Exhausting Concern for Boosted Engines with ANY Flex pipe for waste gate

  • My waste gate flex collapsed and was making the slingshot Over Boost.

    Even with the waste gate wide open ( should be 0 boost ) it was building 10 psi.

    If you have seen any higher than normal boost and have any Flex on the waste Gate Side , I STRONGLY suggest that you take the time to make sure it has not melted and caved in on itself.
    I could not even fit my pinky in the hole that you see in the picture .
    The Flex has been cut out and block off plate has been installed on that intake port of the muffler and a straight dump tube has been installed.
    Huge Thanks to @Dave@DDMWorks and @Jeff@DDMWorks for the tenacity of sticking with it to find the issue and come up with a viable permanent solution.

  • Yes i agree. After seeing this in person I guess this should have been up on the top of my list to remember and make sure @Wrenchmn posted about it.

    This is one of those things that could bite you in ass real fast. ..
    The flex pipe squeezed itself inside till it was closed off.. I don't know if this is something that would happen eventually with all of them or if it's because it's so close to the turbo and heat. Maybe @Dave@DDMWorks can weigh in on this Monday.

  • yeah @WOLF , I did too. This is no joke on this and very serious for the collapse .
    If that had kept melting the melting process would continue upstream and that would make things go Boom !
    I am so glad I had it in for insurance against boom with my fat foot and sloooooooooooow Red

  • It would seem that this is something the turbo/exhaust kit manufacturers should be responding to in terms of exhaust design.
    I wonder if anyone who knows more about exhausts than me (just about everyone :D ) thinks it might be possible to install an internal pipe to allow the flex connector to work while preventing collapse of the type shown here.

  • Here is a slightly better picture after the flex joint was cut out of the exhaust -

    With the wastegate of the turbo venting exhaust through this flex, with a failure like this, the boost will continue to climb since the exhaust can not get out of the wastegate. On @Wrenchmn setup I only noticed it at first because we installed the innovate boost controller and I was having a hard time controlling the boost level on the dyno, then the boost towards redline just kept climbing higher and higher. We removed the baffle in the exhaust and it kept doing it, so we then kept changing springs to lower and lower pressure springs, still the boost would climb at redline. Eventually, we removed all springs and even the cap to the wastegate and boost still climbed, after removing the tube going off the wastegate, this picture is what we found. To fix it, we just converted him over to a dumb tube for the wastegate which goes through its own smaller muffler now, the turbo exhaust still goes through the muffler that came on the kit. The good thing with this setup also is we picked up some efficiency (power), the bad thing is his setup is running a little leaner than we would like because of the extra efficiency. Fortunately @rabtech was here with his ride, so we swapped in the ECM from his Slingshot with the latest Alpha turbo tune from Bob @MEFIburn and the air/fuels looked great. So, @Wrenchmn is sending out his ECM for a quick retune and he will be good to go. :thumbup:

    This is just something that I would recommend checking, or watching for on your boost gauge. If you see boost climbing toward redline in the upper RPM ranges (above about 5000RPM), you might want to investigate further. Typically on forced induction setups with higher EGT's than naturally aspirated we used the interlock liner's like this -

    Vibrant Performance ::.

    Hope that helps,

  • Is that the Hahn setup? I have Hahn and it looks lie yours. Were you running baffles in it too, and if so, would that have contributed to the collapse of the flex?

    Yes It is and I am running unwrapped baffles. I am sure that my driving habits and the design so close to the heat source was not advantages.

  • I like the design of the Vibrant Flex connector Dave@DDMWorks pictured. I've got a Hahn Turbo system on order, but have some concerns after seeing that collapsed flex joint. I guess this points out the need for an AFR/Boost gauge.

  • I like the design of the Vibrant Flex connector Dave@DDMWorks pictured. I've got a Hahn Turbo system on order, but have some concerns after seeing that collapsed flex joint. I guess this points out the need for an AFR/Boost gauge.

    I think it warrants a controller and not just a monitor.

  • I've been following recent efforts to get the new Innovate AFR/Boost Gauge/Controller installed, but folks seem to be having trouble getting it working. Even if it works perfectly, when this flex connector collapsed, boost was still hitting around 10 psi w/a wide-open waste-gate!

  • Before everyone shits a pickle....I dont think we have seen this before on any other SS. So I would just say this for now.... let's just keep an eye on it and see if anyone else has this issue...

    I'm a big advocate on having a boost and AFR gauge. As a matter of a fact I personally wouldn't run it at all without it.. you will get used to seeing the AFR and boost and it will be second nature to just sense when something may be out of wack.

    The "controller" part is not needed if you want to just "set it and forget it". You will be happy with the Hahn system. It's pretty bulletproof. And it's hard to beat just putting the red and natural colored springs in the wastegate. And then drive it like you stole it....

    I like the AEM Failsafe just to display both the boost and AFR. It's easy to read and it works...

    I'll have mine for sale due to switching to the innovate boost controller. (I need to be able to run my boost down from 16psi for certain roads and conditions). I think 175.00 is what I'm going to ask for it. I think they are 250.00 new. I'll send everything you would need except a gauge cup (mount). You will need to order the mount you like. It doesn't come with the gauge "mount" even when it's new..

  • I Agree with @rabtech, I have beat the snot out of my Hahn Turbo with no problems whatsoever. I was running the Failsafe along with a full set of gauges Oil pressure and Water Temp. I like the way the innovative controller works for several reasons mostly that I can set to a lower boost for just running around town. Then bump it up when I want to play. I have a sever case of OCD so when I change to the innovative Boost Controller and Gauge I will also be changing my Oil Pressure gauge to the innovative which also shows oil temp and naturally the water tem gauge needs to match and the innovative also has voltage. So I will be selling a complete set of AEM gauges cheap.
    I will be removing my flex but only because we are playing with some exhaust options. I am running a side exhaust which restricting my HP.
    I can't let @rabtech always have the most power. Someone has to try and get 1 up on him.... Because it is just plain fun.

    Can you say Curly?
    Hey Larry what do you think