How do I lower my C4?
Le Mans Master
Joined: Oct 2000
Posts: 5,086
Likes: 0
From: Northern tip of Virginia
Re: How do I lower my C4? (Dave's1991vette)
use the search engine on the forum to access dozens of posts on the subject.
Search "post bodies" and "archives".
also check out this thread in the Tech section
https://www.corvetteforum.com/techti...=194&TopicID=2
Search "post bodies" and "archives".
also check out this thread in the Tech section
https://www.corvetteforum.com/techti...=194&TopicID=2
Intermediate
Joined: Sep 2002
Posts: 43
Likes: 0
From: Winnipeg, Canada
Re: How do I lower my C4? (Phil-tha-Rush)
This is from the tech section:
"Whenever I think about lowering a car, the old Cheech & Chong movie pops to mind that begins with Chong strutting around his “Chebby” dusting it off to the tune of “Low, Low, Low - Low Rider”. Well, to quote famous engine builder Myron Cottrell, “Lower is better”. I often wondered about the lowering options available to C-4 owners, and just completing the job on our ‘90 Polo Green convertible I though I better jot it down before it’s forgotten.
Besides better looks, a lowered Corvette has reduced wind drag and enhanced cornering ability. Translation: higher top speed, quicker 1/4 mile ET’s, better gas mileage and lower lap times. Just be careful entering and exiting driveways with different grades or you’ll be replacing front spoilers. I’m on my third one, how about you? The specifications for the C-4 Corvette in your service manual call for a higher trim height in the rear than in the front, and us drop-top folks riding even higher than the coupe-group. I like a car to sit level. I’m not suggesting that you drop the bumpers to the ground and make showers of sparks, just lower your car an inch or so. I used to be able to stick my whole arm above the tires to clean the inside fenders, now I can barely get my fingers in there -it’s great. Since you can’t see in there anymore, I no longer have to clean in there. And it LOOKS much better! Just remember that if your want to race your Corvette, check your NCCC competition Rule Book first - most suspension modifications will put you in a different (faster) class - which should tell you something about the performance benefits!
Lowering the rear of your Vette is easy, just be careful and follow the instructions in your service manual. C-4's use a lightweight transverse spring on both ends of the car. Just move some spacers from the top of the rear spring to the bottom. Another way to lower the rear of your car is to buy a lowering kit (under 30 bucks) from Mid-America Designs. Included are longer spring bolts that’ll do the same thing and are infinitely adjustable. Here we go again, on the creeper. Sometimes I think I spend more time UNDER our Vette than actually driving it...
Lowering the front of a C-4 Corvette is where things begin to get nasty. The rubber bumpers need to be cut off the top of the transverse spring and replaced with smaller urethane wedges included in the lowering kit. The only problem is that you gotta take the car half apart to lower it ½”-1". Is it worth it? I think so - I can’t stand to see gobs of wheel well above the tires. Once the car is up to the moon on (very high) jack stands, the wheels are removed. Then the lower ball joint, sway bar end links and shocks are unbolted from the lower control arms on both sides of the car. The lower control arm on one side of the car is then removed. After removing the spring protectors and spring retainers, the spring can be pulled out. You then cut the rubber bumpers off from the top of the spring and glue the urethane wedges in their place. I used my hackmaster (SawZall) to cut the rubber. Friends stopped by our house one Saturday afternoon in their ‘62 and watched in horror as I used this very tool to cut a big hole in the radiator shroud of our Vette for a cold air intake system. It seems ironic that such a crude tool would have a use on a precision automobile like a Corvette.
Yet another way to lower your C-4 Corvette is to install “coil-overs”. These are shock absorbers surrounded by a coil spring and a threaded collar for ride height adjustment. This system replaces the transverse springs and shocks in your car. Each wheel is truly independent, so there’s no “crosstalk” from side-to-side like the stock setup. They’re the racers choice. The downside is cost (about $1300) and they take a very long time to install (just ask my wife), requiring modifications to the front and rear frame in the shock mounting area. The front sway bar must also be moved forward 5/8". I would guess the weight difference is about the same between the two systems. Those transverse springs are really light, but there’s lots of mounting hardware associated with them.
Heck, now that your Corvette is in a bazillion pieces all over the garage floor, now is the perfect time to install those BIGGER ANTI-SWAY BARS you’ve been thinking about! The front bar on our car was surprisingly wimpy - it was hollow and weighed practically nothing. No wonder our car had so much body roll. I fixed that pronto with a solid 30mm (Z51) bar and new urethane bushings. In the rear I went with a solid 24mm bar and new urethane bushings. The stock setup was 26mm hollow front and a solid 22mm rear, with rubber bushings. If you change bars, try to approximate the stock front-to-rear size ratio or your car will have oversteer (back end likes to lead the way into and through the cones), or understeer (car plows into the cones without turning). Stock, the car had understeer - a safer, more forgiving alternative.
Now go get an ALL WHEEL alignment. It only takes about an hour and runs around $75. Sometimes I pick a sunny day and call for a while-you-wait appointment. Usually though, I’ll drop it off the evening before and have them park it inside - nice and secure. Enjoy cruising in your LOW RIDER"
-Bill Rauch 2/3/1998"
:cheers:
"Whenever I think about lowering a car, the old Cheech & Chong movie pops to mind that begins with Chong strutting around his “Chebby” dusting it off to the tune of “Low, Low, Low - Low Rider”. Well, to quote famous engine builder Myron Cottrell, “Lower is better”. I often wondered about the lowering options available to C-4 owners, and just completing the job on our ‘90 Polo Green convertible I though I better jot it down before it’s forgotten.
