[Helldriver]

yes awesome cars but guys wrong thread, please back to topic.

Question was still not answered, what is a safe rev limit on a stock V8? Can I raise it safely from 8700 to 8900U/min?
With V10 Throttle bodies installed it has enough air to pull full and hard on 8700 compared to stock so raising limiter will give me even more power and acceleration...
Third question: can I set the rev limiter different per gear e.g. 1 till 5th gear 8900 and 6th 8700?
Raising the limiter for me will be due to higher acceleration as I can keep it longer in one gear and use the additional power but I don't want to run Vmax in the 6th on this high rpms longer time as it certainly stressing the engine.

 

[Spinnetti]

That's not really true, it's not wasted at all.

The power may tail off slightly compared to peak, but the power output just before the rev limiter is still way higher than the power you'll be at when you change gear.

The torque at the wheels, through the gearbox, will be much lower once you've changed up.

If you wanted maximum acceleration through the gears you'd change literally a split second before the limiter kicks in.

Almost but not quite true, and based on gearing, the shift point for each and every gear can be different. Basically you want to shift so that after the shift for that gear, the rpm is at the torque peak.. fancy aftermarket systems will give you shift light programming for each gears optimum shift point

 

[Paul_D_UK]

Almost but not quite true, and based on gearing, the shift point for each and every gear can be different. Basically you want to shift so that after the shift for that gear, the rpm is at the torque peak.. fancy aftermarket systems will give you shift light programming for each gears optimum shift point

No, it is true in this instance because I was talking specifically about the Audi R8 V8 engine.

You can go away and do all the calculations you want, but I think you'll come back and agree that changing up just before the rev limiter provides the greatest acceleration on this type of NA engine.

A turbo'd engine which drops off in power dramatically near the red line would be a different story.

 

[Bobley]

I cant find any accurate power curves to hand so I've only got the published curves and gear ratios to go from but if I plug all the numbers in then my model predicts 0-62mph in 3.95s with one person on board and the top end is 190mph so it's not far off...

Anyway, if I extrapolate the end of the declared torque curve from [email protected] to [email protected] then it says the optimum shift points are 8700+, 8700, 8500, 8400 and 8250rpm. A stock engine would be going into soft cut by then so there's very little to be had by revving that high.

My minds gone fuzzy but I remember revving a V10 to 9400rpm.... Not sure what we got the V8s to..

 

[Sherif Ahmed Soliman]

my audi r8 v8 mk1 r-tronic rev at 6400 RPM and no faults in the ECU ?

 

[Mws]

Got 70k in mine hits red line all day everyday since I owned it motor is stout as ****

 

[Sherif Ahmed Soliman]

s

my audi r8 v8 mk1 r-tronic rev at 6400 RPM and no faults in the ECU ?

Same problem here but i removed flap runners
did you think the flap runners cause this problem ?

 

[ezmaass]

s


Same problem here but i removed flap runners
did you think the flap runners cause this problem ?

You've responded to yourself stating you have the same problem... as yourself?

Nonetheless, it's still not clear what your problem is here. The V8 can go well above 6,400 rpm... so is it revving this high when you're not expecting it to... or something else?