New owner with questions

[50Megaton]

Hi folks. I inherited my sister's 04 GT with 132,000 miles last month and I've been getting to know the car and some of it's quirks. I have some questions that I've found some answers to but I just wanted to get second opinions. I apologize ahead of time if some of these questions are redundant, having been posted and answered elsewhere on the forum.

1) I'm not used to the rev happy 2ZZ engine and though I have taken it to lift a few times, I don't feel comfortable doing so, normally shifting up at around 4,000 rpm. However, if it's bad to rev your engine high all the time then why give it lift at such a high rpm(6400 is my understanding for the 2004 year) unless it was safely engineered for that. I had read somewhere else on this forum, I believe, that it's actually good for the engine to rev up on occasion. I'd just like to get opinions on this since what I've read is all over the place, with some people saying it's bad to rev too much(does that mean to lift or short of it) and others that profess to revving high frequently with no detriments. What is the powerband for this engine anyway? What are the average shift points that some of you follow in daily driving?

2) I've gradually gone to lift on a couple of occasions and noticed that nothing kicked in. Does the engine have to be under hard load for the lift to work or does it mean I have to clean/inspect something. The other couple of times it kicked in when I wasn't being gradual.

3) When crusing along, I hear a faint whirring noise that goes away when I depress the clutch. What could be making the whirring sound and is it something to be alarmed at or am I being hypersensitive about every little noise. I'm going to go under the car and check the tranny fluid level. I assume there is a side filler plug somewhere for the C60 transmission. On another post the recommendation was for 1.9 liters of AC Delco 75w-90 full synthetic GL-4. (GM fluid 12346190), is this correct for this transmission? I have no owners manual or shop book for this car.

4) Maybe related to 3 above. When the car is cold, up or down shifting into 3rd causes a grind if you do so quickly. When warmed up, it doesn't do it anymore. Any ideas?

5) Final question/query. What is the true horsepower of the 2ZZ-GE for 2004? The wikipedia entries say that from 03 to 04, the hp went down to 173, because of the way the hp was measured. Does that mean the 04 GT and models beyond have 180 hp( at the crank) in reality and the lesser numbers are simply the result of new measuring systems, or do they really have less hp. In the case of the latter, why reduce the horsepower? I know, it's a nit pick, but 7 hp is 7hp and I'd like to have as much of it as possible.

Thanks for any responses and I'm really enjoying the car.

[vibrologist]

Welcome to the forum, 50Megaton!
I can't answer all your questions but I'll give a few cents worth:
Before you go to high rpm and lift let the engine warm up. The oil needs to really flow in order to do its job. This engine is designed to handle lift. So you could go for maximum acceleration just about any time. Once you reach (legal) cruising speed you will be out of lift anyway. But make no mistake, high load will shorten the life of the engine. Lugging the engine does too. Why should you do lift at least once in awhile? The engine uses the oil pressure in a devise that engages the lift mode. If somebody never uses lift then the oil will stay in that part of the system and deteriorate there. It will sludge up the lift system.
You say sometimes lift does not work. Quite possibly -and depending on how your sister was using the engine- there is already some sludge in there. There is a screen that catches sludge particles and when that screen gets clogged up it prevents lift from engaging. Somewhere in the "Maintenance Bay" is a post on how to clean that filter.

You asking about the horsepower rating. I don't know the history of that. But here are my two cents: For regular driving and cruising you are hardly ever going to use peak horse power. Peak horsepower will come into play shortly before the red line. You will get there only in very hard acceleration i.e. in lift mode. And how often will you do that? In regular driving torque output in the lower rpm range is more important.

The gear grinding is a sign that the synchro ring for that gear has seen some wear.

Enjoy your GT, post some pictures and put your location into the signature. you may have help nearby.

[runningslow]

My '05 GT has an even higher lift engagement rpm... 6800. It took me awhile to get used to get used to this high revving engine, too, and a long time to learn how to best hit lift. I kept trying to "do it wrong" and being disappointed, until I figured out what I was doing wrong. I find lift to be fun, but not very useful on my car with such a narrow window between lift engagement and the redline.

I have found the best best way to experience lift is in 1st or 2nd Gear. If you try to do it at highway speeds in say 3rd or 4th gear, you won't ever "feel" it, because the hp boost at those gear ratios is negligible. I will consistently hit 6800rpm in 2nd gear and feel a nice power surge... then promptly hit the redline and sputter.

The engines are built to rev high, so you're not going to hurt it by hitting lift. Pro tip. Since you have an '04, its actually a direct swap to use an '03 ECU. Using an '03 GT (or Matrix XRS) ECU will lower your lift engagement to 6200 and would allow you to delete the air injection system (lose a little weight and clutter from the engine compartment).

For your other questions, I don't really have a good answer. I'd suspect something is worn out in the transmission, at least the synchros in 3rd, but I'm not the right guy to ask. Is the whirring you hear in every gear?

That's my 2 cents.

[vibenvy]

Welcome to GenVibe! You've definitely come to the right place to get your questions answered! Post some pictures of your "new" GT when you get a chance !