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      07-31-2013, 07:48 AM   #1
gmd2003
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Dyno trouble shooting session of Z4M ESS VT - 525

So I finally got the old girl on the dyno to sort out my limp mode issue and lack of top end. The limp mode after installing the VT-2 525 has been very different than before and despite not having any leaks during leak testing the car didn't feel as strong as it should. The dyno clearly shows oscillating boost which is consistent with belt slippage, with corresponding glazing on the belt as well. The belt is also noticeably looser than after install. I believe my hydraulic belt tensioner has given up the ghost as well as my belt is not tight due to an incorrect crank pulley. Annoyingly during the install my shop installed the wrong crank pulley (the VT-1 pulley) which means that even without my belt slipping I was not making full boost. I can't believe I made 398 whp at 5psi lol. Ignore the boost spike after let off this sampling system for this dyno does that on all cars for some reason. My peak boost was barely over 5psi at 8,000 rpm.This explains why my car has felt consistent but weak and the limp modes that all of a sudden were not temp related. The tensioner failing added belt slip on top of the pulley issue and thus my problem worsening as of late.
George
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      07-31-2013, 12:22 PM   #2
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Ouch. Welcome to the club with the boost. I am only hitting 6psi at 8000 rpm's, but I am hitting 5psi at 5500 rpm's. We are going to smoke test it tomorrow and check the pulley size that was sent. ESS said I should rule out belt slippage if not hearing it and because it is a new unit. We will see. Keep us update.
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      07-31-2013, 12:49 PM   #3
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Quote:
Originally Posted by seank View Post
Ouch. Welcome to the club with the boost. I am only hitting 6psi at 8000 rpm's, but I am hitting 5psi at 5500 rpm's. We are going to smoke test it tomorrow and check the pulley size that was sent. ESS said I should rule out belt slippage if not hearing it and because it is a new unit. We will see. Keep us update.
Was your boost oscillating like mine or just reaching a plateau ? Sounds more like a leak on your end.
George
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      07-31-2013, 01:40 PM   #4
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How much torque were you putting down?

hehe, not to laugh at your misery, but this makes me feel a tad bit better about my current situation as well (as we're both currently putting out the same whp) jkjk

Hopefully we all have full power in the coming month or two

edit: on a side note, I was able to record a conservative 4.4s 0-60 even without the full 470rwhp and 330rwtq that I should have. And it was able to smoke the tires through 2nd gear. I wonder what full power is like
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      07-31-2013, 02:48 PM   #5
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Originally Posted by mfanatic325 View Post
How much torque were you putting down?

hehe, not to laugh at your misery, but this makes me feel a tad bit better about my current situation as well (as we're both currently putting out the same whp) jkjk

Hopefully we all have full power in the coming month or two

edit: on a side note, I was able to record a conservative 4.4s 0-60 even without the full 470rwhp and 330rwtq that I should have. And it was able to smoke the tires through 2nd gear. I wonder what full power is like
Ha no offense taken, it just sucks that I find a new problem every month lol. I was putting down 295 lb/ft to wheels again not bad considering how low my boost is. Its going to be monster when running at full steam. Fortunately, i have 265/285 Michelin sport cups to keep her glued to the road.
George
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      07-31-2013, 03:00 PM   #6
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Quote:
Originally Posted by gmd2003 View Post
Was your boost oscillating like mine or just reaching a plateau ? Sounds more like a leak on your end.
George
No, it just plateaus although it is hard to read with a digital gauge.

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I was able to record a conservative 4.4s 0-60
I can do a 4.17 with the current numbers.
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      07-31-2013, 06:15 PM   #7
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Welcome to the club of the underpowered!

Replace your belt tensioner ASAP, everyone here. See my build thread. My old tensioner was weak, evidenced by the belt coming off-center one time. Eventually, it ripped out the mounting point on the oil filter housing, so I had to replace that. $1k+ total repair job

Also, my replacement belt isn't the same brand as ESS used, and its slipping badly. I just ordered a new Contitech 6PK2315 belt, I think thats what I had before
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      07-31-2013, 07:28 PM   #8
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Welcome to the club of the underpowered!

