Cracked flex on exhaust downpipe

#21

jblack wrote:

[quote]Can you point to the part that you have issue with on the attached picture? I don’t remember the flex section on the 325’s exhaust - I do remember it on my Honda - but - that was a very different application.

I’m not discounting your argument, but - the data points in this series are pretty high with no issues with the exhaust due to cracks due to the lack of a flex section. Also, consider that the rules allow for much more robust engine mounts than stock 325i - I would guess that this should reduce the movement that may cause the cracks you are talking about.

Also - we do drive with our windows down (at least most of us). And the Spec Exhaust is NOT for street use - matter of fact the rules forbid driving your car to the track with the Spec Exhaust, so all time with a driver in the car should be with the windows down. [/quote]

Even with the windows down, CO can overwhlem you quickly, even in open air. I grew up waterskiing and heard horror stories about kids playing on the swin platforms of boats while they were idling, even the minimal amount of exaust produced at idle made the kids pass out and drown.

I believe that just one data point in the series’ short span involving a driver passing out in a car is enough to raise serious concern.

#22

OK - but - what’s the issue? If we are cutting the down tubes where the red arrows are - what’s the problem? We retain everything to the left of those arrows, and everything above them (Manifolds). We’re including the flex part as a piece of the spec exhaust, per the rules.

#23

mikeski38 is saying the flex joint can crack

#24

They crack where the circle is in the other guys post. The scary part is that the other tube will support the entire thing for a time so you won’t know you are leaking fumes until it is too late. You see in the picture the stock tranny mount is, just after that is where a flexible joint should be, along with reinstalling the trans mount. This isolates the down tubes from the flexing of the rest of the exhaust system.

#25

I understand now. I read into your post that you were taking out the flex joint and putting it in a new place. We are on the same page.

I would suggest you contact your regional director and suggest a rule change if you feel strongly on this. Don’t know how others feel on the topic - hope that helps on the process.

Thanks for helping me out on the area we are talking about. I don’t even remember the flex joint when we assembled ours - I’m sure it’s there - I think I vex at it every time I do the oil…

#26

I am in the process of discussing options with my regional director and hopefully Carter when he responds. I hope the rules guys have the ability and the participants are open minded to changes, it will help the process. I will be approaching it from a safety perspective, not performance.

#27

For sure, Spec E30 wants the cars to be safe and if a rule needs to be reviewed and/or changed, we are always willing to look closely at any situation.

Is flex joint cracking/failure an issue with several cars or is this an isolated incident? Our cars sometimes live a tough street life for many years and also sometimes live in tough environments.

Do other drivers see this on their cars?

Thanks for bringing it up.

Carter

#28

I broke the flex joint on my old car. The car would backfire and run extremely rich until I figured out what the problem was.

Usually you’ll notice pretty quick when a crack or seperation occurs because the exhaust note sounds terrible.

JP

#29

Carter wrote:

[quote]For sure, Spec E30 wants the cars to be safe and if a rule needs to be reviewed and/or changed, we are always willing to look closely at any situation.

Is flex joint cracking/failure an issue with several cars or is this an isolated incident? Our cars sometimes live a tough street life for many years and also sometimes live in tough environments.

Do other drivers see this on their cars?

Thanks for bringing it up.

Carter[/quote]

I have run across a few guys who have complained about the issue. This thread was started by someone who had a cracked pipe and wanted to know the legal way to fix it. Someone responded commenting that due to the design of the spec exhaust it puts added load on the down tubes and has been known to crack them.

I just finished my first SE30 build, and we competed in our first event. The car was a ton of fun and we were amazed how competitive our car was right out of the box, very little tweaking required. However, we were not impressed with the spec exhaust from a safety stand point. My critisism is that it is one piece from head to bumper, and the stock tranmission mounting point was removed. The portion or the exhaust in the engine bay is not isolated from the flexing of the rest of the exhaust, and the stock down tubes are the weakest link and will likely crack first since they are made from much thinner material then the spec system. To make matters worse, there is the little flex section in one down tube that is even thinner the the rest, and since this flex section is only on one of the tubes, the other one will support the entire system for a time so the exhaust leak will not be plainly obvious to the driver. Since the spec system does not isolate the forward section of the exhaust, it is not a matter of if it will crack, it is when. In cars with stiffer engine mounts and fewer off track excursions, the occurances will be less frequent, but will happen eventually.

I was not comfortable with the safety aspect of the design, so built my own exhaust system. It cost me less them $150 in materials. I copied every detail of the spec system including pipe size, collector and exit location, routing, muffler position and type of muffler. I did change the legnth of my muffler because the spec system is quite load and I would only loose performance with a longer quieter muffler. The important bits I added was the solid hager mounted to the back of the transmission, and just aft of that I added a flexible coupler. It is only of those spring loaded jobbers you see on most japanese FWD cars. Total cost on it is around $20. All you need is two, 2 bolt flanges, 2 bolt and 2 springs, and the tapered gasket. All of which is readily available at any muffler shop, and if it is not in stock, ask them to order the High Temp cat gasket for a Honda S2000, or integra type R. Now the section of the exhaust in front of the driver is isolated, any impacts the exhaust may take will either not damage the system because it is flexing freely now, or if the hit is big enough, will more likely break aft of the driver, reducing the risk of CO poisoning.

On my very first comp weekend in the car, Will has a big off and went John deerin’ for a few hundred yards. The off damaged the exhaust and it began to fill the cabin with CO. Will was able to finish the race, but when he arrived in impound, he was all but passed out and could not exit the car under his own power, or talk to anyone. Luckily, the Grid marshall here in NorCal recogonised the situation and called the ambulance and they began treatment. The situation was serious enough for them to have the helicopter on standby. Luckily, his condition started to improve and he just had to spend the rest of the afternoon in the medical area under supervision. He was expected to be fully recovered by the end of this week.

