crossing speed bumps and driveway enterances

[grumpyvette]

Every once in a while I see, some guy driving a corvette , who probably has little experience doing that, try speeding over speed bumps, or turning into a drive way with a noticeable dip or stepped concrete rain gutter at the entrance,too the property or man hole covers that stick up well above the road surface level, the usual result is damage to low hanging chin spoilers or the suspension, or deeper oil or transmission pans or low headers etc. you quickly learn that these low clearance performance cars like most corvette, and similar cars , that they have limited ground clearance, and you have little choice but to slow down, and cross over these hazards slowly or do your very best to avoid them, I know several places I choose not to drive my corvettes due to excessively steep drive way entrances or speed bumps, if you drive a corvette youll quickly realize its NOT a 4x4 truck, and can,t drive over stuff that would hardly be noticed by one.
Now purely from a geometry and clearance perspective , many times you effectively gain a bit more road to under the car clearance, if you use an angle of 30-45 degrees of approach vs perpendicular to the dip in the pavement on entering a drive way or trying to cross a speed bump AND REMEMBER too cross it at very low speed,.... obviously not always an option. but failure to anticipate and drive carefully can get rather expensive and time consuming as a result of damage inflicted to the cars lower areas
you,ll ideally want 4" minimum oil pan sump, and transmission fluid oil pan, to pavement clearance with YOU and a BUDDY sitting in the car to avoid problems,
anything over about 4.5 inches of oil pan sump, trans pan and exhaust to ground clearance should be just fine,
if thats measured with you seated in the car, in fact lots of guys squeak by with 4"
obviously more is better but thats not always an option.

I added a deeper trans fluid pan to my corvette it was about 1.5" deeper than the stock pan, and reduced the ground clearance by about 1" I avoided issues with ground clearance by having previously swapped to larger diameter rims and tires which had previously raised my under car clearance by about a similar 1.5", but without that previous wheel and tire upgrade I think I would have been in serious trouble with the lower ground clearance under the vette!

the extra 2 quart capacity and ribbed surface that significantly increases surface area,
plus a trans fluid cooler lower trans fluid temps a great deal,
but its also going to marginally reduce under the corvette road clearance.
http://garage.grumpysperformance.co...all-and-run-a-deeper-pan-to-compensate.16378/
http://garage.grumpysperformance.co...ans-cooler-on-a-c4-corvette.10514/#post-44478

viewtopic.php?f=80&t=1158&p=2361&hilit=skid+plate#p2361

IF YOU DON,T THINK OIL PANS AND FRAMES HIT SPEED BUMPS WHERE ARE ALL THE GROOVES IN THE CONCRETE FROM??

IF YOU DON,T THINK GETTING YOUR OIL PAN,TRANS PAN,HEADERS,AND FRAME UP AT LEAST 4" UP OFF from the pavement as you drive is important!

HERES A RATHER TYPICAL RAISED OBSTACLE, (its a fuel tank access port but man hole lids can be very similar)that can cause quite a bit of under car frame, and oil an damage

HERES AN UNLUCKY CORVETTE FRAME THAT HIT IT

viewtopic.php?f=80&t=10730&p=46843#p46843

hitting chuck holes, speed bumps curbs, and raised manhole covers ETC. is a well documented way to severely damage the internal structure of tires as well as the corvette suspension and oil pans.

just a few pictures I found posted that easily demonstrate internal tire damage can cause serious issues with stability, braking and control, and yeah, hitting a few curbs, chuck holes and speed bumps with your corvette,or muscle car,will be unlikely to help tire durability

I'D POINT OUT THAT TIRE BALANCE , does not necessarily have much effect on the cars ride or ride vibration, simply because a tire can balance perfectly, while its still not perfectly concentric, with the axle center line or perfectly round,and even in the tire tread and side wall constructional thickness
internal structure failures can also cause vibrations and thats what your complaint seems to point too.
Ive had tires balanced that were so far out of concenticy that if you put the car on jack stands and spin the tire next to a strait edge , you could easily see the change in distance as it rotated.
obviously theres a wide range in the degree of wear and damage and tire quality , so if you have some hard to locate vibration I suggest checking the tires, or swapping locations on the car to se if the vibration changes or replacing the tires

 

[philly]

SOMETIMES ITS UNAVOIDABLE, especially since my vette is lowered. i just go slow and try to avoid as much crap as possible... every time i scrape it hurts tho.

 

[NOT A TA]

The video with the Chevy II looked like it had a really deep trans pan. Guess he never looked to see how close to the ground it was. My bird had less than 3" clearance to the exhaust so I had to be very cautious.

A lot of the newer cars have plastics that take a beating like the Corvettes. I've been learning and practicing plastic repair/fabrication/paint techniques recently. Hopefully I'll be learning Nitrogen welding plastics sometime during the next couple weeks.

 

[87vette81big]

I never lowered my 87 Corvette convertible.
I never will.
Need the extra ground clearance for real world driving.
The C4 Verts sit 1/2 -5/8" higher than the coupes.
For extra room to get 5" inches to the ground with the Big X-brace intact.
If anything it needs to be higher up in the air.
Fitting 31" meats out back would do it.
Then can use 4.30 to 5.38 gears in the 9.3 Pontiac rear I want to 4-link in.
Turbo 400 trans.
Drag Race. Old School Gasser Tech that still works.
I have the parts & lots of them.

