TPI C4 Opinions?

"G_Body_Man: Sponsored by the number 3" (gbodyman) 09/15/2017 at 11:12 • Filed to: None

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Keep in mind that this is for way off (1+ year away).

While my Crown Vic is a boatload of fun, I’ve realized that with more and more parts becoming NLA and with metal fatigue starting to settle in, I should be on the hunt for a new everyday car in about a year’s time. I know the TPI C4 isn’t objectively the best car out there, but it’s always held a special place in my heart, and it’s relative focus on comfort (for a sports car at least) would lend it well to daily driving. Now that good ones are down to $6k Canadian, the omnipresence of the SBC and the relatively low mileage of good examples make them quite tempting. So Oppo, who here owns one? Is the 4+3 as big of a dog as some people say? How is it for commuting? Who knows, maybe in a year’s time I’ll be daily driving something with a targa roof.

Yowen - not necessarily not spaghetti and meatballs > G_Body_Man: Sponsored by the number 3 09/15/2017 at 11:26

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For $6k I like the way it looks. If it really is a dog, are there easy ways to get some additional power out the 5.7? Is it an L98?

Tripper > G_Body_Man: Sponsored by the number 3 09/15/2017 at 11:29

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My dad had one the same color when I was a little kid! My mom and I resprayed my power wheels corvette BRG a little too close to his real one...he was not happy it came off though.

G_Body_Man: Sponsored by the number 3 > Yowen - not necessarily not spaghetti and meatballs 09/15/2017 at 13:08

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It’s an L98. The main thing I’ve told was a bit of a dog was the 4+3 gearbox, although even if the throws are ropey it would still be better than the utter pile of 4R70W that Ford stuck in my car.

merged-5876237249235911857-hrw8uc > G_Body_Man: Sponsored by the number 3 09/15/2017 at 13:17

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I had an 1987 with an automatic. It was a decent car to drive around. Lots of plastic though. If it were a stick, I would have hung onto it though. I restored it with new paint and new interior. You can buy almost every trim part and all that, but it gets pricey. I wouldn’t want to be in a collision with it. There is no real structure to speak of.

G_Body_Man: Sponsored by the number 3 > merged-5876237249235911857-hrw8uc 09/15/2017 at 13:44

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Gotcha, It’s best to make sure all the weatherstripping is good and whatnot.

ITA97, now with more Jag @ opposite-lock.com > G_Body_Man: Sponsored by the number 3 09/15/2017 at 14:23

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I have no experience with the 4+3, but I did own a 93 LT1/6 speed C4 and daily drove it a year and half and 30k up until May of this year. My experience has led me to not recommend C4 vettes to people unless they have a particular affinity for the C4 itself. This is not because they are necessarily bad, but because the compromises that come with owning and driving them compared to newer and better options that cost not significantly more money. Don’t get me wrong, as I thoroughly enjoyed owning the car, and daily driving it made even a mundane trip to the store feel just a little bit special. That said, I may well pickup something like a corvette to use as daily driver agin after I pay off the new truck, but I won’t own a C4 again.

They are not particularly comfortable in general, and the early TPI cars were even more focused on handling with considerably stiffer spring rates than the later cars. They are low, and they ride properly stiff even with the much softer spring rates of the later LT1/LT4 cars. They require vigilance in regular driving to not damage running gear over potholes and bumps you hardly notice in a miata, and to not tear off the front air dam (which is a critical component of the bottom feeding cooling system). The entry and exit is best described as a fall in/climb out experience, as the door sill is literately a foot tall. They’re comfortable enough once seated, but the ergonomics of pretty much everything in the car will leave you never mistaking a C4 for a modern automobile.

As for that targa roof, you’ll probably not drive with it off more than once. The roof panel is a structural member of the car (which is why it actually bolts into place). When you remove the targa top, the car becomes a wet noodle flexing considerably over even very minor changes the road surface. I drove another C4 once without the targa top in place, and it was such a significant change in the car that I never once removed the targa top from my own car. The original owner (and also next door neighbor) of my car disliked the flex from removing the top so much, that he only drove it twice in 22 years without the top in place.

I’m not sure what the attraction would be to an early, TPI C4. With not more than 240 hp, they’re not quick. The later LT1/LT4 cars are at least still somewhat quick by modern standards with low 5 second 0-60 times, and the price difference isn’t much from an early car. I guess their upside is that they don’t have the a the no good replacement option for the optispark and no longer existent dual mass flywheel issues.

