Ok it’s really late so I’ll make this short and get to the point. From what I’ve heard the gs-r model DA came with something like 1.8 mm thick frame rails opposed to 1.6 found in all the other models. Obviously honda felt it aided in making the car more “rigid” so I was thinking what if I just boxed in my frame rails with some steel plats cut to fit the bottoms and sides and then welded in? Seems like a simple and cheap way to stiffen up our chassis… Please discuss
The reason the DB2 has thickened frame rails is because they removed the center support that the LS/RS/GS utilizes… because it would not fit with the vtec header on the B17.
Theorcally your idea ‘should’ strengthen the frame of the car… But I don’t think it is going to be as functional as the OEM design.
Many people have taken the center support off of their non-DB2 with no ill effects to the frame.
If you’re that worried about it, I would fabricate a bar that uses the factory stabilizer bars mounting points, and also clears your header.
I could see that being better than welding a bunch of plates to the frame of the car that may or may not serve the desired purpose.
I don’t know where that document is, but I too have seen something about the chassis being stiffer up front. I’ve owned both and while I don’t have any back to back comparison or anything with science to back it up, I don’t think it’s a huge advantage. The front end of my DB2 still flexes like a mo-fo when I put it up on jackstands. With that said, I think anything you can do to increase the rigidity of the front end would be good.
As for how to do do such a thing, that’s a tough question. But I would think that you’d get a lot more benefit (especially considering materials, labor, and weight) from simply connecting the firewall to the strut towers better. A 3pt strut bar would help, but you’d have to do it right. Most of these don’t do much since they connect to a part of the firewall which is pretty flimsy. Another option would be fender braces - something I’ve actually been thinking a bit about recently. You may also be able to beef up the frame rails themselves but I think supporting them is probably the better way to go. If you wanted to beef them up then simple plates will be heavy and not add as much support as other methods.
[QUOTE=Colin;2301339]I don’t know where that document is, but I too have seen something about the chassis being stiffer up front. I’ve owned both and while I don’t have any back to back comparison or anything with science to back it up, I don’t think it’s a huge advantage. The front end of my DB2 still flexes like a mo-fo when I put it up on jackstands. With that said, I think anything you can do to increase the rigidity of the front end would be good.
As for how to do do such a thing, that’s a tough question. But I would think that you’d get a lot more benefit (especially considering materials, labor, and weight) from simply connecting the firewall to the strut towers better. A 3pt strut bar would help, but you’d have to do it right. Most of these don’t do much since they connect to a part of the firewall which is pretty flimsy. Another option would be fender braces - something I’ve actually been thinking a bit about recently. You may also be able to beef up the frame rails themselves but I think supporting them is probably the better way to go. If you wanted to beef them up then simple plates will be heavy and not add as much support as other methods.[/QUOTE]
Do you have an example of these fender braces you mentioned? I think I have an idea what you’re talking about but not sure if its something different . Also if I did still want to beef up the frame rails what do you think a better method would be to go about it?
Nvm just searched them. I’ll prolly be making a set this weekend. They look to be as, if not more effective than the frame rail idea.
The fender braces are a great idea… triangulation etc. That is definitely a good idea for stiffening up the chassis.
Quick question. I just went to install my PWJDM three point strut tower bar and it hits this sendor thing that’s connected to the throttle body and has a little arm that connects to the throttle cable. What is this? And can I remove it? My friend da also has a b16 but he doesn’t have that sensor?
Picture?
Unfortunately my digital camera was recently stolen so no go on pics for now. The best I can do is try to describe it .when the throttle is pressed the little arm moves up into the circular shaped metal part which is directly above the throttle cable about an inch over from where the throttle cable connects to the throttle body.
Sean, where did you hear this? I’ve never heard that before. I wish I could find the document that explains the changes they made when they made the GSR - I don’t remember them using that logic but I could have missed it.
