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I have a 2018 SS and I just finished installing one of Hahns original turbo kits from a previous owner on here (MACAWS). I have it setup for 2X power level with the green wastegate spring. I have a few issues/questions/concerns that I wanted to run by some of you that have this kit to see if it's normal.

1.) I have the side exist exhaust and after every ride, I smell like fumes. It's very bad and noticeable. What could be causing this? I read another post on here where owner said his flex pipe had failed under heat expansion. Is that a possibility? Also this exhaust just seems very very loud. It's like there is no CAT/sound deadening built into it or something. I'm even considering purchasing the silencer kit bill offers if it'll help.

2.) I have some issues with popping at idle and engine RPM jumping up sometimes in stop and go traffic.

3.) If I floor in first gear at the higher rpms, when I go to shift into second, the engine sputters as if it's about to stall out and then it catches it self.

I have the AEM failsafe gauge installed along with the Fab Factory intake. You can see in the picture below where I have the vacuum connected for the boost gauge. On some of the pulls I did, I would see the gauge hit about 10.6 psi before coming back down to around 8 or 9 psi. I'm still waiting to connect the tach on the gauge before I can do some datalogging.

I've reached out to Bob at MefiBurn who did my turn and I'm even considering purchasing his Slingshot Scan tool so I can do some logging and send it to him. I don't want to pay the $370, but it seems like such a small invest when I consider the possibility of blowing up the engine.

If anyone could provide some insight (@Bill from Hahn RaceCraft @[email protected] @BKL @RABTECH), it would be appreciated. I'm located in Central NJ if anyone can recommend somewhere local that specializes in Slingshots.
 

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Hi Liard! Thanks for posting. Although we've been communicating via message, it's always beneficial to the community as a whole to discuss in open forum.

1. Your side-exit exhaust should benefit from the baffle kit we offer insofar as sound. If this is your first Slingshot experience without a catalytic converter, it's not unusual to find the un-catalyzed exhaust to be more "aromatic". In addition, the turbocharged condition does tend to run at a richer overall AF ratio. I'd also suggest you have a close look for any exhaust leaks. The flex section we use for the wastegate discharge is typically fairly durable, but as this is a used system with some years on it it's worth a look as well. Along the way we did upgrade this flex section to an interlock liner style as well, but that wasn't so much an aspect of leakage as it was an effrot to improve durability of the earlier flex which had in inner braid that could collapse.

2. The natural operation of the larger 60 lb injectors is to have an idle "burble", which is also a different sound than a Slingshot with stock injectors. The idle rev hanging is not typical, but can tend to correct itself over time as the PCM adapts.

3. Flooring it in first gear will invariably engage traction control as the tire spins from the additional torque produced by the turbo. The shortcoming is that if this condition is allowed to persist, the traction control can induce an over-rich condition whcih will load up the spark plugs and create a stuble upon upshift until the engine sees load and claens out the excess fuel. My suggestion is twofold:
A. Try it with the traction control disabled, which will leave you in complete control and diminish the resultant over-rich condition from TC intervening.
B. Develop finesse with your throttle foot. Understand that full throttle in first gear is essentially unuseable without extensive wheelspin. "Feathering" the throttle in first and second gear to keep the tire in traction is the best practice. It takes some re-learning, but once you've mastered it, your experience will be much more satisfying, and your spark plugs less likely to become loaded up with excess fuel from both tirespin (which creates insufficient load) and TC.

One other area of interest that occurs to me as I examine your findings: be very sure all your charge air piping connections are snug and leak-free. Loss of air from these connections can also create an over-rich condition under boost, as all the air the PCM is calibrated for is not being delivered to the engine. Leaks in these areas can be insidious; just because they "look" good doesn't mean they are leak-free under boost. Sometimes removing the pipes and couplers is the only way to fully explore this aspect, and it's a common area of issues on first-timer installs.

Keep me posted as you examine these aspects. Perhaps also send me/post here a video of the machine in action under these conditions, whcih would also help me ensure proper blow-off valve operation. By the way, it looks gorgeous!
 

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1. I have the Hahn StreetRace exhaust on my Hahn Stage 2 turbo setup. The StreetRace exhaust looks to be a little longer than the Hahn Side exhaust, but I had hoped the Side exhaust might direct the fumes and noise away from the Slingshot body. The StreetRace exhaust exits underneath the Slingshot and can add a booming sound from the exhaust reverberating under the body and when combined with a Top can result in exhaust fumes being drawn back into the cockpit, especially with a taller windshield. I wonder if an exhaust shop might be able to add some additional pipes to the Side exhaust to run the exhaust along the side of the Slingshot so the exit point is back near the rear of the tub in hopes that having the exit farther back might reduce the chances of exhaust fumes being drawn back into the cockpit. I've had the exhaust baffles in my setup since the beginning as I like to ride at night want to not disturb my neighbors when returning late at nighgt.

2/3. As far as the popping at idle and fluctuations in rpm, I have been lucky enough to not have much problem with that. About 20,000 miles after my install, I started occasionally experiencing a stumble under hard acceleration when shifting into 4th at around 50-55 mph. When it first happened, I was afraid I might have gotten some bad gas and added a bottle of Heet, followed by a can of Sea Foam or Walmart SuperTech equivalent every other tank for the next few tanks. I now add a can of Sea Foam or SuperTech equivalent around the first of each month and that seems to keep things under control.
At least one owner suggested I check my vacuum lines, but I'd expect a vacuum leak to cause problems at all rpms and not just when shifting at a specific speed range.
I occasionally see boost going up to the 8-9 psi range, but it hasn't occurred often enough for me to get concerned. I have seen posts in various turbo forums about cleaning/lubing waste-gates and Blow-off valves. I haven't tried this on my stock BOV or wastegate, but if either can be disassembled, it probably can't hurt to clean and lube everything. Here's a couple Google searches -
 
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