Advice on suspension tinkering
 

Background: Car is a 99 NB1 (2380lbs with rollbars/harness bars/seats/hardtop)

I am currently on FCM flat rides (550/425) with sport bumpstops running 1" front bar and 11mm rear. Alignment - F Camber -2.4/ 0 toe/ 4.6 caster, R Camber -2.1/ 0 toe - Ride Height at 12"F/12.25"R roughly 4.25"/4.5" - 225/45/15 NT01s on 15x9 6ULS

Car turn in is absolutely fantastic at my home tracks (MRLS/THILL/Sonoma) but am having issues with oversteer. Have taken rear bar off and it has helped slightly but still unsettling mid corner.

Have been too meek to ask for additional support from FCM besides the initial email i sent to which i was instructed to remove rear bar and play around with alignment.

I am thinking of changing spring rates at this point. Was told front shocks could handle +/-100 and rear +/-50 lbs. Also getting 1.25" RB Front Sway Bar.

Would 650/425 with 1.25" front bar/ 11mm bar be feasible? Or would i understeer like a pig?

Any input from more experienced drivers would be highly appreciated.

Thanks!

A missing part to the equation is what tires you typically run.

-Ryan

Sorry about that. Edited first post. I run NT01 225/45/15 on 15x9 6ULs.

Either increase the front spring rate or decrease the rear rate. 700/425 or 550/350.

As a rule of thumb, 1.5-1.65:1 is a good range for front to rear ratio. 550 is on the soft side for NT01s, I'd stiffen the front springs.

-Ryan

I bet that bar makes a big difference as well. Maybe keep the current rates with the larger front bar and see how that goes. Still not what you want then start playing with spring rates.

In my autocross car I noticed a massive difference in feel with a slightly stiffer front bar. I am on 140TW R1Rs though. I am sure the NT01s have much more to offer in overall grip.

Yeah I'd do 650/400 and the rb race front bar and see how with or without the rear sway works for you.

what is your toe looking like?

zero:

echo leafy and thepass regarding spring rate. Any reason you went to an 11mm bar over the stock nb1 12mm bar? RB race front bar is a necessity imo.

I'm sharp :noob:


might want to double check your toe before spending $$. the suspension bolts might have loosened, it sounds like you have a bit of + rear toe.

<p>With regards to spring rates, have you tried playing with FCM's suspension calculator? &nbsp;I've played around with it a bit, you'll want to search the forums for threads about it so you can know how to interperate the results.</p>

Needs more front spring.
I'm at 600/350 right now with the 1.25" rb front and 14mm rear with similar alignment numbers and have just the touch of understeer that I desired over the 550/350 spring rates.

Same home tracks as you...

Or try dialing in more rear camber... that's what some of the local folks seem to do. +2/10ths split in back.

700 front springs and 1/16" rear toe in

Pretty sure Emilio means 1/16th inch toe in.