rx7 SE

iTrader: (5)

What kind of times does Pete run at VIR?

Brent Dalton

iTrader: (31)

Mid 2:0X's I believe. While we are all chasing lap times, there is more time out there for him if he wanted it. I don't think he has ever had A6's on his car, for example. And has no major aero on the car either. 99spec front bumper and wing.

Fritz Flynn

iTrader: (263)

Pete love the As which provide him with the same heat cycles but a lot more grip. For some reason his lap time isn't coming to me but I think he has run a 2.07

Yep and more YEP

Thanks for the compliment, that's a big one

Doing more with less is always a big pat on the back but I'll repeat not changing things too much and relying on perfecting your line and driving to lower your lap time is a gratifying/satisfying feeling

Because I'm a cheap bastard and have 12 SSR comp 17 x 9.5 LOL

KevinK2

esses, what esses? he straitened them out ! I never saw a countersteer. That's crazy fast.

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wrankin

VIR was repaved over the winter. They widened out a few sections which were a bit narrow. Lap times are definitely better.

It was my understanding that the overhaul was targeted more at attracting and maintaining a good standing with the major professional road course series (ALMS, the return of IMSA, et. al.) rather than any specific focus on NASCAR.

Smokey The Talon

iTrader: (33)

Want to sell me a pair of those 17x9.5+42s?

Fritz Flynn

iTrader: (263)

I can sell a set but not a pair.

do you have a pair of 8.5 inch for sale

KevinK2

Watching it again, it looks like the driver is only pushing 9 tenth's at most. But you see 3g's when he accelerates out of a corner, etc. I bet he's got $6-10K in the net suspension value. Sounds like a sequential trans.


Makes you wonder if Fritz or other's here could turn faster times with it, with a little practice.

https://www.rx7club.com/race-car-tec.../#post11772854 SRT


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Fritz Flynn

iTrader: (263)

Yep sequential trans it's a viper GT3 R that cost 450k plus out of the box and I'm sure this one has another 100k invested.

I couldn't turn faster times with a life time of practice but I'd sure like to try LOL

He's 10 10 all the way. With out the car at track out of t3 he would be a couple of 10nths quicker and he was already close to or beat the qualifying time for that type car when it last raced there.

He's braking just after the one on the back straight at 171 MPH........trust me he is all in He also went off in t10 during one of the session and Pros don't leave the track often. He was trying very hard.

For the record that's also the fastest time ever at a UTCC event. Badass driver and BADASS car

KevinK2

Got cha. Speaking of brakes, would 18" wheels allow larger rotors up front for improved braking capability? Is it worth the cost of upgrading?

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Fritz Flynn

iTrader: (263)

Obviously bigger wheels allow for larger brake rotors but the real question is what size do you NEED or how fast is the car etc.....? A larger rotor isn't going to stop the car any faster in fact it could potentially stop slower because of the extra weight so the last thing you want is a huge brake kit on a light car making 300 rwhp. In other words if the brakes work well and don't fade etc.... you just need to keep them COOL enough.

Currently on my car I have the brembo GT kit with 13 inch rotors and have a serious problem with cracking rotors because of too much heat so I need to invest in an improved brake ducting system. Sure I could go with larger and fatter rotors and they would last longer but the cost would be a slower lap time and that's the last thing I need.

Smokey The Talon

iTrader: (33)

I'm running 8.5s along with my 9.5 rears. I've always been tempted to run 9.5s squared, although I don't think I could run my 275/40s in the front as I already rub with the 255/40s. I also happened to just buy about another season or more worth of tires on a good deal.

That being said, I'm always open to ideas. You thinking we could horse trade a set of 8.5s and cash for some 9.5s?

Fritz Flynn

iTrader: (263)

I have 2 8.5s so I need to either sell those or get 2 more for one of my DD cars.

I'm willing to sell 2 sets of my SSR comp C type for 1200 each picked up and will include some race rubber that has a couple of days of fast laps left in them before they are heat cycled/worn out.

KevinK2

As long as you feel there would be no advantage in braking quicker with 14" rotors, then the 13's are fine, if not crack prone which is likely fixed with ducting. I think higher exit speed is more important than saving a small fraction of a sec by less time braking, so the better wheel tire combo may be money better spent.

As to the extra weight, that seems to be a small %, given the total weight of the car with gas, or the total weight of the unsprung mass at the front corners (need high resonance to follow rough roads, or curbs).

I know for the tire wheel combo, a 6 lb heavier combo per corner will be like 1.7 x 6 = 10 lbs added weight in car, including the rotational inertia effect on accelleration, per corner. The OD of the tire ia assumed to be the same.

So for a 2800 lb car wet and driver, you get a 1.4% weight increase. And assuming you are accelerating at wot 70% of the time, then a 2:00 time rises by (.7 x .014 +1 )x 120 -120 = 1.17 sec's.

So you are right, you need some payoff in reduced time to justify heavier tires&wheels per my example, or heavier brakes.

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Fritz Flynn

iTrader: (263)

I'm a simple man with a simple plan but the info looks good to me.

The best way to reduce braking time is investing heavily in wheels and tires but again they come at a price to your bank account, your weight plan and wear and tear on the car.

A 13 inch kit will stop 315 R6 rubber on a 350 HP car that weighs 2800 pounds. If you are running michelin blue slicks then you'd likely have to upgrade or you'd be blowing through pads and rotors. You'd also have to change pretty much everything about the susp and setup. However you'd be braking at the 1 to 3 marker and running some sick lap times LOL.

Brent Dalton

iTrader: (31)

Don't want to clog up your video thread, but thought you and Pete would enjoy this. Saw Ziegler's TT3 video the other day from the NASA event. 2 flat in TT3 is amazing, but he was really killing it on the front half of the track. No lift through the esses is impressive. After he rolled up on Brian on the 1st lap of the video, Brian felt the heat and ran his 1:59 the next lap. Sigh, this makes me miss VIR and RA.

Fritz Flynn

iTrader: (263)

The rotation is SPLENDID. Talk about turning it on a dime.

Also note the late braking, just after the 3 front and arrow back.

Effing AERO on that car is SICK!

I have soooooooooooo much work to do

PS my 2 pennies, brake a little earlier at t1, carry more speed in and he's at 1.59.....really amazing T3 car and driver.

PSS Eric Wong wasn't far off with much less car (aero)/wheel so keep an eye out for him. I think Eric runs 18 x 9.5 (275s) and I think Ziegler told me he was on 10.5s or 11" wide wheels. 275s I think?

KevinK2

I assume Zigger has a 3 rotor with twin turbos (not sequential like the Cozmo) ?

He must have a very stiff suspension with big bars, to get that "zero degree lean" in 2-3g corners!

Speaking of tires, I remember a tire width test on the 1st gen VW Scirroco. They used the same brand and type of tire, same OD, and on a track like Summit Point original, they checked times as they increased width. They hit a max width, beyond which lap times increased. I know that was a super light car with a 1.6L engine, but just wondering if there is a limit for your 300 hp rx7, regarding tire width. Would you go faster with tires from that Viper GTR-3? I think the answer would be yes for an autox, but for VIR, although exit speeds may be up, would the tire friction and extra weight slow you down on lap times?

Note you could give him tips on how to position an in-car camera, securely.

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Brent Dalton

iTrader: (31)

He is in a C5 Corvette with the stock LS6 V8.

There is def. a point of diminishing return with tires/wheels when you are balancing grip vs. weight. When I changed from 275s to 315F/335R, I picked up 2 seconds at VIR and RA. Too many variables to say it was the tires though.

No doubt on the late braking on the front straight as well!

Saw Eric's times as well. Very impressive indeed!

KevinK2

Thanks for the correction Brent .... I should have looked (at dash) and listened (to that V8) before typing. It did look like Zigger was catching up on the last lap.

