Lowered stock bolts only....

 

What is the best procedure to slightly lower on stock bolts and still maintain the desired rake? I've checked the DIY threads however the instructions are for full lowering?

 

I've seen various write up threads, but these are great pictures.

So basically, the front bolts will show more threads after lowering and the rear bolts will show less threads after lowering?

 

Yup !

 

OK. I have looked and I am sure that there is, but after looking all day I can not find a thread that explains how to lower...
Sorry, I tried.

 

I believe this is the link that the pictures above were taken from. The CF links I've seen were pretty much word instructions only. I personally like pictures.

http://www.frankhunt.com/FRANK/hobbi...5_Lowering.htm

 

Try just a search engine like Google. There are good tutorials on other forums as well.

The kicker for the fronts is to support the end of the spring, not the lower control arm. Let the control arm dangle and support the spring as close to the end as possible. Then turn the end of the bolt counterclockwise with a 10mm wrench.

One mistake I found on a tutorial was for the rear bolt. It said use a 18mm and a 13/16 socket (I think that was it) but in reality it is a 18mm and 21mm socket you need.

Once you get it jacked up and the wheels off....it is exceptionally easy.

ps....and moving the shock is not necessary at all.

 

Never mind

 

Here are some links to DIY lowering

http://www.frankhunt.com/FRANK/hobbi...5_Lowering.htm

and

http://www.z06vette.com/diy_lower.php


use the pics in the first two, BUT FOLLOW THE INSTRUCTIONS FROM THE THREAD BELOW, as this is the proper and safe way to do it, go to post # 92 of the following thread:


http://forums.corvetteforum.com/c5-t...in-here-5.html

 

Here, I will cut and paste the post in the DIY thread here...the origanal post was made by SOLOFAST....thanks for the post Solofast:

"There is a huge amount of misinformation as to how to lower a Corvette, and how much you can lower it before it messes up the handling or even worse, it becomes dangerous to drive. I’ve tried to put together in one place a how to and, more importantly the why behind it, and hope this saves some folks some time and heartache by getting it done right the first time.

First of all, you shouldn’t lower these cars all the way on the stock adjustment bolts. If you take your car to any good race shop (like Phoenix Performance) to have it set up for the track, they won’t lower the car all the way on the stock bolts. This should tell you something right there. Moreover, I've tested these cars on the track at various ride heights and the stopwatch doesn't lie, they are faster and corner better when they are set up right, and that isn't as low as you can get on stock bolts.

The reason for this is that the suspension works properly when it is in the right range of motion, and if you lower it more than that it won’t. There are two technical reasons for this. The first is that the suspension camber gain that you get from a properly set up ride height goes away and you won’t get as much grip as you would if it was at the right height. The second reason is that if you lower it all the way on stock bolts in the rear, you will be nearly on the bump stops and have almost no travel. If you cut the bushings in the back you will be into the bump stops and have no travel. Using longer bolts in the back with stock shocks guarantees that you will be into the bump stops and have no travel. The rear bump stops are built into the shocks, and are progressive. Lots of people don’t realize they are into the bump stops because they don’t hammer the car if you don’t hit them that hard. So what’s the big deal about hitting the bump stops in the rear suspension? Well, first of all if you are cornering fast, hitting the bump stops results in instant oversteer. This means the tail will jump out and you can, very likely, lose control and wreck your car. Secondly, if you hit a good size pothole or bump, the rear shock acts like a wedge and this pushes the rear alignment adjustment eccentrics out of place and you will be taking the car back to the alignment shop because the car will be driving funny as you have knocked the rear alignment off.

I hear lots of people who say “I’ve taken out the front bolts and cut the rear bushings and my car feels really tied down, it only feels a little bouncy”. Well, it feels tied down because you are on the rear bump stops and the ride is going to be real firm, but if you take a corner quickly and hit a bump, or crank the car to avoid an accident, you are very likely to lose control and wreck your pride and joy. Ask anybody who has taken his car to the track like this and they will tell you that, at high speeds, these cars, if not set up right can be dangerous.

If you want your car down in the weeds the only way to avoid bottoming out the rear shocks is to get shorter rear shocks, or go get a set of dropped spindles. The right amount to lower these cars is about without dropped spindles is ¾ of an inch, and the absolute maximum for decent handling is 1 inch. Notice also that I haven’t suggested taking out the front bolts because this will A) cause the car to be too low for the geometry to work correctly, and B) it will result in the spring gouging into the control arm and will eventually ruin one or the other unless you put some kind of pad in there to allow the spring to slip on the control arm. The stock pads on the adjustment bolts allow some motion and this prevents damage to the spring and control arm.

So let’s start with how to lower your car the right way, assuming that you don’t have a race setup shop or access to a set of scales to corner weight your car when you are done, which is actually the best way to do it and really, the only way to do it if you are going to track or seriously autocross the car.

