F Body Bolt in "Firewall to frame" bars [Archive]

WS6

05-21-2008, 07:14 PM

67SSDan

05-22-2008, 02:54 AM

Those don't look like what I expected them to (out of the car). Does any one have a picture of those bars in a first gen?

Dan

BA.

05-22-2008, 08:56 AM

I have a couple of pics here..... I hope to put something similar into mine.

https://www.pro-touring.com/forum/showthread.php?t=27695&highlight=frame

Those one's in the link a few posts up look like they connect to the bolt of the upper control arm, vice bolting/welding to the front of the subframe.

redfire69

05-22-2008, 09:43 AM

last time I checked with Martz, they said they would sell me the "down bars" separately and they would fit with other subs, Ron

http://www.martzchassis.net/page1.htm

https://static1.pt-content.com/images/noimg.gif

Damn True

05-22-2008, 10:29 AM

The Pozzi's have them on Mary's car. According to David and Mary they did offer a noticeable difference.

barraza

05-22-2008, 01:18 PM

http://pro-touringf-body.com/chassis_components.html

g-braces is what they call them here. It's not the same as what's on Dale's car but it's similar and it's what Jake is referring to. These work very well since the whole front subframe is held on at the firewall and back. The engine and all that weight is forward of the firewall. The second gens use the front fenders for structural support which is why they are so beefy. Adding these only helps as does using thicker bars in the very front connecting the fenders to the core support.

Those look just like what Herb Adams sold about 25+ years ago. The front connection was to an upper a arm stud and the rear connected to the fender bolt on the firewall and another connection to the upper cowl. Just about any additional support to the front sub can't be a bad thing.

romar 02 SS

05-22-2008, 02:51 PM

I noticed on Mary Pozzis' car they go from the front UCA bolt to the firewall. Any difference? Advantage? Just curious. Larry

XLexusTech

05-22-2008, 03:13 PM

I noticed on Mary Pozzis' car they go from the front UCA bolt to the firewall. Any difference? Advantage? Just curious. Larry

To add to that do they make that type for 1st gens?

James OLC

05-22-2008, 05:56 PM

I have seen these recently on ATS sponsored One lap camaro and on the car DSE did for Dale jr. (the 2nd Gen)

With respect to the ATS sponsored OneLapCamaro project...

They help. Especially if the firewall is tied into the cage on the interior side.

the bolt-in bars are tied directly to the roll cage.

those boltin bars have tubes coming off the main cage and they weld the flanges on each side to make it bolt on.

Jake is exactly correct. I should have some build pictures back at the shop that I can post or PM next week when I get back. To make a long story short, Matt at RFR Custom Fabrication machined us some male and female plates out of 1/4" steel. The females were welded into the subframe to the front and were sunk into the firewall and tied to the dash hoop via a short length of tubing. If there is enough interest we could probably do a short production run of the plates (like we are with the hood latches and coil brackets).

We went the bolt in route for assembly purposes and because removal of the dry sumo tank and some of the other components will be a ton easier without the bar in place. Modifications, however, are required of the inner fenders since stock ones cover the front of the subframe just before the rad support mounts.

WS6

05-22-2008, 06:55 PM

Those look just like what Herb Adams sold about 25+ years ago. The front connection was to an upper a arm stud and the rear connected to the fender bolt on the firewall and another connection to the upper cowl. Just about any additional support to the front sub can't be a bad thing.

Yep, that's who designed them the first time around. There are a couple companies that make them now.

I'm sorry if I threw anyone off with my link. Those bars are for second gens and are the best way to brace the front subframe if you don't have a cage. I would use downbars if you have a cage. Downbars would be much stronger. I'm sure if you don't have a cage, something similar to those second gen bars could be made and should work well on first gens also.

zbugger

05-22-2008, 07:37 PM

To add to that do they make that type for 1st gens?

No, they don't as far as I know. I do know that LowbuckX made a set himself for his Nova though. You could do the same for your own car. You could do a search and see what he came up with.

LowBuckX

05-22-2008, 10:22 PM

Allen you make me blush when you recollect things Ive done.... LOL Kidding of cource.

Here is a thread with pics. Over look the bickering it happens sometime lol https://www.pro-touring.com/forum/showthread.php?t=28306&highlight=lowbuckx

TonyHuntimer

05-22-2008, 10:28 PM

I made my own and they helped a lot. Mine tie to the firewall and the front frame. They are in my GM book on page 69.

