Saturday, April 19, 2014

Updated Tune, Corner balancing, first alignment in 2014 and fixin' stuff!

Autocross is about racing inch perfect through dozens of closely spaced corners for a few hundredths of a second advantage and while power is important, handling is even more so. Two weeks ago at the NNJR SCCA Test and Tune, I got about 24 runs in and got to shake her down really well to test engine power and reliability but not handling because after the shocks were sent out, I couldn't really tell what my new alignment would be after reinstallation. I think I have the rear tire clearance fixed after hacking up the over fenders last week so now it's time to tackle the very important task of sorting out my alignment.

First up though was to sort out some of the tune issues I uncovered at the last event. Unfortunately there is only so much simulating you can do on a dyno or during a street tune so you can't really tell for sure if everything is 100% until you putting through some real testing. I got in touch with Jeff at Evans Tuning to provide some feedback on the tune and he promptly sent me back an updated tune that turned down the threshold for VTEC engagement and some idle adjustments. I loaded it up and the idle was definitely better and I'll be able to test tomorrow if the adjustment in VTEC threshold helps during the part throttle stuff mid-slalom.

Dave Corsaro has now teamed up with Steve Farkas of SJF Performance to provide combined corner balancing AND alignment services. This is awesome news for autocrossers in the tri-state area since these guys really know their stuff. First up was Dave for the corner balancing.

Dave meticulously setting up the scales - 4/19/2014

Once Dave finished setting up the scales to his liking, we lowered her down to get her first weigh in for 2014 in full race trim with almost a full tank of E85. She weighed in at 2622lbs without the driver. There is definitely some room for improvement in weight there if I can get the fuel load down but I'm not too concerned about that. The main data point here is that she was 2820lbs weighed in at Toledo in race trim without driver with a bit less fuel so she dropped at least 200lbs over the winter. I got in the car dressed like I normally would with my helmet on and Dave found the cross weights to be off by about 100lbs. He made his adjustments and got the cross weights perfect . Front to rear balance of the car was also measured to be true 50/50 as well. There is also about a 1/4" forward rake to the car.

Initial weigh in - 4/19/2014
Corner balanced with me on board - 4/19/2014
Now that the ride height was set, it was off to the alignment rack so Steve could do his thing. I was really curious what the current alignment setting was and why the car felt so insanely tail happy (read as: wanted to kill me) at the last event. I think we all burst out in laughter when we saw the number...a mindblowing 0.3" TOE OUT in the left rear and definitely not nearly enough camber. I still don't know how I was able to drive her into submission and put down a respectable time two weeks ago with these settings.

Pre-alignment measurements...all over the place - 4/19/2014
Alignment done - 4/19/2014
The car sits a bit higher than I might ultimately want but at least for now I need it for clearance. I'm sure we'll do more alignments this year but for now I think this is a good starting point:

Front:
-3.3 camber
5.9 degrees of caster
0 toe

Rear:
-2.5 camber
1/16" (0.06) total toe in (ok, really we ended up with something like 0.04-0.05) but that's basically it.

We also got some maintenance out of the way and changed the diff fluid in preparation for the brutal red line launches next weekend.

Old diff fluid out - 4/19/2014

Of course as we're working on suspension stuff we closely inspect everything suspension related and found that the Ankeny rear bar was touching the Innovative 75A differential mounts. While it wasn't touching it too badly, this isn't a good thing as it can bind and affect handling so we spaced it out a bit and now the bar rotates freely. We we also discovered that my front Gendron bar shifts a bit side to side because I'm missing those shaft collars that I have on the rear bar so I'll have to order up some 1.25" ID ones from McMaster this week and hope it arrives before the DC Pro. For now we've marked it where the bar should be and I'll reset everything once I get the collars in place...easy to do on an open trailer.

Spacing the rear bar mount - 4/19/2014
Tiiiiight tolerances - 4/19/2014
Random photo of the pretty billet Hasport 96A
motor mount nobody sees installed a few weeks ago
Tomorrow I give her the full shake down at the MSNE Autocross at the meadowlands. The weather is going to be sunny with a high of about 60F. Race in the morning with a test and tune in the afternoon should give me adequate runs to dial the suspension in. It's now or never...less than a week left before the DC Pro and it's time to break the cycle of suckage that goes on every time I head down there this early in the season.

1 comment:

  1. Yea buddy!
    " Do you want to build a racecar? " Why yes, yes he has!

    ReplyDelete