Spring rate question?

[Guest Anonymous]

I noticed there are 3,476 Hybrid members which means there is about 3,477 different responses to spring selection..2 inch section.. 10 inch coilovers 4 or 5 inch adjusting sleeves. 185 front/200+ rear with non adustable Tokico or KYB GR2 Use the Strut cartridges from a 1985-92 Golf/Jetta (KYB GR2 # 364014) in the front and the 280 Z front strut cartridges in the rear with a one inch plus spacer placed at the bottom of the rear strut tubes. web page or web page modern-motorsports.com/catalog/default.php.........put some cushions on those motor mounts

[Guest Anonymous]

I see a lot of different spring rates being used. Some guys use heavier in the front, and other heavier in the rear from 200 lbs/in to 275 lbs/in, and I am not sure where to start. The car is a 76 280z, and it will have a 5.0T5 combo. lowered 1.5 inches. It will be street driven only, but I would like a sporty ride, but not to harsh. I'm going use factory rubber motor mounts to dampen the engine vibration, so I'm leaning towards comfort. Also, I see most pepole run the Tokiko Illumina struts. I don't see any need to have adjustable struts for my perposes, so can anyone suggest a good non-adjustable replacement that will work with the shortend strut housing, and coilover springs.

 

Thanks.

[randy 77zt]

i run 225 lb x12" front and 250 x 12" rear but car is a street/track car.the tokico illumina struts are used becuase you need a strong strut to control the rebound of the spring.i have to run struts set harder in rear because the rear of car has more of a rebound/bounce problem.if suspension is working correctly car will hit bump-body wont move or bounce.you car hear the fuid in shock when hitting bumps.your spring rates soung good for pure street car.

[Modern Motorsports Ltd]

I don't see any need to have adjustable struts for my perposes.

Well in an ideal world you wouldn't need adjustables, but the strut valving isn't all public/nailed down/documented as to what works best with what spring combos/weight cars/power combos/intended ride characteristics etc. The Illumina's allow you to further dial in the correct strut characteristic to match your springs/overall ride. Many daily type drivers with Illumina's will run them softer from 1->2 or 3 for lower speed and if they go on a trip or to an autocross (I'd say never rule out the fact that you'll start into events.....they're quite addicting and one more way to greatly enjoy your ride) or long distance highway they'll typically bump up the rate for some tighter responses at higher speeds. It's similar to coilover flexibility except the struts aren't as flexible (ie. we can't swap from 150 lb/in compatible (spring rates) valving to 350 lb/in compatible valving like some of us would like...).

 

For a stock 5 liter and street ride at moderate speeds with ordinary brakes I'd reccomend 150-175 10" fronts and 200-225 rears. At 200 on the rears you minimize a significant amount of rear squat and you're not looking to eliminate all so further stiffness can just increase ride harshness for your 'sporty' street goals. I'm not too experienced with non-Tokico struts. If you search 'gr2' or kyb/koni etc you'll find experiences on some of the less stiff strut options that would suit your desires and setup.

 

Generally 250 and above is more track oriented with specific tighter handling goals and matched struts to take that spring rate. Around 250/275 is the upper limit for Illumina's to match properly, they'll work above that but lifespan is limited....it was short on my ride with my prior 375lb/in fronts I really liked, but on another customers car he runs 400lb/in all around on a fully reinforced hybridz (400hp/2200lb, rear weight bias ) and uses Illumina's quite successfully......but he's only doing Autox (lower speed) and driving to/from events....not higher speed/longer event uses. If you run too stiff out back for your steet use you'll sacrifice some ease of launching as the rear will be quite stiff and some of us have found it 'skips' more than biting and digging in which we'd like on the street. My car will launch a lot better with softer rears but I choose the higher rates for at speed.

 

HTH