PORSCHETTE ON TRACK SOON!
08-20-2011, 04:59 PM
#16
Rennlist Member
Anyone who thinks I'm not crying about the head failure doesn't know me very well. More $$$ for new heads and then more $$$ for the CNC work and then more $$$ for some additional machining for the rocker stands and then more $$$ for putting it back together and then more $$$ for dyno time. Better believe I'm crying.
As to the tires, pretty much agree with everyone. But, aren't A6s a little too soft for high speed tracks, compared to R6s?
As to the shifting, my TQ curve is within 10% of peak from about 3k to over 6k. My peak HP stays pretty flat to 6.5k. My old shift point was 6.6k, but I frequently found myself stretching to well over 7k, in order to avoid an additional up shift. We figure that rpms = heat and heat = increased rebuild intervals which = $$$. So, keeping the motor down to about 6.2k should save $$$. May not win races, but that has never been the real goal in the past.
The EMCO gear set was selected for 6.2k shift points and an absolute max of 6.6k. The motor can still go to 7.5k, but what's the point. I really don't have enough intake to make more power at higher rpms. I'm also running 6 gears and they would all be usable at the really big tracks. 6th isn't usable at TH since 5th can get to 160+ (and I'm already scared ****less that my brakes might fail going into T1).
So, while we could have a very extended discussion of HP vs TQ and the appropriate shift points, let's not. Until we get on track and can get some logging data back, I'm just guessing at what is the best set-up. Some of you may already know the answers, but I have to find out for myself.
As to the tires, pretty much agree with everyone. But, aren't A6s a little too soft for high speed tracks, compared to R6s?
As to the shifting, my TQ curve is within 10% of peak from about 3k to over 6k. My peak HP stays pretty flat to 6.5k. My old shift point was 6.6k, but I frequently found myself stretching to well over 7k, in order to avoid an additional up shift. We figure that rpms = heat and heat = increased rebuild intervals which = $$$. So, keeping the motor down to about 6.2k should save $$$. May not win races, but that has never been the real goal in the past.
The EMCO gear set was selected for 6.2k shift points and an absolute max of 6.6k. The motor can still go to 7.5k, but what's the point. I really don't have enough intake to make more power at higher rpms. I'm also running 6 gears and they would all be usable at the really big tracks. 6th isn't usable at TH since 5th can get to 160+ (and I'm already scared ****less that my brakes might fail going into T1).
So, while we could have a very extended discussion of HP vs TQ and the appropriate shift points, let's not. Until we get on track and can get some logging data back, I'm just guessing at what is the best set-up. Some of you may already know the answers, but I have to find out for myself.
i did this when i first got the stroker, and even with 50 more hp or so, i was slower on the track. went back to optimising the shift points (with in reason) and my times improved. its pretty simple . just look at gear spacing and optimize the HP . if you shft at 6200 vs 6500 and dont lose but a few hp, thats fine and a decent trade off.
sounds like your 6 speed has just as many usable gears as the S4 gear box.
(if your 5th gets to 160mph, my 4th gets me to 155.
) you might have an extra gear between 2nd and 5th though so thats a good thing, BUT with that wide HP curve, you might not even need a close ratio box. Nice to have one with the sequential shift, save that time between shifts and it can handle the HP/torque.Tires: No, the A6s are just fine on the high speed tracks. guys with more power than you have and more weight and running a heck of a lot faster than both of us, are running them with NO issues at all. dont get scarred of the "A"s they just mean, " thy are softer than Rs" thats it.
sounds like a beast. I forgot you got the LS7. randy in the camaro gets near 530rwhp out of his now. its going itno a vet chassis after his bad wreck.
08-20-2011, 05:24 PM
#17
Rennlist Member
Thread Starter
I still intend to get into AV8SS and am looking for ways to meet 6:1 lb/hp. Really want a good testing and learning to drive group. Also want to find two day+ groups at Laguna - too far from Tahoe for one day.
08-20-2011, 07:33 PM
#18
Race Director
441 ci is hard to argue with....... Larry's machine is very well built..... Of course all the custom fabrication comes at a price.... The brake failure is concerning.....my 1st ??? is why...overheating or a component failure?
08-20-2011, 08:30 PM
#19
Rennlist Member
Thread Starter
Brake failure caused by a stainless line going to the bias adjuster making contact with an electrical hot lead behind the dash.
08-21-2011, 01:48 PM
#20
Rennlist Member
I had this happen once. i was an idiot and used stock line, believing they were as good or not even better than stock rubber lines. mabybe true when new, but 20 years old, i was reallly playing with a loaded gun. I lost mine in a race (video on youtube) at laguna into turn 2 (andretti hairpin) amazing after BLOWIG a hole in the line and having NO brakes, downshifting and turning in to the turn, slowed the car down to not even go off track. definitely code brown moment, but the car survived.
