Carl

iTrader: (2)

MazdaMotorsports sent the wrong gland nut, so will have to try and sort it out tomorrow. The correct Bilstein part no. appears to be B4-B30-U226B1, whereas they sent me B30-627-B1 which is exactly what came with my shocks for a Porsche. Dang it!

mhr650

I will probably end up turning down the nuts I have, I have already turned the hex off the OD to be able to fit my coilover sleeves. My new concern is if the coilover tops will fit over the big shaft.

eage8

iTrader: (9)

the shaft (actually the damper body) is ~34mm wide on the P30 bilsteins.

EDIT: sorry, I misunderstood. the coilover top shouldn't fit over the entire body, just the top stud. The stud should be stock sized.

Here is what my old R36 (slightly bigger) bilsteins looked like:

I had to add extra spacers because I had ground control camber plates with double bearings:

mhr650

Looks like that is pretty much exactly what I will end up doing, looks like the camber plates I have are from Ground Control and I need new spacer bushings anyway since the ones in the car are pretty worn out.

Carl

iTrader: (2)

I think I just figured out that the right strut is F4-P30-0032-HD that you show in the Bilstein dwg. Mazda Motorsports shows the P30-0104 shock and that is what I ordered from AllShocks. The -0104 is 14" long which does not leave any room for the externally threaded gland nut. The -0032 that you posted is a little over 12", which would leave plenty of room for the gland nut. Dang it again!. MM still hasn't figured out what they were trying to send me.

The -0104 would work with the Porsche internally threaded gland nut with an adaptor machined to fit over the end of the stock strut housing and then tack welded in place. I think a piece of 2"x0.156" wall steel tubing would be the perfect place to start for an adaptor.

Carl

iTrader: (2)

eage8,

Do the struts you show without a stud in the bottom fit int he first gen strut housings. If so, does the gland nut on the top thread down into the stock threads? If so, do you know the Bilstein part no and where did you get them? If so (yet again), are the strut inserts the -0032's for the VW's? Sorry for all the questions. I am just trying to sort out my options here and you seem to have a lot of experience with these.

Thanks,

Carl

mhr650

If you are trying to find those struts the new part number is 34-184530. Good news is they seem to sell for a little less than the 924 -944 part number

Carl

iTrader: (2)

I actually was able to find them. I am kind of waiting to see what MazdaMotorsports comes up with for a gland nut. It should be here tomorrow. If it is the same internal thread type nut, they already sent, I think I will just get some adapters made and stick with the Porsche version of the struts. I talked to Bilstein today and they have no idea what gland nut I would need. So unless someone can tell me the right gland nut part no. I will have to machine something anyway.

With the Bilstein construction, you may not want to just machine your old gland nut out. You really kind of want the seal that comes with the Bilstein gland nut to wipe the grease from the insert as it goes up and down. The design really does seem kind of weird, because the whole strut body essentially moves up and down inside the yellow shell. It truly is an "upside down" strut as eage8 pointed out.

BTW thanks for the info on the big brake modifications. I convinced my ChumpCar team captain to go with the machined 1st gen "hubs" and 2nd gen vented brakes in the rear. All the parts are sitting in my garage waiting to get modified/installed/whatever.

mhr650

I was talking to one of my friends who has ran IT7 for many years and he said that he thought the VW struts were the right ones, he has a pair and was going to check out the part number for me, if he can find them……..

eage8

iTrader: (9)

I'm not a first gen guy, and all of my bilsteins have been in custom housings... but I thought the first gets used the same size threads as koni inserts which are the same as the P30-0032 bilsteins.

I do know that AWR uses the P30-0032s in their FC race cars. and I think they're interchangeable with koni 8610s and 8611s...

and yes, the picture I used are the P30-0032 bilsteins (mk1 golf VW)

mhr650

I have everything modeled up in CAD if you need any info on modifying the parts to make everything work.

Carl

iTrader: (2)

Thanks. The CAD models would be great. That would be alot easier than mocking everything up one piece at a time. My email is cbjohnk@inetworld.net.

Regards,

Carl

Carl

iTrader: (2)

OK. I have the Porsche 924/944 struts (P30-0104 old Bilstein no.) installed in the 1st gen strut housings. I had to make a threaded adapter that slips over the top of the strut housing and is tackwelded in place. The Porsche gland nut that came with the struts (or is available separately from MazdaMotorsports for $40) threads down on to the top. I really think you need the Bilstein gland nut, because is has a wiper seal on it that keeps the grease, lubricating the sliding strut where it belongs. With out the seal, I think you would have a mess and fairly quickly and possibly a strut that doesn't work very well.

The VW strut that is shorter would need the same kind of seal. There is not a lot of clearance between the strut housing and the "shaft" of the Bilstein if you try to thread a gland nut/seal into the top of the Mazda housing.

Hopefully the pictures help explain what I did.

I think the top will fit directly into my ground control camber plate. Worst case, I might have to machine a couple of simple bushings. I am not that far yet.

Carl

iTrader: (2)

Of course, forgot to add pictures.

mhr650

I am glad you are out in front on this, I can copy from what you learn. Since my car will not be ready I am going to the race at Road Atlanta as a volunteer and will be watching what shakes out in tech before I order my shocks……………………

mhr650

Follow up on how I was able to install Bilstein struts on my car. It is not a simple bolt on proposition but once you do it I believe the results will be worth it. First I ordered B8 struts for a MK1 Volkswagon part number 34-184530, they are shorter than the struts for the Porsche 944 and on the market they sell for less which helps me with my 2X math for ChumpCar. For rear shocks I ordered the Fox body Mustang shocks 24-021478, everything fits except the bottom eyelet is 8mm too wide for the axle housing, I just machined 4mm off each side and it fit perfect. Now for the fun part, getting the struts to work on our cars, since I discovered that one of my strut housings had a bent spindle I got to do everything twice so I will show the better way which is how I did it the second time.



