S14 suspended 280ZX

[260DET]

Two seater 280ZX like avatar car, VG30DET engine but the car has been stripped out so relatively light, bit shorter wheelbase than a S14, track the same of course, 4-500whp, R tyres, Torsen type LSD. Weekend driver and sprints, timed circuit laps or battles or whatever they are called elsewhere.

 

The custom made Proflex suspension is just about ready, three way adjustable with remote cannisters. The maker has suggested as a starting point 400 pound front springs, 250 rear, big front ARB, light rear ARB. I'm happy with all that except 250 at the back seems low to me although I'll be happy to accept some high speed understeer for better corner exit power down.

 

So whats it going to drive like do you think? We can assume that the spring rates are about the effective wheel rates.

[tec280zx]

Very nice!! How much work was involved in fitting the rear suspension? Any more pics of the work involved? Keep us posted.

[David K]

Wait a second 260det, do you have pics of this thing? Im building a serious time attack car and im wanting to stray away from the stock suspension, might go with MM coilovers in the rear. Lets see what youve got.

[COmputoman]

Where did you purchase the gauge cluster? I need one for my s130.

Will this work on the US left hand driver version?

 

Thanks!

[David K]

I saw the pics on your site. We need more details on fitment. This is awesome!

[260DET]

Will do a writeup on it when finished, in the meantime careful examination of the present pics will clearly show how the rear end was done. But really the stock suspension is quite good, I may have been better off just improving it.

 

Now, where are the comments on the spring rates question?

[David K]

Will do a writeup on it when finished, in the meantime careful examination of the present pics will clearly show how the rear end was done. But really the stock suspension is quite good, I may have been better off just improving it.

 

Now, where are the comments on the spring rates question?

 

Ill be waiting for that writeup, or anything you come up with on that s14 swap

[tube80z]

The custom made Proflex suspension is just about ready, three way adjustable with remote cannisters. The maker has suggested as a starting point 400 pound front springs, 250 rear, big front ARB, light rear ARB. I'm happy with all that except 250 at the back seems low to me although I'll be happy to accept some high speed understeer for better corner exit power down.

 

So whats it going to drive like do you think? We can assume that the spring rates are about the effective wheel rates.

 

When I have no clue I first calculate the magic number for the suspension and use a few rules of thumb. What this gives me is a baseline to test from.

 

The magic number is the concept taught in Rouelle's (also in Milliken) seminars and is nothing more than the percentage of total weight transfer seen at the front of the car. The idea being that this percentage should generally be in the 3 to 5 percent higher than the percent of static weight on the car. 5 being for sporty street car and the 3 to 4 range for racing cars. This is driver and course dependent but will almost always be in a .1% range. You can use this number to play with track, spring, bar, RC changes to your hearts content and keep the balance the same. I made simple spreadsheet to do this that makes many assumptions but works reasonably well (no tire stiffness or chassis stiffness is used).

 

My rules of thumb are to try and not go more than 60% of the front stiffness with bar and no more than 30% in the rear. For track cars I prefer to use half that, YMMV. My guess, without knowing too much about your car, is that you have too much front percentage and it will end up understeering more than you want.

 

I'm not seeing an option to attach a doc to this post. If you want I can send you my spreadsheet but be forewarned it was quick and dirty and I didn't try and make it user friendly. Just PM your email.

 

Cary

[260DET]

Thanks for the offer Cary, have decided to start with the makers recommendations and take it from there. Race setup S14/15's run much heavier front springs compared with the rear so I'm hoping the front end grip those cars must get will transfer to mine.