Slalom4me

Does anyone have data indicating what accel/decel/lateral loads
(and for what duration) a C4 can generate in various states of
suspension/brake/tire development? Such as totally stock with
street tires through to full cage, high rate leaf/coil springs, slicks
& aftermarket brakes?

Thanks,
Ken R.

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Sidney004

The following is data taken from a Gtech Pro RR, uncalibrated, undropped and out of the box. I don't know the tolerance or stated accuracy as I didn't read it. The data was taken at Thunderhill raceway yesterday on a 94 LT1 with 280 RWHP running on Hoosier GAC's, sway bars(32mm and 26mm), poly bushings, heim jointed end links, heim jointed camber rod kit, RD cross brace, RD cross brace, J55 brakes with SS pistons, Motul 600 fluid and KFP Purple pads front and rear with the DRM bias spring. 3600# weight with fuel and driver.

Accel - .52g first gear at 4500 rpm, above .50g from 4800 Rpm; .43g @5800 Rpm redline, 1.8 sec duration from 4300 to 5800.

Braking - 1.05g peak; .1 sec duration, g load above 1.0 for .6 sec, total braking event 2.8 sec from initial application to let off

Left hand lateral accel - 1.19g for .2 sec, 2.2 sec of left hand accel above 1.0g

Right hand lateral accel - 1.24g for .2 sec, 4.4 sec above 1.0 g

shotchkiss

Another Gtech run here from an autocross, '89 C4 auto with Z51 bars, springs, and front brakes added. Using somewhat worn 275 Victoracers.

BrianCunningham

Some nice data runs there.
I was thinking of getting a G-Tech, but I wanted to hold off and get something that can to track maps.

Slalom4me

Thanks for the feedback. I have parts that should improve the
capability of my car but I feel I have oiling problems at the level I'm
at now. I started the thread to get a sense of where the mods might
take me to and decide whether to proceed or stay where I am for the
sake of my engine.

My current configuration is '89 FE1 (stock ride height), 32mm & 26mm
aftermarket bars (big time push), newish Bilsteins (Z51 valving), tired
GY GS-C's (275/40 x 17), C5 calipers w/ Dura Stop pads & rotors and
DRM bias spring, R-D Camber Bar, Cross Brace and Cross Bar.
If memory serves, front camber is currently limited to 0º, rear camber
is -0.5º. I thought the car scaled at about 3,400 lbs with driver before
adding the R-D parts and removing some others, but Sidney004's value
of 3,600 has me doubting my memory and my notes are not at hand.

The following trace segments are from data recorded with a RacePak
G2Extreme. The lateral graph is as displayed in their software and I
added spot RPM & MPH values to the image. The braking graph was
created with MSExcel so I could plot 'G' and MPH indicator values on
both sides of the Y-axis (from raw G2X data exported to Excel).

A rough patch mid-turn upsets balance in this left turn but the car
is at 1 G lateral for about 4 seconds. Poor balance means the front
tires complain and there is a lot of feedback at the steering wheel.
I expect the bar, rear spring and 315 x 18 Hoosiers I have would up
the lateral figures.


On this run, I eased up on braking because I was going to stop short
of the stop box. I have other traces that demonstrate the car performs
these stops to a standstill consistently within a range of 0.95 - 1.05 all
day long. Notice the entry speed and the time duration. I expect better
tires, pads and rotors will improve the braking.


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Slalom4me

I need to qualify this statement.

The car can deliver that performance once at the end of each 105+ sec
run, with 6 - 8 runs in the course of a day.

In an HPDE-like setting, the brakes heat and the rotors check/crack
in short order.

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