I just have a "cheap bastard" intake right now, however I want to get a down pipe and cat back as well. But before I do so I want to upgrade my ECU so I have no chance of running lean, or detonation.

I was looking at the Pettit Unlimited ECU, my question is, will it protect me from boost spikes and creep, or do I still need to get a boost controller, with only the above listed mods?

 

The ECU alone won't control spikes or creep.

A boost controller will control spikes.

 

Yep. The ECU will, however, have better fuelling/timing so in the event of boost creep or spike you're more likely to be OK than on the stock ECU.

The biggest problem is the factory boost control is set up with a defined map. When you start opening exhaust/intake, you're outside of the parameters it was designed around and you start getting boost problems. A good boost controller will let you disable the factory system and give control back to you. If you just disabled the factory boost control, the car would be VERY slow - you need the boost controller to hold you at the boost you'd like to run.

Dale

 

The great thing about spikes is that they can be moderated (depending on your level of mods) with a simple $2 part, a carb jet.

I had boost spiking after just a DP and CB, well I replaced the WG pill with a .073" Holley carb jet and the spiking is gone.

Save some $$ and try it that way first.

 

Turbojeff can you expand on the carb jet mod

 

I don't have any spikes right now, just very cautious. Right now I just have the intake (I might see some boost creep in 3rd and 4th) however I want to put a cat back on and also a down pipe.

Should I skip the ECU for right now and just get a boost controller (funds are not as abundant as I wish they were) or what are your guys' suggestions. I keep running into contradictions as to what the best mods are to do first.

 

The carb jet is placed in the wastegate line instead of the "pill" that is put there by Mazda. The jet that Jeff is referring to allows slightly more air to pass than the stock pill.

You don't need this because you have a boost controller.

 

I thought that spiking and creep would eventually, like in the case of a midpipe, put the wastegate beyond 100% and at that point it wouldnt be able to bleed off enough exhaust gas to lower the turbine speed.

My feelings on a good mod order:

Upgraded radiator
Downpipe
Silicone vacuum lines
Intake
Cat-back
Fuel pump + filter (filter should be replaced at the very least every 25k-30k)
ECU
Intercooler
Midpipe (This is a touchy subject as this is the leading cause of creep/spiking)
Boost controller (A simple homedepot controller will suffice and only costs about 10$ to make)

From here you'd get into the PowerFC or other standalones, heavy fuel system upgrades, etc... I always felt the reliability and supporting mods should be done first to handle performance mods.

~Kris

 

IMO, get a boost controller, manual or electrical of your choice and stop depending on the stock system all together - regardless. I put a pair of manual controllers on and felt an instant difference for the better. So, get something no matter what mods you have!