My statement is based on trying different settings on my own car.

I can clearly feel it getting more and more nervous in high speed when give it toe in.

From 0 and tow out it starts to get more and more relaxed.

I now run 3mm tow in on each side as a test with my new setup but i will change this back to a suitable tow out again.

What adjustments do you recomend for stability?

 

Great to see it out running hard! Looks killer...and I bet it sure wakes up the crowd when that L-88 thunders by vs those *little* motors everyone else has!


Need some in car video at WOT on the track next time!

JIM

 

You could figure out your camber needs by tire ware at the end of the day.

Were you out one one of the perfectly smooth tracks with lots of run off? I was watching MotoGP today from Italia and it was a wonderful track.

 

Sounds like maybe you're thinking of toe in/out wrong?

Toe-in: front of tires closer together. Toe-in will make it stable at speed. Toe-out makes it responsive at low speed (like auto-x), but twitchy at speed.

 

Sh*t, i really feel like a fool now.. Sorry

//Ricky.

 

Toe in
when i sayed slightly toe out , i meant just 2mm ( 1/16"-2/16" ). my experience with toe in has not been succesful

 

The racetrack is really nice but not as fast as Monza for example
it's the technical racetrack where all european cars factory takes the cars for testing ( around the handling track there's a 15 miles circle track used for testing cars up to 240mph)

this is the track explanation ( italian sorry)
http://www.youtube.com/watch?v=yz8z1kialjQ

this is a lap on an Audi R8 ( start watching at min 1.10 )
http://www.youtube.com/watch?v=M0ZN8...eature=related

i carefully studied this video before and after going to the track : i used as reference the audi R8 speeds and lateral G in the various turns etc

 

Your 500+ hp and 4.11 gearing would be a good time. That is if you can get your power down out of the slowest turns. Do you drive the whole coarse in 3 & 4th?

I watched the movie, 1.2 "G" out of the R-8


That track looks pretty safe. You need to loop the car both entering and exiting corners and get it out of you system. You will find that it is not a big deal if nobody is to close.

 

I did the slowest turns in 2nd , the others in 3rd. i used the 4th on the straight and in some parts but just to relax the engine a bit, lowering rpms, othrwise the track should be done in 2nd and 3rd only (next time) putting the 4th just in the straight and in few other points : it was a test session so i was more concerned in checking everything and stay on the safe side about engine , transmission , differential etc.

next time i think i can push harder but i have to solve an annoying problem with the exhausts pipes. after 2 laps there's a bad smell : some oil from the transmission going onto the pipes but ,above all ,pipes cooking the fiberglass body underneath. not nice when you are concerned about driving

btw yes the 4.11 and m21 is nice on that track ( because not that fast on straight) and i've been really focused on doing well the tight 180 deg turn before the straight :hard braking before that turn, downshift from 3rd to 2nd, late apex enter ,i think i pulled about 1g ,car slightly slidin out flat at the end of the turn, out of the turn pulled hard 2nd and 3rd till redline then 4th till 120mh passing in front of the pits . wow! what a sensation!

 

You probably need to consult redvetracr because he has a similar Vette, the most track years, and a 4 speed.

But I watched the video many times and the rear car appears to be being held up by the front car. So the slowest speed id about 73 Kph

That is 45.3 to US all. when you were exiting a turn in second gear and your rear would slide out when you floor the car and or imedeatly have to shift to 3rd gear. You would probably benifit from just leaving it in third and not upseting the balance. 3rd gear can take on full throttle maybee at the turns apex without spinning the rear tires.

When you can't change the gear ratio for a turn after practise it is good to try each turn several different ways and see what works best. A big motor with lots of TQ is best to shift less and use the engine.

 

No worries. We're all entitled to the occasional brain fart.

 

have fun! Engine performance as expected?

 

Gkull
you are right. i recall now that i have used the 2nd gear just in the 2 slowest turns : those that the Audi R8 makes at 75kph and 60kph (45,3mph and 37,5 mph) . then 3rd everywhere and 4th somewhere.
with 4.11 rear the 3rd gear can be used on most of the track using the TQ and RPM, you are right. My engine has a flat TQ response so it's ok.
btw the TQ numbers of my engine are not that hi : 466 lbs ft at 4800rpm so the car doesn't spin the tires so easily as you think. The Avon tires and the nice grainy asphalt of the track makes a great job.
actually i slightly ( but just a bit ) retarded to floor the gas pedal out of that turns i made in 2nd just to avoid to spin but actually i could floor earlier because there was no sign of spinning at all

as i already pointed out , my engine is pretty manageable till 4000-4500 rpm and it really screams above 5000rpm . this makes hard to "loose" the car applying power unless you really want it. I think this is as it should be on a road course

 

Kevin , i answered your question above , in the reply to Gkull. I think the engine is perfect for my use.
sometimes i feel i would have a little more power , yes... because the racetrack puts you in such good feeling and safety in releasing power that you can actually do more and better.
i have lost some HP for sure because of exhausts ( short headers , 2,5" pipes and silencers by Car Chemistry ) . i'm sure that with better exhausts would be top but...