Replace your belt tensioner ASAP, everyone here. See my build thread. My old tensioner was weak, evidenced by the belt coming off-center one time. Eventually, it ripped out the mounting point on the oil filter housing, so I had to replace that. $1k+ total repair job

Also, my replacement belt isn't the same brand as ESS used, and its slipping badly. I just ordered a new Contitech 6PK2315 belt, I think thats what I had before
So, that fixed it. Just like that. Nothing else was the issue. Where the link to this thread. Thanks for the tip.
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      07-31-2013, 07:34 PM   #9
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So do you think you will still have the limp mode (yellow brake light) at the track?
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      07-31-2013, 08:15 PM   #10
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been seeing almost everyone with the vt5 series with low hp, are they not claimed to produce over 500hp on our m's?
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      07-31-2013, 09:15 PM   #11
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Yes. 500, 525 hp at the crank or 400, 425 rwhp at 8psi respectively.
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      07-31-2013, 10:45 PM   #12
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Quote:
Originally Posted by seank View Post
So, that fixed it. Just like that. Nothing else was the issue. Where the link to this thread. Thanks for the tip.
http://www.zpost.com/forums/showthre...558729&page=39

Not sure if you're asking me, or saying that you fixed something similar...

I'm still down on power, waiting for a new belt to arrive. Going catless today or tomorrow. Custom tune hopefully soon after
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      07-31-2013, 10:46 PM   #13
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Quote:
Originally Posted by Chee_Dog View Post
been seeing almost everyone with the vt5 series with low hp, are they not claimed to produce over 500hp on our m's?
between 400-420rwhp. really sensitive to ambient temperatures..
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      07-31-2013, 10:59 PM   #14
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Quote:
Originally Posted by ZStig View Post
http://www.zpost.com/forums/showthre...558729&page=39

Not sure if you're asking me, or saying that you fixed something similar...

I'm still down on power, waiting for a new belt to arrive. Going catless today or tomorrow. Custom tune hopefully soon after
It should have had a question mark.

So, you don't know that your belt was slipping?

Last edited by seank; 08-01-2013 at 12:35 AM..
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      08-01-2013, 01:55 AM   #15
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Quote:
Originally Posted by gmd2003 View Post
Ha no offense taken, it just sucks that I find a new problem every month lol. I was putting down 295 lb/ft to wheels again not bad considering how low my boost is. Its going to be monster when running at full steam. Fortunately, i have 265/285 Michelin sport cups to keep her glued to the road.
George
Oh wow, we are EXACTLY at the same power output right now
What are the odds of that haha

Well, here's to better times ahead!
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      08-01-2013, 06:28 AM   #16
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Quote:
Originally Posted by Gtfour
So do you think you will still have the limp mode (yellow brake light) at the track?
Ha , that's the million dollar question . I think I have the temperature side of things calmed down , fuel delivery is solid after the Aeromotive , colder plugs are in . I think it will be good , but I'm always an optimist .
George
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      08-01-2013, 07:06 AM   #17
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Quote:
Originally Posted by ZStig View Post
between 400-420rwhp. really sensitive to ambient temperatures..
Well since I'm making 398whp on 5 psi , i expect between 440-450 whp at 8psi, with my SS headers. I also fully expect to go plaid at my next track day.
George
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      08-01-2013, 08:38 AM   #18
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The number one issue with these kits (in general) on the Z4M is pulley slippage? Seems like I read more and more topics regarding this. Don't the vendors supply the proper hardware so that this isn't a drawback?
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      08-01-2013, 10:16 AM   #19
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Originally Posted by dre99gsx View Post
The number one issue with these kits (in general) on the Z4M is pulley slippage? Seems like I read more and more topics regarding this. Don't the vendors supply the proper hardware so that this isn't a drawback?
It appears when you install the kit it would be wise to replace the OEM hydraulic belt tensioner . I'm a little pissed at myself for not doing it when I upgraded my VT-1 kit. It's a good part but at high mileage and with extra strain from a supercharger can and will fail. The only option which is not a good one would be to recommend a mechanical tensioner which would be a PITA as one would constantly have to check it. It is only a 75 $ part so I agree it should be replaced no matter who's kit you are going to install.
George
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      08-01-2013, 11:15 AM   #20
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Quote:
Originally Posted by gmd2003 View Post
It appears when you install the kit it would be wise to replace the OEM hydraulic belt tensioner . I'm a little pissed at myself for not doing it when I upgraded my VT-1 kit. It's a good part but at high mileage and with extra strain from a supercharger can and will fail. The only option which is not a good one would be to recommend a mechanical tensioner which would be a PITA as one would constantly have to check it. It is only a 75 $ part so I agree it should be replaced no matter who's kit you are going to install.
George
That being so, we still don't know if that is the issue since Zstig still does not have his car back together to verify if that was the issue. He still is waiting on a new belt. It is too premature to tell and he has not shown that it was his issue.

My car only has 50,000 miles and only 1 track day. It is not like reading the threads where some of the e46m3 guys have 120,000 miles on the tensioner.

I also don't want to throw parts at it. Well, not yet anyways.
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      08-01-2013, 12:47 PM   #21
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Well at 70k and 8,000 VT1 track miles my tensioner anyway IS shot .
George
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      08-01-2013, 01:08 PM   #22
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Probably true.
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