How to achieve best acceleration ?

[dilyanyordanov]

Ok...so something wrong is going on... I got my dragy and today since it was 19 C i got the best 1/4 mile time of 11.59 sec @ 196.45 km/h and 60ft @ 1.99s, 1/8 mile on that run is 7.69 s @ 162.10 km/h....
Strange thing is at that run....the 0-100 km/h 4.32 s and yes it was 5.25 % slope.
However a few weeks back with my winter tires I got 4.12 when it was 5 C and after i just put my summer tires on, i got 4.06 s but the slope was -4.62% so dragy would not let me upload it. Ok, so far so good....Still with my winter tires i managed 11.58 s which was an unvalid time @ 204.27 km/h because the slope was -1.32% and dragy allows of up to -1%.Okay and the 60ft was 1.92s and 1/8 mile 7.66s @ 159.04 s while my fastest 0-100 time is 4.12 s @ 0.51% slope at 5C still with my winter tires.

So....I can't seem to launch it properly....First times (all with winter tires) i held the brake, esp fully off, AC off of course,left foot on the brake , right foot on gas and was holding at around 2000-3000rpm...I don't like that on the gearbox so today I managed that 1/4 mile time with small press on the gas at around 1500-2000rpm but the car is at around 780 hp and 1040nm and it seems to spin every time when leaving. I tried giving it slightly less gas at first and then full throttle but then results were around 4.3-4.5 seconds. Summer tires are Michelin PS4S. AFter some driving the temp of the tires was around 35C.... Do I have to wait for a warmer time when the tires will be above 40 C...or for a more gripy asphalt or maybe both....What do you guys do for a perfect launch ? I don't want to constantly think about it...I just want to see if the car can achieve around 3.5-3.6 seconds 0-100 kp/h and around 11.2-11.4 for a 1/4 mile... Still my 1/4 is pretty decent from what i read around and watch at YouTube but 0-100kp/h sucks and moreover 100-200 time is 7.13 s valid time and 6.94 S best time but it was -3.8% slope so dragy disqualified this. Both runs were with the winter tires.

[Nige_RS4]

Firstly you need to warm your tyres up by firm acceleration and braking for a period. Then, as it's your car and tuned you need to find the sweet spot on launch where it doesn't bog down and also doesn't wheelspin (I can imagine this might be quite difficult with over 1000Nm!) You also need to be aware that the cooler it is, the turbocharged engines (and naturally aspirated engines to a lesser extent) perform better, so waiting for a warm day is a bad thing in my book.

[don0301]

I've timed mine 0-60mph 2.9s 0-100mph 6.3s, don't recall ever doing (or logging) anything else, apart from top speed

There's no proper launch system so you need to find/feel the sweet spot as already said.

I only did it a couple of times to get numbers.

[dilyanyordanov]

By warmer time,i didn't mean 40C but just a bit warmer since the air temperature might be at 17-19 C but the asphalt is still cold at least where I live. @don0301...what do you have so you can achieve 2.9 s ?

[don0301]

stage 2 770ps 1100+Nm

I bought a racelogic performancebox

[RMC83]

Hi don,

Do you have a copy of your power / torque curve that you can show me, your torque is pretty good, but it would be good to see how the curve looks. Ie, is it able to hold at 1000+Nm throughout the rev range, or does it dip quite sharply from around the 5k rpm range?

Cheers
Roy

[don0301]

Hi

holds over 1050Nm from 3-5000 revs, then falls to 850Nm by 6000 revs, 700Nm by 7000 revs

[IanH755]

but it would be good to see how the curve looks. Ie, is it able to hold at 1000+Nm throughout the rev range, or does it dip quite sharply from around the 5k rpm range?

Roy, heres a few dyno graphs for different setups so you can see the various curves but long story short the stock turbos just can't hold boost when tuned so to get solid curves the turbos need changing, the TTE850s hold well til 900 and the TTE1000's hold well past 1000hp - you'll make power past those figures but the turbos are dropping off boost.