Tony Huntimer
RaceHome.com

Rick Dorion

05-23-2008, 05:36 AM

I have a set of the 1st gen Herb Adams. I haven't them in yet but it looks like the heater box is in the way on the pass side. Nothing a spacer wouldn't fix. There may be other improvements that could be made. I'd be willing to provide them to someone who would be interested in making a run and maybe improving the design.

BA.

05-23-2008, 10:11 AM

I would buy a set right now if they were available for the 1st gen!

Rick, are Herb's to the front subframe, or to the UCA mount/bolt?
Also, just one bar to the firewall, or 2, as in a 'Y' design?

Lowend

05-23-2008, 10:34 AM

The PT F-body versions are basically updates copies of the VSE braces.
Instead of the brace connecting to the inside of the UCA shaft (and replacing some of the alignment shims) it connects to the outside.
This allows for the wheel alignment to be more finely tuned.

...And for a 2nd gen it is one of the best investments you can make in the car.

Here is a write up I did on them
http://www.nastyz28.com/forum/showthread.php?t=86423

Rick Dorion

05-23-2008, 10:36 AM

It's a 'Y' design. It anchors on the front UCA bolt, the firewall edge and the leading fender bolt that goes into the firewall, if I'm making snce.

67SSDan

05-24-2008, 09:28 AM

Ah okay... it makes since now that I've seen it in a car. That Y shape was throwing me off. I had only seen the ones like in the Martz picture.

Here is a thread with pics. Over look the bickering it happens sometime lol https://www.pro-touring.com/forum/showthread.php?t=28306&highlight=lowbuckx

So after reading that thread (or at least the first few pages), it shows that it in theory helps on upward lift on the front of the subframe... so are we talking minimizing chassis twist (flex) or what? That's the only scenerio I can see the front wanting to raise up like that in a road race car, and only one side at at time at that... (I'm a noob to the suspension game, so forgive me if I'm overlooking something obvious).

Dan

JPMACHADO

05-24-2008, 09:54 AM

It's a 'Y' design. It anchors on the front UCA bolt, the firewall edge and the leading fender bolt that goes into the firewall, if I'm making snce.

what OD are those bars? Thanks

MrQuick

05-24-2008, 10:04 AM

The ones I have seen were 1.250 .095 wall.

Damn True

05-08-2009, 11:48 AM

I made my own and they helped a lot. Mine tie to the firewall and the front frame. They are in my GM book on page 69.

Tony Huntimer
RaceHome.com

Wasn't there some content around this on RaceHome.com?

MarkM66

05-08-2009, 06:08 PM

I remember when you could buy these from Summit, under Herb Adams line of parts.

67bird

05-09-2009, 08:03 AM

I think there was a post about these awhile back. I think someone found a link where CA chassisworks sales them.

Serpa69

05-11-2009, 06:09 PM

I think there was a post about these awhile back. I think someone found a link where CA chassisworks sales them.

They do and they are nice

Serpa69

07-24-2009, 09:03 AM

Here are some that I made. They are bolt in

Restomod Z28

07-24-2009, 10:27 AM

Nice job ^^^.

I have the CA chasisworks ones as well. They made a quite noticable difference in the car.

They now sell a re-enforcing bar that bolts between the two cowl mounting points as well, but I can't comment on that piece.

silver69camaro

07-24-2009, 10:34 AM

I'm not saying those bars don't help, I just don't think they worth much. Check out this photo:

https://static1.pt-content.com/images/noimg.gif
Here the jack is raised about 6", and the only wheel touching the ground is the front right. Not at any time did the gaps change, nor did I hear any popping or other strange noises coming from the front fenders (which would indicate weak front-end stiffness).

What I'm saying is weak area of the car isn't the front end, it's the middle and rear half. Solve that problem and you'll notice a big difference. Bolt-in downtubes look cool, but to me they're like bolt-on subframe connectors...hampered by the too-common need of "bolt-on" designs when welding them on and spreading the load over a larger area on the firewall is really what works.

I can see bracing the UCA mounts, but taking a look at how much lateral load is actually applied to that mount is really quite low. Take a car fully on the brake coming into a turn. Let's say the entire front weight is on that wheel, with 1G of lateral. That's applying about the vehicle's weight (roughly) on the UCAs and LCAs on that one wheel. Divide by two for each control arm, and you only have about 1750lbs on the UCA mount. Not a big deal. Yeah, shock loads and everything will increase that, but those braces aren't there for potholes and such. My opinion, anyway.

