Mike1982

I was thinking today about this. Take a stock 951 and see what the top speed is. Then see what your top speed would be at certain HP levels. Example, when I had a MBC, no cat, chips, 16psi I was able to get to 160 but it was still pulling some, not sure how much I had left. At that time I had 240rwhp/300rwtq. Right now with my current upgrades I have more like 300rwhp/300rwtq or so, so just wondering how much more top end I would have. I know a lot has to do with elevation, temp outside, condition of car, etc.

George D

I've hit 6500rpm in 5th gear. The 180mph speedo was well past that. The cars redline is 7K, but I was gettin a tad scared. The car was still pulling. Someone could certainly figure out the speed based on 6500 and TurboS tranny.

This was with around 400whp and 350tq on a 2.5 motor.

George D

Oh, this was at around 7000' in the middle of nowhere on a road that you could see for miles and miles on the way to a race in St. Johns, AZ.

Markus951

I had some calculation chart somewhere in excel where you could mark. gear ration, final ration, tyre size + rpm.. with stock turbo S tranny, and 295/30/18 tyres and 7250 rpm it gave result 314 kmh..

markus

porschefig

195.11 mph... Nice Markus... Can your car do it? (Mine can't )

Under Pressure Performance

Once you reach a certain amount of power, and as long as that power is available up top, then the limiting factor will be redline. In other words, if two cars have a redline of 6,800 RPM, and one car makes 300 RWHP, and the other makes 700 RWHP, they will both have the same top speed - Who gets there first is a whole different issue.

So, in short, to answer you question, given enough power to hit redline, the redline itself will be the speed limiter, not horsepower. Many cars are power limited, in other words, they do not have enough power to hit their redline in top gear, but in most cases, these cars are RPM limited.

At this point, many people have aftermarket chip sets with higher rev limits, or the rev limiter removed. Others have engine management, or some form of piggy back engine control which allow them to hit a higher redline than the factory's 6,400 RPM.

The fastest I have been is 207 MPH - The engine was a 2.8L 8V with Electromotive EMS. The power output is a bit irrelevant as it was WAY more than sufficient to hit this MPH. That said, at 207 MPH I hit the rev limiter, smiled, and slowed down. The car got a little light at about 190-195, then is started to become a lot more stable once I got past 195. The car had stock bodywork (1986 944T), vented nose panel, stock rear spoiler. The ride height was a bit lower than stock, but nothing more than an inch and a half up front, and about the same out back.

Hope this helps.

George D

The rears were 275/40/17.

George D

So many folks have told me that it's impossible to hit 200mph with our drivelines, I always said BS. Thanks for posting Scott.

bearone

sorry but i don't buy over 180 @ 6500rpm in 5th unless you've got some real tall gearing or way off size tires.

it's a simple ratio as gearing is the same.

2400 rpm/60 mph=6500/x
60x6500=390000/2400=162.5

87951

George D

I never told you what speed I was going. I simply told you what my speedo was reading and my rear tire size of 275/40/17. I've had my car over 160mph many times at the track. Should have had a GPS.

If my car redlined at 160 in 5th gear I would have to change the R&P from stock or have monster truck tires.

porschefig

Who knows our gear ratios by heart?

jasonlp

I took it to the end of the speedo and it kept going so something past 160 at the time was around 300hp give or take 20hp

bearone

no you didn't until now but you damn sure made it sound like you were over 180

your rear tires in the link look bigger than 17's

Mike1982

So how much power RWHP do you have to have to max out at 6,400rpm or even 7,000rpm?

LFA951

Stock 247 hp Turbo S does 162 mph