Blooze Own: An F355 Six Speed N* Build Thread (Page 64/126)
kennn FEB 17, 09:47 AM
Damn! Gorgeous drawings. Which software are you employing? Even while asking this I am reminding myself that the true contribution made is the measuring you have done to arrive at the drawings. That is the part that I have found challenging in my own endeavors as I attempt to achieve as much accuracy as possible.

I too am modifying my subframe, but not to the extent that you are. Like you, however, I am raising my lower inboard links 1" to somewhat coordinate with my 1 1/2" raised spindles up front. A thing that caught my attention about the relative locations of the lower links is that the forward link is shorter as you have indicated. I wondered why, so I took the links through their range of motion and found that the result was a small amount (1/32-1/16) of toe-in that resulted in jounce. It seems to me to make sense with a rear-biased weight wanting to easily come around that the engineers may have wanted to either compensate for bushing deformation or merely wanted to make sure there was some toe-in and not toe-out, which would seemingly contribute to some dicey handling. The result for me, then, is to retain the offset just to be conservative. But then, my timidity may be a result of my in-the-body memory of the time I drove my brother's 356 Porsche in to a turn at a pretty quick pace and through some miracle was able not to wreck it as the back end wanted to be in control of the whole process.

edit to add: Sorry, Blooze. I just read in a prior post where you have considered this and feel that it is resolved with the more rigid SLA design.

Ken

------------------
'88 Formula V6
'88 GT TPI V8

[This message has been edited by kennn (edited 02-17-2013).]

Bloozberry FEB 17, 07:50 PM
Thanks Kennn. You certainly got the part about the true contribution right! I have yet to tally up the time I've spent just running back and forth taking and re-taking measurements, then still finding something that didn't add up. I do keep track of the time I spend in a spreadsheet though, so it will be interesting when I find the time to plot out the hours for different tasks.

As for the drawings, I wanted to keep the source files accessible to the largest possible audience so I use the simple vector-based drawing tool available in MS Office. In hindsight, I should've used a more sophisticated CAD program, but again when I make the source files available, just about anyone will be able to manipulate them as they are now.

Do you have a build thread somewhere?
Bloozberry FEB 20, 03:08 PM
Big day today... ordered my wheels: Motegi MR116's 17 X 7 ET48 fronts, and 18 X 9 ET45 rears.
F355spider FEB 20, 05:05 PM

quote
Originally posted by Bloozberry:

Thanks for your support guys. The most recent changes to the forum have given me reason to consider staying on. Kudos go to Cliff for making a simple, but much needed change regarding how the forum is moderated... I hope it lasts. I'll update my thread in a couple days.



I let a few run me off for a couple of years and went to the Fiero kit car forum during that time. Decided to come back after a name change to the forum and not having a kit car anymore. I decided to not let the Hatters get to me. So I understand why you wanted to but really glad you are here to stay.
deloreanant FEB 22, 02:33 AM

quote
Originally posted by Bloozberry:

Big day today... ordered my wheels: Motegi MR116's 17 X 7 ET48 fronts, and 18 X 9 ET45 rears.




Those look sweet. Can't wait to see this all come together.
aaron88 FEB 26, 02:31 AM


In regards to your upper forward lateral link pocket mount. I'm not sure how you plan to weld it in, but what I have found with that type of pocket is that it's a lot easier to make the full pocket. Then cut your opening front and back so that you can just slide in your pocket, weld it on both sides of the frame rail and have a solid full weld with no open holes for water to get in. Also use a 10 degree or so angle on the bottom of the pocket so water and gunk doesn't collect there.

I made a quick sketch it's not to scale or detailed but it should help you understand my text


Access for welding. Frame rail gets closed up. You have access to the bolt (also weld a nut on the back end since you won't have access to that after).

Before cutting your angles into the pocket. Cut your opening in the frame rail, slide in your pocket. That way you can scribe both sides with your exact contours. In order to get the nut to pass though the opening cut a slit, peal back the sheet metal (that way to close you just have to bend back the sheet and lay a short weld bead).

I'm not trying to tell you how to fabricate, I'm just giving you options and ideas.

Nice to see that you decided to raise the inner lower link mounts too.

[This message has been edited by aaron88 (edited 02-26-2013).]

Bloozberry FEB 26, 07:50 AM
Thanks for the input Aaron. I think you may have misinterpreted my drawing though. I can see how you might have mistaken my upper inboard mount as being inside the frame rail, but if you look closely, it's actually sitting on top of the rail. If you look in your own engine bay, you'll see that the top surface of the lower rail is fully exposed inside the compartment. Since my new mount will be welded on top of the rail, I'll have full access to the pivot bolt for the link inside the engine bay. The hole in the sheet metal where the link protrudes through is actually just the metal wheel house liner. Hope that helps clear things up.
aaron88 FEB 26, 10:09 AM
Got it! It was late when I read through your latest posts, I guess my brain wasn't really working well.

You've got me re-thinking my SLA design though. I've got my current design done (which is a strut design) and I'm about to make up the fixtures for the lower control arms, but I'm looking at my design and I still don't like that I only gain 1.8 degrees of negative camber per inch of travel. I'd rather have 3.4. My SLA design mounted the upper control arm rearward not forward like yours. I just don't seem to want to go though the extra expenses, but I'm starting to re-think it now.

my current design



You said you needed to pass an inspection for safety. So are your upper link rod ends DOT approved for street (I know there are some but they are expensive)? Or is there something I missed when it comes to upper mounts?

One cool thing about my SLA design was that it was swapable. Rubber bushings, poly and rod ends were all interchangeable. So if I was going to do a track weekend I cloud just swap in my rod ends(...then do an alignment).

Anyway, we are way off topic now.....sorry.

.
katatak FEB 26, 07:44 PM
Always amazed at your detail Blooze! It's always a treat to get caught up on this thread. I too am very glad you decided to stick around. Thanks for sharing all your hard work!

Pat
Bloozberry FEB 26, 09:39 PM
Thanks Katatak, glad to see you're back in the game again.

Aaron, your drawing looks great. I'm not sure what year knuckles you're using but it looks like an '84-'87 given the lower ball joint, but then I don't see a tie rod. Are you using your CAD program to simulate how much camber gain you're getting?


quote
Originally posted by aaron88:
I still don't like that I only gain 1.8 degrees of negative camber per inch of travel. I'd rather have 3.4.



That is the fundamental limitation with a strut design... not only is camber gain limited, but the rate of camber gain decreases rapidly as the wheel moves up in jounce. This is one of several reasons I moved away from the strut design. If you have '88 knuckles, the modifications to get rid of the strut aren't really that complicated once you determine the new coordinates for your upper and lower control arm pivots. You certainly don't need a pushrod shock absorber to complicate your design since there is room vertically to replace the strut with a shock absorber in place of the pushrod. The key is to decouple the rigid mount of the shock to the top of the knuckle by making it a pivot since a rigid mount is what limits the camber change. If you have '84-'87 knuckles, I'm sure there is a way to do the same, I just haven't studied the particulars of that set up.


quote
Originally posted by aaron88:
You said you needed to pass an inspection for safety. So are your upper link rod ends DOT approved for street (I know there are some but they are expensive)?



These are the rod ends I'm considering:

QA1 HMR8-10 (5/8R" X 1/2") RH thread
QA1 HML8-10 (5/8L" X 1/2") LH thread

The QA1 website details all of the properties needed to help make a decision which one is right for your application.