mine did the same thing in 5th on highway so turned the gain on the boost down and it was fine.

aps tbe
ams intercooler
ams licp
255 lph
blitz sbc id
272/272 cams
samco cold pipe
319whp
290wtq
ams tuned

 

Was driving my car tonight. Noticed that it seems more powerful, even my friends noticed and i turned down the boost. Still have the problem but sometimes it doesnt happen.. This is quite wierd i must tell ya..

 

If you log what your car is doing it would be much easier to diagnose...That said, I am going to guess that you are either over-boosting or with your given map are knocking a ton and pulling a lot of timing...

Get mitsulogger (free) or buy evoscan (~$25) and see what your ECU and maps are really doing....

 

but this just started and i've had these exact mods for 10+ months, why now?

 

There could be a ton of reasons....Just log and it will be very easy to diagnose....

 

I was just put a Forge MBC over the weekend and set it to 22psi. I went for a little cruise last night and we started driving up a huge hill. I was in 5th at about 2800rpm when the it my car started to sound like the BOV was fluttering like crazy. Also felt like the car was about to fall on its face. I downshifted into 4th. Same thing, only a bit more violent this time.

I backed off and got to the top of the hill turned my boost down to 20psi, and everything was fine.

 

Clutch is slipping.

 

+1

 

 

sounds like your clutch..

 

There is no logging parameter for a slipping clutch, though.

 

Actually if the clutch were slipping wouldn't the log show RPMs jump and speed stay relatively flat???...Also if his clutch was slipping that should have been something that he noticed while launching hard in lower gears (from my experience)...To me it sounds like he is either hitting boost / fuel cut or having major amounts of knock and thus timing being pulled (but this just a guess without more data)...

 

He can already see that when he's driving - he doesn't need a log to show that. No, the clutch won't slip in lower gears with lower load, and especially not when launching unless it's almost all the way gone. He only has a slight slip in top gear where the load is highest, because it's just beginning to go bad. Plus, he didn't mention launching - he only mentioned going WOT. Lower gears have less load and less overall boost, so if the clutch is only slightly slipping, then it will not be noticed in lower gears. I thought this was common knowledge by now.

This sounds nothing like fuel cut - the rpms don't fall back down then catch and go when you have fuel cut.

 

LOL....Classic Clay...The logs would show the slip or other issue, but you want to rather just speculate (on your guess vs. mine)...Your guess could very well be right and my suggestion of logging would validate it ...Enjoy Clay...

 

Hate to say it, but I believe Warralton's right about it being the clutch. That's another reason why after ten months the original poster sees this "now".

And as far as the guys adjusting the boost controllers, if you tune the car in 5th gear you won't have to worry about the spike since the load in 5th is higher. I tuned my Greddy at highway speed to avoid that little problem. After a tune I did have to tweak it a little more -- I turned down the Set Gain a little (Greddy) because the Set was turned down a bit on the tune.