 

Yesterday i've been again at the same Nardò racetrack.

no mods to the car in respect to past year's trackday but took the chance to make a video and do some tires check ( i bought a precision tire gauge and IR pyrometer )

here is the video ( sorry for wind noise and vibrations) but my target was mainly to check by viewing it : rpm , pedals, shifter , oil pressure gage .



http://www.youtube.com/watch?v=9370p...G4Rx6kI9J8Vrk=

in the video there are laps 4, 5, 6 ( before i had other 3 laps as warm up and with my father as passenger)

after lap 3 i have adjusted tires pressure at 2 bar=29 PSI

after lap 6 i have checked tires temperature

as last time at the same track i've been more focused on doing checkings than getting good times. Everything went good and pulled the engine quite a bit this time: always at 4000-5000 rpm , shift light setted at 6200rpm ( my engine peaked on the dyno at 6400 rpm).in the video , when the tach needle is straight up , it's 6000 rpm.

but a couple of issues forced me to don't do better: TIRES and OIL

TIRES

when doing left hand turns , the grip was not good and sliding. everything OK on right turns. unfortunately i discovered the problem only when back home.

here is the report about wheels-tires after lap 6



even if I setted the right rear wheel ( a couple of months ago) at same camber value of the left one , when back home after the track , i measured it at -2,25 deg !!!!!!
checked quickly the smart struts and they are OK , not loose. so what happened?
something got loose anyway? i did a mistake when i setted the right wheel camber? i will check better.

btw the tires temperatures measures say that :

right rear : i have to adjust to correct camber
left rear : needs slightly less camber and some more pressure
right front : OK
left front : slightly more camber and pressure , otherwise quite OK


OIL

during the first 3 laps with my father in the car i told him to watch the oil pressure gage in the 180 deg turns because i expected some pressure loss in those long turns. 1 qt oil overfilled pan . told my father to scream "OIL !!!!!!" if he would see the oil pressure needle going lower tha mid ( 35 psi) . It didn't happened.

But....... while doing the laps 4-5-6 i checked the oil and saw that in every turn it went to 30-35 psi . i was a little scared but i stepped on the gas pedal anyway
By watching the video once at home ( hi resolution ) , i've been more scared by the oil matter : in the video i see that the oil drops to 30-35 psi in every turn , also in the shorter 90 deg ones and probably also under braking ( i have to watch the video more carefully)

engine guys, with such 30-35 psi pressure at 4000-5000 rpm have i damaged the engine already? or risking too much anyway?

after the laps i haven't checked if the oil pressure was as usual, i think yes. a damage would show low oil pressure in normal conditions , right?

 

I am sure no engine damage. The Amsoil gives you some margin for error there and it never dropped a lot. With your tires and suspension upgrades you are probably surpassing the stock road race g forces the oil pan was designed for in 1967. With a stock pan and pickup I would expect a little pressure drop in hard corners as you were too, that is the reason for road race pans. I would bet a road race pan will solve all the oil pressure issues if you choose to vary from the stock configuration. If you do add a new intake and a roller cam to that list. An accusump will fix it all and is really the way to go if your car is a dedicated road race car. As you are probably aware thicker viscocity oil and an oil cooler would probably help on track day. The thicker oil will not slosh over to one side as much or as fast and also be thicker to maintain oil pressure at a higher level when the pickup gets exposed a little but I know the oil is really expensive over there and running thicker oil on the street I wouldn't recommend. I think a factory oil cooler was available but I bet a stoxk L88 oil cooler is pretty pricey.
Glad to see an in car video. The wind noise and light difference between inside and outside was distracting and I couldn't read the oil pressure guage but the car sounds nice and looks solid out there. I noticed at one point a car went by you in the corner but on the straight you were closing really fast.
15" tires, the massive weight of the car and the limitations of a 50 year old suspension design are going to make running competitevly with lightweight modern higher end sports cars with modern, massive low profile road race tires improbable but you understand that and, as you said all the eyes are on your car in the pits.

 

Here is the part number for the factory oil cooler. Harrison 3157804
Seems they were an over the counter only part and used on L88 road race cars, Yenko cars and Trans Am series camaros. Good luck finding one. Oil temperature thinning the oil could have a lot to do with it since it was not apparent during your warm up laps.

 

Subject to how hot was your in-lap and how quickly data was recorded, here's my general read of the tire temps above...

Insufficient front static negative camber and/or negative camber gain. The inside edges shouldn't be cooler than the outside edges, and should typically be higher. You might well get away with a tad more static camber, but you could possibly be a candidate for long upper ball joints to increase gain. However, in any event you don't want to take either static or gained camber so far as to make for unstable or less effective braking.

Left front and both rear pressures appear low. Middle temps shouldn't be below outside edges. Suspect the RR will indicate low pressure when camber is corrected.

Left rear camber looks to be pretty good, but after correcting the right side I'd recommend getting a baseline read on -1.75* static rear camber, then following up with 0.25* reductions (-1.50*, -1.25*...) until/unless performance suffers. Also, as they determine gain, at what height in the "camber inlcination" slots are your inner camber strut links?

Per your feedback and temp data, I'd suggest to get the rear corrected and dialed in and adjusting those pressures to achieve better temps before looking to any additional chassis tweaks. That said, the two best instruments by which to judge things are always going to be 1) the stopwatch, and 2) your backside.


Disclaimer: For other viewers, do bear in mind that settings which improve performance on a given circuit on a given day for a given car/driver combo won't necessarily translate to everyone else's benefit.

 

Great to hear it getting a workout! That thing looks and sounds sweet!!

JIM

 

like this? this one has never been mounted or seen a drop of oil.