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Found a good strake replacement

3305 Views 46 Replies 15 Participants Last post by  jakermc
I successfully made some new underside strakes that won't break, from a very durable plastic that is heat formable. I can make to order if you need a set. Price TBD, don't know if any need from owners. I also hear 650 strakes are similar problem, any others (if interest, send me hole pattern template)?
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Is there any point in fitting these to a 570, or do they need the other aero tweaks to be effective?
Yes the strakes are surprisingly effective alone in increasing front down force and reducing drag. They do this by shedding vortices, which efficiently accelerate and constrain underbody air flow towards the rear diffuser tunnels.
Ok, count me in for a set.
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You will need to measure and template your 570's front strake hole positions. I am not sure it will be the same as the 12C & 650 - which is what Rory has made.
I'm thinking it may not have them. Where are they located on the 12C?
Inboard and slightly behind the front wheel wells.

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Inboard and slightly behind the front wheel wells.

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Thanks for that, I shall get my head under there and see if the mounting points are present. I was thinking they mounted under the frunk rather than directly onto the tub where I'm not willing to drill holes.
Here is the underbody of my 650S with the MSO diffuser, you can see the positions of the air guides. Hope it helps a little.

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Thank you, those shots are very helpful. It has them at both the front and rear?
Yes, the first two pictures (after the picture of the rear) show the positions at the front, the last four pictures show the positions at the rear. In total, the car has four such air deflectors on the underbody.
Thanks. My concern about just fitting front strakes is upsetting the aero balance at high speed, although I doubt it would induce rear lift. I really don't like spoilers, and they're not easy to fit anyway on mine, and presumably a spoiler would shift the handling bias rearward anyway, which is the problem I'm trying to solve.
To be honest, I wouldn't change anything on your car. The risk of creating a wrong result with negative effects is high. I have attached the pictures of the air deflectors of my 720S below. As you can see, the 720S already has a completely different solution than its predecessor. The 720S has four deflectors at the front (two on each side) and two very small air deflectors at the rear in front of the diffuser. This tells me that these solutions have been very specifically tuned for a particular car.
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No doubt they have, but anything that removes air more rapidly from underneath is going to reduce air pressure in that area, and the alternative is to adjust in a lot of negative camber, which also has undesirable side effects. The 720 I drove on track had a completely different handling bias to mine, but I don't know whether it's because of those strakes, or because McLaren tweak out the understeer on their track cars.
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It's because the 720 is nowhere near anything the same car as a 570.
Please explain in terms of the handling balance.
Primarily it is the PCC system that the Super Series have that the Sport Series doesn't. The strakes in this discussion are for airflow control under the car, primarily for downforce (controlling how it flows under the car and how smoothly/quickly it reaches the Diffuser).
Right, PCC for damping, strakes and other aero devices for downforce. I can't see how adding strakes to the sport series wouldn't help with reducing front end lift.
The splitter is the primary for that with the front openings as secondary. The strakes don't provide any downforce, they simply "control" the airflow to keep it out of areas (brakes/wheels/wheel wells) that would ruin/decrease the downforce that everything else including the underside pans etc are producing....

I guess it could help but it makes me wonder why McLaren didn't put them on...
They do more than that, they direct air from the underbody out to the sides, increasing the speed of the airflow and reducing pressure, thereby providing downforce, which translates to less understeer. In the 650S underbody shots that @Iron5 posted, the front strakes are directing air outboard behind the front wheels.
Nah, it's more to allow the "main" airflow (down the center of the car) to be less turbulent and flow more cleanly to the diffuser... The strakes take the turbulent air at the corners by the wheels and direct it back behind them out of the main center flow....
Same effect. If you're cleaning up the airflow, you're making it faster.
Not denying that, but as far as ADDING downforce in and of themselves, I don't see the strakes doing that... It's more of not ruining what you already have created....
Same difference! Lower pressure under the car means higher downforce because you're increasing the pressure differential. It's like having a diffuser for the front wheels.
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