Stock Suspension Vs. Custom Frame

[john31s]

I've been reading a lot of build treads lately and I have seen three main courses people take with their chassis.

Route 1: leave the stock frame the way the factory made it. Clean it up and replace the suspension with bolt on parts.

Route 2: use the stock frame but box it completely along with other stuff like rewelding factory welds or adding more bracing.

Route 3: go for broke and ditch the stock frame and replace it with an after market frame using c-6 components.

I get why people opt to go for each route, but when does the next level become necessary. Home much horsepower or how big of brakes make the next level a must. I'm still planning my project and I want to know how much brakes and power can my stock fame handle (1970 Pontiac Lemans). At what point will I need to reinforce the stock frame.

Thanks.
John.

[Eric Howell]

IMHO it depends on how much track time the car will see. Autox and track days will will put a lot more stress on the chassis and body then a cruise night car would see. You have to take it all into consideration. My next build will be a nice day daily driver that sees a road course or two and gets tossed around the cones any chance I get. That said it will be a full frame/ full cage build.

[exwestracer]

A lot depends on what you are starting with, as well. Some chassis have a reputation as being better than others; as far as geometry, how much tire will fit, etc. I guess WHEN you switch to a custom frame (C6 suspension or otherwise), depends on how soon you reach the limitations of the stock chassis...

[BMR Sales]

I've been reading a lot of build treads lately and I have seen three main courses people take with their chassis.

I get why people opt to go for each route, but when does the next level become necessary. Home much horsepower or how big of brakes make the next level a must. I'm still planning my project and I want to know how much brakes and power can my stock fame handle (1970 Pontiac Lemans). At what point will I need to reinforce the stock frame.

Thanks.
John.

John,


This is a great question that all of us have to deal with concerning many different aspects of a build. Although I could try to sell products to you it really boils down to a few things first:

• Budget
• Performance goals for the car (ride quality vs. straight-line perf. vs. handling, ect.)
• Time to acquire, fab, build as needed
• Fabrication skills/tools, facilities to work on car

IMO, it is easy to get caught up in the build and lose track of the four considerations above. It is of my personal opion that most guys shoot for the stars when they begin planning a car in all aspects and usually run out of money, time and/or interest because it isnt coming along as they originally thought it would.

Try to lay it all out on paper so it becomes a visual image for you to work with since the experts say that men are "visual" it helps me to actually "see" a plan more so than to think of a plan.

[UMI Tech]

I've been reading a lot of build treads lately and I have seen three main courses people take with their chassis.

Route 1: leave the stock frame the way the factory made it. Clean it up and replace the suspension with bolt on parts.

Route 2: use the stock frame but box it completely along with other stuff like rewelding factory welds or adding more bracing.

Route 3: go for broke and ditch the stock frame and replace it with an after market frame using c-6 components.

I get why people opt to go for each route, but when does the next level become necessary. Home much horsepower or how big of brakes make the next level a must. I'm still planning my project and I want to know how much brakes and power can my stock fame handle (1970 Pontiac Lemans). At what point will I need to reinforce the stock frame.

Thanks.
John.

Hi John.

Our '72 LeMans works great as an all-around Pro Tour style car. It has the stock frame and high quality UMI bolt-ons.

http://www.umiperformance.com/catalo..._page=72lemans

The next step for it is a full frame-off resto. We'll clean up the frame and weld some seams but don't anticipate any custom fabrication will be required.

Currently it's a fun daily driver which is quite capable at the occasional corner carving session.

ramey

[bret]

I'm going to over-simplify here...If you are working with an A body and are capable of driving beyond the limits of a stock chassis modified with good bolt-on components, you already know that and have made the appropriate plans. Use the oem chassis. Research, purchase, and install the components that will give you and your car a happier driving experience.
As a point of reference...our 66 Chevelle will corner as well, and brake better than my 2007 Z06 Corvette. I've proven it several times.
Having said all that...nothing wrong with an aftermarket chassis either. The right one might add some additional performance benefits, but if all it does is make you smile then it is a good value for you. In some cases it even makes sense financially compared to repairing a rusted or damaged frame, or when you want a SUPER low ride height.

[darkling]

this is exactly what i'm going through with my nova. Can i drive it to the limit of the suspension i'm planning probably not. So where to i step back and say wow those goals are beyond my reach .
guess this is where the champagne taste on a beer budget comes in

[RobNoLimit]

First off, I have to commend the Pro's here for being honest. As a chassis & suspension parts builder, I spend a lot of time talking people out of buying expensive parts. BTW, this is not the way for me to make a quick buck. So, hats off to the honesty here. 'A' body's suffer from being two dimesional, and the floor layout forces aftermarket chassis to follow the same plan. - the chassis is long and wide, but has no hieght. Making it taller, or, more three dimensional is the way to gain strength. Welding the factory seams, and adding an X member will help, but the biggest chassis gain will be from a 6 or 8 point cage. - or 10 pt. As has been said, there are planty of A-body suspension parts that work great and been well proven/beat-on. Make a plan to get it done before you die, and go have some fun with it.

[icemanrd19]

well im in this debate too. My subframe needs to be replaced and i dont have coil overs, control arms or anything. looks like if you buy a used subframe and load it up with all the goodies it will cost you around 4-5k correct? Well if your going to spend that money why not spend another 1k or 2k and get a dse subframe or ridetech?

[olason]

RobNoLimit, when you talk about adding a cage, I was wondering on the cages with removable cross-bars, roadster shop in their cars have done some with removables. What strength disadvantages does this give? If planned right the removable bar should be able to give the same strength I believe. I will probably go with a custom frame on my 1968 olds 442 because I have more of a proof-of-concept to myself (I am an engineering student). So that will be my route. As for roll cage tie-ins to the frame how do you go about that as the body is mounted on rubber to the frame?

[john31s]

Ok I get what you are all saying. Thanks for clearing this up. I'm going to keep my orginal frame and just add some bolt on parts. This should give me the preformance gains I want over all the orginal parts.