My cars running like crap
#1
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My cars running like crap
I went to the track last night for the first time in a couple seasons. I've lost 4-5mph and 0.30-0.50 seconds on my 1/4 mile.
The car has about 40,000km with the stage 3. Just wondering if there is anything I should be looking at refreshing? When I rev the car quick I hear a bit of a squeal sound, also at idle in the back driver corner I can hear a bit of a puffing noise. I've felt around and don't feel any boost coming out, hoses all seem tight on the back.
Any else have their belt to start to slip? I'm just trying to think of what would cause this power loss.
O2 sensors and spark plugs have probably 10,000km on them. I'm wondering also, can the tune degrade over time or need a re flash?
The car has about 40,000km with the stage 3. Just wondering if there is anything I should be looking at refreshing? When I rev the car quick I hear a bit of a squeal sound, also at idle in the back driver corner I can hear a bit of a puffing noise. I've felt around and don't feel any boost coming out, hoses all seem tight on the back.
Any else have their belt to start to slip? I'm just trying to think of what would cause this power loss.
O2 sensors and spark plugs have probably 10,000km on them. I'm wondering also, can the tune degrade over time or need a re flash?
#2
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Tunes don't "degrade" over time. However, if something changes with the car, the tune will be "off." Have you thoroughly checked for any vacuum/boost leaks? I mean doing a real leak test - not just feeling around. At idle, you aren't going to "feel any boost coming out." You'll be pulling vacuum. Are you seeing/feeling anything that would indicate belt slip? I'm assuming you aren't running a good boost/vacuum gauge...
#3
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2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
I'd start off by doing compression and leak down tests. That should tell you if it's something outside or inside the engine and give you a better idea of where to start looking. Hope it's minor dude.
#4
Super Member
The squeal you hear when you rev it could be belt slippage.
I remember that when my buddies and I put blowers on the Chevys and the Fords, a stronger tensioner was always part of the kit because otherwise the tensioner would eventually cause the belt to slip.
Jim G
I remember that when my buddies and I put blowers on the Chevys and the Fords, a stronger tensioner was always part of the kit because otherwise the tensioner would eventually cause the belt to slip.
Jim G
Last edited by JimGnitecki; 06-25-2017 at 02:17 AM.
#5
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I doubt that squeal is from belt slip. Belts don't typically slip from quick revs. They slip while flogging the car higher in the rpm band. And yes, I've got first hand experience with owning high boost supercharged vehicles. The reason I asked about the boost gauge was that if he had one and the belt slipped, he see his boost drop. The other way to tell if your slipping is that you'll be eating the belt up. There is usually black powder (the belt) in the engine bay around brackets, etc. If his tensioner went, he'd likely be having other issues. Doesn't hurt to press on your belt and see how it feels though.
#7
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A properly spec'd belt with the right tension won't. I'm assuming you have experience with the Weistec kits and know something I don't. I didn't say it can't happen. I'm saying it is unlikely. Especially if he isn't seeing dust.
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#8
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C63 amg Custom 67 Camaro GLK 350 4matic 2017 AMG GTS
I can't tell you what his issue might be, but belts on super chargers can slip. It happens. It happened to me. You can have proper tension and still slip. Lots of factors can happen under the hood. Little bit of oil or foreign liquid getting on the belt, not enough belt width and or not enough going around the pulley, too much heat. Crazy stuff happens under the hood to say it won't happen from quick revs, or from slow pick up. I just don't want him discounting that based on a forum post.
#9
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I understand what you are trying to say. Yes, weird things can happen. I think that an undersized belt is unlikely. It is a Weistec kit and I don't think there are many reports of the belt being too narrow, If his belt is slipping so bad that it slips near idle or from quick stabs of the throttle, he'd be falling on his face under WOT. A belt won't slip under low load/low rpm and grip under high load and higher heat. The OP doesn't say that his car was falling on its face. And, again, if he is slipping and went to the drag strip for multiple passes, he's going to have dust all over the pulleys. Based on the foregoing, I think I'm making a reasonable call in saying it is unlikely.
OP - is there belt dust around your pulleys? How does your belt look? Glazed? Hardened? What about your pulleys?
OP - is there belt dust around your pulleys? How does your belt look? Glazed? Hardened? What about your pulleys?
Last edited by BadCompany; 06-25-2017 at 05:28 AM.
#10
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#11
I went to the track last night for the first time in a couple seasons. I've lost 4-5mph and 0.30-0.50 seconds on my 1/4 mile.
The car has about 40,000km with the stage 3. Just wondering if there is anything I should be looking at refreshing? When I rev the car quick I hear a bit of a squeal sound, also at idle in the back driver corner I can hear a bit of a puffing noise. I've felt around and don't feel any boost coming out, hoses all seem tight on the back.
Any else have their belt to start to slip? I'm just trying to think of what would cause this power loss.
O2 sensors and spark plugs have probably 10,000km on them. I'm wondering also, can the tune degrade over time or need a re flash?
The car has about 40,000km with the stage 3. Just wondering if there is anything I should be looking at refreshing? When I rev the car quick I hear a bit of a squeal sound, also at idle in the back driver corner I can hear a bit of a puffing noise. I've felt around and don't feel any boost coming out, hoses all seem tight on the back.
Any else have their belt to start to slip? I'm just trying to think of what would cause this power loss.
O2 sensors and spark plugs have probably 10,000km on them. I'm wondering also, can the tune degrade over time or need a re flash?
