Matt Marks

I think that there's plenty of evidence out there if you want to do the number crunching. As a 944 guy, this may be easier due to fewer variations of HP and weight, but with identical chassis and suspension setups.

Take any of the club race results and compare the lap times of the fastest couple of 944's from I and from F (944 Turbo). Assume that all cars make factory rated HP (which they should using race exhaust, no cat, etc.), and use PCA minimum weights, and voila - you have fairly empirical evidence going back years.

This assumes two things, of course - that everyone is running coilovers, and and that you exclude the small number of 1989 944's with the 2.7 liter engine. Also, there are some gearing differences, but the chassis is as identical as you can get accross the whole range of years the car was built.

Crunch the numbers, and you'll have an answer - compare something tight and twisty like CMP Watkins Glen. Way beyond my math skills - but there's hard data out there.

jerome951

This would be fairly easy to prove/disprove in an approximate sense by someone w/ a turbo car and variable boost. Of course, they'd need to know the power output at differing boost levels, but would be pretty easy to test. Heck, you could even do it in the same run session to eliminate that variable.

Larry Herman

There is certainly enough data out there to help verify a formula that would be track specific, but that would still be quite difficult, as it must take into account not only the HP of the car, but the torque, the weight, the frontal area etc because all of those factors have varying affects on acceleration as speed increases.

mark kibort

its this simple, it changes your straight line acceleration from turn exit to the next braking point.

ive got a real poor mans telemetry system (video and a stopwatch) when you calcualte what you gain from 40mph to 130mph with any hp, in seconds, you can usually subtract this from your lap time. do that for all straights and you get a good idea. however, as was said, there are so many other factors. usually, more power with novice drivers, yeild close to the same times, (unless it is a Huge HP gain) as they end up braking earlier and that counteracts the increased acceleration gains! It also depends on the track.

for some of my local tracks, 50hp seems to be worth about 1-2 seconds. so can tires, so can driver , so can 200lbs , so can a lot of things!!

in racing, HP /weight is only about 1/3 of the total car equation (leaving out suspension , driver, etc)
brakes and cornering is the other 2/3rds.


MK

Lemming

Well, I actually ran the numbers. When my 924S had the original engine I was running low 1:51's at Barber. I then dropped in a 968 motor and now run low 1:47's. According to the calculation, I should be running a 1:43, guess I need to get in gear.

RedlineMan

Math?

Sheeeesh. I'm always better off avoiding that.



As for the more subjective aspects, it would be my opinion that the extra HP might indeed improve the driver's lap times, but probably not his driving... right away at least. Given some time, the driver may familiarize himself enough with the added ooomph to make good use of it... or not.

At first, I would guess that it would have a negative effect on his driving. As others have stated, I agree the time may never come when that power could be exploited fully.

More power will not make you a better driver, but more skill always will. More power is never the real answer, is it?

DanS911

First of all let me be the first to vollunteer to have my car be the test car for data.
Anyone out there who wants to drop a 3.6 in and remove my stock 3.0? Please?

Secondly we may have a car to test some of this stuff.
My buddies Kevin and Luis blew up the motor in the 944 race car. Then they blew up the 968 motor in the 944 race car.........now Master Porsche Mech Mike G. is installing a Z06 motor and it will no doubt make somewhere north of 385 RWHP.
It is close....I have seen it run.....soon others will see it run with Kevin S. Hal P. and Luis O. at the wheel.

We will be able to see the difference in times at Homestead and Sebring soon.

Larry Herman

Come on John. Some of us can use more power! I could only get to 165 going into the bus stop at the Glen.

Skip Wolfe

Seems way too aggressive too me. I run 1:47's at Mid-O at 240 rwhp. According to the calc, once I install my new turbo I should be running 1:43's. While I'm sure the car will be capable of running that fast given a more skilled driver, I can't see me being able to shave 4 seconds at that track just with a nice hp boost. I agree with everyone else, skill plays too big of a part in the equation. Maybe under ideal circumstances if you take a pro-driver and artificially limit the hp on his racecar, let him run some laps, and then take away the restriction, it might be valid. It would be an interesting experiment.

bobt993

I think the best formula is: fast driverX + fast car = your ideal goal. Have driver X mentor your driving time and buy him/her at least beer and dinner every track day you get coaching.

