BlackNotchLX

hi, i'm looking at this '98 Firebird (3.73, hypertech programmer, 160* thermostat, lid, k&n).

1. when driving casually and right before it shifts to 2nd, the A4 would seem to hold it in gear....like a stall converter....and then kind of launch it into 2nd. hard to explain, but the shift is not fast..but kind of slipping like.

the owner says that it's the HYPERTECH PROGRAMMER that's set to 100% firm.

but does it sound like the tranny is on it's way out? the car's got 48k miles and the guy looks like he beats on it once in a while.

2. does the Hypertech Programmer require a 160 degrees thermostat? he says that's what it calls for. the car runs under 170 deg. with the A/C on and sitting at idle for a while.

this is not good for the engine right?

thanks for any help.

bbentley40

Can't help you much with the tranny question. But the HPP3 does like for you to install a 160* thermo. There is nothing wrong with having it in the car and it is not going to hurt anything for sure. Only adverse effect might be the heater not getting as hot in the winter.

JoshuaH82

I've got a 98 car with HPP3. 100% shift firmness won't hold a gear before shifting, it just shifts HARD and fast. If it feels like it's slipping, it probably is. When the A4 shifts, it doesn't think about it. Well, I take that back. The only time when you'll notice a delay in shifting is when you go WOT and it down shifts. There's a fraction of a second before it shifts.

Lots of people run the 160* stat. Not sure how much of an advantage it really. But I've heard reasons for not running it. If you live in a cold climate, it might not be a good idea. There was some concern about it creating a possibility of the throttle body sticking open. You know you don't want that. I don't think I'd worry so much about it though. Lots of people are running one without this problem.

If it's holding RPMs before shifting, the transmission may be a concern. The feel of it lunging on a shift is normal with 100% shift fimness though. Maybe take it to a GM dealer and have them check it out?

BlackNotchLX

hey thanks guys!

JoshuaH82: the owner is the kinda guy who'd beat up on it. hey we all do, like i get on my Mustangs quite often when i'm driving....but i guess it's a big concern when you're the buyer

it does feel like the transmission is slipping. like a noticeable hesitation before it goes into 2nd during normal driving.

ULTIMTEORANGESS

ask him to take out the HPP and see if that cures it.my bet is that hes BSing you.as far as a 160 tstat goes its not harmful but you might lose power if its not tuned to it.i have a stock tstat and my car runs fine.

JoshuaH82

Oh! Also ask him if he's done anything to the MAF. If it was modified at some time and he didn't correct it with a MAFT or upping shift firmness, it puts A LOT of wear on the transmission. The MAF, when modified, will not read the actual amount of air that's going through it. That tells the car that you're not going as fast as you are and in turn tells the transmission it doesn't need to pump as much fluid through on shifts. This'll kill the transmission eventually.