frankinvett84

I've just installed my new to me Dana 44 with 4.11 gears. Before I wrap up the installation i figured i would put some new poly leaf spring bushings because they looked a bit warn. I thought about just taking them off my old 36 but the $15 off amazon would be worth it. Getting back to my question I would expect the 95 NYR spring to be softer but how soft? My build is for the most part straight line performance but I will have a chance or two to take it to a road course near me. would the softer spring greatly affect the cars handling? Im not the most experienced driver but I know with the stock Z51 suspension Ive impressed a few of my freinds with much newer corvettes. The question is do I try and put the original spring back in? will it fit? will it handle the same with the 44? AND is there ant other suspension components I should "freshen up" while Im doing this? I know its long winded but I would appreciate All the info I can get . Thanks.

odxr

The BMH rear spring was a 1984 z51 spring and 1 of the stiffest rear springs you can get.the specs on the net are published in metric N/mm.The bmh spring was rated at 87.5N/mm.The NYR spring was rated at 39.9N/mm.84 cars were noted for being tail happy sliders.My GUESS would be to run the nyr spring for drag racing + street use.If you put the bmh spring on to try on a road course and find the car tail happy take 1 of the rear sway bar end links off and try again.I would make sure all the bushings are not worn.There is a company called Viking making compression/rebound double adjustable shocks.You could set the shocks up for what ever you needed-like weight transfer for drag racing.If you find you dont need the bmh spring I would be intersted in buying it.

frankinvett84

Thanks for the info. If I do sell I will pm you ( you got dibs)
I also have a FHA front . I was told it was out of a 94 ZR-1

mtwoolford

if you want to try comparing apples to oranges or N/mm to lbs/inches, call the folks at VBP; they "cook" their own springs and can get whatever you want, or they can just tell you more about OEM springs or the Z51 spring, which, as it turns out is really isn't all that stiff. Or any thing else suspension / brake oriented.

blackozvet

Dont know if youve seen this, but some info on springs and swaybars,

https://www.corvetteforum.com/forums...84-96-z51.html

frankinvett84

Thanks,
there is a lot if great info in the thread in the link above. I'm gonna try it out with the 95(NYR). I know with the original 84 Z51 (BMH) when cornering aggressively the back end would be the first thing to go(slide out)but with practice Ive learned to "pull it back in" .
maybe the softer leaf spring might give me an additional nano second before I loose it

blackozvet

The NYR is a 228 lb spring, so its on the soft side.

The BMH is a 499 lb spring and is as hard as you can get.

The NYU is a 326 lb spring and was used in the rear of every z51 car from 85 to 95, because just like in the goldilocks story, it was just right !

The BMH spring causes way too much rear roll couple for the c4 chassis to handle, especially when combined with the higher rear roll centre of the early C4 suspension. Its probably a good spring tho if you have a circuit car with slicks and aero, and a lot more front spring rate.

dont forget the effect of sway bars too, the 84 had a 23 mm rear bar and the later cars had 24 mm.

MatthewMiller

As a point of reference, I run a 550lb VBP rear spring in my 96, but with an 1125lb front spring. It's a good balance that way. The BMH spring would be pretty stiff for a car with a much softer front spring (as any OE spring would be). And yes, the higher rear roll center for the early C4s would exacerbate the tendency toward oversteer.

blackozvet

What swaybars are you running matthew ?

MatthewMiller

I have several sets in the garage that came with the car, and I'm honestly not sure which ones are on the car now. I guess I should figure that out the next time I'm under it!

rklessdriver

If your mostly drag racing you want to KEEP the 84's Z51 rear spring.

All the soft ride spring is good for is street driving.

This is my 84 on the stock IRS.



Went a 1.24 60ft on this pass.



My 84 went a best of 1.21 60ft and 5.69@121MPH and 8.59@159MPH on the stock IRS.

Will

frankinvett84

rklessdriver, Thanks for chiming in. I have seen the times you have posted in the past and have always wanted to know more about your suspension. Gears, tire size,and shocks.
thanks .

rklessdriver

Gear- 3.90 D44 rear with a th350 trans.
Tires- 28x10.5 stiff wall slick MT pn 3055S
Shocks- Koni Double Adjustable and Viking Double Adjustable... but I did run 1.31 60fts on dead stock 84 Z51 Bilstines.
84 Z51 springs front and rear.
No sway bar front, 23mm rear.
Will

frankinvett84

Thanks again
I think those tires look great the way they fill the wheel well.
My rear wheels are 18' with the tires I have on now (285/40) they measure 26.5.
Was the sway bar removed for weight reduction only or was there some other reason?