I am about to go with the Hypertech programmer and am getting conflicting advice about changing the thermostat......

I was told that putting in a 160 degree t-stat will do no good, even if I change the temp sensor, and if I re-program, I HAVE to change the temp sensor......Now, this is coming from a guy who SELLS the temp sensors, so I would like to hear REAL-WORLD advice from you guys on this.

So give me the poop.......do I need to do anything when I re-program, or what?...Right now, i'm a little confused, so tell me what you guys think......

:seeya

 

All I did was 160 t-stat and reprogrammed, now it runs alot cooler :yesnod:

 

Cool.....How about performance?...Did the re-program substantially enhance it?

:seeya

 

I'm no expert but a temp sensor is just a sensor right? It does not SET any temp it just tells the computer what the temp IS! Temp is controlled by other things like fans, thermostat, radiator flow, rpms, water pump etc.

I think its just a sensor, why would you change it?

 

Hey,
I did the 160 with the repogram. It still runs hot in summer traffic, only way to prevent that in my opinion is to get a bigger radiator or a better water pump. I hear stewart may be coming out with a high flow water pump for lt4's and there is the meziere.
Bottom line it runs cooler but will still run very hot. As for performance I felt it did improve, but thats just seat of the pants testing, I felt the car ran better, overall I felt it accomplished what I wanted it to do well. I also recalibrated the speedometer.

Gonzo

 

I forgot to ask in my original post........Does anybody know where to get the best price on a Programmer?

$300-$329 is what I'm seeing...anything better?

Thanks Guys!!

:seeya

 

not that I could notice. its just nice to see the temp below 200. Since getting the programmer I have done cam/headers/cats etc. so I am going to have to get it tuned elsewhere. As far as a better price, try e-bay got mine there for under 200.

:cheers:
jeff

 

First, my unsolicted opinion about the Hypertech after witnessing several dozen dyno runs over the past two years... :bs Why?...I've yet to see a single LT4 gain power (i.e. 5 rwhp or more) with the power programmer. I have seen some LOSE that much. Also, the dyno curves tend to look very choppy at the higher rpms, likely due to too much timing advance causing detonation.

:bs There's no need to change the temp sensor. Putting in a 160* t-stat will delay reaching the higher coolant temps at idle and will allow cooler highway cruising. To take "full advantage" of the 160* t-stat, you do need to reprogram or I believe a manual switch is now available for '96s ('95 and older units will not work due to OBD II on the '96s)

$300, or even $200, is a LOT of money IMO for a glorified fan switch. If you really want the fan turn on temps lowered, contact PCMforLess (they have a website). I believe Brian makes simple changes for $75 + return shipping of your PCM.

FWIW...I have a 160* t-stat and still have the same temp sensors :) I reprogrammed my fan temps using LT1 Edit.

 

I've seen the same thing... I have a HPP+ on my Vette, but only because it was a carry over from my 97 T/A and it worked on the Vette also...

I originally bought it for the code reading/resetting, and data logging ability you get with the $100 scan cartrige... The fan temp was an added benefit...

I use the fan settings only, the power programming is worthless...

I simply programmed the fan temps for the 160F thermo but left the stock 180F thermo in... Temp runs right at 197F all the time now because the fans kick on a couple of degrees before the thermo even opens.. So even in the summer with harder driving, the cooling fans are pulling air at slower speeds even if the system is already below 200F...

I'd rather take 007's advice and just have the PCM modified for the lower fan temps... It's cheaper, and unless you get the HPP+ used, and buy a scan cartrige for diagnostics/data logging, I'd consider it a waste of money...

 

Back-to-back dyno runs with & without HPP III Plus on my LT4. Gained 5.1 HP. This may be real, or may be variance between runs. Who knows? To me the HPP III Plus was worth it because I could reprogram the speedo for my 4.10s, and make the fans come on at 200 and off at 180 instead of the factory setting of not coming on until 228 and going back off at 200. You do not need to change the temperature sensor(s) to change the fan setting in the computer. Also, IMHO, you don't need to change fgrom the facctory 180 stat. Once it's hotter than 180, they're both open. Changing to a 160 will not make it run cooler in the summer with the A/C on. BTW, I will have a LT4 HPP III Plus for sale soon - used once. My new 383 will have different cam, etc, so custom programming is required. As soon as I can restore the stock program (everything is apart right now), the HPP III Plus can be reused on a different VIN, so I will sell it for $250. It was worth it for me. Paul

 

HPP is good for setting cooler temps. yes you need the 160 stat. but in my experiene, everytime i used the HPP engine tuning, i fried my 02 sensors.

i removed the engine tune and no problems since. i recommend you dyno tune the car for more accurate optimization of your pcm. but i would do the bolt on mods first you want to do, then reprogram to those parts.