That leads to my next point; what you get for the money. An early TPI C4 runs 5-7k for an example in good shape that probably won’t require more than 2k a year to repair and maintain as a daily driver. A good LT1/LT4 car runs 7-9k, and is a much better car with similar running costs. The real problem is that 10K is starting to get you a serviceable C5, and a C5 is a vastly superior car in every way (and especially in comfort/convenience and ergonomics).

In terms of running costs, a C4 is like any other big-boy sports car in that they are not a drive it and change the oil every once in awhile ownership experience. Suitable tires will cost several hundred dollars each (at the low end), and are not always common anymore (just see how many 285/40/17 tire options are out there these days) and are not long lived. C4's without staggered wheel sizes are probably more desirable at this point. Ball joints and rear wheel bearings tend to have lifespans of about 50-60k on these cars. Despite their somewhat of a Luddite for a car image, C4s were really fairly advanced cars for their time (and particularly in terms of electronics). These cars mostly had power everything, ABS and traction control and things like automatic climate control and audio and alarm systems that are integrated into the BCM and ECM systems in the 80's. Combine that with 80's GM electronics and quality control, and they’re not all that different than maintaining any other old complex car. If electrical faults on an aging BMW are something you don’t mind dealing with, then an aging C4 should be up your alley, although replacement electrical parts are less available than you might think. This would be the reason why finding a C4 for sale in which everything actually works is pretty uncommon.

While I used mine as a daily driver, it was certainly not my only car. In terms of parts availability, your local parts house is unlikely to have much more than the most basic of items like filters sitting on the shelf for a C4 at this point. Most parts are an order it and wait for the UPS guy type deal. Even with mine being a fully documented, one owner car with 55k on it when I bought it, it would not have really worked as an only car, or at least not as an only car if you have a grown up’s job and a commute. I probably could’ve made it work as an only car as a college student.

G_Body_Man: Sponsored by the number 3 > ITA97, now with more Jag @ opposite-lock.com 09/15/2017 at 15:24

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Thanks for the detailed info. Care over potholes and bumps shouldn’t be too much of an adjustment (my current suspension setup is both low enough to necessitate crossing speedbumps at a very dramatic angle and stiff enough to wear the driver down on a long drive), although it’s good to know that it is genuinely terrible without the targa roof in place.

The main attraction to the TPI cars comes due to experience, namely the TPI system being fairly decent and Optispark being a pain in the ass to replace and practically an ASAP item once an LT1 car is bought. With the speeding laws being what they are in Canada, I don’t really need a ton of grunt, either. Another reason I like them is because they run a smaller tire size, meaning that decent tires are $130-$140 a corner. 50-60k out of ball joints and rear wheel bearings is good to know, I find most American cars of the era go through some item bizarrely quickly (I’m lucky to get 6k on a set of pads).

I don’t really expect everything to be working, it is a high-end older car after all. Would you say that module reliability is on-par with a pre-LCI E38?

I know all too well about the “order parts and wait” lifestyle. They’re discontinuing more and more parts for the 92-97 Crown Vics, and all of them in Ontario got crushed long ago so junkyard parts are very difficult to find. When my right taillight cracked, I had to order a used one from across the border.

I’m in a bit of a different market in terms of pricing. A good TPI car is $5-7k, whereas a good LT1 car is $11-13k around me. As much as I like the LT1 cars, they just don’t seem to be exactly twice as good as a TPI car.

Manwich - now Keto-Friendly > G_Body_Man: Sponsored by the number 3 09/15/2017 at 16:07

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In addition to what ITA97 said, I’ve heard that to make the Doug Nash unit last (the part that gives the ‘+3'), you have to change the transmission fluid. Some of those units failed because owners didn’t change the fluid.

Someone on this thread:

http://www.digitalcorvettes.com/forums/showthread.php?t=24327

Said that you should change the fluid every 10,000 miles or once a year.

And here is info on the type of fluid:

https://www.corvetteforum.com/forums/c4-tech-performance/1783515-doug-nash-transmission-fluid.html

And info on replacing the filter:

https://www.corvetteforum.com/forums/c4-general-discussion/2046704-doug-nash-4-3-maintenance-question.html

G_Body_Man: Sponsored by the number 3 > Manwich - now Keto-Friendly 09/15/2017 at 17:29

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Good to know. The footwell is on the tight end anyways, so maybe a 700R4 wouldn’t be the end of the world.

merged-5876237249235911857-hrw8uc > G_Body_Man: Sponsored by the number 3 09/15/2017 at 17:39

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That’s for sure, I replaced every piece on mine and it’s not cheap. Sun baked Florida car. The carpets were literally turned to dust.