I wouldn’t waste your time. But off the top of my head the right way to do it would be to cut the frame rail open so you could put bracing inside that would prevent the front of the car from flexing up/down compared to the rest of the car. The firewall is sort of a “hinge” point. You’ll notice that if you jack your car up, put jackstands under the pinch welds, then lower the car down on the jack stands the front end flexes a LOT after the car is resting on the stands.
Since our cars don’t have the TB mounted MAP sensors I’m assuming you’re talking about the Dashpot Valve - it is not a sensor. It’s purpose is to slow the speed at which the throttle plate closes. I am not sure of it’s purpose, but my guess is that it has to do with prehistoric engine management needing a physical component to help the car from stalling or having too fast of a drop in rpm which the ecu can not compensate for. None of the newer B series motors had that dashpot - I’m assuming because the electronics are much improved or they found another solution to whatever problem they were solving. You can definitely try taking it off, it may or may not pose an issue for you. I’ve seen people run w/o it and I have as well w/o any problems.
I’ve read it numerous times here on G2IC. Though I’ve never worked on an original DB2 so this is definitely not a first-hand account.
But you peaked my interest so I did a quick search…
Part #1 in the illustration is valid for the LS/GS/RS, but when you pick a '92-93 GS-R chassis, Part#1 is not listed so I do believe this to be true.
When you look at the clearance between the OE header and this center support, it is virtually non existant… so it makes sense that if they re-designed the lower part of the header to improve exhaust flow for the vtec powerband, that they had to also re-design the center support, or remove it entirely.
Sorry, I guess I didn’t clarify. I’m aware of that piece only being on the non-GSR models (I’ve had multiple DA9’s and DB2’s) but I have never heard of the removal of that piece being the REASON why the beefed up the front end on the GSR.
Ohhh, got ya.
Again, that’s just what I’ve read on here. It made sense in a way so I just rolled with it.
Here I go spreading misinformation again 
Not saying that… I just don’t remember that specifically from the document I read. And very likely it could be part of the reason regardless of what they had in their press release info.
I’m just givin you shit brotha.
It makes me wonder if some type of custom fabbed support, playing off that OE design, is a worth-while idea.
The fender-braces are quite popular with the Subaru kids though. Definitely worth seeing if there is a way to produce a set for use on our chassis.
I would think you’re better off bracing things from the top, but a bottom brace wouldn’t be a bad idea. Like I said before, I’ve really been thinking about fender braces recently. Dustin made some for his car but it looks like he had to fab a forward mounting point. His aren’t pretty, but they are probably funcitonal. Too bad I have a million ideas in my head and not enough time/motivation/money/tools to execute them all!
ok, I’m going to be honest and I really forgot how the underside of the DA looks like; it’s been YEARS since I had the car up on jackstands/lift let alone drive and wrench on the sucker…yet I’m still hoaring stupid parts for it lol
But onto the subject of frame rail braces, I remember some time ago I saw in a parts catalog and it showed a set of frame rail braces for a miata; I remember specifically since in my mind that it was a little neat idea, since I now also own a stupid 240sx and they’re infamous for having really weak frame rails- just jack it up and whoops I just crushed it haha. Just a little neat thing to look into; should give you an idea on how to fab one up if needed be…
Those are the “fender braces” that we’ve been talking about… They’re very popular in the Miata crowd. I’ve heard mixed reviews about them on Hondas.
Wow thanks for all the great feedback guys!
Also as for that thing on my throttle body I ended up removing it and I was able to
install my three point strut tower bar from PWJDM. took it for a drive and holy shit you can definitely feel the difference!
As for the frame rails I should be making my seat brackets this weekend so I think I’m going to go ahead and do my frame rails as well. If it doesn’t actually improve handling then shit at least I’ll have a nice shield to protect my frame rails from getting
Dented and scraped by speed bumps ha
yea I know that you guys are talking about fender braces, but I the OP wanted some actual frame rail braces- and like I said before it’s been awhile since I had the car on jack stands so I can’t remember the actual layout of the underbody of the car so I can’t verify that can be replicated to fit on our chassis - merely just throwing the idea out there ;). The frame rail braces that I was referring looks like this, again not to be confused with fender braces:
