Sebring Time Trial Video 10/02/2011, NASA TTC Class 2:34.8 Options

[Jeff94TA]

This is my first track video with the new to me Drift HD170 camera. This was a new personal best of 2:34.8 and still only good enough for third in class but that was behind a couple of really talented friends that I have no problem losing to. This is the first wide angle camera I've run and the first time I've had good footage of the inside of the car. One thing that really struck me was the amount of flex my Corbeau FX1 Pro goes through. Keep any eye on the right winglet in the turns! (IMG:http://www.frrax.com/rrforum/style_emoticons/default/blink.gif) I picked up an I/O Port seat brace and will be installing it before the next event.

Sebring Video Oct. 2, 2011

[Steve91T]

This is my first track video with the new to me Drift HD170 camera. This was a new personal best of 2:34.8 and still only good enough for third in class but that was behind a couple of really talented friends that I have no problem losing to. This is the first wide angle camera I've run and the first time I've had good footage of the inside of the car. One thing that really struck me was the amount of flex my Corbeau FX1 Pro goes through. Keep any eye on the right winglet in the turns! (IMG:http://www.frrax.com/rrforum/style_emoticons/default/blink.gif) I picked up an I/O Port seat brace and will be installing it before the next event.

Sebring Video Oct. 2, 2011

I can't believe how much that seat moved. I've got the same seat and while I know they are flexing, I didn't think it would be that much. How are they mounted? Mine are bolted directly to the floor, no slider. I wonder if that helps at all.

Great video!

[Jeff94TA]

I can't believe how much that seat moved. I've got the same seat and while I know they are flexing, I didn't think it would be that much. How are they mounted? Mine are bolted directly to the floor, no slider. I wonder if that helps at all.

Mine is bottom mounted on two individual single sliders. I can see where side mounting it with a solid connection would probably help some but that fiberglass shell is so flexible I know there will always be flex. I was just surprised at how much.

I'm plumbing in a catch can system and relocating the battery at the moment so when I finish that up I'll install the new seat brace. There is only the one mounting screw that comes with the seat and I'm afraid to drill the fiberglass to mount the brace more securely so it may not help much. NASA is running Homestead on Nov 5th & 6th but I need to evaluate my budget to see if I can justify it or not. I want to go of course and compare video after the brace install.

[Blainefab]

There is only the one mounting screw that comes with the seat and I'm afraid to drill the fiberglass to mount the brace more securely so it may not help much.

There's the catch-22 with this seat and brace: The addition of a single hole for a back brace was an afterthought on Corbeau's part, and of course drilling more holes in the fiberglass shell is not recommended.

The IOPort brace was designed for aluminum seats and is supposed to be bolted with 2 bolts to the back of the seat.

So this combination cannot be mounted without violating at least one of the mfr usage requirements.

[Jeff94TA]

So this combination cannot be mounted without violating at least one of the mfr usage requirements.

I'd like to say I wasn't aware of that but I did understand before I ordered the brace. Do you think I'm being unsafe? I respect your opinion very much and if I'm being foolish then I'll shelf the brace until I get a real seat for the car.

[Blainefab]

So this combination cannot be mounted without violating at least one of the mfr usage requirements.

I'd like to say I wasn't aware of that but I did understand before I ordered the brace. Do you think I'm being unsafe? I respect your opinion very much and if I'm being foolish then I'll shelf the brace until I get a real seat for the car.

I think you WERE being unsafe - with the amount of movement of the seat, its ability to protect you in a wreck was compromised. You recognized that and took steps to fix it - I would not call you foolish for your selection, that is what has been made popularly available from an industry that doesn't really care about anything but selling parts.

Those parts have been sold for at least 10, maybe 15 years, virtually unchanged. The Corbeau seat was not designed to go in a race car, and the IOPort back brace was not designed to go on a fiberglass seat.

In the last few years, club racing recognized the need for sturdier seat mounting, and an easy solution has been to adopt the back brace. Some rules simply say 'back brace required'. Rulebooks can't tell us how to build a safe car, just set minimum standards, and in general, require that equipment be installed per the mfr's instructions.

A better solution is to mount the seat such that the mounting area does not flex. Bottom mounting any seat puts bending loads in the area around the mounting bolts - take the seat cushion off and watch the seat bottom flex as you reef the body of the seat around. You might see stress fractures radiating from the holes. Side mounting is much better - it puts shear loads on the mounting points, there is little or no local flexing of the sides of the seat. The rest of the seat will move a lot less.

The slider is another source of movement. All sliders have slop compared to a fixed mount. The one that seems to be the least sloppy is the Sparco double locking slider. If you don't need to seat wildly different sizes of drivers I strongly recommend solid mounting it, with side mounts. Other sized drivers can sometimes work by mounting the seat for the tallest, and adding padding for the shorter driver.

Seatback braces - rules are rules, braces are here to stay. The IOPort brace is specifically designed to be bolted to the seat back. If not bolted, the flat part of the brace can flop down horizontally and knife thru the seat. Bolting works fine with an aluminum seat, they are not supposed to flex, and a few holes won't harm them. Bolting onto a fiberglass seat will act much like the bottom mounts - put cyclic bending loads on the fiberglass.

There are a couple seatback braces made specifically for fiberglass seats - They attach to the rollbar only, and press against the seatback with a large padded area - designed to limit the extension rearward, gently, without causing any local points of stress.

this is one: http://www.bkauto.com/porsche/r9020.php

(IMG:http://www.bkauto.com/porsche/images/R-9020.jpg)

and I make this one:

(IMG:http://www.blainefabrication.com/projects/2011_03_18/IMG_4141.JPG)

This post has been edited by Blainefab: Oct 13 2011, 08:55 AM

[NJSPEEDER]

I love getting down there for the 12 hour weekend every few years. I can't believe how rough the track is. In an era where every facility seems to be bent on boring tracks with no personality Sebring has survived with it's character intact.

