Author
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Topic: I think i have belt slippage
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90gtverrt
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Member # 1437
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posted
Well i got my 42# injectors in yesterday and I went for a test drive....right at 5000RPMS and 10lbs of boost the boost will drop to 6 then flucuate.......that sounds like belt slippage right? The belt is fuckin tight and i dont know how to get it any tighter. What else could be the problem if its not the belt.
Mike
Posts: 1199 | From: Livermore, CA | Registered: Jun 2002
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chosen1
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Member # 1906
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posted
it sounds like belt slippage...
is there a chance, for whatever reason, there is detonation you cant hear, and the computer is pulling out timing, thus not allowing for full boost?i had those exact same symptoms on a grand national i was working on, and that doesnt use a belt (turbo). we adjusted the regulator a little bit and ran a little race gas and it made everything better.
just a few suggestions from left field. [ February 20, 2004, 12:13 PM: Message edited by: Chosen1 ]
-------------------- 1967 Fastback. Should go 10's -but doesn't 1993 Cobra 2003 Suzuki SVS 1966 Coupe -For Sale
Posts: 2205 | Registered: Sep 2002
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Jeff S
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Member # 371
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posted
Sounds like belt slippage to me. How old is the belt? Are any ribs missing from it? Try tightening it again using a 1/2" breaker bar and little MUSCLE!
You insert the 1/2" square drive into one of the two square holes in the idler bracket:
[ February 20, 2004, 02:00 PM: Message edited by: Jeff S ]
-------------------- '90 Mustang LX: 8.53 @ 157.92 w/ 1.33 60' on DR's '10 ZR1: FOR SALE '14 E63 S: RENNtech ECU '04 Gallardo: UGR TTG
Posts: 2121 | From: San Jose, CA | Registered: Aug 2001
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Jeff S
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Member # 371
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posted
The only thing besides the belt/blower that I can see causing boost drop is the bypass valve.
-------------------- '90 Mustang LX: 8.53 @ 157.92 w/ 1.33 60' on DR's '10 ZR1: FOR SALE '14 E63 S: RENNtech ECU '04 Gallardo: UGR TTG
Posts: 2121 | From: San Jose, CA | Registered: Aug 2001
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93PONY
Mr. Valve Events
Member # 60
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posted
Turbo GN's have a knock sensor. The computers can pull timing based on these sensors. Mustang computers don't know if the motor is detonating or not....& can't compensate for it.
-------------------- www.advancedenginedevelopment.com SCT dealer Dynotuning
(916)715-7569
Posts: 4266 | From: Fair Oaks, CA | Registered: Nov 2000
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1SLOWLX
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Member # 558
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posted
I wonder how this car is going to dyno
-------------------- Built Tuff with your stuff ;)
Posts: 5231 | From: bay area | Registered: Nov 2001
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chosen1
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Member # 1906
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posted
quote: Originally posted by 93PONY: Turbo GN's have a knock sensor. The computers can pull timing based on these sensors. Mustang computers don't know if the motor is detonating or not....& can't compensate for it.
Thanks Shaun!
-------------------- 1967 Fastback. Should go 10's -but doesn't 1993 Cobra 2003 Suzuki SVS 1966 Coupe -For Sale
Posts: 2205 | Registered: Sep 2002
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90gtverrt
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Member # 1437
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posted
quote: I wonder how this car is going to dyno
Gotta sort the gremlins out first :/
Mike
Posts: 1199 | From: Livermore, CA | Registered: Jun 2002
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DropTopFox
drama
Member # 1689
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posted
If it was belt slip wouldn't it be random when it occurrs not only once you get to 5000 rpms. I find it odd that it would occur at the same point all the time
-------------------- Go out and do something for yourself today everyone, quit depending on others
-Me http://www.CaliforniaFords.com/cgi-bin/album.pl?album=00001689
Posts: 4003 | From: San Bruno | Registered: Aug 2002
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90gtverrt
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Member # 1437
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posted
Belt slippage only occurs usually at high rpms, where there is more tension on the belt as it has to spin the supercharger harder and harder.
Posts: 1199 | From: Livermore, CA | Registered: Jun 2002
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CobramanPhil
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Member # 2170
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posted
I'd say simply check the belt. Do you have a lot of belt dust? Try experimenting with different brands of belts and see what happens. Perhaps yours is just worn?
I never did it, but some people put that vht stuff on the blower belt just to see if the symptom goes away. If it does it is the belt. If not it is something else....good luck.
-------------------- 2013 Shelby GT500 2011 Porsche 911 TurboS/AWD 2014 GSXR750 2002 GSXR750 Track Beater Bike 2016 Explorer Unlimted
Posts: 1016 | From: California, Bay Area | Registered: Dec 2002
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2stangs69-91
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Member # 1951
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posted
If you look at the pic posted it had the answer there already. I purchased one of those belt tensioners and it works great.
-------------------- 69 Mustang on hold 1991 LX hatch getting a make over 1994 F150 4X4 351 2006 Yamaha V-max 1200 Modded
Posts: 3711 | From: Redding | Registered: Oct 2002
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Bill/APEX Motorsports
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Member # 636
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posted
Are you using a Goodyear Gatorback belt with the perpendicular slits in the ribs, or are the ribs smooth all the way around? We've had the best luck with the smooth Gates/Napa/Dayco belts.
-------------------- Bill Kaiser APEX Motorsports Santa Clara www.apexmotorsports.com 408-562-1000 bill@apexmotorsports.com
Posts: 488 | From: Santa Clara, CA | Registered: Dec 2001
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98slowhoe 'FIFTYLX'
Uncle Frank
Member # 895
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posted
quote: Originally posted by 2stangs69-91: If you look at the pic posted it had the answer there already. I purchased one of those belt tensioners and it works great.
I made one of those Belt tensioners and it is pretty sweet, but I also know a guy that use to just put VHT on the belt and that solved a lot of problems.
-------------------- AKA Franky Freaking 5 liter
Advanced Engine Development SCT dealer Dynotuning Engine building 916*275*8212
88 4runner on 42's
Posts: 4206 | From: Folsom | Registered: Feb 2002
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90gtverrt
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Member # 1437
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posted
How tight does the belt have to get for a 2.95" pulley (14-15 #'s with a power pipe?
MIke
Posts: 1199 | From: Livermore, CA | Registered: Jun 2002
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98slowhoe 'FIFTYLX'
Uncle Frank
Member # 895
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posted
quote: Originally posted by 306ci89Vert: How tight does the belt have to get for a 2.95" pulley (14-15 #'s with a power pipe?
MIke
Pretty dang tight.
-------------------- AKA Franky Freaking 5 liter
Advanced Engine Development SCT dealer Dynotuning Engine building 916*275*8212
88 4runner on 42's
Posts: 4206 | From: Folsom | Registered: Feb 2002
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2stangs69-91
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Member # 1951
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posted
I don't run that small of a pully but I would use a 1/4 twist on the long side of the belt. I know Vortech recomends 1/4 to a 1/2
-------------------- 69 Mustang on hold 1991 LX hatch getting a make over 1994 F150 4X4 351 2006 Yamaha V-max 1200 Modded
Posts: 3711 | From: Redding | Registered: Oct 2002
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90gtverrt
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Member # 1437
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posted
Well when it stops raining im gonna tighten that up, its got 1" of twist and i thought it was tight.
Mike
Posts: 1199 | From: Livermore, CA | Registered: Jun 2002
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