Serpa69

07-24-2009, 06:53 PM

Well, I guess I just waisted my time then. Shoot. I will just have to settle for looking cool:smoke: Here are some finished pics. I wish I could find the tire that will take the entire front weight of the car at 1G in a turn, then I could have the 4G machine.

Serpa69

07-24-2009, 07:06 PM

And the last those bars disappear in black. At least I wont look like a fool for putting them in my car.

Roadrage David

07-25-2009, 12:08 AM

http://pro-touringf-body.com/chassis_components.html

g-braces is what they call them here. It's not the same as what's on Dale's car but it's similar and it's what Jake is referring to. These work very well since the whole front subframe is held on at the firewall and back. The engine and all that weight is forward of the firewall. The second gens use the front fenders for structural support which is why they are so beefy. Adding these only helps as does using thicker bars in the very front connecting the fenders to the core support.

I have been asking you a couple of times over the last 3 years if you could make them for First gen,s!!!........

neki67

07-25-2009, 02:20 AM

I have been asking you a couple of times over the last 3 years if you could make them for First gen,s!!!........

CA Chassisworks catalog page 55: http://www.cachassisworks.com/CatPages/CAC/CAC9947.pdf

Marcus SC&C

07-25-2009, 12:39 PM

We`ve used the Chassisworks bars in the link above (thanks!) several times and personally I like them and think bars of this type have merit. While the chassis may seem rigid enough sitting on a jack in the garage that discounts dynamic forces entirely. Are the loads on the front subframe/unibody interface the same in a static condition as they are hammering the 6 piston brakes and throwing the car into a corner at 100mph? Nope. We`ve got large amounts of weight transfer and cornering loads coming into the picture then. Since the subframe is basically cantilevered out in front of the firewall any additional triangulation you can get should be welcome. It`s also nice to gain a few more subframe to body mounting points to help share the loads. Cars with aluminum subframe mounts and beefy weld in subs may not notice as big an improvement with this type of chassis bracing as a car with rubber or poly bushings and bolt in subframe connectors (or none at all!) but I have noticed a subtle improvement in responsiveness and a slightly more solid feel. The Chassisworks bars have to be welded to the mounting plates but other than that are bolt in. This one elded joints lets you adjust them for brake booster etc. clearance. I`m not saying you can`t have a good handling, fairly rigid car without bars like this but I am saying they certainly can`t hurt and will more than likely help. Mark SC&C

John McIntire

07-25-2009, 03:34 PM

Hey Matt, what is on that 69 Camaro to make it so stiff?

WS6

07-25-2009, 05:12 PM

I have been asking you a couple of times over the last 3 years if you could make them for First gen,s!!!........

David, I was just posting the link. I'm not connected with PT Fbody at all. I just simply knew they had them and showed a good picture.

neki67

07-25-2009, 10:39 PM

Trey,

PT Fbody is only selling these for 2nd gen's and David wants them for his 1st gen.

WS6

07-26-2009, 04:59 PM

I understood. I just thought he thought I was connected to PT Fbody. I'd love to make some for the 1st gen guys but I don't have the resources. Heck, I wish I had the resources to get the PT Fbody ones for my own car.

silver69camaro

07-27-2009, 05:17 AM

While the chassis may seem rigid enough sitting on a jack in the garage that discounts dynamic forces entirely. Are the loads on the front subframe/unibody interface the same in a static condition as they are hammering the 6 piston brakes and throwing the car into a corner at 100mph? Nope.

Sorry Mark, I just flat disagree with that. You're only getting enough weight transfer to compress a couple 550lb springs less than a couple inches, technically on my car 1G of negative acceleration provides a bit more than 700lbs of weight transfer. Your fenders will provide much more strength than a couple bent round tube bars bolted to the firewall in a single location. I stand with my statement, which I have done lots of R&D on for a couple years now, the weak area of first gen Camaros is the mid to rear section. I'm not saying that having a jack 24" ahead of axle C/L is the same as heavy deacceleration, but your statement of "hammering the 6 piston brakes and throwing the car into a corner at 100mph" is not anywhere near as serious as you make it sound to be. I don't think we need to be making statements about these bars that make people think they are absolutely necessary without any real testing. If you say they're a must and I say they are for image only, then it's probably somewhere inbetween. But, again, only my opinion.