G_Body_Man: Sponsored by the number 3 > merged-5876237249235911857-hrw8uc 09/15/2017 at 17:55

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Sun-baking sucks. It’s the big reason part of my Crown Vic’s clearcoat is nonexistant and the trunk seal is absolute garbage.

ITA97, now with more Jag @ opposite-lock.com > G_Body_Man: Sponsored by the number 3 09/15/2017 at 18:19

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I would say module reliability is similar with German cars of the E38 era, but with less availability of replacements parts. They are also less fun to work on than German cars of that era, as there is not necessarily always a method to the madness. Sometimes GM just gave you madness. Another thing to negotiate over is the condition of all the weather stripping. While all of it easily available from the restoration parts companies, it will set you back $500-$600 (US money) for a complete set of it. Also expect the door panels to be pulling back from the top of the doors. They all do it, and replacement door panels are available, but they run $350-$500 each.

I’m surprised as the pricing in your area. 13k would get a good C5 with less than 100k on it in the Southwest.

G_Body_Man: Sponsored by the number 3 > ITA97, now with more Jag @ opposite-lock.com 09/15/2017 at 18:33

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Yeah, pricing changes a bit when you cross international borders. Weatherstripping really is worth its weight in gold, I simply can’t find a new trunk seal for my car, so I can’t keep anything nice in the trunk anymore. I’m convinced all American automakers of the era were mad, because even one of the most reliable cars (1996 Crown Vic) has hard to find and stupidly expensive lighting and body control modules, as well as both SAE and Metric fasteners on the same car, and both ISO Metric and DIN Metric head sizes on the same part!

ITA97, now with more Jag @ opposite-lock.com > G_Body_Man: Sponsored by the number 3 09/15/2017 at 18:41

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The other thing I forgot to mention is that I did notice some LT1 cars in the price range you described, but from what I can tell, either the sellers were never serious about selling the car or the cars simply never sold. LT1 cars that actually sell in my area (even really nice ones) sell for far less than 10k. I also see of sub 5k early TPI cars, but those are always in pretty rough shape. They would be project cars and not really reliable drivers. If you’re serious about buying one, you might also look into joining some of the vette forums and/or the local corvette club in your area. I don’t really advocate for the people you’ll usually find in either place, but it is common for really good C4 vettes to be sold among people who already know each other, or at least know of each other. The really good cars don’t necessarily come up for public sale all that often.

ITA97, now with more Jag @ opposite-lock.com > G_Body_Man: Sponsored by the number 3 09/15/2017 at 18:51

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We’ve made printed circuit boards that have left the solar system and are still working fine. Those modules were originally built to a price point, and I think now there just aren’t many replacements left out there and not enough demand to justify anyone making another production run of parts. This is going to be one of the bigger problems for classic car enthusiasts down the road.

 You’ll find a variety of fasteners on a C4 as well. On mine, anything related to the chassis and suspension was metric, anything related to the body or interior was SAE, and anything on the powertrain could be either under the hood.

G_Body_Man: Sponsored by the number 3 > ITA97, now with more Jag @ opposite-lock.com 09/15/2017 at 19:21

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Very true, it’s the same deal with FB RX-7s. There are no really nice ones left on the public market, so it’s best to either go to the boards or buy a fairly solid example and do a rolling restoration to remedy the more careworn bits. I figure since whatever I get is going to be driven every day, I should focus on the mechanicals, electricals, and weatherstripping and be okay with crappy paint or roughed-up bumpers, simply because I just know at some point someone will tap it.

G_Body_Man: Sponsored by the number 3 > ITA97, now with more Jag @ opposite-lock.com 09/15/2017 at 19:24

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“Electronics to a cost” is more or less the same deal with some of the 90s Benzes, although I think an R129 or C140 is absolutely worth the inconveniences.

I’ve taken to just rolling with it. It’s why I carry metric, SAE, and Torx bits everywhere I go.

merged-5876237249235911857-hrw8uc > G_Body_Man: Sponsored by the number 3 09/16/2017 at 08:38

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Yeah, I always thought, “great, a Florida car, no rust” now I think twice. But I’d rather deal with new seals and carpet vs rust replacement. Paint is paint, so that’s still a wash there. But wow, the sun really kills interiors, well rubber, plastic, and fabrics anyway.