Question about airbox "modification" and mounting


“ The stock unmodified intake airbox assembly shall be retained, and in its original mounting. The stock airbox front rubber hose shall be removed.”

My radiator is slightly deeper (front to back, it has an extra row I believe). This puts the upper hose tight against the airbox (actually pinching the hose). It appears with two minor modifications (that do no impact performance), everything could fit and be happy.

If I grind off one of the external ribs on the front of the airbox, I gain about 1/4 to 3/8 of an inch (this would have no effect on the internal surface of the airbox, therefore no change to airflow). If I then slot the mounting bracket on the fender to allow the airbox to come back about 1/4 inch, that should remove all of the tension on the the hose, with it just barely touching the hose. If I notch it a little further, I can get the hose out of contact with the airbox, removing the possibility of friction causing the hose to fail.

To me, doing this would be in the spirit of the rule as neither modification results in a performance advantage or in an unsafe condition. Would that be correct?


I have the same problem for the same reason. My solution was to use thick/strong zip ties to move the hose forward and away from the air box. Then I cut a piece of AL from a soda can and taped it to the hose to protect it from the air box abrading it. The air box does push on the hose, but they seem willing to coexist.

Grinding off an external rib from the airbox should be no big deal. I’ll have to check mine to see if I did that. If I didn’t, I might, because it sounds like a good idea. I just don’t remember precisely where, on the airbox, the contact is occuring.

Moving the air box might create some concerns tho

In regional races, no one’s going to care about any of that, as long as the movement of the airbox is really minor, your competitors are aware, and you’ve encouraged them to take a look. That’s just cultural stuff. Everyone’s there to have a good time with their buddies, and folks don’t get worked up over little stuff. Talk to your regional director and that’s what he’ll probably say.

National champs events can be different tho. There might be a competitor that prowls around cars and looks for things to complain about. There might be an Impound official with funny ideas re. what is reasonable and what’s not. So national events need to be approached carefully.

I can certainly commit that at, a Nationals event, that I’d stand by your side and help defend the mod. But my actual authority ranges from zero to not much. My success rate with talking the other person to exhaustion can work pretty well. The best solution tho, if you’re going to Nats, is to take some pics and send them to Shawn for an official ruling.

It used to be that we could have trouble at nationals events because the NASA guy running Impound might not see an issue like we would see an issue. But now that Shawn is wearing the additional hat of NASA Tech Director, that can’t happen to us anymore.

If you’re going to COTA for Nats, I’ll be there at Impound and Shawn will be looking over my shoulder. So nothing crazy will happen. Just don’t let there be any surprises found. Anything that might be iffy, get it discussed prior. Heck, we could stand up in front of a driver’s meeting at COTA and say, with a big stupid grin, “Weaver here is pulling some cheat again. He’s moved his airbox 2mm rearward. Go look at that wreck he calls a race car. Does anyone want to spend $100 to protest Dan’s car? By the way, Dan’s buying us all beer tonight”. And that shit would get fixed right up.

In SpecE30, you are surrounded by your friends.


I put a red solo cup on my radiator hose one Saturday night because I noticed the same issue. I cut the end off, cut a slit down the side, wrapped it around and zip tied it. The cup may have already been used to drink a few shots of whiskey at the track that night, but it’s still there working great a few years later!


If you look at the airbox from the front, it only contacts the left most rib. I don’t even think that rib is structural, unless BMW had some outrageous strength requirements. I’m already planning to put something around the hose, great idea on the beer can idea.

The airbox, if I paint the oversize washer, nobody would be the wiser I think. But I’m not trying to hide it either, that’s not how I roll. I have witnessed (in many classes, not just SE30) some pretty ridiculous protests. Someone protesting over a minimal relocation of a part would be pretty ridiculous. Hell, I know of a SE30 car who had to slot their mount because of some front end incident in the car’s past, it’s all bent to hell looking, but in the same place, maybe that’s the trick… a little love from a prybar to bend the entire bracket back.


How about you just put the correct radiator in your car. Are you kidding!!


Yes, I was thinking along those exact lines. There’s a certain charm in achieving 100% compliance via the application of a pry bar. I was just a little hesitant to come right out and say it. Me being a bit of a shit-magnet and all .


It is the “correct radiator”. It is a C&R/Bimmerworld race radiator for E30s and E36s.

Thanks for the helpful tip!


Why criticize him? I have a big triple pass radiator. I like the additional cooling capacity.


If it were correct it would Fit. Your welcome.


Your right, we should change the rules for you and you alone.


It does fit. It’s just a tight fit, we get it, mine is large and a tight fit, yours smaller and has plenty of room. There is a dick joke in there somewhere, but I’ll leave it alone.


Your reading comprehension really sucks. Please highlight exactly where I asked for or even suggested a rule change, especially one for me alone. I asked for opinions on the interpretation of wording and meaning, not irrelevant and immature personal attacks.


Radiator envy. :slight_smile:
That’s my reason too. I see the temps my current car hits and don’t like them and want to avoid it with this one.