Spring rates with V8

[kristov]

Hi,

What kind of spring rates are you guys running with the heavier V8s up front?

[Red_liner740]

which v8? cuz that makes a huge difference in peoples answers.

The BMW V8, the M60 is all alu and weighs 30lbs more than the M20 (give or take), due to the shorter design it actually sits further back than the I6's...so for all intents and purposes the weight gain is negligable.

[Gertech]

I'm running 550 lb/in front, 700 lb/in rear GC coilovers in my LS swapped car. It's pretty stiff and not a daily driver. Rides surprisingly well for those rates though.

[e30s50dan]

^^ Yea,but what size sway bars are you running

[shiboujin]

which v8? cuz that makes a huge difference in peoples answers.

The BMW V8, the M60 is all alu and weighs 30lbs more than the M20 (give or take), due to the shorter design it actually sits further back than the I6's...so for all intents and purposes the weight gain is negligable.

I'd imagine you'd want softer springs. Not by a huge amount though. All that weight is now behind the front suspension.

I'm running 550 lb/in front, 700 lb/in rear GC coilovers in my LS swapped car. It's pretty stiff and not a daily driver. Rides surprisingly well for those rates though.

I run 550/1000 (mimicking Jstock). I want to go probably 450/800. I'm LS2. I bet most people here want M60

[jalopi]

I was rocking H&R races, not sure what those spring rates are. Apart from the rear being a little too gooey I thought the car was pretty sweet

[Hooffenstein HD]

The BMW V8, the M60 is all alu and weighs 30lbs more than the M20 (give or take)

I'm having a hard time believing that.

[Red_liner740]

I did too, but I researched it and I can't quote and link now but those numbers came from people actually weighing their engines. It's on a bimmerforums topic. M20 came in at low 400s with all accessories while the m60 was closer to mid to high 400s.

[jalopi]

I believe it. For some reason people think aluminum is this magical substance that's both 1/3 steel/iron's weight and only needs the same amount of material to be just as strong.

The reality is (we're comparing cast aluminum to cast iron here, nothing special going on, let's not nitpick about alloys) as a general rule, aluminum is about 1/2 as strong as iron. Manufacturers compensate for this (only when ultimate strength is needed... like when making an engine block) by using extra material. This can be in the form of thicker walls, extra webbing, ect.. you see where I'm going here. Basically, the end result is that cast aluminum parts are typically about 2/3rds the weight of their cast iron/steel counterparts, just as long as strength/longevity was a concern during design.

Add in all the extra bits - an extra head (both of which are wider), three extra cams, two extra rods & pistons, a (probably) heavier crankshaft, ect and it's easy to see how the m60 could weigh as much as the m20.

That being said though, I'm pretty skeptical that the m60 is heavier than an m20. I've seen a few m60 swapped cars in person and they're fairly compact... now if we were talking about something big and long like an LS then that's a different story

[kristov]

which v8? cuz that makes a huge difference in peoples answers.

The BMW V8, the M60 is all alu and weighs 30lbs more than the M20 (give or take), due to the shorter design it actually sits further back than the I6's...so for all intents and purposes the weight gain is negligable.

It's an LS1.

Currently on H&R coilovers:

Front - 210 lb/in
Rear - 485 lb/in

The car feels sluggish and unpredictable in the corners. I would think the springs are way to soft for the heavy engine and transmission up front.

[shiboujin]

210? My dick is stiffer than that.

[Chris916]

450/650 here with m60.
Very streetable and hold corners pretty good.

[LoneWolf]

210? My dick is stiffer than that.

[kristov]

Seems like it is time to try som stiffer springs.

[JGood]

I'm running 450/600 with 22/19mm bars, M3 front links. Koni S/A's. It's a daily driver, and I'm very pleased with the mix of firm ride and comfort. There's no body roll.

I weighed my car with an m20b27/g260, then an m50b25/g260, then an m60b40/zf320, then an m60b44/g420. Same car, same NHRA racetrack scale, across a ~5 year time span. The difference in engine weight is negligible IMO, but the supporting mods for the engine may impact overall weight more significantly (trans choice, huge radiator with lots of coolant, remote oil filters/coolers/extra oil, P/S and/or A/C delete, brake booster delete/relocate). In my case, it was less then 100lbs difference from m20/g260 to m62/g420. And most of that weight is in the trans, which was well worth it for the extra gear, as a daily driver. All of the weight gain was between the axles, down low. I've been driving this exact car for 13 years and over 200k miles, I would notice a difference in handling and/or suspension characteristics if it exists. I did not.

Throwing a 180lb passenger in the seat next to me makes a noticeable difference. The V8 does not.

YMMV.