Diablo Roadster Engine Decklid Warping

I wrote up a post of Diablo Roadster engine decklid warping for the lpower site and it looks like it was lost in the crash.

I also saw someone else mention the issue here so I figured I'd post what I wrote up before. I had a lot of data of temperature in the engine compartment and newton force of the struts.

Some people who buy Roadsters notice that the decklid over the engine seems to be warped. It doesn't sit on the gaskets that are below it.

The first thing to know is that.. the decklid isn't supposed to sit on those gaskets. It is supposed to ride high for engine venting.

You can see this because the rubber thing with the holes that you slide the hood into.. it has rubber under it that creates a space between the decklid and the gasket below.

That is the spacing that is supposed to be between the decklid and the gasket. It is not supposed to lie on it.

Now, there have been cases of actual warping. The reason for the warping is high newton force decklid lift supports under high temperature (engine running hot for a long time).

This is only a problem with the roadster because the lift supports are so small (short and also small around). Other Lambos have longer supports and they are placed differently. The Roadster ones need high force because they are near the front and short.

Since the lift supports are gas, when the gas gets hot, the pressure (newton force) increases.

To make a long story short, the first thing I did after reading about the possible warping was pull the lift supports out of my car. It is pretty easy.

That becomes a pain, though, because then you have to prop the hood whenever you need to look around (show people the engine usually).

Then I put a thermometer in the engine compartment tied in the lift support area to determine what temperate they get to and drove around getting different temp readings.

And then I talked with two different people at two different lift support companies to come up with a solution and did the calculations to determine what newton force the lift supports were going to under high temperature.

The stock supports are 510N. Here are the calculations. The first column is degrees celsius, the second is at 510N, the third is at 400N and the fourth is at 360N

21 510 400 360
31 526.83 413.2 371.88
41 544.2154 426.8356 384.152
51 562.1745 440.9212 396.8291
61 580.7263 455.4716 409.9244
71 599.8902 470.5021 423.4519
81 619.6866 486.0287 437.4258
91 640.1363 502.0677 451.8609
101 661.2608 518.6359 466.7723
111 683.0824 535.7509 482.1758
121 705.6241 553.4306 498.0876
131 728.9097 571.6939 514.5245

After calculating that, I ordered some lower force lift supports. I ordered a couple different pairs with different forces to figure out what would work best.

One thing you will notice is that the left lift support is much closer to the engine so it gets hotter. That is also the side that tends to show actual warping in some cars. The right is usually fine.

So, I ended up putting an even lower force lift support on the left side.

I ended up ordering one 360N and one 400N. 360N for the left. That keeps the decklid up and shouldn't warp anything because from the calculations above, you can see that even at 131 degrees celsius 360N will have the same force as the stock ones at 21 degrees celsius.

When you pop the decklid, it pops up a bit and then you lift it into position and it stays there. Probably won't keep the decklid up with the roof on but I don't drive it like that anyway.

The part numbers I ordered were:

W5W5B50-087-258/360N
W5W5B50-087-256/400N

from www.easyliftsprings.com

The removal/installation is easy enough that you can do it yourself. Just go slow moving the carbon fiber side pieces out.

The stock 510N are strong. If you pull one out, try and press it down yourself. Damn near impossible.

After replacing them, I never had a problem and I didn't worry about it any more.