#12
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Well I took it to the dyno today for the first time ever. Only making 5-6 psi when it should be 10-11psi, there's my power loss.
Belt doesn't appear to be slipping, no dust, etc. The boost slowly climbed and wouldn't climb anymore. It didn't climb and fall or jump which leads me to believe the belt is not sleeping.
I had my laptop hooked up and watched/log'd some engine parameters. The throttles are opening at 87%.
I'm thinking either the blower bypass set screw or something is not working correctly and air is being bypassed around the blower. I'm going to change the stock OEM air filters out, they didn't look very dirty and don't have many km on them. Might throw a new belt on it just to make sure.
Might do some pulls with no air filters in and see what happens too. will report back to update in case anyone else runs into these issues.
Belt doesn't appear to be slipping, no dust, etc. The boost slowly climbed and wouldn't climb anymore. It didn't climb and fall or jump which leads me to believe the belt is not sleeping.
I had my laptop hooked up and watched/log'd some engine parameters. The throttles are opening at 87%.
I'm thinking either the blower bypass set screw or something is not working correctly and air is being bypassed around the blower. I'm going to change the stock OEM air filters out, they didn't look very dirty and don't have many km on them. Might throw a new belt on it just to make sure.
Might do some pulls with no air filters in and see what happens too. will report back to update in case anyone else runs into these issues.
#13
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#14
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C63fora2w1 (06-29-2017)
#15
check for belt slip if not check for boost leak? also check little valve behind supercharger is not releasing boost
Also check icetank hoses are not blocked
What were you IATS? did you check timing while it was on dyno?
Also check icetank hoses are not blocked
What were you IATS? did you check timing while it was on dyno?
#16
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I just pulled the air filters, cleaned the boxes and ran it, still 6psi.
I'm going to get that gates green belt that I had on it before, will install a new one tomorrow and see what happens.
That valve is of concern, it controls the blower by pass valve, so under vacuum of idle it's open and letting air straight into the intake, when boost happens, it closed and lets air into the blower. It has a set screw that stops it when closed, the screw looks fairly seated.
I do hear a noise, where it's the belt or boost leak I can't tell. I don't know where would be leaking boost... my fuel trims are pretty damn good around 5% so if there was a leak I'd assume they would be out of whack.
I emailed the data log to weistec for their input... will see what happens tomorrow with the new belt on.
I'm going to get that gates green belt that I had on it before, will install a new one tomorrow and see what happens.
That valve is of concern, it controls the blower by pass valve, so under vacuum of idle it's open and letting air straight into the intake, when boost happens, it closed and lets air into the blower. It has a set screw that stops it when closed, the screw looks fairly seated.
I do hear a noise, where it's the belt or boost leak I can't tell. I don't know where would be leaking boost... my fuel trims are pretty damn good around 5% so if there was a leak I'd assume they would be out of whack.
I emailed the data log to weistec for their input... will see what happens tomorrow with the new belt on.
#17
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#18
I just pulled the air filters, cleaned the boxes and ran it, still 6psi.
I'm going to get that gates green belt that I had on it before, will install a new one tomorrow and see what happens.
That valve is of concern, it controls the blower by pass valve, so under vacuum of idle it's open and letting air straight into the intake, when boost happens, it closed and lets air into the blower. It has a set screw that stops it when closed, the screw looks fairly seated.
I do hear a noise, where it's the belt or boost leak I can't tell. I don't know where would be leaking boost... my fuel trims are pretty damn good around 5% so if there was a leak I'd assume they would be out of whack.
I emailed the data log to weistec for their input... will see what happens tomorrow with the new belt on.
I'm going to get that gates green belt that I had on it before, will install a new one tomorrow and see what happens.
That valve is of concern, it controls the blower by pass valve, so under vacuum of idle it's open and letting air straight into the intake, when boost happens, it closed and lets air into the blower. It has a set screw that stops it when closed, the screw looks fairly seated.
I do hear a noise, where it's the belt or boost leak I can't tell. I don't know where would be leaking boost... my fuel trims are pretty damn good around 5% so if there was a leak I'd assume they would be out of whack.
I emailed the data log to weistec for their input... will see what happens tomorrow with the new belt on.
if it is leaking i recon its arounf the back of the blower where the valve is
#19
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Anthony at Weistec has been helping me trouble shoot, he's a smart guys and follows the logs for clues. The mass air flow values are down from a normal running stage 3 which he said is a sign of not losing compression or boost. The air flow coming into th blower is down. Leads me to believe it's the belt losing tension or slipping, or possibly that by pass valve not functioning properly. Changing belt today and will report back.
#21
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FYI...belts slip on superchargers all the time...there is a reason why upper tier superchargers as well as upper tier dry sump oiling systems use cog drive
hopefully a new belt fixes your issue!
hopefully a new belt fixes your issue!
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Mazspeed (06-29-2017)
#23
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Bet it feels great now. Glad it was minor dude.
#24
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Jim G
#25
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The two belts I'm comparing are different. They should be around the same size I assume. The new belt is way tighter and working great.
This is my third belt now. It's the gates green belt, seems to work good. I park the car for winter, 6 months. I'm going to take the belt off the blower to reduce the stretch in the future.
This is my third belt now. It's the gates green belt, seems to work good. I park the car for winter, 6 months. I'm going to take the belt off the blower to reduce the stretch in the future.