Unichip EBC + large exhaust = 15-19 psi

[CasopoliS]

Well I installed the Unichip boost controller tonight. When flooring it I have gotten up to a 19psi spike in first, most of the time when I gun it I will get around 15-17 it seems, and it levels off to ~12 from what I have noticed. I have nowhere to test this because the car is so damn fast, I will just get pulled over.

I talked with Josh from Unichip and we both think it could be due to the GHL 3" turbo-back exhaust. The turbo spools up so quick we don't have time to control the boost and get much larger spikes than a car with, say... a catback exhaust. That is the theory at least. He mentioned sending me a unit programmed to give lower boost. I guess he would just lower it a bit and hope it brings me down to levels I want. Its a shame there is nobody close to me that could do this.

Just figured I would share. This has happened before, I am going to do some thread searching to see if a large exhaust is common to this problem. Oh yea... I have never driven a car this fast. I cannot even controll it. I got so scared of blowing up the engine I just stopped driving. I need to build quick because that would be wonderful. There is a huge difference between 10psi with a 13 psi spike and 13psi with a 17psi "spike" (Unichip programs higher boost in the lower range). Its unreal.

Your thoughts please.

 

[MazdaSpeedSter]

19psi!!!! wow be careful! I would use a different controller the unichip one seems to spike wayyy to much! Hopefully the new one will work out better for you though.

 

[CasopoliS]

another one...
http://www.msprotege.com/forum/showthread.php?t=114005

 

[geomatics_tech]

thats a big spike, I wouldnt be driving like that either. How is it with the boost controller off, any big spikes?

 

[CasopoliS]

thats a big spike, I wouldnt be driving like that either. How is it with the boost controller off, any big spikes?

no with it off, stock boost control. I am about 8psi stock which shows how my mods have changed things slightly. No spikes.

Remember, Unichip programmed a rise in boost in the low end where there is fuel to play with, then pull the boost back down at the high end. The raise in boost is intentional, they just never had a test car with my mods which allow for faster spool and prove to raise even stock boost levels.

With a custom tune with 10psi, 13psi low end I think this thing will haul. I cannot get over the amount of power from the 13-15 psi. 250WHP+ no problem.

 

[blthlt]

Are your internals stock? I ought know this.

 

[MazdaSpeedTurbo]

i will gladly install your unichip onto my car i have custom turboback 2.5" drive on down here we can try it out

 

[JBreed]

I have an apex downpipe and a 3" exhaust back...I noticed a difference immediately, but only sometimes. So I agree, larger exhaust=more boost... I keep my boost at no higher than 8psi now, but I would love to feel 17psi! woooo! (forged)

 

[CasopoliS]

I have an apex downpipe and a 3" exhaust back...I noticed a difference immediately, but only sometimes. So I agree, larger exhaust=more boost... I keep my boost at no higher than 8psi now, but I would love to feel 17psi! woooo! (forged)

its unreal. I stepped on the gas in second gear, the wheels spun uncontrollably as the boost rocketed to 15psi. Response was that of a cheeta. I will never go back. Must forge. Now. Ok well not really, because the rock, wedding, and 2 week honeymoon in Hawaii wiped all money I ever had. Oops.

 

[CasopoliS]

IIRC a few people with uprgaded exhausts and Intercoolers had this problem. I may be wrong but i think it has to do with the "programmed spike." when you unblock the stock bottle necks such as the exhaust and the intercooler the spike that should only be 13psi jumps to a higher psi

very correct. This is what Josh and I think. He will program me another module and try to lower the boost settings to see if that helps. If I can find a somewhat local Unichip tuner I would rather do it there so we have some feedback. Well that and they can tune for larger injectors. Josh and I talked about getting a program made for larger injectors, with the help of Ben too. We will all work something out I am sure. I want to do this now and get it over with so later when I want to upgrade more parts, the fuel is avail.

 

[low_psi]

Yea I hit 12psi and just hold it all through the rev range. No spike, just BAM 12psi. Stock boost is fine, get a small spike and hold 6-7psi. I'm pretty sure its either the soleniod or module. I'm gonna have JDMSam look at my boost module settings when we can coordinate schedules.

Let me know if reprogramming the module helps. 12psi is fun, i can't imagine 17psi.

 

[JBreed]

its unreal. I stepped on the gas in second gear, the wheels spun uncontrollably as the boost rocketed to 15psi. Response was that of a cheeta. I will never go back. Must forge. Now. Ok well not really, because the rock, wedding, and 2 week honeymoon in Hawaii wiped all money I ever had. Oops.

haha...yeah, rocks, weddings, Hawaii= big bucks! congrats!

...imagines spicy msp pulling at 17psi... (drinks)

 

[atticus1398]

Thats pretty close to my levels to.
Corksport 2.4" + Perrin FMIC + Unichip + cool morning temps= 16psi spike down to 12psi to redline. I was scared too. I also called Jack. But so far its been ok(8-9months). My longblock should be done in the couple of weeks for backup.

 

[ChopstickHero]

19psi!!!! damn. yeah, too bad you aren't close to a custom Unichip tuner. if you were, you would be able to custom tune it for your mods.

 

[Saban]

I'm just (lurk) from unichip thread to unichip thread, but you guys really put on a nice civil discussion. No freaking (flame) like some of the EMS threads.

Good Read!

 

[atticus1398]

If youre nervous, try a MBC (first)

 

[JBreed]

Yea I hit 12psi and just hold it all through the rev range. No spike, just BAM 12psi. Stock boost is fine, get a small spike and hold 6-7psi. I'm pretty sure its either the soleniod or module. I'm gonna have JDMSam look at my boost module settings when we can coordinate schedules.

Let me know if reprogramming the module helps. 12psi is fun, i can't imagine 17psi.

I live on Big T also , north richland hills...you?

 

[CasopoliS]

Yea I will just tell Josh to knock the programming down 3psi and that will do it, at least I hope. Stock settings for now.

 

[Professor MSP]

I am with mx3ownzj00 it is likely the solenoid or the programming, assuming, of course, no others issues with vacuum lines and the like. If it were me, I'd start by replacing the solenoid first, as I vaguely recall that a few others were having this overboost issue and found that the solenoid was at fault. Moreover, if the solenoid is indeed faulty but instead the unit is reprogrammed, then that strikes me as problematic, and at the very least less than an ideal solution. Also, the solenoid is far easier to swap out than the brains of the Unichip.

One other thing that I have observed is that my eye is not all that good at determining peak psi while driving. I have an electronic boost guage with a peak recall feature, an overboost warning light, and more than an 180 degree sweep from 0 to 15 psi. Often I find that what my eye sees as peak boost doesn't coincide with the peak recall reading.

I hope you solve the problem as soon as possible.

 

[silverspeed03]

15 -17 psi, with a 19 psi spike.........long pause.......................that's just insane!!!!

Not sure how safe that is with out being forged.
Now I desparately want to get a UNICHIP.