Hitting a "wall" in power as RPMs climb
 

This happens both NA and while I'm spraying nitrous.. only when I'm spraying nitrous it's a bit more pronounced...

So I'm climbing RPMs at WOT and I feel the car just stop making power for a sec... it's almost like a throttle cut but my RPMs stay where they are as if it were being limited. I let off the throttle a tiny bit and floor it again and then it climbs normally again...

This happens between 6-8k in both 3rd and 4th gear... and doesn't happen every time and ONLY at WOT.

I'm leaning towards my CAT being clogged.

It's an 05 with 30k miles - my entire ignition (COILS WIRES AND PLUGS) is less than 5,000 miles old.

Any ideas?

how old are ur coils? May be ur cat...are u running colder plugs with ur nitrous?

i would lean toward cat going.

are you premixing?

beers :beer:

yes sir, the last 10k miles.

and as I said my ignition was all replaced within the last 5k.

what are you premixing with, and how are you doing it?

beers :beer:

idemitsu, 5oz in the gas tank.

you think maybe fuel pump?

oh and I put my mazsport midpipe on tomorrow - i'll know then.

coils

coils were replaced less than 3,000 miles ago as were my plugs.

no flashing cel or anything when this happens.

check your aux port valves are opening

are you doing the dump and pump?

if so stop... but i doubt that is the issue if you have been using idemitsu. but do buy a 1 liter aquifina bottle. and mix the oil with gas then dump it in at half tank full.. ;)

and really you are putting a midpipe on tomorrow.. that will answer the question quick..

beers :beer:

yeah, i fill up 1 click after the pump stops and then administer the premix. ;)

how exactly do i make a determination of a clogged cat? I had my cat off a few weeks ago and looked down it.. all I saw was pitch black?

with my carpc i always had my exhaust gas temp in front of me and I would routinely see it at 1700f+ on the highway.. and that was before I got it leaned out.. so I wouldn't be surprised if my cat is indeed shot.

1700 on cruise is silly hi.. i see ~ 1620 at 74 mph..

if the problem goes away when you install the pipe it is simple the cat was going. have you had a decrease in mpg?

and if the cat is going, you should get it replaced... and save it.

AND START PREMIXING THE PREMIX!!!!:) you might look for a thread i started lately.

beers :beer:

i saw that thread you made swoope.. makes one think for sure..

and yes, my mpg has been drastic recently.. i don't know if it's just me having a heavy foot with the nitrous >.>

I'm having the same problem - around 7000 RPM, and only at WOT, I hit a 'bump', where the car seems to hesitate for a second.

I don't think it's the cat - I think we'd see a more generalized power loss than just that momentary 'blip'.

I'm not premixing, though I've only owned the car for 5000 miles (it has 44k) so its possible, though doubtful, the previous owner did.

I dont know how the mechanism responsible for opening the secondary and auxiliary ports works, but the symptoms are more consistent with that sort of problem - as if whatever's responsible for opening the ports is sticking.

straight pipe FTW

well I got the midpipe on last night.. I may been overcome by the thrill of just driving around with it.. but I certainly didn't hit this "wall" then.

Coils, Wires, Plugs

Read. My. First. Post.

I dont think its has anything to do with the ignition either - again, don't you think we'd see sustained performance deficits, rather than only at very specific RPMs?

Also, my coils were also replaced when the car was purchased by the dealership I bought it from 5000 miles ago.

I saw it at only WOT at high speeds.. so it might have been my CAT because isn't it logical that at those times is when most exhaust gases are flowing and at the HOTEST they can be?

I'll let you guys know if I feel this happen again now that I have no CAT.

If the cat was clogged, you would have the problem in lower gears also. You are trying to move the same amount of exhaust gas in 1st gear as you are in 6th for a given RPM.
Have you given a thought to clutch slippage?

I had not. If it happens again I'll see what I can determine.

The wall your hitting may be an aero wall. You just can't push anymore air and the clutch starts slipping.
I had a friend with an A4 that couldn't get his car above 70 MPH. He didn't know what to make of the problem I diagnosed it as the clutch, he had it replaced and that was cured.

/\ clutch slippage would be accompanied by an increase in rpm with no corresponding increase in speed ...

which didn't happen in my case.

rpm and speed just stuck at like 6,500rpm in 4th.. i let off the throttle a bit then WOT again and it went then.