RBodeman

I've had my HHR SS for a few years now (85,000 miles) and I have always wanted to do some mods to it but never have gotten around to them. I've done some reading up on various tuner companies and options and it seems that ZZ Performance has a lot available for our LNF engine.

So my question is... what is your take on ZZ Performance and what they have available and which mods are best to start with from a stock HHR SS. Only thing I have right now is a K&N drop in.

Also, what is your opinion on the GM available turbo upgrade kit for $700 plus install as compared to a tuner option.

Thanks in advance for anyone's help

RBodeman

I'm guessing that nobody has any experience with ZZ Performance regarding their HHR SS?

Oldblue

I was hoping someone would chime in, but alas, nobody.

firemangeorge

Don't remember too many members here that went with the ZZP tune. Those that did, it was a while back. They may not be active here or may not have their SS anymore.
I've had the GMTU for 8 or 9 years. Happy with it. No issues.
As far as getting the GM turbo upgrade now, I couldn't recommend it. It has to be GM dealer installed and reflashed by them. That is the problem. The dealers are not going to be familiar with it because it's a 12 year old, outdated option. Plus, if you needed any tech support from GM with it, you probably couldn't get any.
(just my 2 cents)

RJ_RS_SS_350

A new thread has been started, but reposting here to respond to OP.

Ohiocruiser

I had my hhr dyno tuned by zzp. If you are choosing between those two, definitely go with zzp. Solid company that specializes on these engines.

RBodeman

I was kinda thinking that since the GMTU has been around for so long, that it would be a good option. You know...worked out the kinks kinda thing. The physical install does not sound all the complicated and wouldnt the reflash be just the dealer plugging in their system and running something. I don know...I might be being naive here.

firemangeorge

Yes. The physical install is very simple. The dealer does the reflash but has to get (buy) the files from GM and they are VIN based. So no. Not something the dealer has "stored" in their computer.

(Disclaimer: Yes I know there are some individuals that have those GMTU files. They may sell them or even give them to you free. I'm just not in support of using pirated software like that )

rorr

I purchased the GM Turbo Upgrade kit from my local Chevy dealer and they installed it, maybe 6 months ago. They had never installed one, but they basically included installation with the kit purchase. It took them half a day and there is a noticable difference in power. Mileage didn't get much worse, I was averaging in the 27-ish mpg before, now I'm in the 26-ish all the time. Boost on the dash gauge went from 15 psi before the kit to 19-ish under long full throttle pulls. It'll creep up past 20 occasionally. Mine's a stick, so it had a bit more than the auto SS to begin with. I don't know if the kit puts the auto and stick at equal power levels (I believe the transmission is the limiting factor for the stock power difference). I purchased HPTuners at the same time, anticipating I'd want to clean up the tune file a bit, but after logging many miles with the laptop, I don't really see much I can do with it. The GM kit just works, as-is.

I did have one issue. I hauled my car out west in my trailer, behind my RV. I made the mistake of unloading it at high altitude in West Yellowstone and not cycling it a couple of times to test the ambient air pressure / elevation... I passed a few cars, right after unloading it, which it did, without a problem, but then after that, it had a low rpm, high throttle miss. I changed spark plugs and it didn't cure it completely. I then gapped the plugs a bit tighter and that cured it. I will probably put some colder plugs in it the next time I change the oil.

Now that the weather is cooling down here in north GA, it is even more fun to drive 😁. Knowing the kit would not have affected my warranty, if I we're still covered, is just added piece of mind.

Robert

RBodeman

I did read somewhere that the GMTU adds a number of protective programs into the computer that keeps the car from destroying itself from the added hp. I dont know if this is true because I only read it in one place, but it does makes sense that GM would program stuff like that into the GMTU and still be able to keep the warranty (back in the day lol) in place.

Does this sound right?