Do you do anything about the stock oil cooler in the S2/968? My oil temp seems very high, >120 degC.

 

can you fit a small fan somehow?
the 951, S2 and 968 have nice oil coolers but they aren't in a great spot for airflow in.

 

We run ducting to a Setrab cooler on the 8v 944 but stock cooler on 968, no fan.

The 968 is a work in progress though with a lot of development to come.

Street, a fan may be a viable route but unless you are on grid waiting on track out signal, there's more cfm going over a ducted cooler than a fan can supply and even then, you are really hoping your warmup period is long enough before tracking out, not looking for cooling.

Usually we don't start engine until driver gets in the seat and is strapping, hooking up cool suit, etc.

There's so much to do that there's not as much time as people think.
Torque wheels after every session, judge and add fuel, check all fluids, look over entire car in general, check cv bolts, rotate tires for optimum wear (may have to adjust pressure specific to corner that tires are shuffled to, for ex, if LF is taking most beating, it would have to have more pressure margin to fall off psi, if you move RR to there, you must correct), bleed brakes several times per weekend, check preload on wheel bearings at least once per weekend, etc., etc., etc.
Generally, we leave cold at 26 psi on Hoosier r7.
These tires at full tilt with a fast driver setting top lap times come up 8psi to 34 hot which thereafter, they fall off top grip and get greasy.

T

 

TIRES:

What hot pressures do you use with R7's (anyone much different than the 34 hot mentioned in the post above)?

And some background info for clarification:
- pressure taken in pit lane right off the track, or back in the paddock
- size of wheel/tires
- weight of car
- duration of typical session/race

 

Im interested in the modifications you are doing to the 968 motor going into the car. I have 2 SP1 cars live in Washington state. Almost no racing. Im going to put a 968 motor into one of the cars and bring it to Florida end of year. boat of my SP1 motors have been built with the crank cross drilled oil pickup mod, newer pan etc. just wondering about what i should do to the 968 motor

 

34 max limit
Pitwall, all sessions except sprint, practice-enduro
2600lb with driver
16x8 phone dials F/R, 245/16/R7

Best heat race lap usually comes in at around 7 laps in. I never go on pitwall for heat/sprints, have it pretty much figured out by then.
In enduro, best laps come 2-3 laps after stop.
The tire is saturated heat wise so I go -2/3psi to leave a couple psi to ceiling if they have actually made it to 34max, sun/temp/weather, difficulty of a battle all play into that.
My goal is to send back into enduro at 31-32.
I pit 3 cars on race weekend, the 2 S2 guys at +60hp and 150lbs, 275/17 F/R want to leave pitstop at 34, so they are ok with targeting 35-36 max.

You can take temps across tire, you can test pressures, etc, etc, (and I do) but your best indicator is going to be what lap number your fast lap comes.
If 1-3, you left with too much pressure, if 80-90% of laps into a session, you left with too little.
In a 12-15 lap sprint, I am looking for fast lap at 7.
If my driver (my son or people I help at track) isn't in P1 by then, he knows he'll have to back off to make a charge or drive a conservative line for a few laps first.

You can also use pressure a a tactic.
Leave high where you will be fastest right at the green then back off 5% while the competition overheats the rubber trying to catch back up.
This both demoralizes and puts the chaser at a disadvantage if he actually does catch up because you have grip left in the bag.

It's hard if you are by yourself and have to take temps after you get out of the car.
Most people overcompensate for distance/time and never take into account that pressure can actually come up because of soak and transfer from the rotors.
That's why I hit tires right away over the wall, except for opening driver door wide open in enduro, attend to driver, check wheel torque, clean windshield etc., after
If you drop pressure to target, finish rest of work and recheck in 3-4 minutes they will be back +2-3 psi from rotor heat through wheels.
Do it it once, do it right away and leave alone.

Man, I love to be at the track......

T

 

Here's a perfect example of what I mean in the long post.
Takes green at P1 SP2 right behind the SP3 group.
Gets a 3-4 second gap to P2 who comes charging too hard to catch back and overdrives his tires.
He manages a pass for the lead but driver of camera car isn't too concerned.....
You can tell by engine tone and line from lap 1-3 that the guy that makes pass for lead is actually holding up camera car.
Stays on his bumper for a lap or two, picks spot (learned from previous lap weakness) and goes back for the lead.
Pulled away at 2-3 seconds per lap from there, set track record for SP2 and finished 30 seconds ahead of P2 at checkers.


T

 

Southeast has a good representation in SP1 class so I think it'd be a mistake to change your car over and be tossed into GT3 or something where you are only 1 in class.
Even if you bring the car up to 968 weight at 3000 lbs to make it a legal SP3 car, you would need the 6 speed too to be competitive and the top tier are really really quick so you will have to have better suspension and bring your A game as a driver.

On the engine, it's stock other than pan baffle.
The late 104mm blocks have the ported crank main webs and the centrifugal oil drum/sling baffles at upper crankcase that IMO, are each a plus for road racing.

Coming from NWest, maybe take a look at your oil, water, brake cooling in moving a car to Florida.

Good luck,

T

 

Thanks for your great insight. PCA racing is not popular in the west. Im not sure why. All the classes are in one run group. Usually a few newer cups, mixed old cups some alphabet cars but mostly Boxters. I think the 16 valve 3.0 will keep me in pace with at least half of the boxters.

 

This is my car i want to put the 16 valve into.

 

Nice...., all 3 of the colors on my paint scheme too....

And yeah, the Boxsters can be a problem, a 944 8v SP1 and 2 catches most Boxster/drivers then they just walk away in the straights.
Tough when you are trying to guard your position with a competitor closing on you, you are faster overall in a total lap but you just can't get by them.
Luckily for us, we know a lot of the S/SE drivers and they tend to be pretty fair.
For the ones that aren't, the others will give them a little side talk....

It used to be such a problem, we coined a term for it.... "Boxster Hell".

Any of the SP3s have enough potential power that with a good driver, the Boxsters pretty much melt away.
With the extra power, you'll want a bigger wheel than those 15s.
Wheel choices pretty limited with early offset.

T

 

Lone 944T in E Class at Road America last weekend. This run group had a split start with the SPEC 944s, so about 30 E and F cars in the front half and maybe another 20 in the SPEC group taking the green about a minute later.

 

Pretty smooth driving, Jim. Is that you in your [replica] Turbo Cup?

 

Nope, not me. I was there with the G-Car but in a different run group.

 

Hmm, the 911 SCs definitely have advantage in E, no doubt....., they even have custom wheels, etc.
The fast ones are hard to beat with a 944, that's why everybody was leaving PCA and moving to NASA until PCA went with the SPEC classes to stop the bleeding.

A 944T should fair pretty decent though.

Definitely track dependent (I'd expect the 944T to shine at RA) but at Hallet for example, my son Eon can beat 1/2-2/3 of the E 911s in his NA SP2 car.....

At the link, 5/30 overall with a slew of 911s behind, only 11 seconds behind winner (Jim Buckley = no slouch) at checkers in a 14 lap sprint -

https://speedhive.mylaps.com/Sessions/3307150

T