That's pretty strange regarding your handling issues. My car shows none of those traits. We should have you brace the rear axle with gussets throughout, and maybe test it somehow for stiffness while it is off the car. It sounds to me like it is flexing.
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Yeah, I'm pretty sure it's not in the design, it's in my construction. I should do some testing on it since I have it all the way out now.
On the other note. Here is what I came up with as my best attempt at an independent rear suspension. It is using a 5-link setup arranged in 2 virtual a-arms with a toe-link. So, for all calculation purposes, think of it as a dual wishbone although it has some differences but they are small.
My measurements:
1.) Camber curve: 1.33 degrees negative camber per 1" of suspension travel.
2.) Rear roll center height at static rest (6.5" rear ride height, 5" front ride height) = 7 7/64"
3.) Lower arm practical length = 18" (arms are longer but angled. This is the lateral measurement)
4.) Upper arm practical length = 9" (same as above)
5.) Toe, while it theoretically can toe out on bump, it is minimal to the point where you don't even see 1 degree at the usefull range of movement.
Construction:
1.) All joints are heim joints.
2.) Nothing is permanent, in fact some bolts don't even have nuts. And the toe link is attached on the wrong plane. Brackets are tacked on.
3.) The materials used are all extras from where I originally purchased the wrong length items for the plan build.
4.) The virtual a-arm setup is based from the Porsche and Mercedes setup which are similar.
5.) The toe-link design I got from my Elise. It uses a similar attachment for rear toe control.
6.) The shock is mounted in the same location and will connect to the upper bracket.
7.) The upper brackets need to be welded together to reduce the possibility of flex.
Function:
I have no clue really. I based this on all the basics that I took from my suspension book that were meant to be used as starting points. I put the roll center slightly above the front roll center (if my measurements came out correct). I made the upper arms approximately 50% of the lower arms. I made the lower arms as long as reasonably possible. I adjusted the camber curve to be a little over 1 degree per inch of bump.
It would need an anti-roll bar, which would be pretty easy to fit I think, but I'm not sure how strong a bar yet. Haven't fully understood that chapter of the book yet.
So, looking it all over, it appears I can mount everything and not have it interfere with the old setup if I choose to go back so I may end up attaching it all and taking it for a spin...who knows. It's all very rigged up right now.
And last but certainly not least...the CV boots are now in the open.
I am constantly amazed at the creative juices that talented people have! That is a neat design. The way you mounted the upper a-arm links is really neat. I'd actually like to see a close up of that.
Several things I want to point out. the upper a-arm brackets on the chassis side are mounted along the middle of a chord and we really should look at triangulating that node back to the frame. Just another tube triangulated behind the bracket to stiffen those points as I think there may be some flex.
The static roll center is not as important as the instant roll centers, specifically the 'migration' of the RC from left to right as the car experiences roll and bump or droop. It has the effect of making the car feel unstable. The best advice I can give is to read the chapter in Allan Stanisforths book 'Competition Car Suspension' regarding the string computer he devised to locate the suspension pivots to minimize the lateral movement of the roll center. I may be able to pdf you some details if you can't find a copy. _________________ Components, core kits, premium component kits and rollers now available
I'll have to read that one. I've been looking over roll centers and roll center migration in my book and around the internet and I don't even know where to start. I know how to measure it static now. But that's about my current level of knowledge on the subject.
It would help if there was really a catch all "right" way to design a suspension. It seems it all involves trade-offs for various reasons. Do this thing to make the car faster on the exit, do the opposite to enter the turn faster.
Well, I've got time to learn. It'd be nice to have some track time to test out the various concepts.
I'll have to read that one. I've been looking over roll centers and roll center migration in my book and around the internet and I don't even know where to start. I know how to measure it static now. But that's about my current level of knowledge on the subject.
It would help if there was really a catch all "right" way to design a suspension. It seems it all involves trade-offs for various reasons. Do this thing to make the car faster on the exit, do the opposite to enter the turn faster.
