Westers tune

pritch55 · April 30, 2004

Before I got the tune I had the factory muffler removed and replaced it with a Magnaflow 3 in/out with a turn down just before the axle. I have since installed the wester PCM and have put 200 mile on it. I noticed a big improvement with the downshift when passing at freeway speeds and the speed limiter has been removed but I'm very disappointed with the low end power. I was hoping with some of the TM removed that the truck would respond better of the line. When I stomp on the gas from a stop there is still that horrible lag up to 2000rpm. Does this sound like he may have possibly missed the TM removal? Or am I getting less low end because of the replacement of the factory muffler?

PewterC3 · April 30, 2004

If you don't have enough backpressure you will loose some low end. When I put true duals on My C3 it lost some. But the mid range and high end make up for it!

Butch 02 Denali · April 30, 2004

The free flowing exhaust will definatly lose you a little low end torque. How are the shifts? better than stock with out the lag? That is where you really feel the torque management. All these LSI engines are luggy below the 2000 rpm range, it partially caused by the fairly large cam and the high flow heads. Not allot you can do about it. Are you running good gas, at least 91? You might want to try a tank of 93 if it's available in your area. Is the fuel oxiginated where you are?

Butch 02 Sierra Denali

pritch55 · April 30, 2004

I haven't really felt any difference in the shifts, should I be looking for a much firmer shift or how exactly should the shifts have changed from the factory? I have been running 91oct w/o ethanol so I don't think it is the gas. I guess I was expecting a little more performance off of the line, I had the muffler replaced before the wester PCM and I really haven't seen any difference from the factory PCM and the wester PCM from a dead stop. From the review I have read on this forum I see a lot of comments how this tune makes it seem like a different truck, the only difference I have felt is when it downshifts and pulls harder.

PewterC3 · April 30, 2004

The shifts are quicker without the TM and a little firmer...not necessarily "harder". You need some tranny mods for that.

My truck is definitely a different animal with the Wester's. I kept the stock PCM(kind of a waste in after thought) just for warranty repairs. To tell the truth, the dealer cannot detect the Wester's with a scan tool. When I put it back to stock to take the truck in, it was like the tranny had turned to mush and the engine had dropped a cylinder.

o4yukonxl · May 3, 2004

I've been working with Lyndon on exactly the issues you raised. It seems that the 2004 PCMs use different parameters for the low end TM and shift firmness. I'm on my third program and still don't have firm shifts. The problem is that GM does not publish the changes and programmers are left trying to guess what parameters are affected. It appears to be unique to 2004 models. You should call Lyndon and mention the problems you are having. Also refer him to my post so he can connect the dots. Don't worry, it will get fixed, track my posts in high performance.

Chevyfreek · May 6, 2004

Just a quick note. The shifts will be the firmest at WOT(wide open throttle). Also if you have tow/haul mode enabled, your truck will shift firmer yet at WOT....