Fuel cut or boost cut????

[08SPEED3Veteran]

I need some help...i just installed the corksport power series exhaust. Downpipe, midpipe, and full exhaust. Understandably I am now seeing increase in psi which is normal. The problem I am now having is 3rd gear and on at high rpms i get the dreaded feeling of someone tapping my breaks for a split second. Not very fun the first time lol. The only other mods I have done to my 08 speed3 is fujita f5 cai, greddy type rs bov recirculated and thats it. I have the cobb turbo inlet on the way. My question is, am i expiriencing fuel cut? or is it boost cut? If anyone can tell me which it is and how to remedy my problem I would greatly appreciate it.

[Bravnik]

Fuel cut is more like a stutter or miss. Boost cut will be violent and sudden and feels like it is wanting to toss you through your windshield :)

[Cue]

If your keeping the mods you have now (or adding), you'll need engine management.

CP-E flash, Standback, map clamp

[Speed3Rookie]

If your keeping the mods you have now (or adding), you'll need engine management.

CP-E flash, Standback, map clamp
...or an AP.

[08SPEED3Veteran]

would the cobb acessport work? or should i get a boost controller or the MAP sensor thing? let me know what you guys think is best. thanks for the help!

[Speed3Rookie]

Cobb AP will do it. However, I'm not sure if it's compatable with your intake.

[Cue]

I hear some AP users still get occasional cuts?? I could be mistaken...

[derspi]

^^

Yes, I'm one of them. Cobb AP does not have boost cut removed instead they have opted to raise the boost cut limit depending on the map you load.

I recently installed ETS TMIC, Cobb SRI & inlet and loaded up the Stage1+SF 93 octane map and although it only happened on a couple of WOT runs, I want to get this addressed. Logs show that on this map I was spiking to 22.xx PSI and holding anywhere from 17 - 19 PSI. The car felt like a beast but for safety sake, I'm trying a couple of other maps to see what results I get. It's not helping that the weather is warming up so I don't know if I'm going to get definitive results until the next cold spell which could be at the end of the year where I am. It's pretty clear boost cut really only happens when there are atmospheric changes or variables that affect how the ECU perceives as being "safe."

[08SPEED3Veteran]

well i had a friend of mine take my car for a spin and hes an experienced and professional mechanic and he said the stutter is def fuel cut. so i believe my decision is to get the accessport from cobb and possibly a mechanical boost controller just in case. if there is anything else you guys feel i need to know please post it. So far the responses are very helpful.

[AMS38U]

you kno my ap used to let me boost 22 and settle at 19 but then i updated it and now the ap is actually more responsive and reads the car a lot more REAL TIME i dunno if you have updated yours yet but if not i suggest it cause now i spike a 20 and sit like 17 18. on another note my friend has the corksport exhaust and he guets the fuel cut so we tried my ap on his car the other day and he still got fuel cut

[lestat13]

I was getting the same kind of thing except more violent (imo) and thought boost cut with help from my dashhawk. the blame was placed on the corksport downpipe b/c of the divorced wastegate design. if you swap it out your problem might go away.....

[08SPEED3Veteran]

ive ordered the cobb ap and it should be here this week. ill see what happens with it and see if a liitle bit of tuning is all thats needed. if not i guess something along the lines of a fuel cut defender is needed. but feel free to keep leaving comments cuz God knows you guys helped me out a bunch!

[speed3driver]

I hear some AP users still get occasional cuts?? I could be mistaken...

Yeah, with my mods and the catless downpipe ive been hitting 24psi.. and it will definatly cut.

[08SPEED3Veteran]

lol well i needed the cobb ap anyway, but if anyone has any other remedies for my problem if they dont think the ap will work let me know. Ill try anything to get rid of this problem. I know im beating a dead horse but just so everyone remembers...i have the F5 Fujita CAI, Greddy type RS BOV recirculated, and the corksport turbo back exhaust and downpipe. NO CATS AT ALL. anyone know about a waste gate problem???

[lestat13]

if you have the divorced wastegate downpipe, more people than not claim it's a problem. I've talked to people with identical setups running different downpipes with zero issues when I was cutting and overboosting constantly. porting the wastegate a bit may or may not help. I would say swap the pipe out before it really starts causing headaches

[Speed3Rookie]

I was getting cut with the stage 1 map running a BPV/TP/SRI and FMIC. Switched to stage 2 and all is well.
If you have stage 2 mods and are cutting try stage 1 as it will boost a tad lower. Make sure you test with a DH.

[08SPEED3Veteran]

I have a few pro tuning centers around where i live so ill see what they say and ill try the accessport as soon as it arrives and ill let you know how my results are. all comments are still appreciated!

[onelsono]

if u have a ap and ur still hitting fuel cut, it might not be the ap. the fuelpumps on the speed3/6 are weak and cant handle alot of power over stock. your map could be fine but even though the ecu is calling for more fuel ur pump just cant give it, it could be maxed out. hense having fuelcut at WOT.. id get a fuelpump or highflow internals and then see where that gets u, if that doesnt work cobb just released the software so pro tuners can tune the speeds instead of sum basic maps, u should look into that, my cars geting tuned for free by a cobb tuner, first speed 3 to get tuned in my area =]

[08SPEED3Veteran]

So I got my AP today and installed it and im running the stage 2 91 octane and holy balls what a difference! Fuel cut is gone and when I got on the gas the car just wanted to go! Thanks for the help guys the AP is definetly a must have. Im still looking into a pro tuner and definetly leaning towards a fuel pump upgrade.

[dukebrown]

if you have the divorced wastegate downpipe, more people than not claim it's a problem. I've talked to people with identical setups running different downpipes with zero issues when I was cutting and overboosting constantly. porting the wastegate a bit may or may not help. I would say swap the pipe out before it really starts causing headaches

How do you create this idea of the divorced waste gate creating an over boosting environment? Show me your science.

[onelsono]

How do you create this idea of the divorced waste gate creating an over boosting environment? Show me your science.

yea im with u

[lestat13]

How do you create this idea of the divorced waste gate creating an over boosting environment? Show me your science.

Found a post a few months back with quite a few people claiming this. Saw issues on my car that seemed to be the same as everyone else. Do I have proof, no. I am assuming some other people do.

[Jessed87]

Just to go back to the topic of the difference between boost cut and fuel cut, I really would like to know a few things. Why would mazda program 2 different kinds of cut into the ECU? I would think judging on when cars appear to be cutting that either one or the other would suffice as they both stop the car from accelerating further. Does anyone know for sure that people are experiencing boost and fuel cut? And not just one or the other? Just some food for thought, I'd really like to know specifics just so I can further understand why it is happening.