I desperately want to watch your auto-x videos but the buzzing from the camera makes it unbearable. put some foam somewhere so it doesnt rattle

 

yeah... not really sure what that is.... its mounted on my roll bar with an IO port mount, and it doesn't happen on my suction cup mount... maybe I need to tighten it up a bit?



in the mean time you can just mute the video

 

Well wheres the fun in that? I just want to hear the brap brap brap!

 

noise didn't bother me. I like watching these cars actually get driven.

 

just read through the whole thread! the car is looking great and looks to be performing great! what caught my eye was your wheel set up. can you PM me more information on tire and wheel sizes? as well as the widebody?

 

Which wheels?

The most recent ones are 18x12 rota p45r3s +20 offset.

30mm spacer up from, 20mm in the rear

Its a ronin speedworks wide body (same as the old tri-point kit

 

Curious about the 20mm spacer in the rear. Do you know how much gap you have between the tire and swing arm? Presumably setting this clearance is the purpose of the spacer.

 

My street tires are super close to the control arms with the 20mm spacers (17x10 +35 w/ 315/35/17s)

I have a decent amount of room with the 18s, maybe 10mms? We'll see what happens when I try to put a 335 on the back...

 

Wow, you really run your rubber right to the edge. I can't imagine 315's being too small, but you might want to reconsider stepping up to 335's unless those Ronin fenders give you more room expand your spacers out.

It's really surprising that you can get away with 10mm clearance running slicks at an autocross. Must be the 12" width limiting sidewall deflection. I'd think you'd recognize if you had rubbing since you swap between street and race wheels; have you looked for signs of swing arm contact?

 

and yeah, 315s are pretty stretched on 12s, so they don't move a whole lot. I haven't seen any new signs of rubbing on the swing arm . trying to get 275/17 hoosiers on 17x10s under stock rear fenders caused me a lot more issues.

you can see in this picture I have a good bit more room in the back than I have in the front:

 

attempted some weight reduction last night....



- The last speaker I had in the car
- the front tie downs (I have a ronin speedworks aluminum front tow hook)
- rear washer bottle
- rear window wiper motor (need to find a 28mm rubber plug in the junk yard...)

Grand total.... -8 lbs
a bit disappointing

 

Don't despair! That was an easy 8lbs

Weight reduction is one of those things that adds up and you can do a bit here and there as you have time/budget.

Estimates

58lbs- Trade your wide tires/Rotas for my 16" Volks $free (this ones a joke)
40lbs- Remove roll bar when auto-xing $free
22lbs- Optima D51R to Shoria $300
20lbs- Sunroof to non-sunroof conversion $free (off TOP of car)
20lbs- Fiberglass front/rear bumper covers $2-300
20lbs- Fiberglass/CF shell style seats with brackets to floor $200-2,000
10lbs- Fixed headlights $free (B-wave FG bumper or fix the up)
8bs- Power to manual window $free-200
5lbs- Power mirrors to aftermarket manual $free-300
3lbs- Delete factory "wing" $free

Total= around 150lbs for around $700 (not counting joke of course)

 

Yeah, they 200 lbs (literally) of wheel and tire is an issue

I thought about removing the roll bar... and installing it for track days I weighed it before I put it in and it's a solid 50 lbs

I've actually kept increasing my battery size because my car has issues starting... once I get that fixed I'll put an AGM (or a new Lithium-iron) in.

I have a non sun-roof panel and headliner waiting to go on/in the car that one might have to wait till winter though....

If the car does get into SM next year min weight will only be 2700 so I don't have too far to go.

 

So last night I tested some front bump steer:

-2.0" -0.0115"
-1.5" -0.0055"
-1.0" -0.0010"
-0.5" +0.0020"
0" 0.0"
+0.5" -0.0110"
+1.0" -0.0295"
+1.5" -0.0410"
+2.0" -0.0555"
+2.5" -0.0740"

(+ being extension, - is compression)

not too bad, but I think I can get it a bit better.

while I had the strut off to I weighed it:







spring weights to be thorough:





I don't know what normal coilovers weigh

I also discovered they sent me 8" 900 lb/in springs instead fo the 6" ones that I ordered... which I'm not too pleased about. (i thought that had looked strangely long....)

also when I was testing bump steer on the way back down my control arm seized and I couldn't push it down by hand unless I put a lot of force on it, I've known about this for a while and it's probably one of the reasons why my car picks up the front wheel so easily (even without the sway bar now)

so I took the control arm off and replaced the mazdaspeed sourced delrin bushings off and replaced them with some MMR delrin (front) /UHMW (rear) peices I ordered a while ago for this very reason.



you can see the rears have a much larger recess cut into them, hopefully that'll help:

 

FYI I had to hone the front hole in the control arm quite a bit for the MMR delrin bushing to move freely. As machined, they're way too tight. Same with the back, although i just used sandpaper on the shank (shitty).

chances are the MMR and Mazdatrix are the same dimensions

 

yeah... they're stupid tight, I'm going to do the same thing.

I was actually thinking about just grinding off the barbs on the control arm, I haven't measured the ID of the bushing and the OD of the non-barbed section to see if that would be a good idea.

 

I cut the barbs off of mine, because theres no way to check tightness and adjust. once theyre on, theyre on.

 

I'm running polyurethane bushings now, but I'm going to need to switch. I we had access to a lathe some delrin would be cool.

Did you ever get the chance to measure your spacing on the tie rod and lower joint?

I know the height is going to matter, but I'm trying to figure what length bolt to go with for my lower joint, and which spacers i should use for my bump steer

 

did a bit of grinding last night on the front control arms:

before:


after:


it made enough clearance that the delrin bushing I took off is not loose on the control arm (after the barbs removed some ID....) so it should make a decent amount of difference.

 

Also, a friend of mine has been been reworking some top hats I have for the rear to reduce the thickness so I can run them without loosing suspension travel:



not nearly done yet:


the goal is to make them the same thickness as these ground control top hats but with the correct (14mm) center hole:

 

Hey how's the boost creep issue been going?
We had a lot of over boosting issues with the stock turbo, so we ended up porting the waste gate holes insanely, and welding up a tial 38mm external gate to the back plate of the turbo. (Vented to atmosphere) Car still over boosted! So we had to weld a plate to block flow about 6 inches from the turbo in the downpipe.
Seems the stock turbo cant be controlled if you have too free flowing of an exhaust. Just be careful out there lol. Awesome build BTW.

 

So far with the new downpipe I've just been running on the waste gate alone (no boost controller) and the boost has been rock solid. So I'd call the new downpipe a success

 

I've been super busy at work, so not a ton of progress... but the replacement springs came in (they sent me 8" 900 lb springs instead of 6" springs... )

in the never ending quest for lightness I weighed them:





about 3.5 lbs lighter

 

modified top hats for the rear turned out awesome.
lower profile:


and a huge recess for the damper to go into:


tonight I finished up putting the front suspension back together and tightened up the front wheel bearings... hopefully the new rear springs come tomorrow so I can throw those and these new top hats on the back in time for the autocross on Saturday.

after that the rx7 is going to have to hang out outside for a while because I picked up a new engine for the subaru (it's current engine it horribly low on compression and leaks/burns oil like crazy... most likely going to seize any day now...)

 

With my 1" bump steer spacer (plus half of a 0.75" wide bearing) I have 0.525" of tie rod spacer plus half of a 1.25" rod end

so:
ball joint space to center of bearing = 1.375"
tie rod space to center of bearing = 1.15"

the bolt I have going through is 3.5", but I have a spacer on the other end of it and the rod end is pretty thick so you might be able to use a smaller one...