Ok sorry for making another thread, but what bolts do you guys use with stock O2 and aftermarket Downpipes ? The stock bols come with the springs, but they don't work with aftermarket downpipes. Do you just install regular bolts without the springs ?

 

You may want to contact that manufacturer. A well designed DP should accomodate the factory springs which are vital for flex and long term fitment.

 

+1

 

The "spring loaded" bolt set up is a life saver for the exhaust. It can move slightly to "adjust" for slight impacts caused by our wonderful roads here. without them you will fight leaks non stop.

 

you dont really need the same bolt setup. Just find a downpipe with a flex section and it will be fine.

 

which it might leak in the future time..

 

Not only that but also to compensate for thermal effects (expansion/contraction) and not to come undone from all the vibrations. If you really can't fit the thing with the springs, I suggest you use some spring washers (disc springs) and stack them (/\/\/\ NOT \\\\\). I haven't done any calculations, but I dare say that the stiffness is not critical, only that there is some flexibility while providing the clamping force.

As for the grade of the bolt, if you're not sure a higher grade shouldn't hurt. Can't remember US grades off hand, but ISO it would be 10.9 just to be safe. I don't think the stock is anything special.

 

I have RnR flex downpipe. Stock Bolts would not fit through the holes, because in the middle of the bolt there was a built in spacer, that would not go through the hole. I just bought a Dremel and shaved them just enough to go through the hole. This way I was able to keep the stock springs. It took me some time, but the sucker is in, looks and sounds great. So far happy

 

Interesting concepts.

I've been building exhausts for the DSM's/EVO's now for a good 12 years. I haven't seen these failures that are being referred to from not having spring bolts are flexes. Interesting though

We don't use a flex or factory spring bolts in ours. We do supply the downpipe with new bolts/washers for the install though. Are you sure the bolts didn't come with the downpipe you bought and aren't in the packing material from RNR?

David Buschur
www.buschurracing.com

 

Letmein, you followed my advice.

 

As I mentioned, I think the most critical thing is the slight flexibility. How important this flexibility is depends on the rest of the exhaust (weight) and the hangers. If you have well designed aftermarket cat-back or tbe it shouldn't be too much of an issue. Besides, if your dp is strong enough, then there's no reason to bother.

I'm not being a smart **** here, just trying to clarify why the stock comes with all those bits when it appears that some can do without.

 

well I received 5 bolts with the TBE, I guess 1 was missing. This is the first time I was installing an exhaust. Although 3 of the bolts would fit with donwpipe connection, I used 2 of them to connect the test pipe, and for some reason thought that I MUST use stock spring-bolts. It didn't come to my mind that since I have a flex downpipe I don't have to use the springs anymore. Ehh when I install O2, I might go with regular bolts.

heres the picture