willow springs

[agro1]

Richard - I stand corrected

Nice times...

[MistressMotorsports]

Been off the boards for a while and just picked up on this thread. While my 1:32 may be the benchmark for an SPF, it is by no means a benchmark for some of the other cars around, especially a JBL, which is in a completely different class than an SPF or similar when it comes to track duty. A few weeks ago at the HSR-West races, there were a trio of Shelby spec racers running. If I remember, they were running 1:33's on a "good" track, close to my :32. Having run the SPF, several Vettes, and a vintage CP 240Z, I completely agree with Richard that the key to turn 9 is exit speed, which generally translates to how early can you get on and stay on the throttle. Any lifting past the apex kills laptime. Same for turn 1, many people underestimate the banking in that corner and overbrake/underdrive. I had a 5 speed in the SPF, so my shifting pattern was very different from what Richard recommended from turns 1-4, but I'm sure he knows what's up with a 4 speed. The other big corner is 6. A really well prepared car, depending on what class, can run over 6 at WOT, usually with a short shift before the crest. Both my Vettes and the 240Z could do that, the SPF could not. Because of that fact, the Cobra line over 6 is a late apex out of 5, little or no track out of 5, and a VERY late apex to 6 with the car pointed down the straight before it gets light. In the other cars, I can move the apex to 5 back a ways, use a lot of track out from 5, still short shift, but stay on the throttle over 6, making it a non-turn. Getting it wrong is pretty exciting, though, as the left side of the track comes up quickly that way. Now if I could only make my right foot stay down through 8 I'd be really fast.

[coyled]

Mistress motorsports, I take turn 6 the same way, late, short shift and not wot until I land. Those spec racers are well prepped cobras. I think your 1.32 and 1.33's for the spec racers are quite fast. Turn 8 flat out, My right foot won't do it, no matter what I tell it to do. scott

[Richard Hudgins]

Mike,

I would be very interested in your gear selections at Willow. What rear gear ratio and transmission do you run?

You know. Willow is a very hard track to get right. It takes many laps there to really understand the track and how the surface behaves throughout the day, not to mention over a race weekend. Tough place to setup a car for.

[Excaliber]

Turn 9 sounds like a classic case for "slow in and fast out". The last turn on the Hawaii track exits into a long straight. The most important thing there is to carry that exit speed with you. Come IN to fast and you screw up the exit.

Ernie

[coyled]

Richard, what gear ratios would you run at willow? I am thinking aboua jerricho with choice of ratios. 3.89 rear gear. first 1.98, second 1.57, third 1.27, 4th 1.0, ? comments. scott

[MistressMotorsports]

Richard,

To answer your question, the SPF was runningn a 3.55 rear with a standard Tremec TKO 5 speed. Unfortunatley, it still had the 0.6 overdrive, which was horrible and bogged the car on the long straights, but the rest of the gears worked pretty well. I always meant to upgrade to the 0.8x OD, but sold the car before I got there. The car would run 4th gear from turn 1 to 3, then 3rd from 3 to 5 (it was pretty tached out coming down the hill but not enough to go to 4th before 5), short shift slightly to 4th before 6, into 5th near 7, back to 4th for 9, 5th down the front straight, and back to 4th for 1. The car had a 515 hp 393W with a very flat and wide torque curve. Shift points were normally 6200-6300 rpm except for the short shift before 6. Tires were 26 inch tall Kumhos on 17 inch wheels. I had previously tried a 3.73 rear with the same trans, but that required a 3-4 shift between 4 and 5, then a corresponding downshift for 5. Cost a ton of time and was hard to do all that in such a short time. Also, with the wrong 5th gear ratio in my TKO, the 3.73 actually cost time on the straights because the car would bog so badly after going to 5th gear. With the 3.55, I could carry 4th longer and make up a little time that way. Interestingly (or maybe not), the Z has almost the same physical shift points on the track as the SPF did, and is also (will be) a 1:32 car, maybe even a bit quicker. So far, I've only run 1:34's with it, but I've only had the car there once and have tons of notes to try different rear springs, shock valving, etc the next time I go out. I would be interested in hearing your suggestions for what I maybe should have been doing with gears, etc.

