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370z Supercharger Boost Issues
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Greetings from Australia...
My 2017 manual 370z is currently at a reputable shop in Australia getting the stillen supercharger kit with a custom air to air cooler. The shop installed and tuned my car but they keep running into issues after issues. My current mod list:
And not to mention the supporting mods... ie.. clutch, oil cooler The car is tuned using ECUTEK and it made 270rwkw (362HP) on 98 and 308rwkw (413HP) on E85 with 5.5 psi boost, something is obviously not right and the tuner doesn't know what the problem is. They claim they have done the most forced induction 370z in whole of Australia. The shop custom fabricated the air intake setup. After some research and digging, they have tuned a stock stillen supercharger which made 283.7rwkw.... YES.... a STOCK stillen supercharger... After pulling up some previously tuned stillen sc cars in Australia, mine seems to be one of the LOWEST stillen supercharger in Australia, even with the A2A setup. The car has been sitting at their shop for 1 whole month. I am desperately seeking for advice |
Have they done a boost leak test?
Do you have a plot of the boost curve? Are the belt's properly tensioned? |
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I'm going there tomorrow. Will ask about the belt tensioner. They haven't sent me the dyno graph as they are "too busy" |
BOV setup correctly? What is the peak boost?
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They said peak boost is 5.5. Will ask for dyno sheet |
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Off the top of my head there's 3 things you should do/check first:
Temporarily take off your intake to ensure that's not the issue Get the subaru timing belt idler pulley for extra serp belt tension Measure your jackshaft and supercharger pulleys to ensure they're correctly sized |
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Something like this: |
Doesn’t the silicone on the intake like to collapse and pinch off boost to around 6lbs?
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Another thing to consider using are high traction pulley(s)
https://vortechsuperchargers.com/pro...ant=7811182081 |
Update on post...
The shop unfortunatly are not able to work on it. They said they have tried a lot of different belts, different tensioners but they have no idea what's going on. Since the kit is a used kit and it's a custom FMIC, they suspect its something wrong with the either one. They gave me the ethanol dyno sheet as they had it printed but didn't supply me one for 98. It loses boost at around 6500rpm. It makes peak boost before red line. From my research, it sounds like belt slippage to me but the tuner/shop was adamant that they have tried everything possible... They're unfortunately handing the car back like this as they don't have time to diagnose further. They said that if they do, they'd have to charge for every single minute. This shop is one of the more expensive shops in Australia and the build is already pushing my budget. Quote:
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I'll be upgrading to TopgunZ's new Rotrex Kit so I'll be selling my ACE Kit in which I made 543 whp at 14psi and 423 tq
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Have you gotten your car back? How did you go?
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The car didn’t start at all a couple weeks ago then the tuner came down and adjusted the tune. Now, the car gets CEL flashing maybe once every 3-4 times I drive it with NO power at all when flooring it. The tuner said its a safety parameter they put in place. My oil gauge has stopped working, my 3 other maps the tuner gave me are gone. Heavy rattling sound from the undercarriage (maybe exhaust?). I have told the shop about all these concerns but haven’t heard back just yet. The car is meant to go back to their shop this month because they didn’t know about the subaru belt tightener pulley which I supplied with the kit, so they’re going to install it for me. I went with supercharger because it’s my daily and i wanted a “hassle free” build. But this has given me issues after issues even after I got my car back. Very unfortunate. |
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Weird coincidence because that was exactly the same for me after the same tune as you (at same place) with same SC setup. They told me after having a quick look it was my Invidia exhaust resonator's internals starting to come loose. |
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https://youtu.be/ozve1rU6rBE This has happened since day 1... It was there when I picked the car up from their shop. I was very surprised that they gave the car back without fixing it even though the car was there for a month. Only ever happens ~2000 RPM |
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What is the shop name? If they don't resolve your issues, they deserve to be named and shamed. You can probably even take this matter to VCAT if they don't fix the issues at no cost. Hopefully you can get this resolved soon. Goodluck. Keep us posted! |
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Yours sounds like maybe an exhaust leak or the exhaust is rattling on something or is loose maybe? :confused: |
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They were on Christmas break when I tried to reach out to them about my concerns but I couldn't get support from them... I had another tuner check out my data logs since I'm not familiar with all these technical aspects. Jeez did I open a can of worms... I have been advised not to drive the car at all because the tune is that bad... Really, the last thing I want is to make a big deal out of this. When you pay for a service, you should expect to get what you paid for. Quote:
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As described in one of your previous posts boost falling off before redline is 100% a direct symptom of belt slip. Since you already have an RPM belt on the supercharger side that is most likely not the issue unless it's extremely loose (try pressing on the belt with a finger, it should be pretty stiff with little to no movement). Looking back at your pictures your serp belt is way too long without that extra tensioner, I run that K071045 belt WITH the tensioner to take up the excess slack, and even then I've been recommended to run the K071040 belt instead which is half an inch shorter. If you sort out the belt situation and it's still a problem, then it's the intake. Also, what happened to your engine grounds? Were they relocated or did they simply delete them? They are usually attached on the frame near the supercharger and attached at the top of the engine where the supercharger bracket brace is. |
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Also your advice above is spot on. |
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My car is not with me atm but hopefully I get it back from the shop soon. They saw my email about the car running lean and knocking and called me to bring the car in last Wednesday. Haven’t heard back from them yet but hopefully they are making good progress.
Will keep you guys updated |
One of the things I would check are your MAF jumper harnesses since the signal is a shielded wire and the jumper is not. It's possible you might be having MAFs sending an incorrect signal
However being that it's a reputable shop and BYthabay has tune many of them stick with them. Hope you get this resolved. |
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Got the Topgunz anti slip pulley in but it still made the exact same boost. So it's probably not the belt or pulley that's causing the boost issue? Not too much of a mechanic head myself but I do still want to get this all sorted... Anyway, regarding the tune, we're having an issue now where the maps will randomly disappear. The first time it happened, I brought it back to the shop and they flashed the maps on it again. I drove it home the same day and it disappeared again on the second start up. The shop suspects it's the ecutek bluetooth dongle so they took it back to their shop to analyse it. They flashed the maps back on again yesterday and it hasn't disappeared yet. |
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Update on post
I took it to another shop for diagnostic Immediately, within a couple of hours they found the cause of the rattle AND the issue thats causing boost restriction! Amazing! Soon as they took the bumper off, they can already tell that the intake was the problem. They did a dyno run with the intake on and off. With it on, they only saw around 5psi of boost. After they took it off, they immediately saw 10. The shop that worked on the car initially custom fabricated the intake so I gave them a call and they were surprised that it was causing that much of a restriction. And now the rattle…. They chucked it on the hoist and found that the right cat is defective… something is internally loose. Been advised to do a warranty claim. Will keep this thread updated soon as I get updates… |
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I can tell you that I've blown OEM cats and high flow cats on my supercharger set ups on a couple of occasions. Especially if running rich. My current fix is running resonated ART pipes and moving the Cat cells further down the stream. (Suggested by Seb @specialtyZ). I haven't installed them yet, but I'm hoping to lower temps as well that is causing timing to get pulled when IAT's climb in WOT. Should have some logs in a couple weeks + retune for it. I'll post results |
Need a better intercooler, and probably downpipe. Air is getting backed up at wot causing your IAT’s to shoot up. Such a common issue with everyone here.
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