webberman

It seems that the method that you guys are using for getting these times might be a little misleading. In the auto mags don't they usually do a top gear roll on when measuring something like this? For example; start in 5th gear creep up to 60 and once you are at a steady 60mph nail it.

Thene again the Firebird's time of 6.6 might also be misleading if it was an automatic and it kicked down during the test.

my $0.02

chris924

webberman said:
"It seems that the method that you guys are using for getting these times might be a little misleading. In the auto mags don't they usually do a top gear roll on when measuring something like this? For example; start in 5th gear creep up to 60 and once you are at a steady 60mph nail it."

I don't get how this method would be applicable to real world scenarios. If I was going 60MPH and wanted to be @ 100MPH I wouldn't stick it in 5th and go, I would downshift to what ever gear is needed to go faster.

Chris

webberman

Yeah I suppose that's true. I would do the same. I guess my point was to eliminate as many variables as possible in the experiment like they would at say Road & Track, but I agree it's not exactly a real world scenareo.

I guess in order to make a fair comparison we would need to know the method used by the firebird. Was it a top gear roll on? or maybe it was a split time measured at the drag strip.

anybody know how they did it?

webberman

I was curious so this morning on the way to work I decided to try and get some 60-100 times myself.

I was alone so I used a hand held stop watch and watched the speedometer. It was a little interesting trying to watch for police, find level sections of highway(495 in MA sort of gently rolls up and down in places), look for a big enough opening in traffic and watch the speedo. Because of this I only attempted 1 try using each method below.

method 1, starting in 5th gear cruising at 60 then nail it - 9.64 sec

method 2, starting in 4th gear cruising at 60
then nail it - 6.19 sec

method 3, starting in 3rd gear cruising at 60
then nail it - 5.29 sec

method 4, starting in 3rd gear cruising at 50
then nail it, start timer at 60 - 4.43 sec

So results will vary. If Road & track was testing my car they would have averaged 3 runs using method 1 and concluded that the 60-100 time was around 9.6 sec for my car.

In the real world though I would probably be cruising in 5th, then down shift to 4th and then nail it for a real world 60-100 of around 6.2 sec. So method 2 would apply.

On the drag strip I would have been at full tilt boogy by the time I hit 60 probably in the midst of a 2nd to 3rd shift so method 4 would probably be closer to that scenareo.

Just FYI I've got an 86' 951 which I rebuilt this past winter. Go fast goodies installed are: 2.8L stroker kit, Autothority MAF, K29-8 turbo, Tial adjustable wastegate (0.8bar spring), BB tri-flow exhaust, hollowed out cat and Powerhaus ported and o-ringed head. I turned the mechanical boost controller to it's all the way off position so I was running 0.8bar boost at the time.

Robert

86944turbo

The problem that I found with my 86 944 turbo, is that my speedometer was optimistic. What I did was, with new tires, find out how revolutions were required for the rear tires to cover one mile. Tire Rack told me 812. Then you back into the mph with the gear ratio, RPM, etc. I have a MoTeC engine management system and it keeps the last 20 minutes of data logged. The RPM's reported, are dead accurate. As a side note, my tach is fairly accurate too, especially above 1500 RPM. In addition, the MoTeC records 10 times per second. The new MoTeC 800, more frequently. So, I go out and make several runs, remembering what gear I started in, and can then calculate exactly what my speed was at any given 1/10 of second. My 0-60 times on my 245 mm street tires are not great. 1) I'm no John Force. 2) My tire compound is fairly hard, and I did not mess with the 34 PSI. 3) It takes a lot of practice to get a great launch out of a small displacement motor with a large turbo. 0-60 averaged about 5 seconds. Not awe inspiring, but quick. On this warm (90f) day, I had no wheel spin in third. So now I'm fully hooked up. 130 mph comes 7.0 seconds later. I have a 6 spd. from a 968 (w/Torsen), so I have to shift twice from 60 to 100mph, and only once from 100 to 130 mph. Keep in mind when you lift, push the clutch in, you are slowing down. Passengers have told me that I shift fast, but I have nothing to compare, so I really don't know. Each shift consumes 40-55 hundreths. That's the time used when I lift, till full boost is reported again. My times from 60-100 compare favorably with my 100-130 times. About 3.1 to 3.3 or 60 to 100 mph. With the new cam I've ordered, possibly shave a tenth. I would like to get into the high two's, in colder weather, and using more boost. I was using 18lbs. Above 130, or so (depending on C/D and frontal area) is when H/P really makes the difference between "still pulling" and "Oh my God". An example is this. I can accelerate from 0-150, and back to zero in about the same time
that a stock 345 h/p Corvette can accelerate from 100-150. I realize that at first glance, this sounds ridiculous, but the 'Vette takes over 22 seconds from 100 mph to reach 150. Who knows, hell I might lock up the brakes and screw it all up. Anyway, that's my time, 3.1 to 3.3.