As you can see the Bilstein strut is much shorter than the original strut so you will have to cut the strut housing down



I took a little over 2 inches off of the strut housing



You want the strut to stick up so that when you have the gland nut screwed down you have about 2mm clearance before the nut bottoms out.



The VW strut comes with both internal thread and external thread gland nuts with M50 threads on them on my first version I used these. In addition to having to machine out the ID of the internal threaded nut to fit the strut housing I also had to turn down the OD to fit under my spring sleeves, this left the nut much thinner than I would have liked. A much better solution is to order M45 threaded gland nuts from Bilstein. The part numbers are B30-629-F1 for the internal threaded nut and B30-627-D1 for the external thread, you need 2 of each and they come with the seals installed.



On the internal threaded nut remove the seal and machine the ID of the end where the seal fit to fit your strut housings, approximately 45mm or 1.77 inches, I machined them until it was a nice tight slip fit.



Once you get the gland nuts machined assemble the internal and external gland nuts, screw the nuts all the way until they bottom out then back them out 2 turns. Install the gland nut assembly onto the strut and press them until they bottom out and hold the strut tightly in place, now you can tack the modified internal threaded nut in place. remove the external threaded nut and strut and finish welding everything together. Now you are good to go.

Freeskier7791

I know this is old but bumping for good info

Carl

iTrader: (2)

An addition to the Porsche 944 struts write-up above. I did need a different adapter for the strut to go into the ground control camber plate. I just bought it directly from ground control (they new exactly what was needed). I think it was something like $8.

Carl

mhr650

I too had to get new bushings from Ground Control, it was no problem since I needed new ones anyway. The thin part of the bushing that fits between the shaft and the ball is so fragile that it ends up being a wear item when you work on the car.

I have been working with a buddy to do my same setup that I used on a new IT7R car that he is building and we are having a problem finding the 45mm thread gland nuts. It is possible to do it with 50mm nuts but you end up with a very thin wall once you turn down the OD to fit coil over sleeves.

Carl

iTrader: (2)

My installation with the 944 struts uses the old style Ground Control adjuster sleeves which are 2"id. Those may help your clearance issues. You can use a metal ring or O-rings to fill the gap between the strut housing and the sleeve.

As you can see in the attached picture I have temporarily (maybe) gone back to tokico shocks and lighter springs. I did not have time to get the suspension sorted out with 450lb fronts/944 Bilstein and 275lb rear/mustang Bilstein (24-021487). I think the rear shocks were not sufficient to control the 275lb rears. I ended up back at PRO7 design using 350lb fronts/mr2 tokico blues and 175lb rears/rx7 tokico blues. The lighter setup was much more comfortable (and controllable).

I know something was wrong with the stiffer setup but I have not had time to figure it out yet. I plan on addressing that later this year. Having said that, I am not sure that there is much time improvement in the stiffer set-up. Like most things we do to our cars that don't involve increasing horsepower or tire grip the time improvements are pretty small.

Carl

gracer7-rx7

iTrader: (16)

Considering the low grip tires you use in Chump, I'm not sure you really need a stiffer setup

mhr650

Have you raced on what are being sold as 200TW tires nowadays? The tire war is going strong and some of the tires are so grippy that we can’t even use them for a 7hr race without doing tire changes at pit stops. At least one sanctioning body has put in rules to prohibit changing all 4 tires during a fuel stop.

Carl

iTrader: (2)

I have not been on the newest 200TW tires. I am still using 205-15 Falkens. Even with these though I do not seem to be much more than about 2 secs per lap slower than on Hoosier SM7's. I would be surprised if any 200TW tires match Hoosiers.

At 2 secs per lap with 150 laps in a day you need to change the tires in less than 5 minutes (certainly possible when combined with fueling and driver change) to be ahead of tires that last +30 hours of racing.

Of course, your lap times might be more than 2 secs per lap faster on the softer 200TW tires compared to the harder but longer lasting 200TW tires. It would be an interesting test. Especially from the economic point of view.

Carl

mhr650

The big change that is coming is the 245-40-15 size tires. I converted my car over last year with the wide wheels necessary to use them and ran with the Maxxis which was the only tire available in that size at the time, now there are at least 2 more manufacturers getting into the market. Before moving to the bigger tires we had run the best on 205-50-15 Dunlop star specs, the Maxxis was faster and wore fantastic, I am not sure that it is the fastest compound out there or if it was just the extra size, I am looking forward to trying some of the new 245 tires as they are available. One tip using big tires on these light cars is to think outside the box on tire pressures, we run way lower pressure than almost anybody else out there but it works great for us.

Carl

iTrader: (2)

Mike,

I think I got your name right this time ;-) I am wondering what spring rate you are using (or used) in the front with the VW Bilstein struts. It looks like I don't have enough shock travel with the 944 struts. I have bent two pairs of camber plates (mounted on top of the stock strut towers), including the current ones that are reinforced with 1/2" aluminum plate on top. Also broke two front spindles this past May (one on Sat and one on Sun) Do you think the VW Bilsteins are up to 400-450 lb/in spring rates?

Sorry to raise this from the dead, but you are the one with the experience that I need :-)

Cheers,

Carl