Well, I've got time to learn. It'd be nice to have some track time to test out the various concepts.
Right. Well this is the very reason that I have not tackled this problem myself yet. The big car companies spend hundreds of millions of dollars and countless hours developing suspension geometry.... This should be interesting!
I will try to get you the information regarding string computer use. But it will have to be over the weekend. _________________ Components, core kits, premium component kits and rollers now available
Worked through everything, the independent rear suspension is assembled. I took it out for a spin around the neighborhood and all is functioning well. It's amazing how much different it makes the car feel. It's too early to say how effective the suspension is, but I can say that just weaving back and forth did not produce the rear-end slide out I was experiencing before.
So, I need to find somewhere to really test this out. If it all works out, this will be a large step towards being able to use a longitudinal mounted engine. Since the middle area now has a TON more clearance for the transmission. It also will have dropped many pounds of un-sprung weight from the DeDion.
And just so everyone knows, I'm not saying the La Bala DeDion setup is bad (I think my build of it was). I just can't leave well enough alone
Wow Colin! That is really great! I am very pleased that you were able to work up this design and execute it to the point of being able to test it.
Still I have to wonder exactly what was wrong with your deDion that caused it to behave so badly... Mine does not show that problem at all.
The one question I have regarding your design is if you have any bump-steer as the wheel moves throughout it's range of motion. Did you test the toe in-out of the wheel with the shock disconnected? _________________ Components, core kits, premium component kits and rollers now available
Looking at my DeDeion axle which is now off the car I notice 2 things. The first is that the ears had bent on one side again. The other is actually on the frame where I think 1 of the watts links was binding on the frame. Oh, and as I mentioned earlier, I found out I had different sized rocker arms on my shocks which were on opposite ends of the car. I switched them around so the fronts are the same and the rears are the same as each other. I also can see from the tire where that I had some positive camber on the right tire although I swear I had measured it and I didn't, but the tire was clearly wearing on the outside edge a LOT more than the inside. It may have been that all just added up to what was going on.
Bumpsteer. I did play around with the attachment points in getting it to be minimal. The toe control arm is the long arm you can see in the picture at the very back. It's a 17" link with heims on either end, so it's arc is very broad. Over 4" of suspension travel I did not see any noticeable toe change. I did swing the suspension with the shock link disconnected. Actually, did that numerous times figuring out how to package it all. The overall design came slowly, link by link as I assembled it. My original plan in my head didn't involve the toe link. I figured that out after making the 4-link setup and discovering the wheels turned! A bit of research and I had found a similar setup on the Porsches so I added a toe-link like they have, except I attached it closer to the setup my Elise uses than the Porsche design. It's unfortunately not a perfect multi-link design in that if you adjust 1 item (other than the toe link), it affects multiple parameters. So really, it was more of a convenience with the virtual a-arms vs. actually making a-arms. However, the do allow for independent adjustment which is very important in figuring out where things need to go and what length they should be. I think that would be an improvement next, that once everything is solid, replace the links with solid a-arms.
Anwyays, I still have the DeDion. I think it would be best to cut the ears off and start anew with those. I think they got did-in when I bent the wheel over it before I added the gussets. I also have slightly longer ears than originally called for because the original measurements had my wheels too far in and the axles would not fit. Come to think of it, I think that has a lot to do with the ears being weak. Perhaps the best way to assemble the axle for me would have been to mount the ears to the wheels with the 3/8" pieces on there and then set them up on the car. Then, I could have measured and made up the distance with the large tube instead of longer ears.
And remember, I'm lugging an extra 100 pounds or so with the GZE, putting a little extra stress on the rear. An extra 6% weight, all in the rear, I'm sure causes a skew to things as planned.
It would have been a better comparison for me to get all of my old suspension problems straightened out before switching, but meh, there is a TODO list a mile long on my car. This was a major one though so I'm very proud I've even gotten this far.
