Closed Course Top Speed

[Cartel]

[ProjectM96]

Risky taking a picture at that speed.

[Cartel]

At the time the photograph was taken, my vehicle was only mildly modified (Lacking KW V3's, AASCO LWFW, FVD Brombacher ECU Tune, RSS UDP, IPD Intake Plenum/75mm 997 TB, etc.). In my vehicle, I have reached speeds ranging from 147 MPH (as indicated via the odometer) with the top down to 172 MPH with the top up to 166 MPH with the top up and another passenger in the vehicle. 2 weeks ago I was surpassing 165 + MPH in a high speed run w/ a 996 TT and a V10 R8 on the interstates. Fun times.

[Overdrive]

Originally Posted by The Radium King

i've had my car to 150 (so said the speedo) on the highway (i know, i know ...) and the front end does get really light. i think it's (a) the third rad venting down, and (b) high presure in the wheel wells. unfortunately, no way to fix either of those easily.

I dunno TRK, I figure an AeroKit/GT3 nose and spoiler would be an easy fix...just not cheap...so if by easy you also mean cheap, then yea, still not an easy fix.

[landrovered]

Just a word to the wise...it is becoming a frequent phenomenon to have people cited for speeding and or reckless driving because they confessed to breaking the law through internet braggadocio.

This thread is specifically geared towards top speed in a legal closed course setting and not on public roads. I would hope that persons participating in this thread would both understand the importance of and only condone the strict adherence to speed limits and safe driving while on public highways.

Don't be that guy ... like the two idiots in the silver corvettes that had a drag race, a wreck, a short Youtube career and then got arrested for endangering the public.

and now back to our regularly scheduled discussion...

[The Radium King]

aerokits are certainly an improvement and would increase downforce - it would stop a lot of air from getting under the car. i was thinking more to the fact that the centre rad on the box is angled so as to vent the air down; even an aerokit can't fix that. from what i could see it is difficult to angle it up as the bumper gets in the way. you could remove the bumper, drill the bumper or space the centre rad forward, but that's all work. the only easy soln i could was was that, if you deleted your front a/c condensers and plugged the vents on the bottom of your bumper cover, then the third rad would be forced to vent out the side with the two side rads.

it's also interesting to do some reading about wheel well pressure zones; it makes sense why porsche didn't vent the side rads onto the front brakes and sent the air out to the side instead. some vents at the top of the wheel wells would do good things for the boxster.

[Overdrive]

I thought I read somewhere, possibly on here, that someone flipped the radiator's mounting and got it to vent upward out of the vents in their GT3 nose. No idea how easy/difficult/effective it is, but that may be a possibility for anyone that does go or has gone the GT3 route.

[The Radium King]

kpaz did it on his subi build, but he also removed his front bumper to give the air someplace to go, as well as some fabrication to make it work (the rad bracket and the rubber gasket that joints rad to bumper cover).

[landrovered]

The Boxzilla project had a functional top vent for the center rad that reminded me of a Ford GT40, might be some good ideas there.

[j.fro]

I've got my car modded for the center radiator inlet to vent over the hood instead of under the car. The bumper is a 996 GT3 replica, but I had done the same thing with my stock 986 cover. Moving the radiator isn't too difficult, but you do need to lengthen the hoses. On the 986 cover, I used some sheet metal behind the radiator to direct flow to the vents and over the top. On the GT3 cover, there are no holes underneath, so air has nowhere to go but through the vents in the nose.
On the highway at 70-80, the car is very stable. I've hit 100 or so during an AX (on a NASCAR track) and didn't notice and lightness to the front end. Haven't been to VIR for some real speed yet, but hopefully in the spring!

One big advantage I noticed is that the temps drop faster when you go from "in town stop and go" to highway cruising speeds.

[Pat]

I don't have much experience driving the car at very high speeds. That said, the little bit I did drive at high speeds I felt the back end get light. I didn't notice the front getting light. What have others experienced in this area? I'm a little surprised there's so much talk about the front getting light.

[986_inquiry]

Originally Posted by Pat

I don't have much experience driving the car at very high speeds. That said, the little bit I did drive at high speeds I felt the back end get light. I didn't notice the front getting light. What have others experienced in this area? I'm a little surprised there's so much talk about the front getting light.

Recently I had my stock 2.5 at 135-140mph according to speedo (which gps says is about 7% over reality) and I changed lanes on a closed course and didn't notice lightness. Only other car I've had that fast was a LT1 Caprice police car and it felt VERY light at 130 despite the car weighing 4300 lbs

[Overdrive]

He may have been referring specifically to the Boxster's hardtop.