So the car seems to feel okay. Engine isn't making any weird noise. No smoke. Clutch seems to be engaging properly. Boost gauge is reading 15.5 which is where I am at normally (5800').

But the car is lacking power!!!!

I was so sure of it that i took it into my tuner and ran it on the dyno. Sure enough where I laid down 265 on my last dyno, now I was only laying down 214!!!!!! Tq also went down from 230 to 212. I can't post up the dyno graph, but the car was right on track with the old until about 3500-4000 rpm. Then it just went flat. Well not exactly flat, there were multiple ridges, but it stopped climbing.

Now the clutch feels fine. Even had multiple people there drive it off the dyno.

Its not pulling any timing.

My tuner though that maybe it was the tune so he through on a GM stage 2 tune and it did the same damn thing.


So, while it might not feel like the clutch, that is what we are leaning toward, but its really a toss up.

Another Idea was that it was the cat. But the wideband wasn't showing anything that would lead us to believe that.(wideband in the rear O2 slot).

Another Idea was that it was the heat exchanger not working, but my IATs look normal.


HELP!!!!!!!

 

you ruled out my 2 first suspecisions. timing would have been my first guess, and since you have a wideband i'm ASSuming you have looked at the mixture and found that its close to where it needs to be.

how about your plugs? have you taken a look at them? that would be the next place i would dig into. if not look at the air and fuel filter, maybe the fuel pump isn't keeping up but lean 02's would hint towards any of those issues.

what kind of o2's are you getting?

 

I wonder about this too actually. Some days my car is an absolute rocket. Others it seems completely gutless.

I often wonder if it has to do with (and maybe I am over simplifying) the quality of gas your using.
Not brand necesarily, because I always use Shell, but how old the gas is, etc.

Any insight would definately rock.

BTW, I am glad you actually took the time to look at the numbers to verify that this DOES happen! Thats means I am not losing it! LOL

 

any restrictions in the exhaust can cause alot of performance loss, ive seen it with my own eyes, check the cat, make sure you have no exhaust leaks.

 

O2's are stable between 11.8-12.2.

So that rules out fuel. Took the plugs out the other day and they looked normal. Plus no signs of knock. The Knock sensor wasn't picking up any knock on the dyno pulls either.

But losing 50hp????? And the car not running poorly????


Everytime I've come across a clogged cat in a car the car runs like ****.
(i.e. stuttering, not idleing correct, ect...)

My car is running fine, just not producing the power it should.

I only use Chevron premium or Shell V power.

 

maybe you blew something internally??

 

my buddy lost about 35ish hp due to a busted cat and messed flexpipe...
his car ran fine, no codes, we went to go install a header for his car, looked at the dp when we had if off then it all made sense, just a thought...

 

If I did this is the first car to hide it so well.

Really? did he lose this power or is that what he gained from going to the new one?

 

well come to think about it when my flex broke on my downpipe when i had my 2.8 pulley the car ran slower than stock.

 

as soon as he got a new cat and dp with a good flexpipe the hp shot right up.
the flex pipe was detroyed and and the mesh in the cat was loose and you can hear it moving when you shake the pipe in yer hands, these were all aftermarket exhaust parts, i discovered i have the worlds biggest exhaust leak coming from my flex pipe, i always heard a wierd sound as soon as i installed it, but when i got under the car the other day exhaust was pissing out, my car still made 260 hp just recently, im sure it will climb a bit when i get my pipe issues worked out.

 

I don't hear an exhaust leak.....

I had an exhaust leak before and the car actually seemed to pick hp, but that was down right before the muffler.

So it could be a clogged cat?????

 

Lithium, I see you are in ABQ.
I used to live there!

This might be a dumb question, and if it is I appologize, but the highest octane gas you can get there is 91 right?

So would this be hurting you instead of running 93?

*Edit* I know you said it isnt the fuel, just trying to rule out all possibilites.

 

the nosie hear from the dp i would of never suspected it as a leak, but in fact it was, it may be the walls in your flex pipe that have deteriorated leaving you a massive bottle neck.
that you wont hear until yer engine pops.

 

At this altitude 91 acts just the same if not better than 93 at sea level. 93 up here would be like running 95-98 at sea level.

Well, exhaust is already planned, I only have the funds right now to do one or the other (clutch or exhaust), and obviously I want my car running right so I want to make sure I make the right choice.



Oh and here is another tid bit of info. The engine seems to be running hot. It reached 216 the other day. Now if we are moving in traffic its fine (sits around 189-193), but at a stand still it gets hot. not sure if others have had this problem or if this is connected to my current power loss issue.

 

Gotcha. Okay, I will lay off the fuel questions now.

I always thought with a clogged cat you would be able to smell it. Is that not always the case?

 

you wont always smell a clogged cat, you will hear it eventually and notice the car pulls like ****, if yer running the stock exhaust id pull the dp off and examine it.

and a messed up exhaust will make the car run hotter, ive seen this also.
think about it, **** air flow, more heat....

 

As well, mine will also do this.
Running, stays right around 180ish, if I am ideling for a decent period of time, shoots up to over 215.

Putting on the defroster kicks it back down to where it should be.
I just thought this was a chevy thing though as my cavalier did this as well.

Are you saying that this is NOT normal?

 

well depending on how hot it gets, i know my buddy had un heard of temps never before seen, but for cases like this its hard to say, and especially if he is loosing power....
i say check the exhaust system and take it from there.

 

If the cat was going, the boost would be higher than normal. Two things come to mind...belt slip or the clutch going. Belt slip would be evident if boost peaked then lowered. The clutch might only be slipping after a certain rpm or power load is encountered. Dramatic displays occur when the rpms climb but the speed remains the same.

 

hes running a 2.7 and smaller belt, same set up as me and i dont get any slip, the clutch could be on its way out, if it is though you can see it through hpt, spikes of knock occur where the clutch is struggling, this happened to mases car, he put in the bully and no more spikes of knock.

 

See, I'm not seeing any knock, and no timing is being pulled.

The dyno followed the same track as my original until around 3500-4000 RPM. Then it "went flat". It didn't exactly go flat, it jumped up and down a bit, but it definitely didn't continue to make power like it use to.





Example: Original dyno of 265
........................................./
...................................../
.............................../
.........................../
...................../
................./
............../
............/
........./
......./
...../
.../
./

Example: dyno now






............/\/\/\\/\/\/\/\/\/\/\
........../
......../
....../
..../
../
/

 

I wonder if you're logging correctly...putting knock in the graph doesn't log knock, you have to insert it into the PID.

 

Everything is being done on HP tuners. If the knock sensor had gone off it would have showed up. Plus the wideband was reading 11.8-12.2 under load. plus knock leans toward it being a tuning issue, but when we switched out the tune to GM stage2 it did the exact same thing.

 

What I mean is you have to have it configured correctly to read knock. The same way you need to add boost, its not in the normal setup.

 

???? Explain.....


Oh, and I'm not the one tuning it, so I'll just relay the info you give me to my tuner and get back with you.