DB4 Tub Thread

[DB4 Tim]

Very cool...it sounds like you got it whipped...BTW I know you have Dave's new/old tub...what did you have before that ...a DB4?

How many races on it ...that you could see/feel the deference in the two!

[Rick Ross]

The new tub was installed by the previous owner, Paddy O'Brien. Here are a few comments that he recently posted on the subject:

FYI, I was the guy who bought and installed the "last new DB4 tub" on the car Rick now owns. I bought the tub in 2004 and at the time Dave said he had the pieces for two more tubs but that he did not want to go through the pain of building one only to have it sit on a shelf for 8 years, like the one I bought. Dave said he would need at least $7500 to finish another. I still have my old tub and it is in better than average condition for a DB4 tub but old age has allowed the glue to dry up on the bottom aluminum section and caused delamination. The new tub totally transformed the car and instantly dropped lap times 1-2 sec per lap everywhere I went, the car actually responded to shock and spring changes!

My tub now has approximately 1500 miles on it since new. Many (most?) older DB4 tubs have some degree of delamination. This can be repaired, but lots of labor hours are involved. If a new tub is available, then replacement might be a cost effective option.

[Paddy O'Brien]

I have bad news for DB4 owners, except Rick, it is that your tub is probably shot, worn out and flexing alot more than you think. I have done an autopsy on my original tub and have had several qualified racing engineers look at it and they all came to the conclusion that Bruns never expected the tubs to last more than a couple of seasons certainly not 20. Most owners try to fix the floor by re gluing it and that helps but if that area was flexing then probably all of the rivets on the center bulkheads worked loose too as glue has long ago dried up. Basically the conclusion of the " experts" was that to fix a DB4 tub properly would require total dissasembly and reconstruction which is hundreds of man hours. I would say that even with a new DB4 tub, a panel off inspection should be done every 3-5000 miles or after an off-road. By the way, the biggest, source of damage on the DB4 tub is the dirt and water that come in at the lower front a-arm holes in the tub, all wearing the tub from inside out! On a positive note I am suprised no one has taken complete advantage of the more liberal skirt rule for the DB4, that is a huge advantage if someone were to exploit it. When I put the new tub on it totally changed the car and I believe that a DB4 with a fresh tub, maxed out skirts, serious ride height control,no wings, a hot motor, and good driver can win the Runoffs. A complete Ralt Rt41rear suspension bolts right on to a DB4 too!

[Rick Ross]

Hi Brooks,

This should probably be a new thread......but could you expand upon your comment regarding "serious" ride height control on a DB4? Also, do you have reason to believe that an RT-41 rear suspension would be an improvement on a DB4? Thanks.

[Paddy O'Brien]

Rick, A few years ago I befriended F1/Indycar aero guy who was working at the Reynard wind tunnel. He closely looked at the DB4 and then the rule book and then he went "ape sh!t" He said if I could just keep the tunnels sealed with skirts at/near ground at all times, he said I could easily increase high speed corner mph by 10-15% over my non-skirted competition. The problem is that on braking especially, front ride heights are all over the place which will make the skirts bounce around etc so you need packers or third spring/shock to control that. Flexable skirts, how do you mount the tunnels to the tub, rubber mounts maybe? etc,etc, it all just eats money and makes the car way less forgiving to drive. My friend also said that the original tunnels were excellent design but could be made more efficient by making the slope from low to high point about 15 degrees more shallow. I noticed that the Wilcox's have done that modification on thier DB4. As to the Ralt suspension, I think it is common knowledge that a Ralt has better slow corner traction than the DB4 but there are many theories as to how to improve that, the WRD diff was a step in the right direction.

[DB4 Tim]

Rick...we got our own thread...and this afternoon...I will put words to.....

[Rick Ross]

Delamination is of course not unique to DB4 tubs. It can eventually occur in any structure which uses honeycomb core construction laminates......it is just a matter of time, environment, loading, etc. I assume that internal delamination can also occur in more modern carbon tubs, such as those found in RT-41, Swift 008, etc., although I have no personal experience with these cars.

Although it was of course not necessary for my "new" tub, it is possible to repair delaminated areas in DB4 tubs. It involves either replacing entire honeycomb panels, or applying new adhesive and re-attaching the external skins to the core. I know of at least two DB4 owner/operators who have done this with good results. If anyone is considering this repair let me know and I will put you in touch with the right folks.

[Charles Warner]

http://brantleyprecisionworks.com