No offense to Sam, but the big takeaway from this Tech Tips article seems to be "It's Complicated"
Photograph Courtesy Chevrolet
[Editor's Note: This article originally ran in the October 2018 Issue of Grassroots Motorsports.]
Meet Our Expert:
Sam Strano
Strano Performance Parts
stranoparts.com
I just picked up a 2017 1LT with a Z07 that happens to be an automatic. I have a whopping 795 miles on mine. A lot of what needs to be done on one of these cars depends on what suspension setup it’s on, as they come with some very different shocks, springs and bars.
My biggest gripe, on a Z07 car, anyway, is a toss-up between the huge rear bar and the magnetic shock calibrations. In Sport mode, it rides the bumps better in an autocross, but it slaloms less well, too.
I am starting my development on my shop car, and one of the first changes was to play with different rear bars. Base C7s don’t have a rear bar at all. Some versions have a smaller rear bar, and Z07s have a huge one. Lots of bushing changes, too, even on cars that share bar sizes.
I do not think the shock absorber tuning boxes are at a point of reliability yet, and you have to know a lot about shocks to not mess that up.
There was a spate of cars that blew up early, supposedly from clogged oil filters. It is imperative to change the oil at or even before 500 miles.
The automatics have a surge in eighth gear. It seems to stem from not enough line pressure to the converter.
Automatic cars, I’m told, can melt the valves in the exhaust that close for Active Fuel Management–the V4 mode–when used heavily on track. They can be wired open and that only makes it sound odd when in the V4 mode, but if they melt, you get CELs.
The Z07s use carbon ceramic rotors which are very costly, and you don’t want to ding or chip them, or get things like tire dressing or other chemicals on them.
Out of the box these are amazing cars to track and autocross, but when looking for the best speed, tweaks to the alignment, shocks and brakes are just as valuable as with any other car. The rear alignment on these is much more involved than on a C5 or C6, and particularly frustrating at times since it has two cams on the lower arm which has a caster effect, which in turn has a roll steer effect. And the toe link is an eccentric, not a standard tie rod as before–and that actually sucks as it’s fickle and can slip.
Low-buck mods? Lots of them, but mostly cosmetic-type things. I have done lots of little things to make the car easier to keep clean or less prone to scratches, etc. Performance-wise it would depend on the model; I can’t make a blanket statement as you have some cars with setups that literally have no rear sway bar, others with 31mm rear bars, and just adding one to a no-bar car can be trouble without a matching front, etc. Like anything, it will take time to develop all the answers, and this is made far more complex thanks to all the different permutations of the C7 that can exist.
Seems like a modded C5 is still the best for motorsport all these years later. C6 and C7 may be faster stock and better road cars but are hard to develop and have a lot of issues that pop up when driven hard for a season.
GCrites80s said:Seems like a modded C5 is still the best for motorsport all these years later. C6 and C7 may be faster stock and better road cars but are hard to develop and have a lot of issues that pop up when driven hard for a season.
Haven spent some time in a c5 and a c7, I cant IMAGINE why that would be the case. The c7 Grand Sport absolutely rockets around the track and has SERIOUS factory improvements that are not included on any c5. Dry sump. Extra radiators. Extra brake cooling. Aero. Fixed brake calipers.
The thing is also a great place to be when driving to the track as well whereas the c5 has the interior of a 90s blazer.
The reason they are harder to develop is because they are SO FAST from the factory. You could easily tear out the magnaride shocks instead of getting a dsc module and go back 30 years with standard shock and spring setups. The traction control makes you feel like a hero in all conditions. The ABS is MUCH better. I cant believe anyone would pick a c5 over a c7 grand sport.
10 events so far on my brothers and he drops it off at the dealership for oil changes and warranty issues (minor navigation issue fixed with brand new navigation system). Try that with a c5.
Have you had a chance to compare a heavily modded C5 with a lightly modded C7 (since that's basically all that people who aren't pro race teams can do) in as intense as environment as the top modern Corvette people such as Strano and Danny Popp have? I haven't but I have seen them write on the subject. Yes stock for stock the C7 blows away the best stock C5 on a road course during track days/HDPE. It's when you really push that the driver aids become cumbersome on the C7 and the inability to improve the car with mods besides tires and forced induction start catching up with it in relation to the older cars.
There was basically nothing of use in that article. No suggestions on alignments, for street and track, shocks, etc.
Displaying 1-10 of 16 commentsView all comments on the GRM forums
You'll need to log in to post.