robziv

Had mine at the track today (at Sebring) for the second time and had an issue with the passenger side rear turbo. I was attempting to pass and was wondering where my power went. I wasn't sure what was going on until I noticed when going to get gas without my helmet on I could hear air blowing from the right rear when trying to merge back into traffic. Anyone have any issues with their turbo? I have about 3k miles and this is the second time on the track. No issues the first time I had it out there. I was just getting into the meat of the day when this happened. I also just had it checked out at the dealer the day before.

TT Surgeon

Sounds like you blew off a boost hose, fairly common.

robziv

Thank you for the quick reply Chris. I'm sure I sound like I don't know what I'm talking about and that's because I don't so thanks for your patience. Is it something I can get to myself next time at the track? Also, can I cause any other damage by driving it home with the hose off? I made sure to not accelerate enough to engage the turbos. (It was pretty comical on the track as I struggled to get past an old but supped up Datsun)

enzom

Why are these boost hoses blowing off so easily???

speed21

From my own experience (on my 997tt) the short ribbed hose bridging the Y pipe to the throttle body is highly subject to incorrect installation. The importance of having the hoses inner ridge seating 100% correctly around the entire periphery of the mating groove (in the y pipe and/or throttle body) is key to a successful install and I think that is overlooked sometimes and some get caught up in just having the hose on far enough and the clamp tight. The big problem is it is really hard to see if the ridge is sitting properly into the mating groove all the way around particularly at the base, as visibility and movement is highly restricted there. To do it properly requires a good feel that the ridge is clicked into the groove all the way around before the clamp is touched. If the clap is tightened beforehand then the ridge will be deformed and will never hold the same.

Once that ridge becomes forced out of the groove under boost the hose is basically a goner (becomes damaged...no matter how slight) and will always continue to pop off, so a new hose and super close attention is the only real fix from there on I'm afraid. It is job that requires a lot of attention, and over tightening the clamp can also destabilize the ridge in the groove too. So it is a fiddly one....but once it is done right the hose stays on regardless of high boost.

The problem can also happen when the air box is removed and/ or Y pipe is disconnected from throttle body at any stage during servicing. Mine blew off after a service so it just goes to show not even a P tech is immune from making this mistake. I guess it could happen at factory install, but I would assume Porsche has taken steps to avoid that...who knows? Unfortunately any degree where the hoses inner ridge is not sitting 100% perfectly all around the periphery of the mating groove will have a potential for a blow off under boost....no question. It becomes just a matter of time.

neanicu

Speed21,I agree with your conclusion having put those clamps a few times myself and taking extra care to make sure they're seated properly. Although,I do not believe that's what happened in the 2 occurrences I have read about here on Rennlist,since the cars are so new and the hoses were installed at the factory.

speed21

Out of these two occurrences can you be 100% sure the y pipe has never been disconnected since leaving the factory? That is a question.

Regardless of the answer, there can be only two scenarios as the hose won't blow off if the install was correct at time of initial assembly.
1. either the clamp was not adequately secured during install at the factory, allowing the ridge to be pulled from the groove under boost, or, the seating of the ridge in the groove was not 100% correct when the clamp was tightened.

Nick Yoskin

T bolt clamp will solve issue. NAPA sells for ~5 bucks. My C6 vette runs 28psi thru a 427CID motor w/out issue.

speed21

Agree the T bolt clamp is by far superior than any worm screw clamp arrangement but their hose design looks to be stiff enough with the steel reinforcement. Sustained boost brings higher heat loads which will create a softening effect in the retention/groove ridge areas of the hose and any oil vapors would also add to the problem. After the 997tt issue I had personally experienced I am disappointed Porsche has not provided a more robust design for 991tt, particularly in that area. As you say at least provide some T clamps!! Maybe they still had lots of these hoses left in the parts bin? But, on a new car you just know something can't have been right in the install for it to come off so early in the piece. Not a good sign really.

ajag

As discussed above, sounds exactly like my issue, the throttle body boot popped off on the track both times I went out, third time on the street, the hose became misshapen and we finally just got a new one and it's been holding for a few weeks of hard street driving including launch controls, but I won't really test it until I'm on the track next month.

robziv

Speed21, to answer your question, I have 3k miles on a new car and have not had any service done to the turbos since I bought. I imagine they were not touched since the factory.

robziv

Ajag, Thanks for the info, any issue with your dealer making this right? Also, where are you going to the track?
Rob

robziv

Ajag, Did they not put a new one on right away because of the warranty procedures?
Rob

ajag

No, the dealer's service was fairly incompetent, Rizza Porsche in Orland Park IL, took them a week and a half to even diagnose the problem, they just tightened it and said it would be fine. Obviously not. After that I've had it worked on at a race shop, Rennology.

robziv

My dealer found it today pretty quickly and used a new clamp. They wouldn't put on a new hose because they had to try this first for 'warranty purposes'.

Thanks for the info and if you run into anything else on your track days keep me posted if you would. I'll do the same. How do you like your Fabspeed exhaust?

Rob