I have a 94 with only a catback but I plan on doing more mods... What I'd like to know is can I get a chip like pettits unlimited ecu and be alright with just my catback for a little while? If not I'm guessing that I should just go for the PFC? I don't want to buy a chip that I am going to have to send out to get reprogrammed each time I get a new mod. So Unlimited ECU or Programmable ECU? PLEASE HELP AND GIVE SUGGESTIONS?!

 

unless you make the modifications that are given for the chip you are buying the car will not be tuned perfectly. It may run OK but it won't be perfect. If you plan all the modifications to be done in a short time and don't want to change the car to drasticly then the chip should work OK. For myself the first modification I bought for my turbo II was a Haltech E6K engine management system, but my car is also a track only car. Just be careful because these cars are very easy to modify, but can be difficult to tune and make reliable with the stock engine management computer. be careful and be sure the system you chose is tuned to your specific car.

 

So why does Pettit make an unlimited chip? Aren't you able to do just about any mod (except single turbo) with it? So your saying that with this chip I could NEVER have my car tuned right? During the Spring/Summer this car is a daily driver and I want to have reliability with performance. I know that with the stock ECU, if you do mods, the car will run lean so I would either have to buy and install all the mods with an ECU specifically programmed for them at the same time or else get a PFC and adjust as I go. I don't want to worry about having my car run a little rich or lean until I get the next mod for my car in because I have a catback and a chip programmed for intake and full exhaust and I do not want to send the chip out after every mod. I just didn't understand why you could buy an unlimited chip (less $) that you could do anything with instead of a PFC (more $) that you could also do anything with?

 

even with an aftermarket ECU every time a new modification is made the map will need to be fine tuned. what these chip burners have done is take a car and add the mods then tune the car on a dyno or on the road. then they copy the settings and burn the chip for sale. so if your car has all the exact modifications as their test car then the settings will be perfect. if on the other hand you use a different set of parts then you will still need some fine tuning. this doesn't mean the car will be undrivable or that it will cause damage to the engine. most of these tuners are smart enough to make sure they cover them selves. this usually means the fuel is a little rich and the timing is retarded more than necessary. if you are looking for stock type reliability and fuel economy(if the car is street driven) then a custom burned chip or a well tuned aftermarket ECU is needed. I blew a brand new motor on my race car when I changed the exhaust system and didn't redo the map on my Haltech system. just be careful I hate to hear about damaged cars and frustrated owners. if you like the petite chip then make sure you buy the intake and exhaust and other mods from them so it will be a match.

 

crai6m4ck,
I've had the Pettit unlimited chip on my car for about a month now and during this time I blew my engine. I know that it wasn't caused by the ECU though, and was related to boost creep(25psi). Anyway before I put the unlimited chip in I was using the normal chip and was very happy with the way the car performed. I have almost all the mods possible(except the most important: IC) and the car ran real strong. Never had any problems with it at all. The difference between the normal chip and the unlimited is that the second has the fuel cut removed from 14.7psi of boost and moved up to aprox. 17psi. Other than that they are exactly the same. Btw, it is not true that you have to send in the ecu everytime you change something. They come already set for all the mods when you buy it. If you don't have them though then you'll just be running a little richer. No big deal though. I am very happy with all the Pettit products and customer service!

 

Now I'm understanding a little more... So all the Pettit chip does is just richen and move or eliminate the fuel cut? I appreciate all of this help and info. It's really nice to be able to understand your own car especially a Rotary.