Top speed at 300-400 hp

[Terrh]

at stock boost my car went GPS verified 259km/h pushing a VERY strong headwind (probably 50+km/h)

haven't tried since then (at least, not with a GPS in the car) but I have rested the speedo needle on the 0 which didn't happen last time. Running about 1.3-1.4 bar now.

And no, I'm not crazy, I didn't do any of this in soviet canuckistan, I went over to the land of the free, and wide open interstates.


Horsepower and aerodynamics are everything to top speed, unless you run out of gear, or your gears are improperly spaced for how your car makes power. Then it's gearing.

[Daniel1458]

at stock boost my car went GPS verified 259km/h pushing a VERY strong headwind (probably 50+km/h)

GTR or GTS?

[GTR-Dad]

could the motor f*ck up if you go at those speed?? I mean if you didn't mod you car for those kind of speed. Can a STOCK rb motor support those kind of speed?

Heat is your engine's enemy, so temperature is the main thing you'd need to watch.
1 - Exhaust gas temps need to stay below 950C or so. I wouldn't keep them at that level for a top speed run though - maybe 900C. Anyone got any (instrumented) experience?
2 - Intake charge temp needs to stay under control. Higher intake charge temps mean higher cylinder temperature which brings you closer to detonation. (Bad.) Most ECUs will pull timing and add fuel to safe-guard the engine. Pulling timing decreases engine power and sends the extra energy out the exhaust side. EGT increases. More fuel has a cooling effect, but also decreases power. If you tune is good it'll keep you safe. If not, the answer to your question is 'yes'.
3 - Coolant and oil temperatures need to stay under control too. You're dumping more heat into the engine with loads associated with top speed runs and it needs to dissipated or temperature will rise. ECUs will compensate for high coolant temp as they do for intake temp. Oil temperatures need to stay low enough that lubricity is preserved. Run good synthetic oil and you'll be better off, but as a rule, lubricity drops with increased temperature.

Top speed runs are hard on your engine, reduce your life expectancy, and reduce the life expectancy of those you encounter. Doing this on public roads in populated areas is a serious offence and if anyone does it, I sincerely hope you get caught. It'll be better for everyone.

If anyone's got their tongue in their cheek when they talk about doing this on the track, smarten up. The track or other controlled environmnet is the _only_ place for top speed runs. Use them.

Dan

[Shadao]

dont forget that at sustained high RPM's you can end up not having enough oil in your oil pan, since it can get all stuck up in the head...

but besides going 250-300kmh isnt that big of a deal, its only when you need to stop or slow down that things really get scary...

[JzGarage]

The Skylines aren't very good with the wind tunnel i hear

[M-type]

yea but its that drag that keeps a skyline from flipping over at high speeds (see REDLINE a lambo flips at 320mph or something)
drag at high speed is a friend and enemy

you wanna see arabs drifting check it out on a bike( pedal not motor)

[M13]

Hey, resurrection is for Easter, not Christmas.

[DreadedFist]

Type up post about speed vs horsepower vs who cares about speeding, the germans do it all the time... Then look at post date and face palm to death.

[Bugsly17]

Top speed is the same no matter how many hp you think you have.


All about gears and rpm

[DreadedFist]

Top speed is the same no matter how many hp you think you have.


All about gears and rpm

Unless you don't have enough power to max out your gearing. So many cars are drag limited these days.

[Terrh]

so long ago!

I think I ended up seeing 278 km/h later that year with more boost. My car is a GT-R if the poster up there still cares 3 years later, lol

Oil temp climbs ridiculously fast any time you are on the throttle at high RPM for a long period of time. When that gauge hits 115, staying in it is starting to put your engine at risk.

Oil isn't going to stay in the cylinder head. I'm sorry but that myth is retarded. Overfill your oil a little (like you should with any car you abuse regularly) and it'll be happy.

Coolant/intake temps should not be a problem at speed in a GTR. The stock rad and especially intercooler are huge and shouldn't have a problem keeping your engine cool with a 200+km/h wind blowing into them.


If the oil pressure gauge is pointed somewhere near the top, and the coolant gauge isn't, the engine is happy. I'm sure there's GTR's in germany that have seen 250KPH runs for 100 miles or more, especially when these cars were new.

[DreadedFist]

I was always under the impression it wasn't oil staying in the head, but rather just to much oil going to the head. So much making it up there that it can't drain back fast enough and suddenly sucking wind.

[Terrh]

the oil feed is 2.0mm (stock)
the drains combined volume is ~600 mm2 I'm guessing between the 3 of them. It's probably even more than that.

What's going to flow more?

[support@feastauto]

On Fuji's main straight, nearly 1.5KM long, a 550-600PS car is at about 260kph. All I can add here

[xcye]

At Calgary Race City this year, My drysumped R32 GT-R (Guestimated 450whp) hit 240km/h at the end of the front straight.