Do you run with the front arch liners removed? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Kroggers · 02-06-2012, 04:31 AM

I am permanently looking to reduce weight and improve the Boxster racing car.

I recently removed the rear arch liners on the car, as I was having rubbing problems, and I did not see a reason to retain them on a racing car. To ensure I do not get a build up of air and additional drag behind the rear bumper with the liners removed, I opened up the rear bumper - giving clear air flow. I also hope this will help a bit with cooling

But I have now started to look at the front liners and I am wondering if I can also remove these, and if it will give any benefit to do so?

I will be removing the head-lights and replacing them with fiberglass covers, so I do not need the liners to protect the rear of the lights - but what else will I put in danger by removing the liners?

kabel · 02-06-2012, 06:38 AM

having not removed the inner fender lines of the boxster I don't know what is behind them... On my M Coupe I have modified my inner fender liners rather than completely remove them. I still drive mine on the street and occasionally when it rains so I only kept the sections of fender liner that help reduce the amount of dirt & water getting in places I don't really want it.

Kroggers · 02-06-2012, 07:13 AM

Thank you kabel, do you have any more details on what sections you have removed on the M?

I am considering removing the rear half, but then I will also have to create some way to the air that enters into the fender to be able to vent out - And as such maybe a vent just in front of the doors on each fender.

As this is a dedicated racing car, I do not see the need for the liners - unless they give advantage to performance (like reduce drag), or to protect something that would get easily damaged if they are removed, like the radiators...

Topless · 02-06-2012, 08:46 AM

Hi Kroggers,

This topic was discussed a while back on the Boxster Spec racing site. I don't remember all the details but as I recall the risk vs reward was pretty high. All sorts of vulnerable bits are up under the fender wells that could be damaged by 100mph rocks and track debri flinging around in there. The thought is that you cannot win if you don't finish. Also there are many nooks and crannies that will collect sand and rocks over time resulting in a potentially heavier car without the fender wells than with them. This was the general feeling of guys who had been racing these cars for 5 years or more. YMMV

I hope you find this useful.

trygve · 02-06-2012, 09:16 AM

I don't plan to remove them. The front side shields the radiators (unless you leave the fans and shrouds in place, which presumably you aren't; and so removing the liner will radically alter the radiator air flow exit by dumping the air on the leading face of the tire). The rear side on the right protects the fuel filler tube and fuel emissions canister. The rear side on the left protects the washer fluid bottle if you still have it.

Kroggers · 02-06-2012, 09:55 AM

Some good info here, thank you all...

@trygve. My thought was to remove the rear part of the liners only. I do not have anything at the rear of the fenders any more. The carbon canister stuff is gone from the one side and the washer bottle is removed on the other side

It was the radiators I was most worried about....

Your statement about the cooling fans has me thinking though. I have not removed them on my car - is it normal to remove these on racing cars?

Topless · 02-06-2012, 11:23 AM

Yep, pull the fans. They work well sitting in daily stop n go traffic but pretty useless on the race course.

Kroggers · 02-06-2012, 11:48 AM

Quote:

Originally Posted by Topless

Yep, pull the fans. They work well sitting in daily stop n go traffic but pretty useless on the race course.

Cool, then I will remove them

trygve · 02-06-2012, 12:43 PM

Yep, the advice and info I was given:
1. The fans are there to kick on when you are stuck in traffic with no airflow.
2. On track, the (non-moving, idle) fans may be counterproductive because they impede clean airflow!
3. You obviously want to lose the weight. (*)

(*) Depends on what you are aiming for and what other weight loss you have achieved. As a "garage build" Spec Boxster, my car will probably struggle to get down to minimum legal weight. So the fans should come out for sure. However, I am leaving the passenger side fan in for two reasons: A) If I drive the car to the track or to the shop, having it there for situation (1) above is good for peace of mind. B) If I do get down to minimum weight, it was suggested by one expert that the fan's weight low on the right side of the car may be useful, because the driver's weight tends to make the left side of the car heavier. On the other hand, one person advised me that the car will overheat on track if either fan is there to block the clean airflow; however, many of us can attest that that's not a problem we've encountered.