-Tim

[FASTFATBOY]

That has to be the most quiet F body I have ever heard on a track video.

[Jeff94TA]

That has to be the most quiet F body I have ever heard on a track video.

My buddy keeps busting my balls about how quiet the car is and that's with a mostly gutted interior. It's Stainless Works long tubes, off road pipe and a Magnaflow cat back so it shouldn't be that quiet but it is. Oh well.

[Sam Strano]

What's the the steering wheel being so out of whack?

Lines look good, I see two things that really stick out to me. Take this fwiw, ymmv, etc, etc, etc.

1. Doesn't sound like you are doing any rev matching on the downshifts. I heard more than once where it snicked the rear tires on you/brake hopped into the hairpin. If you need to work the pedals so you can heel/toe better, then do it. Also if you need pads with more bite to help you feel more confident, well we can do that too. (IMG:http://www.frrax.com/rrforum/style_emoticons/default/smile.gif)

2. Could be more aggressive on the power on way out of a lot of corners. Not a lot of tire on the limit noise, never really working the car to keep it line. There is more there I think and that of course equates to more straight line speed.

Other than those thing looks good. Car is behaving as I'd expect with the stuff under there, you're putting it in the right places.

[Jeff94TA]

What's the the steering wheel being so out of whack?

I put new outer tie rods on it & had it aligned before the event and honestly hadn't noticed how hosed the wheel positioning is. I know the guy that does my alignments very well and will have him correct it.

1. Doesn't sound like you are doing any rev matching on the downshifts. I heard more than once where it snicked the rear tires on you/brake hopped into the hairpin. If you need to work the pedals so you can heel/toe better, then do it. Also if you need pads with more bite to help you feel more confident, well we can do that too. (IMG:http://www.frrax.com/rrforum/style_emoticons/default/smile.gif)

I'm still not blipping the throttle on downshifts and yes it's obvious that I need to. Watch what happens at the 3:49 mark in the video as I'm going for second gear coming into turn 10. I've exploded two clutch disks so far so that's the weak link for me not rev matching. Braking is just a confidence thing and I'm working on going a little deeper each weekend. The pads are still more capable than the driver.

2. Could be more aggressive on the power on way out of a lot of corners. Not a lot of tire on the limit noise, never really working the car to keep it line. There is more there I think and that of course equates to more straight line speed.

I watch the video and agree about getting back on the power but it sure doesn't feel that way when I'm driving it. I'll work on it. In that video I've stepped back to a 275 section width tire from the Continental race series and they just don't seem to make any where near the noise of my 315 width Hoosier R6's. I've also gone to an 18" wheel and the shorter sidewall is taking some getting used to, especially under braking.

I had a mutual friend, Ian Stewart, tell me he thought my car would be faster on a smaller tire because I don't have the horsepower to overcome the mass of the 315's and he was right. Ian wants to drive my car and I need to let him but I would hate to see how much faster he would be than me. I've already seen how fast you and Danny Popp can be in my car compared to me so I'm well aware of the potential that I haven't achieved yet.

Here's an interesting picture from that weekend of me coming into the hairpin too hot and standing it on its nose as I turn in. Not the fast way for sure.

(IMG:http://a1.sphotos.ak.fbcdn.net/hphotos-ak-ash4/312055_625555521599_203802289_33488459_1033010321_n.jpg)

[Steve91T]

Rev matching just takes practice. I rev match on the street every time. I even rev match my PowerStroke F250! It's now 2nd nature for me on the track.

[JimMueller]

I had a mutual friend, Ian Stewart, tell me he thought my car would be faster on a smaller tire because I don't have the horsepower to overcome the mass of the 315's and he was right. Ian wants to drive my car and I need to let him but I would hate to see how much faster he would be than me. I've already seen how fast you and Danny Popp can be in my car compared to me so I'm well aware of the potential that I haven't achieved yet.

C'mon Jeff, you're going about this all backwards... you don't go with a smaller tire, you add POWA! I don't remember the exact quote... something about you only have too much power if you're spinning the tires in top gear at the end of the longest straight? I bet I heard that from George (IMG:http://www.frrax.com/rrforum/style_emoticons/default/biggrin.gif)

[Jeff94TA]

C'mon Jeff, you're going about this all backwards... you don't go with a smaller tire, you add POWA!

Ian actually suggested that I step back to a 255/35-18 Hoosier R6 which would give me enough points to put heads and a cam in the car and still remain in TTC. I do not have the required big shiney brass ones to drive the car like that so it won't be happening any time soon. (IMG:http://www.frrax.com/rrforum/style_emoticons/default/blink.gif) If you want to volunteer your car I'd be willing to give it a try though. (IMG:http://www.frrax.com/rrforum/style_emoticons/default/ph34r.gif) (IMG:http://www.frrax.com/rrforum/style_emoticons/default/gr_grin.gif)

[JimMueller]

I have no idea where that magical line is far as determining how much power you need to overcome a wheels mass. I'd have no problems with letting you or Ian drive my car in a HPDE environment so long as it passed a thorough safety inspection. Because it's my only vehicle I'm more hesitant with a less controlled track environment. I am switching to running 315's all around on the street, so I'll no longer have wheels to put fat rubber on.

[Jeff94TA]

I'd have no problems with letting you or Ian drive my car in a HPDE environment so long as it passed a thorough safety inspection. Because it's my only vehicle I'm more hesitant with a less controlled track environment.

I appreciate the vote of confidence Jim but it was a bad joke on my part. As much as I would love to drive your car at Sebring taking that risk in your daily driver is something I would never do. Let me know how the 315's work on the street.