MRC stage 2 tune - avg 710-750hp - Stock turbos, stock downpipe, secondary cat removed, stock exhaust, race air filters - Boost drops off past 5500rpm with power flat-lining and torque dropping.



MRC 800hp tune - modded stock turbos (bigger compressor), 3in de-cat downpipe and 2.75in exhaust, race air filters - able to hold boost til redline, nice linear power and flat torque.



MRC 900hp tune - TTE850+ turbos, 3.5in to 3in De-Cat Downpipe and 3in exhaust, race air filters, water/meth - able to hold boost til redline, nice linear power and flat torque.



MRC 1000hp tune using TTE850 turbos - spec as above - turbos now past their ability to hold boost so power starts to flatline and the torque drops off.



MRC 1000hp tune using the new TTE1000 turbos - spec as above - turbos back within boost holding ability, nice linear power and torque holds til redline.

[RMC83]

Hi Ian,

Many thanks for the above info detailing the various stages & the performance levels / curve characteristics of each.

I'm kind of swaying towards the 900hp tune...i like the performance curve across the range with this set up, but as i'll keep the GB stock, i need to decide how much to 'dial it down' in order to keep good reliability. I'll likely have a few differences in spec though, as i'll probably keep exhaust stock but go for the wagner IC rather than the WMI.

Top job, as usual, tbanks.

Cheers
Roy

[dilyanyordanov]

Which makes me think to look over my hp and torque curve. I was also thinking of changing the timing chain and everything that needs replacing along the way and fitting it with hybrid turbos but somehow i am afraid the gearbox won't hold it well over time. Does anyone provide any kits for the gearbox ?

[welwynnick]

….somehow i am afraid the gearbox won't hold it well over time. Does anyone provide any kits for the gearbox ?

So far most people have gone for the Sportmile / Teo Motors upgrade.

RS Engineers / Getriebe Doc now offer a transmission upgrade, but it's rather expensive (can't remember sorry)

https://www.facebook.com/17183085750589 ... =3&theater
https://www.facebook.com/getriebedoc/ph ... =3&theater

Nick

[c3nturi0n]

Impressive figures to say the least.

Thanks for the info!

[dilyanyordanov]

Well guys...to add to the thread... I managed to do 11.59 on 1/4 mile. Don't remember if I've mentioned it before....0-100km/h still a a slow 4.06 sec....my 100-200 km/h is 7.01...The car has a tune, miltek catback, 3" custom downpipes and filters... Do you think this is the limit of the car? I bought the car with Michelin PS4S but they are manufactured at the 44th week of 2016 so i guess they were used in 2017,2017,2019 but still plenty of thread left... though i am somewhat doing it when it is 18-25 C outside... Have you guys managed to do a better time with similar upgrades ?

[V10RS6]

If you care about 1/4 mile times the key is 60ft time. 1.99s on 60ft is rather slow even for a heavy car, drop that below 1.8s and you will have a great 1/4 time.
I would try play with the tire pressure / temp and rpm launch but you need a constant surface to measure it correctly on repeated runs.
I would forget about 1/4 time until going to a drag strip because of the stress on the gearbox and I would do only 100-200km/h times.

[IanH755]

As ours is a torque converter based Auto, rather than a DCT style one, we'll rarely get a good "off the line" time compared to the power level we have as we can't get the revs high enough at standstill with left-foot braking to get a really good launch as the torque converter stall speed is so low.

I mean 750hp AWD cars which then struggle to get below a four second 0-60 should be a big indicator that our cars aren't really meant for launching like a GTR

Here are my two attempts when i was still Stage 2 740hp/1050nm and both are fairly different, not only with 0-100kph but also 100-200kph and 1/4 mile times & speed - all measured using 10hz GPS signal, same as VBox etc -

1.92 60ft @ 30mph, 11.14 1/4mile @ 126mph but a 0-100 of 4.31 seconds



slower 2.08 60ft @ 36mph, 11.79 1/4 mile @ 126mph but a faster 0-100 of 4.00 seconds