Can homebuilt be faster than factory-built? | Factory Five 818 vs. Porsche Boxster S

Tom Suddard said:

BA5 said:

This is a pretty interesting article.  I'd be curious to hear from the GRM guys who did the test: did you feel like the 818 was appropriately faster than the Porsche given being 1000 lbs lighter?  

I feel like the 2-2.5 sec/lap faster times are right on that edge of "that's an eternity in lap times on a track" and "huh, I thought it'd be faster.  I mean, it's 1000 lbs."

Did you feel like something about the 'home builted-ness' was holding it back?

You hit the nail on the head. While our 818 was fun, honestly we never really put the time in to fix some of its inherent evilness. It was a handful.

The Boxster is an amazing, perfectly sorted driving machine. The sort of thing that happens when a bunch of Porsche engineers spend years tuning a chassis. 

The 818 is, well, a kit car. Infinite adjustability and no production car constraints means you can do a lot to improve the driving experience. But it also means you have to do a lot to improve the driving experience, and we focused that project more on the building than the sorting. 

To get an idea of what I'm talking about, check out my article on prepping the 350Z's chassis. This amount of skill/time/effort would have paid dividends with the 818. 

That takes me back to a kit car comparo you did a bunch of years ago. Correct me if I'm wrong, but I think that Keith's Locost beat an Ariel Atom and another car that should be faster on paper. The difference was that Keith's car was much more dialed in. It was the beneficiary of development that the other two cars weren't.

All the experienced guys here understand the importance of prep and tuning. I'd bet that a good deal more time could have been extracted from the 818 under the proper care. 

A follow-up with a prepped 818 coupe and perhaps a Cayman S would be very interesting. 

Reply to BA5 and DaleCarter:

If you look at laps 2-5, my Boxster S laps were all about the same, but in the 818 I was getting a lot quicker with each additional lap. Gaining familiarity, exploring the limits. I think the comparison would be more dramatic after four or five more laps.

"All the experienced guys here understand the importance of prep and tuning. I'd bet that a good deal more time could have been extracted from the 818 under the proper care."

Feels like another win for mundane details, fanatical preparation, and checklists. Competitions (business, sports, dating, etc.) are sometimes won and lost on incredibly small margins and the little stuff compounds. 

I would think building a car for a few fast laps on the track is relatively cheap & easy.  Making it run all day is more difficult  - cooling issues can be difficult to solve depending on the constraints imposed by the body shape.  Building a car for daily use (specifically, one a normal person would voluntarily want to drive) is much, much more difficult. 

The nice thing about a Porsche is it can run all day at the track and be loads of fun & reasonably fast, and then one can take a 1600 mile road trip three days later and it's the car you actually want to drive.  And depending on the model (G 911 perhaps) and age of the kids, it can make a dinner outing and a small trip to Costco with a family of four in it.

I have a kit car, probably on par with a stock GT4 Cayman track-wise.  Similar power to weight, similar grip.  It's a blast on track, and it is driven to & from the track, though it isn't especially pleasant on good days and quite miserable on bad ones (not Super7 miserable, but still miserable).  Also it's difficult for ingress & egress, especially for us over 50 folks.  It took many dollars and hours to get it so it can run 30+ minute sessions in reasonable weather without overheating.  And, while the base 'kit' (aka roller sans drivetrain) was cheaper than a GT4, air cooled engines have gotten shockingly expensive.  By the time it was self propelled and I was happy with it a GT4 would have been considerably less money.  Had I known what I was getting into ahead of time, I'd have run the other way.  Still, sorting it has been (often type 2) fun, and it scratches an itch a GT4 would not.

There is a fellow on the Pelicanparts forum (plavan) who tried to properly sort & track an 818, and he came to the conclusion that it was more cost effective to buy a used Cayman.

burgermeister said:

I would think building a car for a few fast laps on the track is relatively cheap & easy.  Making it run all day is more difficult  - cooling issues can be difficult to solve depending on the constraints imposed by the body shape.  Building a car for daily use (specifically, one a normal person would voluntarily want to drive) is much, much more difficult. 

The nice thing about a Porsche is it can run all day at the track and be loads of fun & reasonably fast, and then one can take a 1600 mile road trip three days later and it's the car you actually want to drive.  And depending on the model (G 911 perhaps) and age of the kids, it can make a dinner outing and a small trip to Costco with a family of four in it.

I have a kit car, probably on par with a stock GT4 Cayman track-wise.  Similar power to weight, similar grip.  It's a blast on track, and it is driven to & from the track, though it isn't especially pleasant on good days and quite miserable on bad ones (not Super7 miserable, but still miserable).  Also it's difficult for ingress & egress, especially for us over 50 folks.  It took many dollars and hours to get it so it can run 30+ minute sessions in reasonable weather without overheating.  And, while the base 'kit' (aka roller sans drivetrain) was cheaper than a GT4, air cooled engines have gotten shockingly expensive.  By the time it was self propelled and I was happy with it a GT4 would have been considerably less money.  Had I known what I was getting into ahead of time, I'd have run the other way.  Still, sorting it has been (often type 2) fun, and it scratches an itch a GT4 would not.

There is a fellow on the Pelicanparts forum (plavan) who tried to properly sort & track an 818, and he came to the conclusion that it was more cost effective to buy a used Cayman.

That's valuable insight 

Zooming out a bit - or a lot:

Things have changed in the 40 years I've been in the shallow end of performance cars. Back in the late 1980's, you could buy a used Datsun cheap, add performance parts right out of their catalog, and end up with a still-affordable car that could beat much more expensive cars on-track. Fast forward to now (or even 15 years ago), and when you show up at the same track with your same modified Datsun, you're facing an entirely different competition. No longer are the majority of the cars old beat up models, modified by the owners themselves. Now, a young man goes to the dealer and buys an STi, Miata, Honda Civic R, Corvette, or any number of Porsches, and they're faster than your "fast" car ever was. The technology has changed and times have moved on. Straight out of the box, many OEM sports cars are far more dialed in than 20 years ago. It's become more and more difficult for a kit car maker to be guaranteed faster just by essentially removing every luxury/safety feature out of a chassis to reduce weight, putting a drivetrain in a tube frame chassis, and counting on the resulting power to weight to be an automatic win on the track. Suspension design is a really involved and complex task to get really right, and as was said, it's rare for a single individual to come up with something that beats Porsche's 50-year suspension development and refinement.