JP Motorsports BG/BF/GT4 Rear subframe production and discussion.

[theredrocket]

Any updates on these puppies?

[JPmotorsports]

Yes! We got what we needed and pulled them out/dusted them off. A couple weeks ago we cut the centers/notched for the diffs-while I was at SEMA last week the guys made plates to cover the notch's and this week I'm welding them all up. Next week we'll start fitting the diffs to the crossmembers/making all the tubing plates. I'm going to fit the diff's first and get all the welding done before I put the legs on---should keep the mounting points from moving around as much. I'll shoot some pics next week when they start to look like something. Saw Kaleo yesterday/popped in from Hawaii on vacation---he's moving up to Washington/Oregon border early next year and he'll be motivated to finish his car...he actually walked out back and pulled the cover off my touring car shell and asked what it would take to put it back together!!

[SgtRauksauff]

I had some friends go to SEMA this year, in conjunction with the Optima / USCA thing. Andy, in his S2000, took 11th, and Ronnie in his Evo took 10th overall.

Great news on the update, looks like I need to start funneling some more cash your way!

--sarge

[FE3-323]

crap. I need to get more $ sent your way (I all but forgot about this)

[JPmotorsports]

Hey guys-just checking in, they're up on the jig table and we're still welding centers---we've assembled a 2wd conversion pc, and cut tubing for the legs to mount the diff's to the bases. We're plugging away a bit each week---it's lot's of notching now-should start to look like something PDQ!

[JPmotorsports]

I had some friends go to SEMA this year, in conjunction with the Optima / USCA thing. Andy, in his S2000, took 11th, and Ronnie in his Evo took 10th overall.

Great news on the update, looks like I need to start funneling some more cash your way!

--sarge

crap. I need to get more $ sent your way (I all but forgot about this)

Take your time guys, cash is always welcome of course, but it's a tough season we've got coming up!

[Wildfire0310]

I need to like sell a kidney or two, cause those look amazing and wish I could buy one.

Great work JPmotorsports. Keep up the support for our little cars.

[theredrocket]

Here's another question for ya Jim. What kind of clearance will these AWD tubular subframes give for exhaust/muffler mounting? The stock Mazda GTR subframe leaves you very little room to shove a tiny little muffler between the subframe and the rear bumper. Will these subframes have extra clearance/be further away from the floorpan of the car so we can fit a bigger muffler onto the car?

[SgtRauksauff]

Muffler? wat? who uses one of those?

[SgtRauksauff]

but on a serious note, I don't think you're going to really be able to fit a longer muffler between the bumper and the crossmember, since it has to get to the body pickup points at the same place, and have the lateral links and axle and everything still there. you might be able to get 2-3 inch longer, because the gigantic lower diff rear-hanger-bushing-thingy's might not protrude so far back and down, but you still have to clear the (larger) diff, and the axle and links are going to be in the same place.

--sarge

[JPmotorsports]

Here's another question for ya Jim. What kind of clearance will these AWD tubular subframes give for exhaust/muffler mounting? The stock Mazda GTR subframe leaves you very little room to shove a tiny little muffler between the subframe and the rear bumper. Will these subframes have extra clearance/be further away from the floorpan of the car so we can fit a bigger muffler onto the car?

Good question---Geronimo installed one (or sold it and installed one)---I want to say that it did increase the room for piping/mufflers---it's certainly not as thick as the oem unit and 1/2 the weight---we've moved the pivot up only 19mm so we're not loosing much above. I don't have a stock unit anymore or I'd look.

[AWDXavier]

Hey Jim, just letting you know where Im at on my swap, as Im finally getting everything bolted up underneath the car.

While I can appreciate how awesome this piece is, and how strong it really is, it needs some engineering work to create the necessary clearances while providing proper suspension and axle geometry.

My uneducated recommendations. The differential mounting position absolutely has to drop, As much as two inches would be good, although less would suffice if not feasible with your design parameters. With the suspension under compression and the control arm at an angle parallel to the ground, the axle is angled fairly harshly in a downwards angle towards the outside of the car. What little I know about suspensions says that the control arms shouldnt be much past horizontal under full compression. The height of the diff and angle of the axles also creates a clearances issue with the framerail. This condition has been verified to be the same on the AWD framerails, clearances being within the same parameters.

Here are some pics of what I happen to be working with on my FWD.

#toyotapoweredford #piercemotorsports by XavierDSM, on Flickr

#toyotapoweredford #piercemotorsports by XavierDSM, on Flickr

While this picture is better to show axle clearances, the next shows the Axle angle compared to control arm angle. While im not a suspension engineer, what little i do know tells me axle and control arm angles should be neutral when compared to one another.

