So, I dyno'ed my SS back in January when I had shorty headers with stock cat-back & hypertech programming. The dyno showed 274HP and 304ft/lb. I heard the numbers and figured the car is just tired and waiting for a rebuild but, when I look at the graph,... OMG! right about 4500RPM the hp and torque lines get crazy. I mean, basically it was a steady climb right to about 4500 and it took a major crap. I raced the car a few times in the past and remember it would feel as if the car stopped pulling around 4500-5000. I mean, it just felt like it bogged down and I suppose now I'm just looking at the same thing on the dyno sheet. I put in an LT4 knock module thinking that might be it. I also changed out the entire exhaust since then. The car feels like it pulls straight through and doesn't bog down at the higher RPMs like it used to. I went to the dyno again yesterday march 30th and the results were 279HP and 319ft/lb. with that same crazy stuff at about 4500rpm. I know I really need to post pictures for anyone to better understand but I dont have a way to do it right now. If anybody would like to see my dyno sheets, I have them saved as jpg files and can e-mail them to you. PM me.

My BIG QUESTION is : Does this sound like an opticrap symptom?

ALSO : Does anyone have any dyno results showing what a bad opti will look like???

 

why did you delete the previous thread?, you got some good answers in there, you could have just made another post in that thread instead of deleting it

 

I did not delete any thread on this site. I made this same or similar post on four different forums so far. I'm just trying to hit-up more folks for ideas. Maybe your confusing it with the same post I made on either LS1tech, LT1tech, or camaronation. Believe me, I dont go deleting any advice or suggestions I get.

 

lol, i could have sworn i replied to it on here, but after checking, i replied to your thread on ls1tech.....my mistake ::free bump::

 

DO you have a scan of the dyno graph.

Often you'll have problems in the tach pickup on the dyno and it will do crazy things.. other times timing (and lack thier of) can cause some funky stuff.

 

I have scans of the dyno runs and I also have the saved dyno run files that you can view with winpep from the most recent run. I can e-mail it to anyone that wants to take a look and give me some inputs/advice/suggestions. PM me your e-mail if so.

 

Send one over.

 

OKAY! Here's the dyno sheets finally...

The first dyno in January

The second time in march

 

How many miles are on the car? Have you ever replaced the fuel filter? I had some really weird stuff going on with my car, it wouldn't run for sh*t above about 3500 rpm. I replaced the fuel filter and that fixed it. Might be worth a try since it only costs about 5 bucks.

 

The car is at about 95k miles. I bought it when it was at 68k miles. I "think" I replaced the fuel filter when I did my first oil change on it. Might be worth it like you say since its only a couple bucks. I'm leaning more towards ignition problems though.

 

I had the problem just appear after doing the header install and I though I majorly messed something up. turns out I repleced alot of parts that didn't need replacing. It definately acted like an ignition issue when mine got bad, so it is worth a try.

 

Looks to me like an ignition problem. You can't rule it to be a opti spark, all you can tell is that something is a wrong with plugs, wires, coil, opti

 

I haven't tried changing the plugs & wires since I dynoed the car. Changed out all that stuff about a year ago when I first put on the shorty headers. I suppose I could get another set of plugs & wires to rule it out.

 

Hey that's my dyno graph!!! :-) I had the exact same issue last year. It would pull until about 4500 and then lay over. Felt like somebody grabbed me from behind at the track. Turned out to be corrosion in the Opti from a leaking water pump weep hole. Replace Opti = No more loss. Now she pulls through the RPM band and has that WOT scream again. Watching mine on TTS showed a rich condition and spark knock from the overrich AFR at the same time. Indicated an incomplete burn on varying cylinders. You may want to scan it if you have the capability and see if you can find some coorelating data. An Opti swap is a pain in the neck, but once I saw the WP going south, you kinda have to sign up for the Opti change as well. Good luck man.


-Paul

 

what is involved in an opti swap?