longboarder

Head to head in very hot conditions with a headwind, the 720S is fast but not nearly fast enough.


991.1 mods:


GIAC tune
Champion/Tial 68's (stock housing)
Champion Intercoolers
Champion Exhaust
Champion diverters
Meth
Rear R888's


720S mods:


catless exhaust
BBI tune
R888's


Cheers.

Jean

That's very fast Funny to see it almost doing a wheelie.

Without methanol and these mods I doubt the 720S can be beaten. I have a hard time catching a 650S on the racetrack straightline, Any runs without meth?

QueueCumber

Fast but not nearly fast enough?

I'm not a big McLaren fan, but it's hardly a fair bolt-on comparison with one bolt on part versus five.

Big Swole

Not a McLaren fan either.


Highly modded Turbo S any day, would my choice.

longboarder

Sorry no runs without meth. I would think the MPH would be very close if I turned meth off.


In a head to head race even without meth a modded 991 is likely to get a fairly large lead from the launch.


Overall the 720 is an amazing car from the factory and looks like nothing except the hypercars (Chiron, 918, LaFerrari, Huayra, P1) can replicate or beat it's acceleration figures. Obviously our 991 stock can't touch it, however with some bolt-ons we certainly can.

pepinozaur

720s with tune and exhaust should be almost P1 crazy fast, maybe close to 900hp and 1400kg... I guess we need Garretts at least to compete with them, no room for tweaked VTGs and bolt-ons imo, maybe that 720s was stock, or I want Champions to set-up my next 991

longboarder

Sorry I should have been more clear - the tune, according to BBI, was just to code out the CEL from the catless exhaust. So boost and timing were not messed with.


Although we know that one of the best mods for the 650S is decat as well. So that's really all that was done to the 720S, to unlock a little more power from lower EGTs.


I think the 720S and predecessor 650 and 616's struggle in hot temperatures because they use an air to water intercooler. On a cold day watch out, I'm sure the 720S could match the GIAC/Champion 991 traps.

pepinozaur

thanks for the info, makes sense now

keep up the good work, I ma following you from 6speed 997 section

Nanook

Nice to see no hidden agendas...tellin it as it is...kudos

longboarder

Thx brother. The 720S is phenomenal yes but a speed freak may see a choice in saving $150k by instead getting a Turbo S and doing some bolt-ons. Cars like yours and mine that are very reliable and crazy fast are proof!

Jean

Adam,

The air to water intercooler is actually THE way to go to reduce temperatures in the turbo system, So on a cold day you would have had more advantage.

In practice, with a similar package than yours (less meth) and 95F ambient, I had a tough time catching a 650S up to 165mph on the racetrack after 2-3 laps in time attack mode, IATs reaching almost 200F. While tuners each has their own little tweaks adjusting timing and boost at different load levels, same hardware and COBB will yield very similar results, a few hp here and there.

On a 1/2 mile straight run, you will not experience this level of heat in the system, but the Mc Laren certainly has an edge when it comes to managing EGTs and IATs under high loads due to its air-water IC.

Typical modified 991 turbos with race fuel and no methanol, run 135-136mph in the quarter on the road, and ~165mph in the 1/2 mile in similar hot temperatures, so the meth does make a big difference of almost 10mph trap.

According to mag tests the 720S does 167mph in the 1/2mile in stock mode and 0-300 in 19s with 98 pump fuel, I doubt there is any "non-meth" modified VTG 991turbo doing near that without race fuel or meth, or both.

You had very strong results at those ambient temps, which speaks highly of your tune, I am just saying the Mc Laren is an engineering marvel, after chasing a stock one on the racetrack for few laps, I understand that much better, our VTGs are the limiting factor.

longboarder

Hi Jean thx for the comments always appreciate your input.

In certain scenarios I agree the water intercooler is terrific. On a race circuit there is constant airflow to the radiators to cool the water. I had an air to water system and increased its thermal capacity with some modifications including a larger 5 gallon reservoir and made a big difference in the system's ability to manage heat.

The Mac system also incorporates fans to assist the radiators when there is no airflow, however are limited. I observed this first hand because it was subject to significant testing by a friend who used to race their 650S at the Shift Sector 1/2 mile events. This car (interestingly owned by Armik Akaghani and driven by his now 13-year old son Steven) required big industrial fans pointed toward the water radiators in between races, in order to cool down the water. Otherwise simply letting the car sit at idle or just turning the car off after a 1/2 mile run on a warm day) would not on its own be sufficient to cool the water. See, when the car is just sitting at idle on a hot tarmac for 10-20 minutes waiting to race down the airstrip, the stock Mac system is not very efficient at removing heat from the water.

And that's the conditions at these airstrip events. So perhaps on a cooler day and/or when the 720S doesn't have to sit at idle 10-20 minutes between races, the water will be cooler and therefore IATs lower.

Also wanted to point out that when DragTimes tested their 720S they achieved a 175 1/2 mile vbox speed. You mentioned other testing at 167. And the 720S decat that showed up at Shift Sector went 166-171 from my observations. So there is significant variation here and just my theory but I think it has a lot to do with the water intercooler not being efficient when the car is sitting foe long periods of time between 1/2 mile races.