Next step is redoing my exhaust It unfortunately won't work with the new setup so I have to figure out another routing for the exhaust pipes. Also, my registration renewal is due next month so I need to start planning for the emissions test. I still haven't got word on if I have to pass 1989 (engine) or 2009 (chassis) standards. If it's 2009, I'm going to have to figure a way to setup an ODBII port that can communicate all of the proper signals...oh boy! If it's a 1989 standard, then I have to hope the tail-pipe test goes well. I do have a Cat Converter on there, but it's a JDM motor without an EGR. Who knows, perhaps I can get an exemption....yeah right.
Looking for some input here. My car has been making some creeking noises and I tracked it down to the steering rack. (I know I accidentally call it the column in the video, nevermind that). The 2 steering rack brackets are shifting around under load. I checked the bolts and they are tight. I'm thinking that maybe the holes have become elongated. So, I'd like some input on fixing this. I was thinking of making a bolt-on structure that ties the rack laterally to the frame in a different spot so that it would be boxed in. But before I did that, I wanted to share and see if anyone else is sharing this problem It would need to be a bolted-on structure that would allow me to still remove the rack.
I had the same issue. So I welded a 1/2 tube from one bracket to the other to prevent racking. It has worked great. Now all of my flex comes from the worn steering rack bushings. It also makes the steering rack easy to adjust up and down, because it also acts as a handle. See pic:
Good deal, so I just did something similar, thanks for the tip, it got me started on mine. I also added a piece of angle iron and bolted it to the frame so now it attaches to the frame with an additional 2 bolts. The car "feels" much better when turning now after a short drive this morning. I still think the rack is too sharp on the car for my tastes. Maybe I can find one with a higher ratio. Personal taste and all. My Elise has a very slow turning wheel so that is what I'm used to now I guess.
Anyways, hooray, this apparently was a major detrimental item on my handling. It also was the source of an incredibly annoying sound. A few more tweaks and I might have all the creaks and groans out of the car.
I had the same issue. So I welded a 1/2 tube from one bracket to the other to prevent racking. It has worked great. Now all of my flex comes from the worn steering rack bushings. It also makes the steering rack easy to adjust up and down, because it also acts as a handle. See pic:
I have added this update to the plans! good idea. _________________ Components, core kits, premium component kits and rollers now available
Here's the deal. It's a 2005 GM Northstar 4.6L V-8 engine complete with it's electronic 4-spd Auto trans setup for a FWD car. It's a monster of an engine and a monster of a transmission. It's a DOHC V-8, aluminum engine. It weighs a lot more than the 4AGZE of course, but most of that weight is coming from the transmission. I'm thinking I'm going to keep the transmission, so it'll be an automatic now. Size wise, it will fit with very little modification but I will be doing some beefing up of the engine bay for this sucker.
I got everything the engine has from the car now. The guy I got it from is sending me all of the controls next (this engine has more computers than a data center!!).
The work so far will entail:
1.) Figuring how to get it attached to the frame, this is looking pretty easy. The motor came with the engine mounts
2.) Cooling: I think I can re-use the same rubber tubes I was using before but I'll be needing a better radiator. But I can get the car running with the one in there now.
3.) I will be using the shifter that the engine comes with and stock electronics from the same car. 1 cable for automatics and you can mount it anywhere!!!
4.) The electrical system is coming complete from the donor car, so I'll be changing the fuses over to that system and only removing what I can.
5.) Dash, I'm thinking of using the donor dash for all of the cool gadgets it comes with but I don't know yet....
6.) Axles, these will be custom. Not sure the exact setup I want to go with yet though.
7.) Transmission cooler: Gotta figure something out, probably will setup so it get's air through one of the side vents. I've never owned an automatic let alone built a setup for one, so I'll be learning about this in the coming weeks.
8.) Oil cooler: Same thing, probably in front of the other vent in the back.
9.) Exhaust: Normal custom exhaust work, no biggy, just a little welding.
10.) Intake, El cheapo air filter on a tube, whoopie.
