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Early Day 1, before we removed the third element from the wing. We ran with it deleted for the majority of the event. Note the hood gap opening at speed. We started taping it shut by session 3 day 1. This looks like session 2, with 275 square on 4 matching Tungsten 15x11" wheels.
Interesting observations of the entire splitter flexing/bending under load, dive plane collapsing on passenger side, wing endplates bowing in, airdam buckling.
This is early day 1, Charcoal rear wheels mean 295/11"s. Probably session 1(because triple wing is still triple) while E was simply scrubbing the 295s.
random pit/paddock shot. Early day 1 with no hood tape dive planes still in existence. Tungsten 15x11 6UL, 275/35/15 Hoosier A7. Wheelwell openings radiused to clear. Custom fiberglass fenders.
Mid day 2. Third element removed, dive planes removed from the splitter, splitter end plate louvers taped up, on 275/295 staggered tires on 15x11" square wheels. 12" wheels simply didn't fit this car's custom steel quarters. Vegas was planned/commissioned before the 12" existed.
Mid day 2, no dive planes, taped over splitter end plate louvers, hood tape. #Timeattack
This was the config that ended up being fastest, considering all the variables I wouldn't put too much stock in replicating this 100%..
From the last shot (SM S1 Aero)Do you know the step down performance difference or did the engine dying not provide any / enough data or feel for even an estimate...?
From the last shot (SM S1 Aero)Do you know the step down performance difference or did the engine dying not provide any / enough data or feel for even an estimate...?
Narrow tyres, S1 aero versus bad boy setup.
It was tough to tell why, but the car was not good like this. Old(at this point) tires, missing lots of downforce and a bad aero balance. We didn't do a normal debrief unfortunately.
I think I broke the image uploader when trying to edit the order those were in....
Here is the setup you are referencing: Last session day 2, "small" 245 Hoosier R7s, APR GT250 single element Supermiata S1 class wing, 4" Supermiata S1 class splitter, but with the flat bottom and diffuser.
Pity about the last S1 run and any info/data. That is likely the end point for most of us...well me anyway. wing, airdam/splitter, flat bottom and diffuser.
1. The diffusers we cut into the splitter allowed the thing to twist. The dive planes generated significant downforce, enough to bend the curved and strongly attached.080 aluminum plate. That load was aft of the diffuser slots. So the entire splitter was basically twisting front to back, pivoting on he rear of the mini diffuser. Unfortunately that mean the ends of the spiltter had a negative AOA at speed. So our entire front end would have worked much better if we had not added the diffusers in the splitter.
2. The wing was simply to big for that course and power we made. We would have been better off with the 72" GT1000 wing from last year.
3. Didn't need the dive planes. Could have just run a shorter, un-vented end plate and no dive planes and gotten our balance.
4. Needed a bit more rear spring (1000#).
Knowing what we know now, I still don't think Vegas would go under 1:40 at the current weight/power but I think we could have gotten down to 1:42 with another day of testing (and healthy motor).
Didn't get our fancy motor back in time so we're putting in a spare PTE points motor. 10:4:1 so it should spool zoomiciously. First race as an S1 next weekend at Buttonwillow. Psyched!
Testing yesterday at SOW went well. 1400/700 rates a bit to much for a few of the really rough sections of streets which are as bumpy as a public road. Good on the moderately bumpy sections of SOW that roughly approximate the roughest sections of most tracks.
So we'll start with the 1400/700 and bring a set of 1200/600 in case it's too much for Buttonwillow next weekend.
Spent a bunch of time messing with the pedals. At Super Lap with the sequential, I wasn't using the clutch so clutch pedal adjustment and heel toe stuff wasn't on my radar. With the AZ6 back in it, the pedals were wonky. Clutch throw was too long. I ordered a 5/8 MC for the clutch to match the OEM. Turns out the Tilton clutch pedal assembly has much higher leverage ration than OEM so the throw was too long and only required about 35lbs to disengage. Weirdly for a race twin clutch. So we swapped in a 7/8" MC which was just about right effort and shortened the pedal travel a bunch. Needed to make a new pedal stop for teh clutch.
That sorted, we moved on to the brake pedal. Original guesses at MC sizes were too large, pedal too hard. Dropped down one step on each and effort is just about right. Needing roughly 80lbs to lock a tire. Pedal height adjustable so we raised the brake pedal. Next was throttle. Too long a pedal travel and too high to heel-toe. Played with the bell crank we made with many adjustment holes. Change the ratio so throttle travel is much shorter, which I like. Perhaps 75% of OEM travel. Because there is no booster, the pedal stays the same so heel-toe much easier now.