But I agree with the last statement, they can't hurt (except for adding a few pounds to the already heavy end of the car).

silver69camaro

07-27-2009, 05:18 AM

Hey Matt, what is on that 69 Camaro to make it so stiff?

Mostly due to the 2x4 rear rails used in our direct-fit rear clip. The subframe connectors also help.

Roadrage David

07-27-2009, 08:48 AM

David, I was just posting the link. I'm not connected with PT Fbody at all. I just simply knew they had them and showed a good picture.

Sorry dude:hand: i tought you where him................

John McIntire

07-27-2009, 08:51 AM

Thanks for the reply, now get to work on that a-body frame! j/k!

silver69camaro

07-27-2009, 10:44 AM

Thanks for the reply, now get to work on that a-body frame! j/k!

Heh, we're getting there. Progress is slower than usual due to the complexity of the stock frame, but already I can tell we'll have something that will really "wow" the crowd.

WS6

07-27-2009, 05:22 PM

Could the 2nd gens be that much different in terms of stiffness than the 1st gens? I ask this knowing that the front subframe on the 2nd gens is superior but these triangulation bars flat out work on the 2nd gens. However, from what you're saying Matt and I believe you, the 1st gens don't really benefit. Am I missing something about the 1st gens that I don't know since I'm not that knowledgeable on them, or did GM upgrade a great deal about the 2nd gens and just didn't get this part as correct?

Serpa69

07-28-2009, 03:16 AM

I am really missing something, 12k to get Morrison suspension on my first gen.

If the frame is better on a second gen why would you put bars on that car?

silver69camaro

07-28-2009, 05:01 AM

Damn True

07-28-2009, 08:09 AM

Is there an appreciable difference in the distance from the mounting points and the suspension pickup points? The 2nd Gens do "look" longer (no idea if they actually are) and if the distance is large enough I could see the extended moment arm of the various inputs causing a bit more "noodleyness" (technical term) on the 2nd Gen than on the 1st Gen.

WS6

07-29-2009, 05:13 PM

Trey, it's tough to say. Only thing I can think of would be the low hood profile provides less of a moment arm to resist movement at the car's nose. The subframes between the first and second gen are basically the same in terms of strength.

Ok so the improved handling came from better geometry and not necessarily a stiffer sub frame? I've seen the first gen sub frames removed from cars and they do indeed look very similar to the 2nd gens. I think you may be correct though Matt. They did the best they could within the confines of the proposed design. In so many areas the car was improved but the improved design may have caused other issues.

True, I think it may be that the 2nd gens had more of a nose than the 1st gens. If you want to measure from your friewall along the driver's subframe rail to the front, I'll do the same and we can compare. My front clip is off still.

silver69camaro

07-30-2009, 05:42 AM

Ok so the improved handling came from better geometry and not necessarily a stiffer sub frame?

Definetly, the 2nd gen had several improvements including being a front-steer design.

Edit: Looking at my models, the 2nd gen places the front spindle C/L farther out than the 1st gen from the firewall mount, but not by that much. I believe this combined with the lowered cowl increases the front ends "noodleyness" (thanks True).

dipren443

07-30-2009, 06:16 AM

Definetly, the 2nd gen had several improvements including being a front-steer design.

Edit: Looking at my models, the 2nd gen places the front spindle C/L farther out than the 1st gen from the firewall mount, but not by that much. I believe this combined with the lowered cowl increases the front ends "noodleyness" (thanks True).

Noodleyness... I love it.

Matt,

Those rear frame rails available for 2nd gens?

Nick

Damn True

07-30-2009, 08:14 AM

True, I think it may be that the 2nd gens had more of a nose than the 1st gens. If you want to measure from your friewall along the driver's subframe rail to the front, I'll do the same and we can compare. My front clip is off still.

To ensure we measure the same things:

1) Distance between LCA bolts. f/r & l/r
2) Distance from rearmost LCA bolt to forwardmost subframe mount point.
3) Distance from rearmost LCA blot to rearmost subframe mount point.
4) Distance between subframe mount points. f/r & l/r

silver69camaro

07-30-2009, 08:41 AM

Noodleyness... I love it.

Matt,

Those rear frame rails available for 2nd gens?

