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Discussion Starter #1
I dont know what is going on, but i am trying to get different opinions on what it could be. I just installed a greddy profec b, and an intake. I tried punching it on the freeway and my boost goes up to where its suppose to and it feels strong untill i get around 100mph then it feels like it just dies. It doesnt really feel like i hit boost cut plus i have a greddy bcc. I possibly think that it might be the #2 turbo going out but I havnt heard the notorious death whine. I also think that it might possibly be the 4th gear in the tranny? Or maybe something with the engine? If anyone can try and give me some input it would be great. Heres my mods if it helps: Dp, exhuast,bov,bcc,profec. Thanx in advance
 

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1st Lieutenant Team BEYAW
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that is a god damn shame, i really hope you get that figured out, i wish i could help you out :(
 

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Former Moderator
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Does the RPM go up and the speed stays the same? Or it just stops pulling?

-Olivier
 

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Registered
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I'd check your connections. Mine did the same thing and it was that one of the hoses was connected wrong not allowing my #2 turbo to build up boost.
 

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Lets go Nets
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AznSupraTT said:
I was gonna say maybe the clutch is slipping like chnco said...
most likely the clutch, i believe a NA supra has the HP to pull past 100 mph, even if the turbo was dead.

Brett
 
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Discussion Starter #8
Forgot to mention i have an auto. I will try and recheck my profec b connections.

Does the RPM go up and the speed stays the same? Or it just stops pulling?
Just stops pulling?
 

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www.ziptieracing.com
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this is a long shot - but what octane and what boost levels are you running? High boost may detonate your gas like crazy once you get the load of 4th gear on it...
 

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Making a ComeBack!
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make sure u have no VAC... lines open on the pressure side, also make sure u have the connecton on profec b set in the back correctly. (4 or 3 buttons on back)
 
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Discussion Starter #11
running 91 octane, but i even tried turning the boost all the way down and still wouldnt go past 100.

-I checked all my profec connections and they were fine.

(4 or 3 buttons on back
Just noticed those buttons back there, what order are they suppose to be in?
 

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GT-R DUN, Son.
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clutch.....
 

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Former Moderator
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Guys...he stated that he had an auto before...

It's weird...how much boost can you build until 100mph, and what happens after that, does it stay the same or does it drop?

-Olivier
 
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Discussion Starter #14
clutch can go out when your at or close to 100mph? the momentum of the car doesn't put as much stress to the clutch compared from a dead stop. it would have slipped before reaching 100. how would it be the clutch? maybe detonation.
 

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NGAPINO
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Bmw6pack said:
clutch can go out when your at or close to 100mph? the momentum of the car doesn't put as much stress to the clutch compared from a dead stop. it would have slipped before reaching 100. how would it be the clutch? maybe detonation.
It very well could be the clutch. When mine started to go it started slipping in 4th. It would not slip in lower gears, however as time passed it did begin to slip in all gears. I would mash the gas and the car would rev but not go anywhere. Then it would finally catch and go. However this was after alot of slippage.
 

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Driver Down
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94SupraTT said:
It very well could be the clutch. When mine started to go it started slipping in 4th. It would not slip in lower gears, however as time passed it did begin to slip in all gears. I would mash the gas and the car would rev but not go anywhere. Then it would finally catch and go. However this was after alot of slippage.
reading is FUN!

He has an AUTO. That means no clutch. !CLUTCH ;)
 

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Ronin
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are you still using a catylitic converter? you may have burnt it out, does it feel a little slower driving around town too? it may just have started, but since you have checked everything else, i might look at that, especially with bigger boost, a dp, and a catback, if its the cat bottlenecks and then shoots out, it would be very easy to melt it...
 

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ankle breaker...
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Bmw6pack said:
clutch can go out when your at or close to 100mph? the momentum of the car doesn't put as much stress to the clutch compared from a dead stop. it would have slipped before reaching 100. how would it be the clutch? maybe detonation.
No, there's definately much more load going at 100mph than a dead stop. You have to remember that at a dead stop, there are no aerodynamic drag to overcome, AND you have all that gear multiplication. Really, in first gear, you never completely load your engine 100%, you generate enough torque to break the wheels loose way before that just from torque multiplication. In 4th, you're at one to one, and you have to remember that the force of drag is proportional to the velocity squared. Remember the clutch transfers power from the engine to the tranny, if the engine isn't even fully loaded, how can the load on the clutch be at 100%

anyway
Fd = [0.5p(V^2)A]/Cd

where Fd is force of drag, p is density, A is cross sectional area, and Cd is coefficient of drag.

p can be taken as 1.2, v = 44.44m/s, Cd=0.31, A... i'll underestimate A to equal 1.5m^2

from this you get an Fd of 5734.76N or about 1400 lbf, assuming that the coefficient of drag is both the from friction and area combined. add that to the weight of the car, plus frictional forces from the tires with an engine at full load.

I'd rather pull 3500 lbs, over 4900lbs anyday.. lol
well, not that i could really move it anywhere.. :p
 

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Useless Member
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i did the clamp mod today to check out the boost levels for a few pulls, and then i took it off and i have the same problem. my car pulls till like 105, and it drives fine and revs higher, but the car won't go faster. also, i can't really feel the 2nd turbo spooling.

i was talking to my friend who helped me do the clamp mod, and he's pretty sure it's the hose that we clamped, it might be cracked b/c its so old (i have a 95). the car was fine before i did the mod, so it's probably the hose causing a boost leak. i'm replacing the hose tomorrow so i'll let you know...

if you fix your problem, keep me updated as well!
 
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