I do not believe that issues like will’s will be very frequent, possibly only 1 or 2 per season, but it is a coin flip that can easily be avoided with a redesign of the spec exhaust. And CO poisoning rarely ends with the driver passing out in the paddock, one more lap and will would have passed out on track. I have been club racing since 2002, and the majority of driver deaths in club racing since then have been a result of the driver passing out for one reason or another, and since 3 of the deaths were from drivers in fully fabricated racecars, a likely cause would be CO poisoning.

Carter, I have taken pics of my exhaust and would like to email them to you for your review. Please send your email to mikeski38@hotmail.com A good plan of action is to allow us to modify our systems until the powers can redesign the spec system to account for this known safety issue. Perhaps reinacting the old exhaust rule for a time. If the failure of a series required part was the cause of a major injury or worse, that could end badly for NASA and SE30. Thank you for the consideration.

#30

mikeski38 wrote:

Comp weekend - so you raced in a Spec E30 race with the system you built?

Not sure I’m following (again) Will - it he a co-driver with you - was this your car, or another SE30 competitor.

Just trying to understand. I follow your logic (but damn - long post :slight_smile: ) - I’m all about making this sport as safe as we can (within reason). Just trying to figure out the data points.

Thanks!

#31

Mine has been broken for a while. Tried a sheet metal and hose clamp hack job fix that does not work well. A rule change that allowed for a fix for this would be helpful.

#32

Red plastic exhaust tape was doing fine on the streets but it lasted only 1 day on the track.

More cheese burger please…

#33

dherrington wrote:

I’m hopeing for a allowance in the exhaust rule that will keep it from happening all together.

#34

Will Faules was driving our orange #37 car when he had his off. He struck a very deep ditch pushing the radiator support back approximately 3" at the bottom. The oil pan was also cracked… FWIW the car should not have been back on the racing surface.

The car will be back at the shop by Thursday afternoon where we will take a close look at the exhaust. Any talk about what or where it broke is pure conjecture. We’ll get the car in the air and inspect it head to toe while taking photographs.

#35

What happened to will’s car will definitely be great info for whatever national desides to do about the issue, but even without his incident, an all one piece exhaust will continue to create problems and should be updated to maintain modern safety standards like flexible joints isolating the forward section of the exhaust from fatigue and failure from vibrations and flexing.

#36

We have the car in house and have completed a post race inspection.

“The 37 car’s driver, Will Faules, was overcome by exhaust fumes while in competition at Thunderhill on Sunday April 26th. The car sustained substantial damage when it struck a drainage ditch during an off road excursion. The hit was hard enough to push the bottom of the radiator support back 6 inches, folding the oil cooler in half and destroying the oil pan. In addition the wiring harness grommet was knocked out of position in the firewall on the passenger side allowing exhaust gasses to be pulled into the driver’s compartment. The SpecE30 exhaust system was welded in place in accordance to the SpecE30 rules and was not compromised in any way.”

Rear wheel drive BMW’s have never had a “flex” pipe in the exhaust system, it simply isn’t needed. Flex pipes are typically associated with front drive cars whose sideways mounted engines will rotate in it’s mounts stressing the exhaust system even with poly mounts. My shop manager has been with BMW for over 27 years, his experience is that the tubing is not prone to breakage on its own. The reason it is there is to facilitate lining up the downpipes. In his experience broken flex joints are due to man handling during removal/installation or rust. The OEM BMW exhaust on the E30’s is no different in design or execution to the SpecE30 exhaust, multiple solid joined sections. Since welding is optional one could possibly use one of the clamps and weld the rest? Our installations are extremely tight to the subframe and chassis with no chance of contacting anything. So far in our region we have never experienced a failure in the exhaust system as designed. It isn’t the prettiest thing on track but it is inexpensive and keeps the playing field even for everyone.

#37

Mikeski mentioned using the OEM exhaust support piece that mounts to the rear of the tranny. I think that this is a good idea because then the downtubes don’t have to support the weight of the front of the exhaust system. All you do is cut the tab off of the OEM exhaust and weld it on to the spec exhaust.

Recall that the Spec exhaust is a fair amount lighter then the OEM exhaust. Maybe the combo of a lighter weight exhaust, and using all the OEM attachment points reduces the probability of cracks in the downpipe to an acceptable margin.

#38

The trans/exhast mount is needed as if the exhast comes off and swings to the side and you run over it, bad things happen…if it comes off and goes stright back, bad things happen to the guys behind you…

#39

FARTBREF wrote:

Yeah screw those guys… if they didn’t want to get hit with parts they should drive faster… :0)

#40

vmwerks wrote:

[quote]
“The 37 car’s driver, Will Faules, was overcome by exhaust fumes while in competition at Thunderhill on Sunday April 26th. The car sustained substantial damage when it struck a drainage ditch during an off road excursion. The hit was hard enough to push the bottom of the radiator support back 6 inches, folding the oil cooler in half and destroying the oil pan. In addition the wiring harness grommet was knocked out of position in the firewall on the passenger side allowing exhaust gasses to be pulled into the driver’s compartment. The SpecE30 exhaust system was welded in place in accordance to the SpecE30 rules and was not compromised in any way.”[/quote]
I’m confused. Where’d the CO come from? If the exhaust was unharmed, wouldn’t it all exit at the back of the vehicle?