Suspension height advice

[racerJoe]

I hate to cross post but I need some answers ASAP. I am cutting a '70 Nova subframe to put in a C4 front suspension. I need answers on:

"ideal" ride height (looks)
Required suspension travel in bump.

Deatils are in the 'new cars' secion under "'70 Nova C4 retrofit project (https://www.pro-touring.com/forum/showthread.php?t=37928)"

Thanks,
Jack (Cutting and getting greasy today...) Wendel

[MrQuick]

ideal height depends on taste.

You can go as low as you want but 3" either way is a good base.

[1FstChevy]

Sounds like you need to slow it down a take a step back before cutting!

You can't be in that big of a hurry can you?

[jerome]

for best suspension geometry, center of the ball of the lower ball joint should be about 1" below the lower control arm mounting holes.

Jerome

[racerJoe]

MrQuick replied:

>ideal height depends on taste.

Hence the reason I was asking. Without asking I only have a data point of one.

>You can go as low as you want

I'm not sure that is true... it would seem to me that there is some miminal ground clearance required to make a car tolerable. I have a 70 Chevy truck that's chopped and lowered. I ended up having to raise it an inch simply because it dragged the road too often.

>but 3" either way is a good base.

You lost me... 3" from what? I HOPE you are not talking about stock height. I thought one of the goals of pro-touring/g-machines was to make the car handle well. These cars are pigs from the factory so they need to be lowered and have stiffer springs and sway bars just to get them to handle decent. Raising one would put the center of gravity even higher than stock and have a huge negative impact on handling. That completely defeats the purpose of putting a 'vette suspension under the thing.

L8R,
Jack (I want 'vette handling...) Wendel

[racerJoe]

1FstChevy replied:

> Sounds like you need to slow it down a take a step back before
>cutting!

Too late! Besides... I'm not sure what I would be slowing down for. This project has been in the planning stage for years now and the suspension id modeled in 3-D on my computer. Now it's time to start building. The original plan was to drop this with a tubular subframe in one of my first gen Camaros. But the Nova became available and along with it the idea to see if this could be done "on the cheap". After I finish this and test it I'm ripping it all out and building the tubular subframe. The tubular subframe is not in the way of the suspension and I already know what I want my f-body to look like at ride height. I was looking for input and opinions on issues specific to the Nova.

>You can't be in that big of a hurry can you?

Yes I can... and I am... 8^)

L8R,
Jack (Time to stop planning and start building...) Wendel

[racerJoe]

jerome replied:

> for best suspension geometry, center of the ball of the lower ball
>joint should be about 1" below the lower control arm mounting
>holes.

Wow... thanks for the information! I would guess this is at normal ride height, correct? I will have to check how close my current setup is. My guess is that it's pretty close to that.

Just wondering... where did this design rule come from? I've never read anything like this in all the books I've read.

L8R,
Jack (I like those 'rules of thumb'...) Wendel

[jerome]

This is for short upper arm and long lower arm. It helps if you draw it on paper, if the lower arm slightly slopes down from the center of the car, then the lower ball joint will be pushed out when the suspension bumps upwards. This makes the negative camber gain more quickly. For example, the drivers side will compress when a right turn is taken, so the negative camber will dramatically increase with just that first inch of compression.

Hope that makes sense, draw the arms and spindle with lines on paper and you'll get it. There's no calculation or anything involved, its just a concept. Higher than the rule won't hurt much, but lower will hurt the handling. So generally people try to make it as low as possible, but still get that aggressive negative camber gain in the beginning of bump travel. That ends up being about an inch.

Jerome

[protour_chevelle]

http://picasaweb.google.com/modernClassics/JackSBirthdayPartyAtRedlineRaceway11102007/photo#5131757286104427778

who is that, then I will answer your question lol

[MrQuick]

You getting funny Joe, so early on the board...
Look around the site, you will see extremes either way.

3" bouncey/jouncey. Suspension travel. Your second question.
The perfect height in my opinion...
https://www.pro-touring.com/forum/attachment.php?attachmentid=9626&d=1145489822
https://www.pro-touring.com/forum/showthread.php?t=29922 2 good info links AA+++

https://www.pro-touring.com/forum/showthread.php?t=17717

[racerJoe]

MrQuick sent:

>You getting funny Joe, so early on the board...

I've had practice... I've been on the classic-f-body mailing list fopr YEARS...

>Look around the site, you will see extremes either way.

Thanks... I did...

>3" bouncey/jouncey. Suspension travel. Your second question.

Thanks... I thought you were still talking ride height.

>The perfect height in my opinion...

Well... you ended up being right. I wanted the lower look of "One Sick gen 2" after I saw it so I hacked the subframe some more (a LOT more work). I like the new look a lot better but now the tire hits the fender lip when turned. 8^( To fix that I would have to either modify the fenders or narrow the track width. I don't want to do either. So if I raise it back up to where it was it ends up like the picture you posted and solves the fender clearance problem. 8^)

Thanks for the help!

L8R,
Jack (Gotta take a break for Christmas stuff...) Wendel

[MrQuick]

no problem. Im in th same (LOW) boat you are. For some reason I've turned into a low life. Everything has to be slammed.

There are ways around the problems you listed but then you have to sacrifice more important things. Hopefully not oil pans and headers.

Have a great holiday and welcome to the site.

[racerJoe]

MrQuick replied:

>no problem. Im in th same (LOW) boat you are. For some reason
> I've turned into a low life. Everything has to be slammed.

The rules for my racing class require 3" of ground clearance so that's what I want on that car. I will likely need to raise it some for the 'street version'. There are some speed bumps around town that are taller than 3". But, then again, that may be where the air bag setup comes in. There are so many options at this stage...

>There are ways around the problems you listed but then you have
>to sacrifice more important things. Hopefully not oil pans and >headers.

Can you elaborate? I really would like to find a way to keep the low ride height if possible.

I had a racing buddy come over the other day before I did the extra 2" drop. I asked him about the extra 2" and he said it couldn't be done because the crossmember was already low. But I explained to him that I am changing the frame height relative to the front crossmember to get the desired ride height. This allows me to maintain the same center ground clearance as a C4 'vette from the factory and therefore the same header and oil pan clearance. Of course I still need to see how the Nova/Camaro headers and oil pan will (or won't) fit. Plus I have two 509 BBC engines pulled from dragsters and I'd like to find a way keep those pans if possible (no crossmember notches). Ideally I'd like to have the tubular crossmember just forward of the engine and be just slightly lower than the pan. This will give the maximum ground clearance and still allow the crossmember to take any hits and protect the pan. My truck is that way so I don't mind so much when I hear road contact. Headers may well be a completely different story. Unfortunately I gotta do this thing one step at a time.

>Have a great holiday and welcome to the site.

Thanks! I am hoping this site will be as valuable to me as the f-body site has been. 8^)

L8R,
Jack (Transforming the idea to reality...) Wendel