Suspension and Chassis Questions about your suspension? Need chassis advice?

Moving front wheels forward

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Old Jun 5, 2009 | 09:18 PM
  #1  
83RDRACR's Avatar
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Moving front wheels forward

Getting ready to start a track day/street project on a 83Z this Fall. After looking at all the available front end options out there, their cost, and actual benefit I was wondering if it would be better from a performance and cost stand point to move the front wheels forward 4 to 5 inches. This would be a custom double a-arm setup designed around the 4th gen spindles, brakes ans steering.

Any comments would be greatly appreciated.
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Old Jun 5, 2009 | 09:24 PM
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91_5.7_TPI's Avatar
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From: East Tennesse
Car: 1991 RS Camaro
Engine: L03 (want LS1)
Transmission: 700R-4 (and T56)
Axle/Gears: 4th Gen 3.23 posi
Re: Moving front wheels forward

What would be the purpose of this? I've never seen it or even heard of it. If you did this, it would require massive fabrication, reworking the the front wheel wells, steering linkages, planning a new steering geometry, not to mention the new front suspension, sprindles, etc. What are you building the car for? How do you see this benefitting the car?
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Old Jun 5, 2009 | 09:39 PM
  #3  
AlkyIROC's Avatar
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From: 51°N 114°W, 3500'
Car: 87 IROC L98
Engine: 588 Alcohol BBC
Transmission: Powerglide
Axle/Gears: Ford 9"/31 spline spool/4.86
Re: Moving front wheels forward

It would be easier to cut the whole front of the car off and install a generic front half assembly. If you go that far, it would be even easier to build a tube chassis car.

A third gen is a unibody design. The front frame rails are heavy sheet metal and are incorporated into the body structure. The inner fenders currently support the strut front end. To remove all that to refabricate something different is a bandaid solution to a proper tube front end.

Nothing is impossible but the cost would be a lot more than changing it completely to something already fabricated.

This is what you need to start on the front. You can position it wherever you want. This isn't going to take into account hanging all the sheetmetal back onto the car, stretching the fenders etc.

http://www.swracecars.com/Files/pdf/CATpg25.pdf

Third gens have a 101" wheelbase. A typical drag car is in the 118-124" range.
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Old Jun 6, 2009 | 12:42 PM
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83RDRACR's Avatar
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Re: Moving front wheels forward

The whole purpose would be to give the car better balance and handle better. These cars are very nose-heavy. I know there are plenty of 3g's that have been made to handle extremly well while working in the confines of the stock design. The standard upgrades like tubular k-members, a-arms and coilovers shed about 50-60 lbs and cost between $1500 and $2000. You also need an upgraded brake kit for another $1200 to $1500, plus wheels that will clear the brakes and spacers to allow the wheels to fit. All in all you have close to $4000 or more invested. The car is still nose-heavy, you still have a strut front end with limited adjustments and poor camber gain and a less than ideal scrub radius.

I could just move the engine back 4 inches but that would require cutting up the firewall, floorpan, trans tunnel, shortening the driveshat and altering the shifter and possibly the pedals. Also the engine would pe partially under the windshield ala 4th gen cars and thats a real pain to work on.

By moving the front wheels forward EVERYTHING moves rear ward in relation to the front wheels, not just the engine and trans. Even the part of the car ahead of the front wheels moves rearward weight-wise.

The car is being built with a full cage with support bars running to the frame just behind the core support. there will also be extra triangulation to eliminate lateral twist and flex. I chose the the 4th gen spindles for a couple of reasons. 1st is their heighth. They are tall enough to allow me to mount the upper a-arms on top of the stock frame rail and still have the ability to set their angles for a more ideal roll center. The second reason is they come with a pretty decent brake package in stock configuration and upgrades are more common/less expensive than 3rd gen. 3rd reason is that I can use the 4th gen rack without any issues of not having enough travel.

I'll be using tubular a-arms from one of the circle track suppliers once i've determined the ideal location and length using performance trend software. Front crossmembers will be 2x3 .120 wall tubing and will probably incorperate a stock car style splined sway bar.

The front fenders will be a cut and paste affair whereby I'll section out the wheel opening move it forward, stitch weld them back in and make a filler pannel for the back. I've been looking at different inner wheel wells and the Pontiac solstice looks promising.

Yes it will be a lot of work, but so is the trditional route and I see more benefit from moving the wheels forward. If you think about it having the centerline of the front wheels nearly even with the front of the motor is akin to the setups in Corvettes and Cobras and they don't handle to shabby.

Thats my reasoning.
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