mhr650

I am building a new race car for ChumpCar since I totaled our other one at Summit Point, it is an 84 that will be run with a 13B swap.

For 2015 Chump loosened up the shock rules a little bit to allow replacement shocks as long as they are not adjustable or rebuildable. The rebuildable part is a bit of a gray area that will be a big problem for them to enforce, but shocks with adjuster ***** are pretty obvious. I know about using the MR2 Koni struts but since those are adjustable they are a no go. I figure I can find some Mustang shocks for the rear but does anybody know of a really good strut that will fit in the front of a FB and not be adjustable? And if so do they make a shock that I could use on the rear?

DreamInRotary

iTrader: (49)

Tokico Blues for the front are non-adjustable and a great shock for the money

Diver22

iTrader: (1)

I tried those and trashed them in 2 races, we are running anywhere from 14-24 hours straight, they weren't durable enough.

DreamInRotary

iTrader: (49)

Crazy! I'll keep an eye on this thread to see if there's a better, more durable and longer lasting shock for the fronts.

Carl

iTrader: (2)

The following was excerpted from this thread.

https://www.rx7club.com/1st-generati...in+koni+tokico




"I have the "correct" Bilstein part numbers for the 1gen cars back at home (can't find the folder right now) and the correct bushing #'s that go in the rear (don't come with bushings for this part #).

1gen Bilsteins are as follows--
Front P30-0104 (insert)
Rear B46-0347 (shock)

Bushing E4-GV1-Z044A05 or #408516 for rear shock."

I believe the fronts are for originally for a Porsche 924 or 944, but apparently they work well and are quite durable for racing. We have been talking about using them in our ChumpCar, but haven't done that yet. I suspect I will get them in my IT car first. Not positive how they fit, but I plan on getting a pair soon and figuring it out.

Carl

wankel=awesome

wat


I WANT! I cant find the rear shock though :C Cant I use a fox body stang rear shock?

Carl

iTrader: (2)

The bilstein rear shock model no. appears to have changed. Here is a listing at AJUSA

Bilstein 24-003179 Monotube Shock Absorber | AJUSA.COM

I think I found them at Shock Warehouse too.

Carl

mhr650

Thanks a lot this is the kind of info I was looking for. Looks like the front strut cartridge part number has changed to 30-001042.

This is probably the way we will go, but the whole 2X shock thing is still up in the air, I talked to Phil at AMP and the thing he feels is important is shocks that are permanently crimped and can,t be disassembled easily for revalving. The thing with Bilsteins is that whether they are crimped or use a screw on cap is based on what factory the shocks for your car came out of, they can be identical in every other way but different factories use different manufacturing methods.

MountainScreamer

Hey Carl,

I'm digging through some Bilstein part #s, and it looks like the shock you listed (pn 24-003179) is almost the same as the fox body mustang shock (pn 24-021487).
Do you have any idea what the difference of valving would be?
Looks like the mustang shock is ~$20 cheaper. Always better for a ChumpCar

mhr650

$20 helps with the 2X rule for sure, the Fox body is a lot heavier than a 70s corolla so they will probably be stiffer.

Carl

iTrader: (2)

The Mazda rear replacement shocks are over $100 each, so that leaves a lot of room for the 2x rule! I think the Bilsteins are actually cheaper.

mhr650

They are actually starting to crack down on that, you have to use shocks available from a national auto parts chain like NAPA, Autozone or the like. All they offer are KYB or Monroe so you have to look to find the most expensive store selling pretty much the same thing. On the other hand I am not sure how close they will be looking at it, when I did the second gen brake upgrade it only ended up being 1.25X over the first gen stuff and they barely even glanced it the paperwork I had prepared.

Carl

iTrader: (2)

Not sure how it affects chumpcar decisions, but the Bilsteins are available at Autozone. They are expensive there though.

MosesX605

Do those Billsteins fit in the stock tubes without any modifications?

If so, they just got on my list for next year.

Carl

iTrader: (2)

I believe the fronts do fit the tubes without mods. Not sure about the top mount. I just ordered a pair from all shocks and will let you know how they fit once I have them in hand.

eage8

iTrader: (9)

I made custom dampers out of 3000GT bilstein inserts a while ago for my FC. They have 36mm pistons (as opposed to the 30mm ones mentioned above) and are valved for a much heavier car so they're good for stiffer springs.


now I'm running custom bilstein motorsport struts, but they're probably too expensive...


info on both can be found here:
www.rx7club.com/suspension-wheels-tires-brakes-20/[fc]-bigass-budget-baller-bilstein-build-thread-955929/

mhr650

Any strut that we run will have to fit inside the first gen housing for sure. Even with that it is a bit of a gray area if the Bilstein struts will be legal within the new 2X rule, from the pictures I have seen of the 30mm inserts looks like the bottom has a cap that screws on, I have talked to Phil McKinney extensively about what he wants to see and his main point is he wants to see shocks that cannot be disassembled and revalved. The problem with this is that Bilstein builds some shocks with a screw on cap and exactly the same design that are crimped at the factory, it depends on the manufacturing method used at the factory your shock was built at. That makes it kind of random what cars can run Bilstein shocks without question and which ones cannot. I expect some clarification before the season starts.

eage8

iTrader: (9)

no bilstein is going to have a screw on cap that makes it rebuildable... the screw on caps are to hold the insert into the housing

This is what the FC insert looks like, it gets held in by the stud and the collar reinforces the top:


The other version looks like this, you can see there is no bottom stud because the stock housings they go into are threaded at the top, so the collar at the top screws into the stock housing.


no oem replacement bilsteins are revalvable without special equipment. you would need racing bilsteins with schrader valves to rebuild them yourself:

mhr650

I understand that the screw cap on the strut only holds the insert in place. The area I am concerned about is the cap on the bottom of the insert, if it is crimped then they shouldn’t have any problem, but if the cap is threaded then it could be a problem.

Carl

iTrader: (2)

There is no way ChumpCar is going to make you take your struts apart to verify that the bottom is crimped, especially if some come crimped and some do not. Anyway, I will let you know what the bottom of the Porsche strut (for front of FB rx7) looks like when I get it.

eage8

iTrader: (9)

it doesn't matter if that part is crimped or not. Bilsteins are inverted, it's an up-side-down strut in a tube, the thing right above that is the bumpstop, and the threaded rod is actually the rod that normally goes through the top mount in a twin tube strut.

This is what my larger bilsteins look like when I un-thread them out of the sleeve:
threaded in:


bottom part threaded out:


you're just taking the actual damper part out of the housing, you still have no access to the piston/valve or the gas pressure.

(sorry for the crappy pictures, they're the only ones I could find.)

eage8

iTrader: (9)

Here is possibly a slightly better picture where you can see where the piston/shim stack is actually located:

Carl

iTrader: (2)

MHR650,

I just received my Bilstein shocks and it looks like the bottom might be removable. Looking at the drawings you and eage8 supplied, it doesn't look like being able to remove that cap makes the shock rebuildable. Removing the cap does not look like it lets you get into the hydraulic part of the shock. Maybe other things inside do, but.... I think they should be fine for ChumpCar. Just my opinion thought.

mhr650

Does it look like you will have to turn down the ID of the gland nut to get them to fit over the large shaft on the Bilstein struts?

Carl

iTrader: (2)

I ordered a modified gland nut from Mazda and it should be here today. You can actually buy the Bilstein shocks from MazdaMotorsports for the same price I paid to AllShocks. I did not notice that before I ordered. I will let you know what the gland nut looks like once I have it. It would also be possible to machine an adapter that fits the OD gland nut that comes with the strut (as a Porsche 924/944 replacement).