Rules change to 3.6 OS Giken (any diff) from the previous 3.9 Torsen affected the balance. Car rotates better under power than before which is nice. OSG has a bit higher locking ratio than Torsen under decel which make the car a bit more sensitive to lift throttle mid turn. Adjusted front bar to full stiff, dropped tire pressures and the balance came in.
Few other little details to sort but basically ready to race this Saturday.
You should have been in the email chain. Most S1 rules updates were done offline. The old 3.9 is technically faster as the ratio has a greater effect on speed than the OSG does. Idea was to lower average rpm to make stuff last longer when running ACS and WSIR. Also makes
moonlighting in NASA ST easier. 3.9T still legal but you can swap to a 3.6 anytime. Diff choice is free now. OSG is the best IMO but I'm biased since we sell them pre-tuned.
Pics from round 1 @ Buttonwillow.
1400/700 was too much spring for the RC1's. Swapped in 600 pound rears for Sunday and the car was almost perfect.
All the S1 guys were having issues with knock-back. I'm starting to think it is hub flex more than spindle flex.
As an experiment, William tried a cheap Duralast (AutoZone?) front hub on Cherokee. Lasted approximately 8 minutes.
Six cars in S1. Tight 4-way battle for the front four positions in all four races. Really exciting stuff. We will have video in a day or two.
Something wonky with the form UI keeps deleting either the text or some of the images I upload while I'm drafting it. Anyway another picture I tried to stick in the post above this..
What’s even more interesting is what we’ve found in our enduro car. Our fastest driver never complains of knock back, where as the pedal sinks half way to the floor for me, whether I’m in before or after him. More curb? Less brake? Who knows. We’re not slow, he’s over 3 seconds under SM record, I’m nearly 2. 185hp ecotec, 225 rs4s or 205 re71rs, stoptech’s 11” kit and cobalt pads.
I'm using a lot of kerb, that's the fast way around Buttonwillow. All the other S1 drivers and fastest S2 drivers are doing that too. What is strange is that I never had knock back in Bullet which had the same brake kit. The only difference was that car had a prototype Hoosier hub on one side, much thicker and stiffer than OEM. So not really enough evidence to draw a firm conclusion, but the basis for my conjecture.
We have some new brake and hub hardware coming in the next 12 months. After the experience of all the S1 drivers this weekend, those bits cannot come soon enough. These kind of unsolved problems with the platform are what drives me.
As an experiment, William tried a cheap Duralast (AutoZone?) front hub on Cherokee. Lasted approximately 8 minutes.
Warranty that ****!
Originally Posted by emilio700
I'm using a lot of kerb, that's the fast way around Buttonwillow. All the other S1 drivers and fastest S2 drivers are doing that too. What is strange is that I never had knock back in Bullet which had the same brake kit. The only difference was that car had a prototype Hoosier hub on one side, much thicker and stiffer than OEM. So not really enough evidence to draw a firm conclusion, but the basis for my conjecture.
We have some new brake and hub hardware coming in the next 12 months. After the experience of all the S1 drivers this weekend, those bits cannot come soon enough. These kind of unsolved problems with the platform are what drives me.
I've been told I use quite a bit of kerb(curb?) compared to some and that might be a problem to some of my failures. Butttttt...... I just want to go fast and those are the fastest lines sometimes.
Just got back from dyno. This is the engine we spun a rod bearing in at Superlap back in November. Some glitch with VVT in the MS so I turned it off. +2 O/S CNC head has enough flow that it still made lots of torque down low.
Running smallest 3psi springs in spec Turbosmart W/G and it still crept up to 10psi at 7000. Running 6.5° timing on top. On gas that would be an EGT problem, but on corn we can get away with it. Usually I can lower VE with VVT on the top end so I can run more timing and have it run crisper. Still, the map came out nice and Nebraska-like. This exact same hardware with different springs in the W/G and tuned for max power will make around 430whp/420tq. I'm guessing bigger cams could nudge that over 450whp.
Racing this weekend. Next week we'll sort the VVT glitch and redyno.
Do you find the engine to be substantially more reliable when it is overbuilt and could handle 430whp, but you only push it to 220whp? Versus just a build that can squeak out the number you are looking for. Seems like an obvious answer, but I'm curious to hear your thoughts on this.
12-04-2018, 02:41 PM
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