I have taken advantage of the strong Australian dollar and purchased my rear coil overs from Techno Toy Tuning from the States. Also bought the Tension Rods and the bump steer spacers. I am awaiting there arrival.

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Another Datsun Project...........

im looking at getting the front and rear coilover assembly's from them, has anyone else fitted there gear?

Hey there, im interested to see on how good these look in your hands, cause the look awsome on the net!! sooo jelous!!!

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1972 Datsun 1600 4 door, SR20DET
1970 Datsun 510 2door import (USA) L20b (4 now)
1969 Camaro 454
1955 Chev 2Door 383
1932 Ford Roadster 350
1977 Triumph Bonneville

And a Garage thats NOT big enough!!!

One of mates bought an LSD rebuild kit from there and it was all good quality, so im sure the coillovers would be good, take advantage of the strong dollar!

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1979 Datsun Stanza Coupe
1979 Datsun Stanza Coupe Project
1979 Datsun Stanza GX
1982 Datsun Stanza GX
1966 Nissan Cedric Custom Six
1972 Volkswagen Beetle
1974 Toyota Landcruiser Stallion (SWB)
EziAutoParts

I've had many mixed opinions about what spring rate to get for rear coil overs. Gabriel from techtoytuning has suggested to keep same spring rate front and rear (I have mad dat 250lb coil overs on front), although my next door neighbour just got the troy ermish coils with 900lbs.

I just want a spring rate that will benefit the rear end geometry in a drag racing setup.

Although the dollar is strong currently, its still a costly exercise to keep ordering different spring until the correct rate is achieved. $140 per new set of springs plus postage from technotoy.

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1600 with FJ20 & Simmons. something different.

Were the 900lb ones for coilovers, or for the stock setup ?

You need much heavier ones in the stock setup due to the leverage generated - the wheel is much further out compared to the spring position (can't remember the exact ratio, maybe 3:1).

Coilovers however are pretty much mounted out at the wheel, so you only need lighter ones. 900lbs sounds way too heavy for coilovers.

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1970 ex Group A Rally P510
1971 P510
1972 180B SSS
1965 SP310 Fairlady
1966 SP311 Fairlady

Dave, he ordered coil overs with 900lb springs.

I've sent a few emails to troy ermish and techtoytuning asking if any of their customers are into drag racing running your coil overs. They don't really seem to interested in helping.

I'm more inclined to buy techtoytuning coils as they have the external adjustment dial. They reakon it adjusts compression & rebound at same time, rather than just one side. Anyone know how this works?

I was told the rear suspension will want to camber out even further with coil overs as the now single mounting point will push wheel that way on take off?

You wanna take a stab at recommending a spring rate Dave? I was thinking maybe start off with a 500lb?

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1600 with FJ20 & Simmons. something different.

I can't imagine why it would squat anymore (or less) running coilovers ? I could be wrong though.

Drag racing 1600's is a bit of a black art, I believe, due to camber changes from the IRS. You have to balance weight transfer with camber changes (and the reduction in the amount of rubber on the track due to camber). So you may have to stick with something stiffer than you would think.

I'll try to dig up some details on the actual "ratio" for the stock setup vs coilovers - that way if you can find out the gun spring rate for the stock setup, you can use that to calculate a reasonable starting point for coilover rate. I'd be loathe to suggest a spring rate for dragging in case I lead you astray, mines set up for circuit.

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1970 ex Group A Rally P510
1971 P510
1972 180B SSS
1965 SP310 Fairlady
1966 SP311 Fairlady

That would be great, cheers.

Is there a general rule of thumb for circut racing? Heavy or the same all round?

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1600 with FJ20 & Simmons. something different.

People seem to run from 250 up to 350 or thereabouts front, 900 - 1100 rear.

That's standard-type rear suspension, not coilover though.

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1970 ex Group A Rally P510
1971 P510
1972 180B SSS
1965 SP310 Fairlady
1966 SP311 Fairlady

Ive messed around a little with spring rates in a standard set-up and found that a 900lb spring reduced traction quite a lot. The 700lb springs I had were a good launching spring, reasonable amounts of squat and traction was much better.
A 900lb spring in a coilover doesnt sound right to me, but im not running rear coils, so what would i know.

OK, really rough figures here (measured with the daughter's 30cm school ruler, in the cold shed, with my only complete rear end on the floor under the car so I couldn't get at it easily). I'm also open to the following theory being proved wrong.

Standard 1600 setup - spring centre is 19cm from the trailing arm pivot line, centre of rear hub is 44cm from trailing arm pivot line, so leverage is 44:19 or 2.3:1. Actually, I can see holes already, maybe I should measure to the point of contact of the wheel on the ground ??? Anyway, close enough for a guesstimate.

Measuring back to the shock absorber mount (ie the focus point for a coilover spring) is 47cm giving a ratio of 0.94:1.

So, I'd estimate that you'll need coiloveer springs that are 2.5 (2.3 divided by 0.94) times weaker than standard-type springs. So if the recommendation is 700lb, that would be a coilover rate of 280lb/in. Which is pretty close to your tecnotoytuning recommendation.

A 900lb/in coilover spring would equate to over 2000lb in a stock setup

As I said, I stand to be corrected, and these may not be the ideal rates, but perhaps it is somewhere to start ?

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1970 ex Group A Rally P510
1971 P510
1972 180B SSS
1965 SP310 Fairlady
1966 SP311 Fairlady

Good enough for me Dave, thanks for getting those measurements in the cold shed.

So if I wanted a 900lb stock spring setup, I'm going to need a 360lb spring for coils. That sounds a little more like it.
A 200 something pound spring just sounds too soft for drag setup.

I might give troy ermish a buzz too. I get $50 of o/s calls in my moby cap, won't last long tho

Cheers Dave.

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1600 with FJ20 & Simmons. something different.

So I had a chat with troy, he believes that a 900lb spring in a stock location is too heavy to begin with. He recommended an 850lb spring. Even though its a small difference, it gives the rear wheels that little bit more grip.

He we are going into the black art again.

He recommended a 250-275lb spring for coil overs when drag racing, then changing back to 200-225lb for street driving. I asked him how he thought my car might handle on the street with the 275lb coils left in...'very free. Drifter style all the time.'

I hate datto rear suspension!!

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1600 with FJ20 & Simmons. something different.

Sounds like you've got somewhere to start

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1970 ex Group A Rally P510
1971 P510
1972 180B SSS
1965 SP310 Fairlady
1966 SP311 Fairlady