16 replies to this topic

[Thorney]

FAO Ricky, was having a long three way chat with Vauxhall, and Guy from Nitron about undertrays. When I mentioned you'd removed yours and left it off both looked horrified. Guy is a seasoned race car chassis designer and has spent literally thousands of hours in wind tunnels and said the removal of the tray for use could have dramatic affects. Vauxhall agreed by saying removal of the understay could have dramatic effect on stability. When I mentioned you'd had no problems they both said that it was simply a matter of luck and really really really recomended you put it back on immediately. I know you want to remove weight but Guy was very clear in saying that the understray was integral to the cars stability and its removal would/could have dramatic effect.

[Steve Crisp]

No disagreement Thorney, but just a comment that all of Palmer Sport's fleet have had there undertrays removed.

[Thorney]

Oh well, life is all about opinions I guess......I'd have felt bad if I didn't at least pass it on.

[Ricky2772]

...tell'em I also removed the (6,7kg) trunk lid..... ...will replace it with a fiberglass sheet tho'....

Edited by Ricky2772, 03 August 2003 - 09:08 PM.

[R1 nur]

No disagreement Thorney, but just a comment that all of Palmer Sport's fleet have had there undertrays removed.

How fast do the Palmersport cars go though? Aerodynamics really kick in at high speed. Excuse my in depth analysis there.

Ricky, IMO with experts giving warnings like this AND pushing your car regularly at high speed, particularly at the Ring, I would reccomend following their advice. Is that second or five a lap worth the risk?

BTW I had numerous friends tell me to put a steering damper on my R1. I ignored them all because I did not have the dosh at the time. A huge tank slapper and a very scary no brakes moment made me realise my friends were right.

Not everyones advice is worth taking but stuff like this is worth listening to IMO.

[earlystock]

I saw 120mph on the palmersport VXT, felt OK, also took a very fast left hander at more than 100mph, no issues.

[waverunner]

No disagreement Thorney, but just a comment that all of Palmer Sport's fleet have had there undertrays removed.

Steve's right. Palmersport told me they removed the undertrays on their NAs. They said it was to assist with cooling because the cars were getting too hot with them. They said they were going to do the same with the turbos because if the NAs were getting very hot the turbos would be getting very VERY hot.

I also agree that removing them will feck up the aerodynamics and cause stability problems at higher speeds.

Not quite sure how Palmersport square the circle on this one. Anyone here booked on a Plamersport day soon who could ask a few questions?

[Thorney]

I'm there next week, will certainly ask.

[Dave T-S]

Vauxhall agreed by saying removal of the understay could have dramatic effect on stability

just a comment that all of Palmer Sport's fleet have had there undertrays removed

From personal experience, the PalmerSport cars are very nervous - lost count of how many times I spun in the wet

[jneill]

I'm still waiting for my Palmersport Day (3rd Sept) so I have no personal experience but isn't their track very safe with lots of run-offs so it doesn't matter so much if the aerodynamics aren't so effective. But it could be a much bigger issue on a less safe track like the 'ring. James

[Ricky2772]

here is how I see the undertray deal... during a hot track-day, I experienced gear cables failure due to build-up heat ....not funny, track day wasted and 800 euros worth of damage (still under warranty, phew... ) for such reason now the untertrays are gone...and, added bonus, -6kg I have tried several tracks at several speeds, and stability was not affected to any noticeable degree....still able to corner at 180kmh with the rear feeling rock-solid....how can that be, w/out those two all-important aero-trays absent? well, my car is way lower now, so less air going under it....the front splitters further enhance the front-downforce. so, even with the 2 trays removed, the car still has a flat bottom up to door-handle length....so air still flows smoothly under the car, getting compressed in the process , than reach the point where the trays are no more, finds more room, and expands, causing the back-end to be sucked down, that is, downforce is created. w/out the trays, the active downforce will probably be higher by the engine area, rather than at the tailpipes.... sure, some turbulence will ensue, but imo you will need speed well in excess of 200kmh to make it a problem.... also my car is much lighter, so less poundage is there to be centrifugated out of corners...(backbox+kat+rear OZ alone are -17kg hanging behind....) will practice more at the ring during the 15-22 august stay.... if needed, I might change something camber or toe-wise to further enhance stability at speed....

Edited by Ricky2772, 04 August 2003 - 09:53 AM.

[Thorney]

Just passing the info on mate, assumed that would be your response but when someone who does this for a living said it could be dangerous I'd be a git if I didn't let you know.

[Ricky2772]

Just passing the info on mate, assumed that would be your response but when someone who does this for a living said it could be dangerous I'd be a git if I didn't let you know.

those kinda of infos are much appreciated, always...

[Marco Polo]

Anyway, many car used on track days have no undertray (like my former MX-5 )...

[R1 nur]

Anyway, many car used on track days have no undertray (like my former MX-5 )...

Yes but the VX is Aerodynamically designed to have one.

[R1 nur]

When I mentioned you'd had no problems they both said that it was simply a matter of luck and really really really recomended you put it back on immediately.

Key point here....

[Ricky2772]

allright, allright, I'll make a partial replacement with a lexan sheet... today I cut the trunk lid, (1 kg) tomorrow I'll do the middle bottom tray....