Mark 4 front suspension assembly question on proper spring rate

[JohnP]

Hi everyone — it’s been a while since I last posted, but I’m finally back on my Mk4 build after a multi-year pause.

I’m currently working on the suspension and have a question about spring rates vs. what was delivered.

My car is a Mk4 Roadster with the optional IRS, and I also ordered both front and rear sway bars.

My parts list indicates I should have:
• 500 lb/in front springs
• 400 lb/in rear springs

However, the springs that were actually delivered with my kit are:
• 350 lb/in
• 400 lb/in

I’m trying to understand whether:
1. This is a packing error and I should contact Factory Five for the springs listed, or
2. The springs I received are correct for an IRS car with front and rear sway bars

Before I call Factory Five, I wanted to check with the forum to see what others with a similar Mk4 IRS + sway bar setup are running and what’s considered correct.

[CraigS]

350 front springs are definitely not the norm.

[Jeff Kleiner]

500 front and 400 rear is standard for IRS. Spring rates don't change with sway bars.

Jeff

[Fuel an]

Having worked on this recently, most of what I have read sounds like you have the springs for the 8.8 3 link differential, not the IRS

[Jeff Kleiner]

Having worked on this recently, most of what I have read sounds like you have the springs for the 8.8 3 link differential, not the IRS

3 link uses 500 front and 350 rear.

Jeff

[JohnP]

OK, thanks appreciate everybody’s help. I’ll give back five a call on Monday to get the right springs for the front.