Mike

Mike

[Richard Hudgins]

Scott,

I think that those ratios should work pretty well at Willow. I am assuming that you have a good power band from 4.5k to 7.5k in your engine.

@4500 rpm with 26.5 dia. rear tire.

1=45.8 mph
2=57.8 mph
3=71.4 mph
4=90.7 mph

@ 7500 rpm with 26.5 dia rear tire.

1=76.3 mph
2=96.3 mph
3=119 mph
4=151.1 mph

The splits look good. I would just look at your current ratios and revs in the corners and see if the new ratios put you in a better point in your power curves.

[Richard Hudgins]

Mike,

I have to agree with your gear choices at Willow with a 3:55 rear.

Chucks car has this gear and I find that I end up the same as you.

Chuck has the .6 top as well and it is just too big a jump. It falls on its face.

I found that turn one was indeed 4th (You run out of third before the apex) and carry 4th until turn 3. But I went to second for 3 and shifted to 3rd before turn in at the top. (Chuck has a 351 crate and the power band was fairly narrow, It did not like to pull up the hill in 3rd.

I would shift into 4th right after the apex of 5 and carry 4th until just before 7. It really was a toss up between 4th and 5th through 8. The tall gear was just too tall to pull well and I could just let the car run up against the limiter in 4th.(6.5k, kind of hard on the motor.)

With Chuck's car, 9 was 3rd gear. The engine would be just below the powerband in 4th at the apex and it would not pull well off of nine. I would shift to 4th just after the apex and this seemed to give the best results in that car.

Of course, I would shift to 5th just past the pit entrance and I would swear that the car slowed down.

I tell anyone who is looking at a JBL to never use the .6 5th. It is useless.

[MistressMotorsports]

Richard, glad we're close, makes me feel better knowing I wasn't too far off. I could never use 3rd in my car for T9. The entrance is over 90mph, about the same as mid corner in 2. Both are well into 4th gear for me. Same with using 2nd for T3, that would be way too high in the rpm band. I've always been a fan of big, torquey motors rather than screaming revvers, as it makes the car come off the corners faster and helps a LOT in traffic. I hate trying to pass someone, especially a lapper and getting caught in the wrong gear. So, my engine had enough grunt in 3rd to paint stripes all the way up the hill from 3 to 4. Still fell on its face in 5th, though, just as you experienced. Even the 3 liter in the Z car was built for torque, with long air horns and inatke runners, etc. It also likes to paint stripes with the little 225/60/14's they make us run in vintage racing.

Thanks for the help,

Mike

[coyled]

Mike, when are you running willow again? I would not mind chasing you around for a few laps. scott.

[MistressMotorsports]

Scott,

Good question. The next two months are really busy at work, so probably some time in June is the earliest I'll be back at Willow. I know I have a race at Cal Speedway in June already, so hopefully I can find time to get to Willow. I signed up for the anual test day deal, so I go up on Fridays and play sometimes. Also, I sold the Cobra a while ago, so you'd be following the Datsun around. The Datsun still runs :34's or better, so it's a pretty good rabbit. I'll let you know as soon as I have a day scheduled, via email most likely.

Mike

[Richard Hudgins]

Hi Mike,

I understand your liking of big torqey motors, particularly with gearboxs that you cannot set the ratios per the track. I am used to small displacement, high reving motors and lots of gears. (and the ability to set each gear to what works for the track.)

I will have say that the 351 crate engine like the one in Chucks car has way too narrow a power band. the engine likes to run from 4200 to whatever redline you are comfortable with. (Knowing the bits in the motor, 7k is very scary, but it still is pulling very strong at this point.) Therefore 6.5 is the limit.

2.2k power band is way too narrow for our type of setup. I think your motor is a much better choice.

Have fun with your Z. When I had the VIR School of Motor Racing, we had one of J. Fitzgeralds 240 BRE cars as a school car. That car was really a bunch of fun around VIR and there was not a AP car that could keep up with me in that car. It used to really piss off those guys.