Darkhorizon + a budget more than a hamburger =

Real tech discussion on design, fabrication, testing, development of custom or adapted parts for Pontiac Fieros. Not questions about the power a CAI will give.

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Sinister Fiero
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Re: Darkhorizon + a budget more than a hamburger =

Post by Sinister Fiero »

It is your car and you can do what you want. All I can say is I don't know of one track that would let your car pass tech inspection with what you've done here. And if you somehow got past tech inspection and onto the track, I wouldn't run in the lane next to you even if they paid me a large sum of money to do it. What was that you said in a Old Europe thread? Oh yea:
by DH on Old Europe:
That is one thing I always try to push on people. It is very hard to do something wrong if you follow common sense while building something.
Seems as though you should follow your own advice - or quit posting statements like this if you think how you do things follows common sense.
darkhorizon
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Re: Darkhorizon + a budget more than a hamburger =

Post by darkhorizon »

The fact that I made 6+ 135mph passes with slicks, a few 3rd gear burnouts on the street with street tires, a few street races with street tires without even a hint of un-easiness, I would have to say my assumption of not needing a strut tower bar was right. Even if the string did go slack, my change of angle on the tires hitting the ground would be extremely small, and with slicks on I could lose a whole ton of angle without affecting tire function. Worst case scenario would be low profile wide street tires, and uneven extreme low MPH loads on the rear, on uneven pavement.... that would probably cause me to track right or left slightly.

I will remind you again that a factory stock fwd is going to have more forces acting on the front than a fiero, with as much or possibly less reinforcing structure on the strut towers.... In this case I did leave the heavy gauge steel fender wells in place on both the front and the rear of the strut tower, not to mention the upper framerails.

I dont know of any track tech dude that knows anything about fieros either... Even if he did I could just say that there was no structural bits in that rail I took out to loophole any concerns he had.
My fiero is cheaper than yours. The end.
Sinister Fiero
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Re: Darkhorizon + a budget more than a hamburger =

Post by Sinister Fiero »

darkhorizon wrote:The fact that I made 6+ 135mph passes with slicks, a few 3rd gear burnouts on the street with street tires, a few street races with street tires without even a hint of un-easiness, I would have to say my assumption of not needing a strut tower bar was right. Even if the string did go slack, my change of angle on the tires hitting the ground would be extremely small, and with slicks on I could lose a whole ton of angle without affecting tire function. Worst case scenario would be low profile wide street tires, and uneven extreme low MPH loads on the rear, on uneven pavement.... that would probably cause me to track right or left slightly.
You can assume all you want. I have a degree in this field so rest assured I know what I'm talking about. But it doesn't take a degree to figure out that a one-sided box is not a good (or safe) setup for a suspension system. I would say you've been lucky -AND- I would be willing to bet you've probably already bent or twisted something in your car because you've removed that strut tower support. The question is: just how much more abuse will it take before something fails. Hopefully you won't find out.
I will remind you again that a factory stock fwd is going to have more forces acting on the front than a fiero
In turning situations I would agree. But not in straight line situations, especially if you are accelerating. All the weight comes off the front wheels in a FWD platform when you are accelerating vs. all the weight getting put on the back wheels in a Fiero platform while accelerating. It is also harder to push than pull (when we are talking about the forces being put on the chassis).
with as much or possibly less reinforcing structure on the strut towers....
I doubt it. Since you like cutting things up maybe you should half off the back of a Fiero’s strut tower structure and compare that to a FWD car’s structure. I bet you’d be surprised what you find.
In this case I did leave the heavy gauge steel fender wells in place on both the front and the rear of the strut tower, not to mention the upper framerails.
And that is going to help lateral support/stability how? I bet two guys – one on each side of the car could probably push on the tops of your strut towers inward and get them to move by a significant amount. The amount of fender well material you’ve left in your car isn’t enough to keep the tops of the strut towers supported when we are talking about side-to-side forces.
I dont know of any track tech dude that knows anything about fieros either... Even if he did I could just say that there was no structural bits in that rail I took out to loophole any concerns he had.
Doesn’t change the fact that you have no idea what you are doing. And that makes you dangerous because you assume you do. People like you make drag racing unsafe. Believe it or not I’ve seen a lot of garbage pass inspection that should have never been allowed on the track; and then most have broken or crashed once they did get on the track. So I can believe what you say about might being able to pass an inspection because the tech guy doesn’t know what he’s looking at. I guess it depends on how much the track pays their people. The problem in this case is: neither the tech guy nor yourself knows what the hell you are doing. And I can tell you this: I certainly wouldn’t feel safe in YOUR car with what you’ve done to it without a roll cage. I think you’re living on borrowed time. I certainly don’t wish that anything bad happens to you. But what you’ve done here is made your car very unsafe.
alltrbo
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Re: Darkhorizon + a budget more than a hamburger =

Post by alltrbo »

As far as I know, he^ knows what the hell he's talking about in this arena, and so does Will. I'd listen to them (and I do).
Sinister Fiero wrote:The question is: just how much more abuse will it take before something fails. Hopefully you won't find out.
In addition, when you launch hard and the car gets a bit too squirrely, you'll be desperately swinging the wheel left and right to correct. When you go from 0 to 140 in 10 seconds, stuff can get out of hand way before you know what happened (and yes, that's experience talking. I've accelerated from 0-150 in 10 seconds)
How do you expect your car to handle it? I'd be willing to bet that you'll have a much higher chance of totally losing it without the proper chassis support. Then you'll really need that roll cage that you don't have.
I've seen a lot of quick cars get real loose on the strip (not to mention the street), and for several of them, it took all they had to keep off of the walls and/or to stay upright.