Besides better looks, a lowered Corvette has reduced wind drag and enhanced cornering ability. Translation: higher top speed, quicker 1/4 mile ET’s, better gas mileage and lower lap times. Just be careful entering and exiting driveways with different grades or you’ll be replacing front spoilers. I’m on my third one, how about you? The specifications for the C-4 Corvette in your service manual call for a higher trim height in the rear than in the front, and us drop-top folks riding even higher than the coupe-group. I like a car to sit level. I’m not suggesting that you drop the bumpers to the ground and make showers of sparks, just lower your car an inch or so. I used to be able to stick my whole arm above the tires to clean the inside fenders, now I can barely get my fingers in there -it’s great. Since you can’t see in there anymore, I no longer have to clean in there. And it LOOKS much better! Just remember that if your want to race your Corvette, check your NCCC competition Rule Book first - most suspension modifications will put you in a different (faster) class - which should tell you something about the performance benefits!
Lowering the rear of your Vette is easy, just be careful and follow the instructions in your service manual. C-4's use a lightweight transverse spring on both ends of the car. Just move some spacers from the top of the rear spring to the bottom. Another way to lower the rear of your car is to buy a lowering kit (under 30 bucks) from Mid-America Designs. Included are longer spring bolts that’ll do the same thing and are infinitely adjustable. Here we go again, on the creeper. Sometimes I think I spend more time UNDER our Vette than actually driving it...
Lowering the front of a C-4 Corvette is where things begin to get nasty. The rubber bumpers need to be cut off the top of the transverse spring and replaced with smaller urethane wedges included in the lowering kit. The only problem is that you gotta take the car half apart to lower it ½”-1". Is it worth it? I think so - I can’t stand to see gobs of wheel well above the tires. Once the car is up to the moon on (very high) jack stands, the wheels are removed. Then the lower ball joint, sway bar end links and shocks are unbolted from the lower control arms on both sides of the car. The lower control arm on one side of the car is then removed. After removing the spring protectors and spring retainers, the spring can be pulled out. You then cut the rubber bumpers off from the top of the spring and glue the urethane wedges in their place. I used my hackmaster (SawZall) to cut the rubber. Friends stopped by our house one Saturday afternoon in their ‘62 and watched in horror as I used this very tool to cut a big hole in the radiator shroud of our Vette for a cold air intake system. It seems ironic that such a crude tool would have a use on a precision automobile like a Corvette.
Yet another way to lower your C-4 Corvette is to install “coil-overs”. These are shock absorbers surrounded by a coil spring and a threaded collar for ride height adjustment. This system replaces the transverse springs and shocks in your car. Each wheel is truly independent, so there’s no “crosstalk” from side-to-side like the stock setup. They’re the racers choice. The downside is cost (about $1300) and they take a very long time to install (just ask my wife), requiring modifications to the front and rear frame in the shock mounting area. The front sway bar must also be moved forward 5/8". I would guess the weight difference is about the same between the two systems. Those transverse springs are really light, but there’s lots of mounting hardware associated with them.
Heck, now that your Corvette is in a bazillion pieces all over the garage floor, now is the perfect time to install those BIGGER ANTI-SWAY BARS you’ve been thinking about! The front bar on our car was surprisingly wimpy - it was hollow and weighed practically nothing. No wonder our car had so much body roll. I fixed that pronto with a solid 30mm (Z51) bar and new urethane bushings. In the rear I went with a solid 24mm bar and new urethane bushings. The stock setup was 26mm hollow front and a solid 22mm rear, with rubber bushings. If you change bars, try to approximate the stock front-to-rear size ratio or your car will have oversteer (back end likes to lead the way into and through the cones), or understeer (car plows into the cones without turning). Stock, the car had understeer - a safer, more forgiving alternative.
Now go get an ALL WHEEL alignment. It only takes about an hour and runs around $75. Sometimes I pick a sunny day and call for a while-you-wait appointment. Usually though, I’ll drop it off the evening before and have them park it inside - nice and secure. Enjoy cruising in your LOW RIDER"
-Bill Rauch 2/3/1998"
:cheers:
Safety Car
Joined: Jun 2002
Posts: 3,941
Likes: 0
From: Arnold Ziffelville CA
Re: How do I lower my C4? (Dave's1991vette)
I used the ecklers kit, but they are the same. It will lower it 1-2 inches. It's not to hard if you have someone to help. The directions for removing the front springs is in the tech area. Plan on making a day of it.
Drifting
Joined: Jun 2000
Posts: 1,335
Likes: 0
From: Northwest Suburbs of Chicago IL
Re: How do I lower my C4? (Dave's1991vette)
I used the mid america kit on my car... its been lowered for about 2 1/2 yrs now... I didnt even use the front wedges.. i just cutt the old ones off.. shaved down the alluminum retainers and thats it...Longer rear bolts for the back... To be honest with u my ride suffered after awhile... My car is stored for the winter but it will have coilovers put on in the spring....
Go with the coilovers if its in your budget from what i heard you wont be disappointed :seeya
Go with the coilovers if its in your budget from what i heard you wont be disappointed :seeya
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Re: How do I lower my C4? (Dave's1991vette)
I just lowered mine last weekend. I also took lots of pics, and am planning to write a tech tip for it... just haven't gotten around to it yet.
All the kits are the same.. but the install instructions are not. You should get at least 3/4" out of the front, and you can lower the back 1-1/2" or so to get rid of the rake angle.
All the kits are the same.. but the install instructions are not. You should get at least 3/4" out of the front, and you can lower the back 1-1/2" or so to get rid of the rake angle.
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Drifting
Joined: Jun 2000
Posts: 1,335
Likes: 0
From: Northwest Suburbs of Chicago IL
Re: How do I lower my C4? (johnboy89)
actually one of the forum members emailed me a spreadsheet with all the parts that are included in a coilover kit... So i am going to be buying each part seperately...Im going with QA1 shocks... :cheers:
