Got a track related question? I'll try to answer.

[redlined600]

Re: fuel usage, my experience has been: 9-11 na tune and 6.5-8 na w/ e85.
As read from the cars computer.

[CSG Mike]

Originally Posted by nico_rsx

OP is talking stock with a tune, not FI.

The flapper also serves no function for a stock car with no tune; you can run on track with the gas light on, without starving in that condition.

[pym19109]

For summer tires DD and 3-4 track day a year what I should go for ?
R1r, Re71r, AD08r and also concern about tread life as I DD 10,000KM a year

[14stu]

Originally Posted by pym19109

For summer tires DD and 3-4 track day a year what I should go for ?
R1r, Re71r, AD08r and also concern about tread life as I DD 10,000KM a year

Hankook RS4 or Falken Azenis 615k+.

[pym19109]

Originally Posted by 14stu

Hankook RS4 or Falken Azenis 615k+.

Those tires are not available in my country

[strat61caster]

Originally Posted by pym19109

Those tires are not available in my country

Dunlop Direzza Z2/3/Star Spec?
Bridgestone RE11/S007A

I would not expect RE71R's to last 4 track days and 10,000km unless your track days are very short (<1 hour per day) or you underdrive the tire significantly, my RE71R will be gone before 5,000 km and only autocross, no track days.

Edit: I can't speak to the Yokohama AD08R or Toyo R1R, one of those might be the right answer but I'd expect they'd wear faster than the Dunlop Z2/Z3 and Bridgestone RE11/S007 in exchange for more grip. I'd bet the Dunlop and Bridgestone would fall squarely into your requirements, 4x track days driven at >9/10ths what the tire is capable of.

[CSG Mike]

Originally Posted by pym19109

For summer tires DD and 3-4 track day a year what I should go for ?
R1r, Re71r, AD08r and also concern about tread life as I DD 10,000KM a year

AD08R

[pym19109]

I would go for Ad08r as I asked many local shop about Z2 and they said Dunlop discontinue this tire in my country (I may live in wrong place XD)

[86_IT]

Originally Posted by CSG Mike

The flapper also serves no function for a stock car with no tune; you can run on track with the gas light on, without starving in that condition.

I can confirm this. I did a full lap at Laguna Seca with the gaslight on. No starving.

[14stu]

Originally Posted by 86_IT

I can confirm this. I did a full lap at Laguna Seca with the gaslight on. No starving.

The fuel flapper delays when you'll get fuel starve, but it does not prevent you from fuel starving.

Long, high g left handed turns cause fuel starve (because of the geometry of the fuel tank).

The lower your fuel level, more g's you pull, longer the corner, and greater your fuel demand the more likely you are to fuel starve.

If you don't pull enough g's, don't have any long lefts, or aren't using full throttle you won't fuel starve.

The flapper valve will only help if you are just barely in the fuel starve danger zone. If you are far below or above the conditions that cause fuel starve, the valve won't help.

At my home course (Motorsport Ranch Cresson) there are two long lefts back to back that in a stock car with real 200tw (not RE71r's) tires you can get fuel starve with as much as half to a third of a tank. In my STX prepped BRZ (93octane, headers, and full suspension) without the valve I could consistently hit fuel cut at a half a tank or less.

With the valve installed I can run down to about a quarter tank before I hit fuel starve, this allows me to run three twenty minute sessions before I have to fill up, which means I can wait until the lunch break to get gas instead of needing to fill up every other session. So in a typical track day I can start with a full tank, run until lunch, refill, and drive home without needing a second refill (no fuel starve on the drive home to worry about). Without the valve I'd have to fill up 2-3 times which would make instructing more difficult.

If I was running slicks, aero, or E85 the flapper valve wouldn't be enough and I'd have to go to a surge tank and/or fuel cell which would require me to wear a fire suit and would impact classing for the SCCA Time Trials and autox that I compete in.

So, for me, the flapper valve is the easiest solution. It's application is very narrow and it isn't a perfect fix, but it does serve a purpose.

[86league]

Originally Posted by CSG Mike

The flapper also serves no function for a stock car with no tune; you can run on track with the gas light on, without starving in that condition.

Depends on how you define stock, but a friend is running Koni Yellows with Swift sport springs and camber mods with 245/40-17 SX2s and fuel starves if a session is started with 1/2 tank or less - so fuel starves above 1/4 tank - probably closer to 1/3. Same track 14Stu mentions - MSRC in Cresson.

Reading this thread to see if the flapper is enough help to be worth the hassle/cost of installing it vs. just filling up more often.

[Joesurf79]

Originally Posted by 14stu

6-8mpg at COTA, TWS, MSR-C, MSR-H, and ECR. The bigger issue is that if you don't have the velox fuel flapper valve long left handers will cause fuel starve as early as half tank (I still get fuel starve under a quarter tank on RS4's with no aero at MSR-C).

*raises hand* - 5/8ths tank WITH the Velox flapper installed, on RC-1s with aero at MSRC = fuel starvation yesterday. Ruining a PB lap on the 3.1 configuration...


I am hoarse today - I was screaming in my helmet as I watched my AIM predicted lap grow from 2:26XXX to 2:28.15 as it coughed , bucked, surged, and coasted across the start finish. tombstone and then Big bend back to back running CCW guarantees fuel starve at the end of a session if I'm not going out with a full tank

[GrandSport]

Originally Posted by Joesurf79

*raises hand* - 5/8ths tank WITH the Velox flapper installed, on RC-1s with aero at MSRC = fuel starvation yesterday. Ruining a PB lap on the 3.1 configuration...


I am hoarse today - I was screaming in my helmet as I watched my AIM predicted lap grow from 2:26XXX to 2:28.15 as it coughed , bucked, surged, and coasted across the start finish. tombstone and then Big bend back to back running CCW guarantees fuel starve at the end of a session if I'm not going out with a full tank

I love MSRC, but man, those turns just are just killer on cars for oil starvation, fuel starvation and tire wear.

When I was riding the 1.7 on my bike, one side of the tires looked new while the other side was down to about 25%. Next time I'm out there, I'm rotating tires every session.

edit: 2:26 is an awesome time at MSRC for the 3.1. You're flying!

I was running a 1:55.8x or so at ECR when a freaking PEN got stuck between the gas and firewall! On the last straight. 1:57.8 Luckily, it wasn't my brakes.

[kch]

Originally Posted by pym19109

I would go for Ad08r as I asked many local shop about Z2 and they said Dunlop discontinue this tire in my country (I may live in wrong place XD)

The Z2 has been replaced by the Z3. I used Z3s for this year's track season and liked them a lot.