It seemed like NASA was just starting to get big when I contracted a problem with constant pain in my left foot, called RSD. Had to hang up my helmet, but kept my mostly stock 93. There was a guy in a Firebird that was fast at Summit, and ran Nasa events. "John" was paralized from the chest down, and used all hand controls. Wonder if you guys saw him at VIR ?

Fritz Flynn

iTrader: (263)

There will always be a diminishing rate of return but the general rule is to run all the aero you can and all the wheel and tire you can. Balancing both of course for your cars handling characteristics. The FD and the C5 are really neutral/balanced cars so you just do equal amounts front and rear and throw the kitchen sink at it which makes them easy to setup. However with that said if you saw Zeigler's car you would be amazed at all the aero work he has put in. Hats off big time

My car is listed at 379 rwhp but probably making approx 350 at this time (11 psi T04r) I'm interested to see what it will dyno on the VIR dyno and can't wait to give that a go the next time the dyno is open.

Brent, those tires absolutely made you faster. All things considered grip is about the biggest advantage you can have on a road course.

I'm anxious to see just how much faster my car will be with 10.5 inch wheels and good rubber like As or C71s. I'm really conservative on braking but believe it or not I couldn't stretch too much further. I was already getting some lock up/abs kicking in when braking at the 1.5 rear and 4.5 front.

I'll take that stock V8

PS Another guy to watch for is the driver of the mitsubishi who was driving on NT01s This car has equal aero to Zeigler or possibly even more LOL.....it's an arms race in the amatuer racing ranks these days. I'm hoping he makes it to SPR in August because I may run TT2 again there and it will be a war

Fritz Flynn

iTrader: (263)

Check this BAD *** **** OUT!!!!!

Fritz Flynn

iTrader: (263)

After watching the eclipse vid it is IN MY FACE obvious I have to address my aero or I will be smoked by everyone LOL.

Silly speeds through the esses on NT01s

KevinK2

For my education, was that 2 sec's faster?

Regarding Tire/Wheel weight, say 10 lbs heavier per corner, but the same OD on tire.

The 10 lbs weight part is easy, it's like you added 40 lbs to the total car weight, as unsprung weight. That could make you slower on rough tracks too, as tire contact with road may be compromised.

Then there is the rotating effect of the extra10 lbs. That will result in another .7 x 10 = 7 lbs added weight to car per corner, but there is no effect on the unsprung weight.

So regarding acceleration, that 10lb heavier wheel/tire weight per corner results in 4 x 17 = 68 lbs added to the weight of the car.


The Mitsubishi, does it have the old 4 cyl 2L engine? Back in the IMSA/Trans-am days, ***** T Ribbs was running a Toyota Celica RWD with that block. Dan Gurney was the manager, and he said their 2.2L version had boost up around 45-50 psi !! Same engine was in those LMP toyotas, #99 and #98, crazy fast series.

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Fritz Flynn

iTrader: (263)

GRIP IS EVERYTHING. Road racing is a momentum sport and horse power and a lower weight are both great but nothing gives you more momentum than going faster which is GRIP.

Improving your cars aero and wheel and tire package no doubt comes at a cost but both will make you FASTER most of the time. Of course the car is slower at the end of A LONG straight away but it will be faster everywhere else including short straights because the car is exiting 5 mph faster........MOMENTUM is the biggest speed factor in road racing so don't use your brakes as much lol. My new saying that I'm sure some famous racer is quoted for: "it's not when you hit the brakes that counts it's when you release them" As in you want the car completely balanced on a nice soft line having fully prepared it to carry as much speed as possible into and out of the corner. Sounds simple doesn't it but in reality it's the most difficult thing to master in road racing and it's the difference between a fast driver and a slow driver. In other words it is what the driver does off gas that makes him fast on gas and guess which one comes 1st and which one must be perfected 1st but is usually learned last.