I have a 2009 SS that had the porous block issue when I bought the car. I finally replaced the engine with a complete LDK from zzp with their tune and GMS1 sensors. After about 1000 miles break in I could floor it in 2nd even with traction control on and easily spin the tires all they way through 2nd and into 3rd. My tires started getting pretty bad so I didn't push the car hard for awhile. Fast forward 3000 miles to a new set of tires. Now it absolutely will not break loose in 2nd. Boost builds quickly up to 25# (used to be 22 or 23# iirc) but it doesn't pull as hard. Its probably weaker than the lnf stock tune under 20#. I contacted zzp and they suggested a clogged cat could be my problem so I ordered their catless dp. After instalation, the car is significantly louder, especially under boost but is not performing like it was. It also smells kind of like incomplete combustiin. It might be a little quicker but traction is still maintained in 2nd at all times. I tried running it w/ the catback disconnected from the dp to rule out clog farther back (good lord). No performance change. It's still making a ton of boost but not power. I'm not throwing any codes. I checked compression today, 150 psi all the way across. Doesnt sound like a boost leak. I'm running out of possible problems. Fuel pump can't keep up maybe? I'd think it would knock then? The engine including turbo only has 4000 miles. A friend suggested the new tires are just much more grippy but that wouldn't explain 25# or lackluster 60+ acceleration. I emailed zzp with my findings since the new dp yesterday morning and zoomed replied asking if I had any other mods. I replied saying now around noon and have yet to hear back. Any ideas?

 

Gunky, shitty valves perhaps? Dirty MAPs maybe too?

 

Would valves get gunky in 4000 miles? Would they hinder compression? Any way to check them short of a teardown? Are you suggesting the dirty maps would cause the sensor to read higher than its actually making?

 

im sure its just ur butt dyno being off. what tires? there are 2 reasons this could be happening? first lets get the gunked valves out of the way, its not that, motor with only 4k miles on it wont have gunked valves. second. the new tires have a lot of grip, and it just seems there isn't as much there cause ur used to the wheel spin. mine did the same thing, old tires, I spun right through 2nd, new tires, nothing, not even with zfr did they spin when they were brand new. second reason, ur ecu adjusts to the way u drive, I notice it on my car a lot, when I drive nice for a long time it just doesn't wanna go, it responds slower, feels sluggish. I can guarantee u that if u drive aggressivly for about a day or 2, ur ecu will adjust and it will be back to its old self. my car, even if I drive nice for 2 days, and I do a pull, the first pull is always disappointing, every pull after that pushes me through the seat. this is just what iv noticed. and if u have anything like conti extreme contact dw tires, good luck breaking loose in second on stock turbo while they still newer, it wont happen. I tried, they just stick to good.

 

The new tires are Hankook ventus v12 evo2. So maybe my 40+mpg is the problem lol. I've tried disconnecting the battery cables and touching them; I was under the impression that would erase anything the pcm had learned about driving behavior? Is a 5 second 60-100 to be expected?

 

I don't think resetting ecu will help, just go for a spirited half hour cruise, it will wake up. yes ur 40mpg tells the whole story lol ur car is in old lady gas saving mode. idk what u should be doing for 60-100 lol never tried.

 

I went to Powercruise (sort of a track day I guess) and after that my "average mpg" was down in the low 20s but it didn't seem to change anything. Is it normal for the car not to pull until around 20#? I'd swear it used to pull hard at 10#. And I know what a slow car is, my back up is an s-series. Maybe you're right and I've become desensitized. When I first started pushing this car it scared me. But now lately I've been shopping for a cbr.

 

I went to Powercruise (sort of a track day I guess) and after that my "average mpg" was down in the low 20s but it didn't seem to change anything. Is it normal for the car not to pull until around 20#? I'd swear it used to pull hard at 10#. And I know what a slow car is, my back up is an s-series. Maybe you're right and I've become desensitized. When I first started pushing this car it scared me. Lately I've been shipping for a cbr.

 

I think u have, it also depends what rpm ur at, if ur at like 2500 rpm at 10 psi it will be more sluggish than if ur at 3500 rpm at 10 psi. its like my zfr, when I first started tuning with terminator2, first few times I literally got light headed and tingly from the g's and had to get out of my car as quick as I could, just felt kinda sick, now even though he says according to the logs its same power, picks up speed just as fast, Im used to it and it feels slower, but its not, when I look at the speedo, its still flying up there. id say ur used to it. stock turbo after awhile gets boring.

 

I agree with Tom. If you're building boost fine and have no codes or stumbling, I'd say your butt-dyno is off. The change in boost pressure and possibly feel of the car might be due to weather. Was it winter back when you had a "faster" car? I know mine is faster in the winter. Gas is usually a better blend in the winter, too. If you want to fall in love with your car again, go with E47 and an HP e-tune.

 

car always has more power in winter. - temps means denser air charge , means more oxygen in air. I think u could see up to 20hp difference in winter compaired to summer

 

I have been considering the temp also. I think it was back in April ot early may which this year in mn was still pretty cold. More power plus less traction in the cold.... Is it normal for the car to jerk under 1/2 to 3/4 throttle or when letting off the throttle at 55 in 5th?

 

i believe in the temp difference at least to a degree. but most days the cars feels as quick as it usually does, and i'm on stock turbo. mods in sig.

 

my car is moody, some days it seems like it doesn't want to go, other days its like u touch the gas and it wants to just go, forever. every car iv had has been like that. its like when u boil water, sometimes it seems like it takes forever, other times it seems really quick, but in reality, it takes the same amount of time every time. I think its just ur perception on this one. I know how it is. the other day I stepped on it in second and my car almost broke my neck, day later, same thing, was more ready for it, didn't feel as bad. in the end, if ur not happy with ur power, I have 3 simple letters for you. ZFR. and hptune. lol

 

Any time you come off any kind of boost, it dumps like that. My wife thinks I'm driving erratically, but IT"S NOT ME.

 

that's where i want to be eventually. how much you making on that set up tom?