S650 Convertible 810HP Build - Looking for Technical Feedback

[Vidley]

I'm moving forward with an 810HP Whipple build on my S650 Premium Convertible. Most of the heavy lifting is already accounted for:

• Whipple 3.0L Stage 2 System
• Ford Performance Half Shafts
• Full Suspension/Lowering Kit

I'm specifically looking for advice or "gotchas" regarding the frame and chassis bracing for this power level on the convertible platform. My current plan is:

1. BMR 2-Point Subframe Brace
2. J&M Full-Length Jacking Rails
3. VMP High-Clearance Strut Tower Brace (to clear the Whipple while keeping the factory K-brace)

I’ve verified the factory cowl-to-tower (K-brace) is in place, but I want to hear from anyone who has run this setup. Any clearance issues with the 10-speed lines or convertible-specific bracing?

If you’ve done this build or something similar, I’d appreciate your perspective on the chassis setup or anything else I might be overlooking before it hits the shop.

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[MAT1955]

@Vidley congratulations on your choices to prepare your frame for the extra HP. As you know convertibles are more prone to torsional twisting than coupes and adding extra HP just exacerbates that. Can you also run a tower to tower strut brace - even if you have to pay to have one engineered. I would also remove the factory insulation from under the hood it needed extra clerarance.

 

[robvas]

Jacking rails do not stiffen anything

 

[Junkyard Dog]

Stage 2 ought to be more than 810 horsepower. I think it is 870. And that is as it comes. E85 and a smaller pulley and a better tune and you get some even higher numbers.

 

[MidLifeManifustang]

Do you have a link for that VMP brace? The only one I can find seems to suggest quite strongly that it’s purely intended to be cosmetic.

 

[Billycar11]

Do you have a link for that VMP brace? The only one I can find seems to suggest quite strongly that it’s purely intended to be cosmetic.

the vmp brace is a floppy pos look here

 

[Vidley]

https://www.americanmuscle.com/vmp-...ower-brace-matte-carbon-fiber-vmp-drs011.html

 

[Vidley]

Manual pressure on a parked car does not measure a component's structural integrity. This brace is a dynamic tension member engineered from Pre-Preg Carbon Fiber, a material valued for its ability to flex under load without losing its shape or strength. It is designed to resist thousands of pounds of lateral force to prevent chassis fatigue and maintain alignment—functions that cannot be evaluated by pushing on it in a driveway

 

[Billycar11]

Manual pressure on a parked car does not measure a component's structural integrity. This brace is a dynamic tension member engineered from Pre-Preg Carbon Fiber, a material valued for its ability to flex under load without losing its shape or strength. It is designed to resist thousands of pounds of lateral force to prevent chassis fatigue and maintain alignment—functions that cannot be evaluated by pushing on it in a driveway

you believe what you want but i believe its not structural

 

[Vidley]

I’m no spokesman for the product—honestly, I didn't even want to spend the $400—but after my research, it was the best move to protect the car. A factory brace is physically impossible with the 3.0L Whipple, and I'm not comfortable leaving the towers un-braced while pushing 810 hp. It’s the most logical way I found to prevent 'tower lean' without sacrificing power, but do you have a better solution or can you recommend one?

 

[Billycar11]

I’m no spokesman for the product—honestly, I didn't even want to spend the $400—but after my research, it was the best move to protect the car. A factory brace is physically impossible with the 3.0L Whipple, and I'm not comfortable leaving the towers un-braced while pushing 810 hp. It’s the most logical way I found to prevent 'tower lean' without sacrificing power, but do you have a better solution or can you recommend one?

i leave mine on with just the rear cross brace
if you get a new higher clearance hood you can put the one from the dark horse sc or gt500

 

[Vidley]

For anyone on the fence: there is absolutely nothing like it—the experience is almost indescribable. I could have bought a performance model out of the gate, but I wanted the convertible and wouldn't settle.

The rumors that you have to rebuild the entire structure are incorrect. Most speed shops will quote you in the high $20k or even high $30k range, but by working with a Ford Performance certified shop at my dealership, the costs were much more reasonable. Including the mandatory (in my opinion) 1-inch drop, the structural changes I expected to cost $5,000+ ended up being around $1,000, and my total build cost was around $17k. I kept my 60,000-mile drivetrain warranty and even the extended warranty coverage.

Ford has spent countless resources engineering this chassis to handle this power. Unless you’re building a race car, it’s not as complicated as people make it out to be. Talk to the Ford Performance team and follow their lead. This build is possible, it is solid, and the result is incredible.

 

[robvas]

You kept a 60k warranty and extended warranty with the Whipple? How so? The Whipple/FP included warranty is 3/36

Also it doesn't matter how much HP you make it isn't going to affect the strut towers

 

[Vidley]

The 60k warranty on the drivetrain stayed in place, the extended warranty to cover the rest of the car did as well, but the SC itself has a 36k warranty.

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