of the owner being a bit mistaken about some things!

 

Thanks a lot for these reassuring answers. I'll ask him about fuel. About the chip, he sent me the invoice from 1999. It is written "custom chip" but it was plug and play. I think it was "customized" by Ron Zimmer, an apparently famous tuner and owner of the brand Z Industries. I don't know if we can consider that as "custom" 🤔

 

I see in the receipt it shows that the CAGS has been eliminated. The CAGS was an annoying way the GM passed emissions by trying to force you to shift from 1st to 4th under part throttle. There are CAGS elimination kits and about 1/2 of these cars had it un pluged before they even left the Dealership. This still left the Skip Shift light flashing on the dash until the bulb burned out. ( Mine still hasn't) So I'm going to say that the shifting at a higher RPM is mixed up with CAGs .

 

I also thought about this but from what I read in ancient threads about this performance chip, "apparently" it was made so that higher RPM could be reached. Hopefully this is wrong. Thank you anyway for taking the time to answer my questions!

 

Doesn't matter, it can't get there with the intake. By the time it gets to 6k it's similar to you breathing through a straw at the bottom of the ocean.

No amount of timing or fuel pulse width can overcome physics of flow.