Nick

Do you mean for a direct-fit style? If so, 2x4 is pretty much out of the question, but 2x3 may be do-able. Those rails are so funky shaped to accomodate the back seat that is pretty much on the axle compared to other cars.

silver69camaro

07-30-2009, 08:42 AM

Damn True

07-30-2009, 09:28 AM

yup

WS6

07-30-2009, 04:23 PM

ok I'll grab this info tomorrow.

Skip Fix

07-31-2009, 06:33 AM

So would these bars on a drag second gen be of any real help? (I've got some old original Herb Adams)

dipren443

07-31-2009, 06:41 AM

Do you mean for a direct-fit style? If so, 2x4 is pretty much out of the question, but 2x3 may be do-able. Those rails are so funky shaped to accomodate the back seat that is pretty much on the axle compared to other cars.

Yes, direct fit.

silver69camaro

07-31-2009, 07:44 AM

Yes, direct fit.

Not yet, if at all. I can't get the geometry correct with the very limited amount of space those cars have in back. Personally, I'd run a set of Hyperco 200# leafs, watts link, and a 5/8" to 3/4" sway bar.

dipren443

07-31-2009, 09:52 AM

Not yet, if at all. I can't get the geometry correct with the very limited amount of space those cars have in back. Personally, I'd run a set of Hyperco 200# leafs, watts link, and a 5/8" to 3/4" sway bar.

Matt,

Don't want to derail the thread. You have a PM.

Thanks,
Nick

WS6

07-31-2009, 04:16 PM

To ensure we measure the same things:

1) Distance between LCA bolts. f/r & l/r
2) Distance from rearmost LCA bolt to forwardmost subframe mount point.
3) Distance from rearmost LCA blot to rearmost subframe mount point.
4) Distance between subframe mount points. f/r & l/r

Ok here's what I did and how I did it. I found the midpoint of the rear bolts by measuring the distance between the rear LCA mount bracket and then dividing by two. I held the tape measure there and measured front to rear. While my front clip is off, my subframe is attached and fully loaded so I simply used my tape measure.

2) approximately 32 inches
3) approximately 37 inches

For the LCAs themselves, I did the same for measuring the spacing between the arms on the LCA, used the bolt mid points. That came out to be 13.5"

The measurement side to side, I measured bolt center line to bolt center line. My rear bolts come in from the rear and my front ones go in from the front. It was easy to just hold the tape measure over the center line and measure to the next one over.

Front bolts are 17-1/8" apart
Rear bolts are 29.5" apart

Damn True

08-01-2009, 09:24 PM

https://static1.pt-content.com/images/pt/2009/08/Presentation1-1.png

WS6

08-02-2009, 03:18 AM

i'm going to need an explanation along with that picture. I have no idea what I'm looking at, lol

vsefiream

09-18-2009, 12:06 PM

getting back to the original post, these are the bars mentioned earlier. I've been told they work better than the down bars that travel to the front of the frame because the angle of triangulation is tighter??
https://static1.pt-content.com/images/pt/2009/09/dcp_3482-1.jpg

MStennes

11-16-2009, 12:01 PM

Damn True

11-16-2009, 12:07 PM

I have been thinking about getting the one Hotchkis makes and modding it a little so it has a better firewall mount like like Alstons and modifing it so it not only connects at the upper control arm, ut further forward again like Alstons setup.

Not an engineer and I didn't stay in a holiday inn express last night but:

I kinda doubt there is much to be gained from a chassis stiffness standpoint in attaching fwd of the UCA stand. All the input (suspension/steering) that could flex the chassis is either at the UCA mount or behind (steering gear).

From a crash protection perspective there may be some benefit.

MStennes

11-16-2009, 12:29 PM

Not an engineer and I didn't stay in a holiday inn express last night but:

I kinda doubt there is much to be gained from a chassis stiffness standpoint in attaching fwd of the UCA stand. All the input (suspension/steering) that could flex the chassis is either at the UCA mount or behind (steering gear).

From a crash protection perspective there may be some benefit.

To be honest, I'm not sure other than to add a little (if any) extra support out on the front, my 69 is a vert so it can use any and all extra support/stiffness it can get. I'm not a engineer either so I was just going on two different theroies and combineing them. It would seem (maybe not) that the little extra support up front might help a little, but who knows? I do know Alstons firewall mount is leaps and bounds beefier than Hotchkis's, who knows maybe thats wheat I based my assumption on? Thoughts?