11.) Starting: Because of the crazy anti-theft stuff on the car, I'm going to just keep all that and use the donor ignition.
12.) Fuel: Simple rubber fuel lines fed by my same pump I was using for the other engine. It was overkill on the 4AGZE but just right for this one.
13.)Belt: Gotta figure out a solution to run without the AC and Power Steering, seems easy enough to remedy.
This is going to take awhile for me for both effort and cost, but when done, HOLY MOLY, there will be a V-8/Auto La Bala. I shall call it....Super La Bala! Hehe.
I've always said that a Northstar V8 would fit in this engine bay, but I honestly never expected it to be YOU Colin! I am impressed! It occurs to me that you may end up needing to swap the suspension bellcranks around so that the short length goes to the pushrod. I guess time will tell. It seems like a very straightforward installation.
Did you ever have any overheating issues with the 4AGZE? I would run with that radiator until you determine that it is too small. It may end up being too small, but like you said, at least run the engine to see what it does.
In any case...
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This is going to be interesting. I'm looking forward to watching your progress. I think you will find it easier if you have someone modify your harness and reprogram your ECU. Vats utilizes lots of components you won't need on a La Bala. _________________ Always remember, ain't nothing is as simple as it seems.
It would be nice, but apparently the newer Northstar ECUs like mine aren't very common. I actually haven't found anyone who can re-program the ECU for an 05 Northstar engine. Most people who tune them seem to either go stand-alone or with the LS1 ECU. However, going with the LS1 ECU requires a separate trans controller. That would be cool, because then I could setup paddle shifters with an aftermarket trans controller, but then we're talking about an additional $800 investment just for the trans controller. Then I have to do my own tuning and wiring harness.
I'm going to give it my best on using the donor stuff and I hope I can get it all. Perhaps I should look at hacking the ECU myself. I am a software developer after all, seems like this should be my kind of thing.
If you decide to out source, contact Jarod at www.currentperformance.com. He helped me with my ECOTEC ECU and wiring. _________________ Always remember, ain't nothing is as simple as it seems.
It fits! With very little effort. That is to say I have to remove the engine mounts to get it in there and then re-attach them. I also need to do some clearancing on the bottom to allow for engine movement, but it fits in the bay.
So, now to plan out engine mounts. Interesting thing, this engine mounts in 4 points, but they are all on the bottom of the engine. I'd like to re-use the factory mounts because they are beautiful cast pieces that are clearly strong enough for the engine.
Because of the clearance I need and the placement of the engine mounts, I have to do something with the lower 1.5" tubes in the engine bay. My choices as I see it are to either completely re-do them with the side rails wider, or to only cut-off just the side rails and angle them so that the bases go to the round tubes but the back end still goes to the same spot. I'm liking the later one because that would enable me to retain a lot of tubes/work already done. Angling the tubes would give enough clearance for the engine to rock a little and for the serpentine belt to be put on.
On another note, I'm going to have to completely re-do the suspension mounting points...DOH!!!
I think designing 350HP 1,800lb cars should be done with a better quality beer.
Seriously though. Your idea to run the bottom engine bay rails to the round tubes is the best one. The Bala engine bay is designed for the engine to hang from the upper rails. By also moving the mounts to the lower rails for this engine you will need to triangulate the lower rails into the round tubes of the main frame for strength. With that layout I think you will still have plenty of clearance for your lower a-arms. _________________ Components, core kits, premium component kits and rollers now available
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It unfortunately won't work with the new setup so I have to figure out another routing for the exhaust pipes. Also, my registration renewal is due next month so I need to start planning for the emissions test. I still haven't got word on if I have to pass 1989 (engine) or 2009 (chassis) standards. If it's 2009, I'm going to have to figure a way to setup an ODBII port that can communicate all of the proper signals...oh boy! If it's a 1989 standard, then I have to hope the tail-pipe test goes well. I do have a Cat Converter on there, but it's a JDM motor without an EGR. Who knows, perhaps I can get an exemption....yeah right.