If your car is stock it was set properly from the factory and the ride height is right from side to side RELATIVE TO THE CHASSIS, which is the important part. First, in the front, take the weight off of the lowering bolt by jacking on the spring with a block of wood on the jack to keep from damaging the spring. If you don’t take the weight off you will likely round off the lowering bolt and make a mess of things. If you are lowering the car from stock, mark the screws with paint, nail polish or a sharpie, and turn the adjustment screws in equal increments from side to side. That is turn each front screws an equal amount of turns. In the front it also helps to turn the screws in full turn increments from where you started. This keeps the orientation of the deformed front pads the same and the car won't take as long to settle out. Turning them until they bottom and then back 1/4 of a turn assumes the car and the spring are level and is not the right way to do it. In the front expect the screws to be about two or three threads from bottoming out. Same thing for the rear, turn them equal amounts from side to side, but you don't need to turn the rears in full turn increments. You will find that, typically, in the rear, one screw is about 3 or 4 threads different from the other. THAT IS NORMAL. If you turn them to the same length you will screw up the corner weights of the car. Expect in the rear that one screw will be about 3-4 threads from bottoming out and the other will have about 5 or 6 threads showing.


If you have already gone in and messed with the bolts you have lost the setup that the factory put into the car in the first place and to get it really right you should have the car corner weighted. If you don't want to do that you can get close by finding a flat surface, (and no, most garage floors aren't nearly flat enough) like an alignment rack or a known leveled slab, and measuring so that the front jacking point is between 5.0 and 5.25 inches from the ground and equal on each side, the rear as measured at the rear jacking point should be a 1/2 an inch higher than the front. You want some rake in the car to keep the aerodynamics right at high speed. If you don’t the rear end of the car will lift at speed and that can be dangerous. NEVER measure from the fender lips. The fender lips are just plastic pieces that are hung on and are all over the place. EXPECT that the car will look different from side to side. As I said, these fenders are just hung on the car and you could see a difference at the fender lips of as much as a half an inch.

There you have it, all done, set to the right height for the best handling, and as balanced as you are going to get without cornerweighting the car. "

 

^^^ Very good information.

So it seems the "recommended" lowering amount is 3/4" to 1". Does anyone know the total inches when dropped completely on stock bolts? The reason I'm asking and the reason I started this thread is that I'm trying to figure out the best starting point since I previously lowered and now I'm considering lowering again, just not as far. If I target 3/4" lowering, what do I measure against?

The pictures above are great, however the information above is a little concerning considering thread count may not be the way to measure the corners equally and fenders are also not supposed to be used.

 

measure at the jacking points per my last post above to get it back to stock height all the way around.....then get one of those 6" precision rulers at home depot for like $3, and measure and mark the lowering bolts with fingernail polish or a permanent black marker to lower all four corners the exact same amount.... dont go by turns or threads... use the ruler and a good marking method...then measure at the jacking points again when done to make sure it is the same height all the way around


you can use the stock fender heights listed above as a referance point for getting it back to stock height, but remember that the fenders can be hung up to 1/4 inch off... so use the fender height as a reference but then measureat at the jacking points to make sure its the same starting height on both sides, this should get you pretty close to back at stock height so you can then relower it from there

 

as an aside, I got a reply from pfadt telling me lowering 3/4" to 1" was ideal for most setups that use shocks and leaf springs

if that doesnt fill the wheelwell enough get bigger wheels lol

18/19's fill the well pretty good lowered 1"...







just FYI.... dont use the pics of my current vette as a reference, I have'nt lowered it yet, am waiting to get some bilsteins and new rubber to lower so I can get it aligned with the right camber setting etc all done together

 

stock height is around 5"-5.25" measured at the front jacking points, and 5.5" to 5.75" at the rear jacking points....if you measure where you are at now you can see how far you lowered it on your setup by just subtracting the differance

 

Thanks. The front and rear jacking points are the crossmember jacking points correct?

 

nope, the side jacking points on the frame rail on the sides of your car

look along the bottom of the frame rails and you will see a whole in the frame rail at the front behind the front tires and at the rear in front of the rear tires

just put one end of the ruler on the ground and the other into the jacking point wholes and you can see where your ride height it compared to the numbers listed above

 

Thanks. To make matters more interesting, I will have to account for the frame rail savers I have installed as well.

 

also, the rule of thumb in case someone gets confused while under the car....for lowering:

loosen the back, tighten the front

and the opposite for raising

 

not so bad...just measure the frame rail savers and account for it....easy math

where those flanges are on the FRS's is where the jacking point wholes normally are...so just measure at those flanges and subtract the thickness of the FRS's from the stock ride height measurements above to find out how far you have moved from stock

 

Who makes those FRS's...they're nice...looks like good quality...I wants me some lol