I'm glad you said you'll put a bar back in there (make sure the strut towers are unloaded by the proper amount first), and I hope you do that and install a cage, both before you drive it anywhere near its capability again. There's been enough good advice here, I hope you listen to it. No one wants you (or especially someone else) to get hurt because of your hack-job.
darkhorizon
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Re: Darkhorizon + a budget more than a hamburger =

Post by darkhorizon »

For the record, the strut tower bar was only scrapped as it was a last minute thing that I could not do to the caliber i wanted to. I will have a light weight and more functional rear brace installed this weekend, and it is not because I was "convinced" via this thread.

I checked around for any signs of stress, strut towers flailing around, anything obviously out of line, and I couldnt find anything. I am planning on getting it aligned again here soon, so I will see if anything changes.
My fiero is cheaper than yours. The end.
The Dark Side of Will
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Re: Darkhorizon + a budget more than a hamburger =

Post by The Dark Side of Will »

One of the big difficulties with Fieros is that the body isn't stressed. It's therefore very difficult to find a point at which the tub has been flexing because all of those points are covered up.

In engineering terminology, you've turned your two frame rails and connecting sheet metal into a "mast". In your case, it's like a diving board on its side. The highest stress is at the base of the mast. Did you get into the stock battery box area to look for stressed spot welds where the upper frame rail joins the firewall? Inside the quarter panel? Get under the car and look at the base of the lower frame rail where it joins the firewall?

If you're not using a tape measure to compare your car to the body specs in the manuals (or even to before measurements if you were that thorough), you're wasting time. If you're inspecting the car static, you won't see if, for example, your strut towers sag inward 1/2" between being jacked up and having weight on wheels.

That's an easy measurement to take... put jack stands under the forward cradle mounts in order to completely unload the strut towers and frame rails, then measure the distance between the strut towers (within 1/16")... Then put the car back on its wheels and remeasure.
Sinister Fiero
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Re: Darkhorizon + a budget more than a hamburger =

Post by Sinister Fiero »

darkhorizon wrote:I will have a light weight and more functional rear brace installed this weekend, and it is not because I was "convinced" via this thread.
God forbid you follow anyone else's good advice... :-o

But ponder this: If you are going to put a brace back in, I recommend you install an X brace and not just a single bar connecting the tops of the strut towers. With only a single bar in there, the chassis could still parallelogram on you (both strut towers try to fold over in the same direction - to one side or the other). The entire trunk wall you cut out acted not only as a strut tower support but also as an X brace that would guard against the tendency of the rear suspension/chassis from wanting to parallelogram/fold over to one side or the other. It may take some extreme circumstances to get this to actually happen, but at 135+ mph, anything is possible.
darkhorizon
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Re: Darkhorizon + a budget more than a hamburger =

Post by darkhorizon »

It is REALLY digging with this talk of torsional... The forces acting sideways on these parts are hardly in the triple digit area with static weight on it... and probably no more than 200lbs each under full load. The amount of surface area preventing twisting and rocking forward and backwards is well more than nearly 2 feet of contact area on the lower framerail, and upper frame rail, along with any of the pressed in rigidity propagating from in front of and behind the strut-main lower frame connection. In simple terms.. To twist that strut perch I would need to stretch or shrink the upper frame rail while crinkling/stretching the lower frame rail connection.

I believed the talk up to this point, as the ability for the top frame rail to bend inward some is probably possible seeing how it is 20 some years old, and it has some good leverage on it. It wouldnt be able to move much without showing in the way the decklid fits though.
My fiero is cheaper than yours. The end.
The Dark Side of Will
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Re: Darkhorizon + a budget more than a hamburger =

Post by The Dark Side of Will »

darkhorizon wrote:It wouldnt be able to move much without showing in the way the decklid fits though.
This is the most intelligent thing you've said in this thread.

As for the rest of what you just posted... "Go pick up a statics text book" is the nicest thing I can say.

http://en.wikipedia.org/wiki/Statics
darkhorizon
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Re: Darkhorizon + a budget more than a hamburger =

Post by darkhorizon »

Just thought I would update.

I am putting some new heads/cam and setting up the nitrous for real this winter.... I expect alot more power considering I had a tiny cam and stock heads, without nitrous last year.

Suspension wise I put in some solid rod end rear link arms. Also put tubes in my slicks (had them laying around) and tossed some real skinnies on the front using spare tire rims, and the car handles like a dream at 150... No wobbling around. Alignment is pretty neat, toe in on the rear with 1.8 positive camber. Front is pretty much normal with a bit less total neg toe than normal.

I bolted a giant piece of plastic to the front end giving me some quite excellent areo.. the stock headlight doors dont fly up at 150 and it completely eliminates any front end rise above 100. It looks almost not horrible. Cooling is bad as you could expect, but with a fan it has no problems making ~100 mile trips.

Image

I still do not have a "strut tower bar" in the rear... Have not noticed any flexing and it handles just fine.
My fiero is cheaper than yours. The end.
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Shaun41178(2)
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Re: Darkhorizon + a budget more than a hamburger =

Post by Shaun41178(2) »

you have any pics of your suspension? I know there is a thread or two here on RFT for the 88's, but I wouldn't mind seeing more and hearing more if its better than the stock stuff.
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ericjon262
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Re: Darkhorizon + a budget more than a hamburger =

Post by ericjon262 »

are you going to ported stock heads?
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darkhorizon
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Re: Darkhorizon + a budget more than a hamburger =

Post by darkhorizon »

heavy ported stock heads....

suspension isnt really "better" than stock... its just more setup for sub 1.5 launching and keeping me straight.... I dont plan on having any control in first gear in terms of correcting a crooked leave.

Image

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My fiero is cheaper than yours. The end.
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