Gary R.

I have 180 HP, yet I entered the straight at LRP about 20MPH faster than the 993 in my avatar.. his 275HP wasn't quite enough to pull away.

Bill935K3

Very interesting ! If I get the chance at Sebring test day I’ll try to give you guys some hard data. I run 3 boost/fuel maps b--- buster mechanic labels the switch $ / $$ / $$$. As I usually go to map 3 during second Friday practice and never go back unless weather changes. If I get a chance late on T&T day I run a few on 2 and see what my time drops. Should be a good bit what with 3 big straits at Sebring
As I progressed my first 930 I use to love to track power to weight ratio gains. Weight reduction being SOOO much more valuable.
for instance here are two very do-able ways to go for a 930
2850lbs / 300HP = 9.5:1
2850lbs / 325HP = 8.76:1 just faster under power (might loose some in corners if tires can't take HP)
2628 / 300 HP 8:76:1 SAME acceleration gain but also shorter brake zones and higher corner speeds,
Of course a 25HP gain on a 3.3 turbo is dead easy and losing 225lbs is major surgery
Any of you engineer types care to hazard a guess on pounds cut Vs hp increase
My guess for above at LRP
Original 1:02
More hp 1:01
Lighter 0:59

38D

I think you are talking tenths of seconds. My guesses:

Original 59.80 (A D class '89 930 can run sub 60...)
More hp 59.65
Lighter 59.60

mark kibort

Speed World challenge touring (bmws, acuras, mazda 626, etc) runs 57-59 and their weights can change up to 250lbs with only a sub second change in time. its the closest they get to the times of the GT cars, (usually, close to the same weight , but 200hp more and only a 3-4 second differnce!!! so, that right there, tosses out the formula.
however at Road america, the difference is up to 13 seconds!! (2:14 vs 2:27) for the GT vs Touring cars. (take a 275rwhp BMW vs 414rwhp porsche GT3 with engine upgrades and close ratio gear box! both at near 2900lbs with driver)

Point is, yes, all things being equal, the formula works, but usually there are too many variables to count. i have more laps in the same car, with few changes than most at Laguna. ive seen 20hp losses hurt me close to 1 second, and ive seen 50hp gains help 1-2 seconds. ive also seen 3 second losses for a bad set of hoosiers vs good RA1s. Weight is definitely a big deal, but some push even harder with rewards weight up to 200lbs, and still seem to be within a second of their best times!

as a real solid note. I used NOS 4-5 years ago, and only on the straight with a dead pedal switch. 50hp for a 10 lap race helped me 1 second a lap. one thing HP does do, is allow for safer, more confident and obvious passes in a racing environment, even though a lap time may be close to the same.

Mk

Bill935K3

Hi 38,
On reflection I agree a D class can just about run 1:00. I went browsing results for the last few years (man CVR has been plagued with rain!!) best D race lap I found was 1:00.37. I sure in qualifying this was bettered.
I also agree that HP only would be 10ths at LRP. I can't agree with you on only 0:00.05 more improvement with the weight loss. That is virtually the same as HP only? The weight loss gives you the same power to weight so acceleration should be dead nuts even. I feel the weight loss would be SIGNIFICANT on top of the acceleration gain maybe not 3 seconds but a lot more than just a HP gain.
Take one fast corner like Big Bend; say for argument 930 pulls 1.35G.
2850 lb car's tires patches are holding 3847lbs, 2628 lb car = 3547 now the advantage in 300lbs. Thus any weight advantage is multiplied in every corner + shorter brake zones.
Or to look at it another way
If all else is equal and the heaver car slides at 1.35G the lighter car should be able to pull 1.46G.