Kroggers · 02-07-2012, 04:32 AM

Based on what you have been told trygve, I will seek to remove both on my car then. The car is a 100% dedicated racing car and can not be used on the road or in traffic - so do not have to worry about that

The Radium King · 02-07-2012, 08:29 AM

Do some research on wheel well pressure areas. Pressure tends to build up at the top of the wheel well and cause front end lift. This is why the boxster rads are vented out the side instead of directly back into the wheels. You may wish to consider maintaining this, or at least vent the top of your fenders and turn that lift into down force.

Kroggers · 02-07-2012, 08:38 AM

Quote:

Originally Posted by The Radium King

Do some research on wheel well pressure areas. Pressure tends to build up at the top of the wheel well and cause front end lift. This is why the boxster rads are vented out the side instead of directly back into the wheels. You may wish to consider maintaining this, or at least vent the top of your fenders and turn that lift into down force.

Good info, thank you...

MaxD · 02-08-2012, 02:22 PM

Actually the radiators vent down on both the 996 and the 986. Cup cars vent differently.

Anyway leave the liners and ditch the fans.

LAP1DOUG · 02-08-2012, 06:11 PM

Yeah, my Lola race car had no fans, but you could not start the engine until well after the 5 minute warning or you would overheat. Your results in Suomi could be different.

The Radium King · 02-08-2012, 07:20 PM

"Actually the radiators vent down on both the 996 and the 986. Cup cars vent differently."

actually, unless your car is different than mine, the outflow from the rads is diverted from traveling under the car and sent out to the sides in front of the front wheels.

Kroggers · 02-08-2012, 08:30 PM

Quote:

Originally Posted by LAP1DOUG

Yeah, my Lola race car had no fans, but you could not start the engine until well after the 5 minute warning or you would overheat. Your results in Suomi could be different.

That is something to consider - once you have started the car, driven slowly threw from the paddock to the grid and been siting there for several minutes with the engine running. Will it start to over heat if there is no fans there?

LAP1DOUG · 02-09-2012, 06:06 PM

Quote:

Originally Posted by Kroggers

That is something to consider - once you have started the car, driven slowly threw from the paddock to the grid and been siting there for several minutes with the engine running. Will it start to over heat if there is no fans there?

No doubt - in the middle of the Summer if your engine is at normal operating temperature, and you sit for several minutes with no airflow, your engine is liable to start puking water / water wetter.

However, if you plan ahead, and get the engine just a bit warm and shut it off when you first get to grid, you will be OK. Then just start it up again when you get the 1 minute warning.

Good luck.

Kroggers · 02-09-2012, 08:40 PM

Quote:

Originally Posted by LAP1DOUG

No doubt - in the middle of the Summer if your engine is at normal operating temperature, and you sit for several minutes with no airflow, your engine is liable to start puking water / water wetter.

However, if you plan ahead, and get the engine just a bit warm and shut it off when you first get to grid, you will be OK. Then just start it up again when you get the 1 minute warning.

Good luck.

Or I could go half-way and just remove one fan - maybe as has already been suggested, to remove the one on the driver side only?

Brad Roberts · 02-09-2012, 10:10 PM

Ditch the fans. Leave the liners in place unless you plan to buy the two piece GT3 liners which BLOCK off the bottom air exit and direct it in next to the body.

We took a new to the track car out this past weekend.. it beat the backside of the radiators up in NO time (with no inner fenderwell liners) ... on Nitto NT01's!!! (would have been much worse with a slick)

Do not worry about grid. NO PORSCHE CUP CAR OR RSR shipped with fans

The second you start moving the temps will drop drastically (even moving through the pits)

Last time I checked

You don't get 100 degree+ days in Finland very often

B

Kroggers · 02-09-2012, 11:05 PM

If I had the cash, there would be a lot of nice GT3 Cup/RSR stuff that I would like to put on my car - but reality sucks at times, and I will just have to dream about it

I will keep the liners and remove the fans.

Can the fans be removed with the radiators in the car, or do I have to drain the coolant and remove the radiators to get the fans off?