#toyotapoweredford #piercemotorsports by XavierDSM, on Flickr

#toyotapoweredford #piercemotorsports by XavierDSM, on Flickr

Another, much smaller, issue that I have ran into is that the OEM control arm bolts located at the inboard pickup points do not fit through the holes designated on the subframe, due to a shouldered standoff. Nor do the alignment spacers included with the control arms have a large enough inner diameter for the same bolts. I currently have everything mocked up with 5/8 all thread as I couldnt readily find a bolt that was long enough for this purpose. I can snap more pics to show the issues, but this is where im at right now. Looking at having a friend come over and most likely modify the subframe, unless you would like to take my suggestions in hand and modify this finished subframe. Ive got some idea floating around that would make things fairly simple. Wouldnt really need to modify much. As it is right now I need to chop my car up (more than I already have) to create the necessary clearances, but I find the extra chopping to be unnecessary just to accommodate non-optimal conditions.

Also Jim, I see youre moving ahead on the FWD units, mind if I ask who else has made deposits on those units? Im excited to know who might be getting one. You havent forgotten about the 4WD guys undertaking this venture have you?

[AWDXavier]

Snapped a better picture of the Axle/control arm angles. (dont mind the inner CV boot, still need to get some spacers made up to adjust for axle length)

#toyotapoweredford #piercemotorsports by XavierDSM, on Flickr

[JPmotorsports]

Hey Jim, just letting you know where Im at on my swap, as Im finally getting everything bolted up underneath the car.

While I can appreciate how awesome this piece is, and how strong it really is, it needs some engineering work to create the necessary clearances while providing proper suspension and axle geometry.

My uneducated recommendations. The differential mounting position absolutely has to drop, As much as two inches would be good, although less would suffice if not feasible with your design parameters. With the suspension under compression and the control arm at an angle parallel to the ground, the axle is angled fairly harshly in a downwards angle towards the outside of the car. What little I know about suspensions says that the control arms shouldnt be much past horizontal under full compression. The height of the diff and angle of the axles also creates a clearances issue with the framerail. This condition has been verified to be the same on the AWD framerails, clearances being within the same parameters.

Here are some pics of what I happen to be working with on my FWD.

#toyotapoweredford #piercemotorsports by XavierDSM, on Flickr

#toyotapoweredford #piercemotorsports by XavierDSM, on Flickr

While this picture is better to show axle clearances, the next shows the Axle angle compared to control arm angle. While im not a suspension engineer, what little i do know tells me axle and control arm angles should be neutral when compared to one another.

#toyotapoweredford #piercemotorsports by XavierDSM, on Flickr

#toyotapoweredford #piercemotorsports by XavierDSM, on Flickr

Another, much smaller, issue that I have ran into is that the OEM control arm bolts located at the inboard pickup points do not fit through the holes designated on the subframe, due to a shouldered standoff. Nor do the alignment spacers included with the control arms have a large enough inner diameter for the same bolts. I currently have everything mocked up with 5/8 all thread as I couldnt readily find a bolt that was long enough for this purpose. I can snap more pics to show the issues, but this is where im at right now. Looking at having a friend come over and most likely modify the subframe, unless you would like to take my suggestions in hand and modify this finished subframe. Ive got some idea floating around that would make things fairly simple. Wouldnt really need to modify much. As it is right now I need to chop my car up (more than I already have) to create the necessary clearances, but I find the extra chopping to be unnecessary just to accommodate non-optimal conditions.

Also Jim, I see youre moving ahead on the FWD units, mind if I ask who else has made deposits on those units? Im excited to know who might be getting one. You havent forgotten about the 4WD guys undertaking this venture have you?

Hey guys---sorry for some reason I'm not getting notified when folks are posting to the thread---I'll have a look at the pics and may have to dig a car out of mothballs to look for a solution. We had originally mocked up everything in a car here about 100 years ago (!) and I don't remember having any clearance issues---It seems like I saw Geronimo's unit installed, but now I'm not sure I remember seeing axles in it. Darren just called me to give me a heads up so thanks for that! I just had a massive black Friday sale and have been preoccupied/trying to keep up with it---just received a 1/4 mile of chromoly tubing (!)---things have changed here and our day to day workload is substantially larger than anything we've experienced/exceeding our expectations---with that said I don't want anyone to get nervous-we'll build the units and make sure they're perfect. Feel free to call me at the shop anytime to discuss---310-542-2977. Beau pm me your number again and I'll give you a call at your convenience-I'll have a look at these asap and starting working on a solution---also I'd like to get that 4wd unit/mock up back when it's convenient-thanks!

[KaleoXtreme]

I don't remember Georonimo mocking up the the first one you built Jim, but I do remember another guy (screen name)"Krono" that did. So I dug up his build thread. Maybe the pics will help? I don't think he ever got past mock up as he had a baby and got tied up with life. http://www.wihandyman.com/forum/show...ild&highlight=

I can try pming him with the link this thread, if you think it might help.