I want to run a pettit unlimited ecu but was wondering if it would be safe to run on my mods. Im not looking for high power goals im just looking to run 300-350rwhp.
-FMIC
-Ported motor and exhaust port
-Stock injectors(as i know pettit doesnt support larger injectors)
-Non-Sequential Twins
-3 inch dp, resonated midpipe, Cat Delete, Muffler.
-Ported wastegate
-Aftermarket BOV
-Aeromotive 340lph fuel pump

Thats basically what i have on performance i was just wondering what everyone thinks about running the pettit unlimited ecu. Will it run rich or lean and at what psi? Also do you think its a good idea? Knowing that i dont big power.

 

Just install a PFC, I have not seen any good chipped ECU's. What I have seen is countless engines with chipped apex seals that were running the Pettit, M2, etc stock ECUs.

If you do go with the Pettit, take it to a dyno and have them install a wideband then do a pull to verify your AFRs. A wideband is the only way to tell if your specific setup is rich or lean.

 

The pettit ecu is designed to support the mods you have with a limit of around 12-13 psi. At that boost level you will still likely run a little rich. Thats what its designed to do.

A PFC is a better way to go because you have the ability to tune it to your specific engine.

 

Agreed. Those are know to run too aggressive of a timing map, which hurt the motor over time. There is also no way to adjust anything. I would recommend a power fc and a customer tune for your car by a professional rotary tuner. The car will run better and be safer.

 

Here is the most recent chipped ECU I removed from a customer's car, 94 with 29K miles. Full exhaust and intake with a Knight Sports chipped ECU, engine had 3 chipped apex seals.

 

Have a source?

 

Yep. Verified with a timing light years ago. You get small knocks and over time it chips the seals.

 

Below is a quote from M2 describing modifications made to their own ECU back in 2002.

"The stock ECU is mapped for stock boost and back pressure levels. Once these values are altered through modifications, the stock ECU can no longer compensate for safe operation," Richards explains. "Our remapped ECU solves this problem by compensating for the increased flow by retarding timing, altering boost controller values, and increasing fuel supply. The net result is a engine than can safely run higher power levels on premium pump gasoline, while still maintaining a margin of safety."

 

I found the same with a Knightsports ecu a customer was running in a TII. Ended up chipping a seal.

 

I've seen blown engine here with chipped/stock jdm ecu in Hong Kong. and people here said because quality of fuel in Japan is higher -----

which is funny because Hong Kong only sells 98 RON fuel ----- and it's higher octane than the highest RON fuel in Japan, and that's 96 RON.
(most ppl here doesn't know **** anyway)

I never verified timing with any of these JDM chipped ECU, but I always get that feeling that these ECU are overrated tho.

 

the M2 ecu and the pettit ecu are not the same, or it would be unwise to assume they are the same.

the JDM tuners have levels for their chips, and can actually tune them for specific cars, and unless you know what you're getting, and stick to its limitations, you are in for trouble.

thirdly at 320+ hp the stock fuel system is pretty much at its limit.

when you add this all up, if you still want to run a chipped ECU, you must stay within its limits, and it is probably a good idea to have the whole setup detuned slightly (run a stock cat, etc).

i've got an RE type A ecu in my REW powered FC, and i really like it, unlike the M2/pettit ecu's they actually retuned more of the map, idle is better etc.

 

This is the point I was trying to make. Lumping all chipped/modified ECUs into the bad group ignores the many variations available, some of them very good.

 

The M2 has more conservative mapping than a Pettit unlimited. Still, they are extremely outdated technology and I have seen a ton of damaged motors running them as there is no way to adjust anything. Here's a housing out of motor I recently pulled apart with about 55k miles. Mostly stock; intake downpipe, catback, Gforce ecu. Was running a conservative 12 lbs driven by an adult gentleman. There are already significant cracks around the spark plugs from overly aggressive timing/heat.

 

This is the result of an M2 ECU with all M2 bolt-ons, stock reman engine, still running the smog pump and high-flow cat. Retired gentleman owner.







Look at how nice the housing would have been if the apex seal was not chipped. Virtually brand new, no wear.




Rebuilt the engine, installed a PFC and tuned the car to 350rwhp.

 

Was that motor premixed?

 

Which is one data point potentially confounded by many other factors. It's nice to have that data point but there are no conclusions to be drawn.

 

No premix, owner was driving around with a blown motor for a few thousand miles, brought it to us to figure out why the idle was so bad, and down on power.

Same with the car posted prior, owner brought it to us to figure out why it was so unimpressive performance-wise.

Every car that has ever come into my shop with a chipped ECU has had at least one chipped apex seal. Obviously there are people out there that have had good experiences and the majority of cars coming into our shop are as a result of some issue. People never bring us their cars to figure out why it is running so well.

Fact is that even with the PFC there is no "one size fits all" map. Every car, even with very similar mods requires slightly different maps. There is no way that any chipped stock ECU is going to give the performance of a properly tuned EMS system