 

[Grumpy]

I found this posted on line and it appears to be a sheet of 1/8" or 3/16" mild steel which would significantly add to the potential protection of the oil pan from running over road debris.
obviously there will need to be a way to secure or support that impact shield like welding brackets that might bolt to extended oil pan bolts or the vehicle frame, welding those brackets that would be required to hold that impact protection plate in place would not be all that difficult too design or install.

 

[Indycars]

I know where that guy lives ........ Oklahoma !!!

 

[Maniacmechanic1]

Nothing Beats A Big Chevy, GMC, Or Ford 4X4 at times Grumpy.
Run over anything.

 

[Grumpy]

I recently read a well documented thread on how to lower the stance on a c4 corvette!
first let me state,
congrats on accomplishing what you set out to do...lower the corvettes stance marginally, obviously it took some though and effort!
now a simple question
WHY?
the reason I ask is that yes its obvious it makes the cars stance look slightly more aggressive.
BUT, having track raced corvettes for decades,and driven some serious high performance cars including several 500 hp plus corvettes, having track raced corvettes for decades,
most real racers may use flex air dams, a few spoilers, under car dispersion plates to get better aerodynamics, Ive never found just lowering the stock car, helped handling as much as stiffer springs , correctly matched sway bars and shocks front and rear, bigger brakes and specifically selected wheels and tires, and heres the big issue GROUND CLEARANCE under the corvette,, anyone who has ever, closely looked at a corvette with a driver seated in it with a full tank of fuel, should be aware that theres very limited oil pan, transmission and k frame to road surface clearance., all it takes to cause significant damage is a speed bump drive way drainage curb or raised manhole cover.
IF YOU DON,T THINK OIL PANS AND FRAMES HIT SPEED BUMPS WHERE ARE ALL THE GROOVES IN THE CONCRETE come FROM??
if your un-aware, most aftermarket oil pans, for engines and transmissions, with increased capacity tend to extend up to an inch or a bit more even lower than the stock components,
most exhaust headers, extend an inch or so lower, further reducing ground clearance.
most c4 corvettes have less than 4" of ground clearance to begin with, reducing it further can potentially cause issues you might not have thought about
many corvettes could not drive over a common speed bump or clear the all too common badly installed manhole cover.

http://garage.grumpysperformance.com/index.php?threads/upgrading-your-c4-to-c5-brakes.13/

http://garage.grumpysperformance.com/index.php?threads/suspension-upgrade.11385/

http://garage.grumpysperformance.com/index.php?threads/upgrading-the-suspension-on-a-c-4.483/

http://garage.grumpysperformance.com/index.php?threads/cooling-off-that-c4-corvette.3954/

http://garage.grumpysperformance.co...ans-cooler-on-a-c4-corvette.10514/#post-44478

http://garage.grumpysperformance.co...nk-to-some-c4-corvette-wheel-tech-info.12099/

 

[Maniacmechanic1]

I recently read a well documented thread on how to lower the stance on a c4 corvette!
first let me state,
congrats on accomplishing what you set out to do...lower the corvettes stance marginally, obviously it took some though and effort!
now a simple question
WHY?
the reason I ask is that yes its obvious it makes the cars stance slightly more aggressive.
BUT, having track raced corvettes for decades Ive never found it helped handling as much as stiffer springs , correctly matched sway bars and shocks front and rear, bigger brakes and specifically selected wheels and tires, and heres the big issue GROUND CLEARANCE under the corvette,, anyone who has ever, closely looked at a corvette with a driver seated in it with a full tank of fuel, should be aware that theres very limited oil pan, transmission and k frame to road surface clearance., all it takes to cause significant damage is a speed bump drive way drainage curb or raised manhole cover.
IF YOU DON,T THINK OIL PANS AND FRAMES HIT SPEED BUMPS WHERE ARE ALL THE GROOVES IN THE CONCRETE come FROM??
if your un-aware, most aftermarket oil pans, for engines and transmissions, with increased capacity tend to extend up to an inch or a bit more even lower than the stock components,
most exhaust headers, extend an inch or so lower, further reducing ground clearance.
most c4 corvettes have less than 4" of ground clearance to begin with, reducing it further can potentially cause issues you might not have thought about
many corvettes could not drive over a common speed bump or clear the all too common badly installed manhole cover.

The Younger Guys with C4 Corvettes on FB groups I am in like the Look super Low Grumpy.
I agree its not practical at all unless its a true Drag car or Road race car. Trailered towed to races. Never street driven.

 

[Grumpy]

yeah its an older thread... but the facts don,t change due to the threads age.
and most people reading the threads are far more concerned with the content than the threads age,
especially if they are researching lowering their corvette in this case.

 

[Maniacmechanic1]

Its the dumbest thing you can do to a Corvette.
Lower it.
It automatic becomes slower because you have to drive it slow all the time or smack into everything on the road.
Might as well leave it parked in the garage & let it sit.