The stock computer, if i recall correctly dread, reacts to 18 for more than two seconds. This will occur with increased air movement available from larger free flowing exhaust, and a big IC, in my limited experience. But the lack of power on the top end is something else, not the boost cut feature I think. I had the no power at the top bad when the car was stock plus Mazdaspeed Cold Air. Really did not want to rev past 6100 with any enthusiasm. With all my bolt on crap I can walk the throttle to 6800 and still pull a bit. There is no such thing as full throttle in third ,4,5,6 though for me. You just can't mash the pedal in those gears with my car untuned. So till next season I have found ways to drive around the overboosting. It takes a lot of restraint to go very very fast. But it can be done. No 1/4 mile car though. I still need to absorb info from you guys before i start playing with ECU. Sorry to drive this topic all over the road, NA allmotor best. sir
how to get rid of boost cut
- Thread starter NAisBST
- Start date
- :
- ‘19 CX-5 GTR Tu
What are your mods?
Why would you continue to drive car with current mods if it boost cut every time you go wot??
You do realize you are now slower than me. And i am stock!!(smoke)
Assuming you have the following mods:
CAI
BOV
Turbo back exhaust
Upgraded Intercooler
The following suggestions may just cure your problem.
Invest in upgraded Cam Drive Fuel Pump (CDFP) and get an EMS!
-C
Oh its on blotter container.hahah. Ihavelots of crap on and you are very nearly correct. I have the Mazda Replacement fuel pump and flash. I am rich and need to blow carbon out before i get serious. I only go wide open after 5800 or so in the higher gears. If you are running into the twelves you have my hat sir. I have my stand alone on the coffee table. i was attempting to be patient and get all my chassis bits and motor bolt ons in place. I have been made aware how to get around the EcU seeing boost and controlling boost with plumbing devices. But you are correct, control of fuel,spark, boost and such will be the only way to go. I apologise I should not talk out my ass without hard data. Iwill not go for it till next season. I am running pretty quickly on the nittos. With no driver mod. I mean I suck at 1/4. not for nothing but I posted 13.74. In spring before I had half my crap in place. so how fast is your car? I GPSd at 162. Love you man! Thanks for dialogue
- :
- ‘19 CX-5 GTR Tu
the Mazda Replacement Fuel Pump & Flash is B.S. if you ask me. From the sounds of it..it won't be nearly as good as the ones on the market w/ upgraded internals.
I suggest that you upgrade to the MrLilGuy Pump or CPE's solution. From what people have said ..the replacement from Mazda will not flow enough fuel to support what you want to do.
I bet you $10 that your downpipe is causing your boost cut.
This turbo spikes uncontrollably (SP?) when you open up the intake & exhaust.
I learned allot from my speed6.(friday)
- :
- 2011 Mustang GT
+1 with what acid said. To really eliminate boost cut on the DISI, you're pretty much gonna have to get a tune (XEDE/CP-E), a more efficient turbo, and the CDFP upgrade. That should cover all the bases required to make the car perform all the way to redline. It's not a simple, do X to get rid of Y problem, but rather a combination of things that have been mentioned. Go find a flow map of a K04, then find one of a GT28, GT3071. You'll notice immediately the differences. There are solutions, but they don't come cheap.
blackmica08
Member
- :
- 2008 mazdaspeed3
i have a gt287 on the car and im getting major boost cut on the higher gears 4,5,6. i cant go wot on those gears i have to keep it under 5800rpm or the car buckles big time, and i have a boost cut defender but still happens. i spoke to ken at protege garage and he said i will need a standback because the ecu is freaking out do to more volume of air. im seing 16 psi on 3rd gear but once you switch to 4th gear if going wot major boost cut. im still undecided on the standback or wait for better maps from cobb ap.
- :
- 2011 Mustang GT
Wow. I thought by increasing the volume of air and adding fuel, you should be able to eliminate the boost cut at the higher rpms. I understand it was initially designed in the factory ECU as more of a safety factor for the K04. This makes me wonder if the Standback is capable enough to tune out the boost cut, or if the XEDE might work better in this scenario.
- :
- 2011 Mustang GT
Yes, both the Standback and the XEDE are capable of being PnP, if you buy the optional harness. I'm not sure which one is more tunable though.
AutoXRacer
Member
OK, since I have recently experienced boost cut since my CP-E flash... I'll share with you what I have learned these past few days...
Fuel Cut and Boost Cut are two different beasts...but at the same time similar. Let me explain:
Boost Cut occurs when you are WOT and all of a sudden, it feels like someone just slammed on the brakes and instantly released it. It can happen once or multiple times through out the RPM band. The cooler the ambient temps, the more pronounce the cuts are...
Fuel Cut occurs in the same WOT condition, but feels differently, more like a rev limiter where the engine stutters/bounces.
Boost cut is a lot more violent...
Boost cut happens for a few reasons, the ECU will trigger its safety mechanism when it sees higher than stock boost (peak base boost), a higher boost curve (maintaining a higher boost profile throughout the RPM band), and increased flow throughout the intake tract.
Fuel cut is simply running out of fuel; fuel pressure loss, a lean condition, and/or the MAF sensor reading high air flow rates (beyond threshold value).
Boost cut and fuel cut both share the same safety mechanism that the ECU employs. But feel different when they occur. There are also a few other triggers that may result in cuts, MAF reading too cold of temperatures and to high of a flow rate. Thats why the StandBack or some other programmable ECU is a much better solution for these cuts...all depends how far along your mods are.
For the average modder, a MAP clamp will solve the boost cut issue, while an upgraded fuel pump with solve the fuel cut issue.
Regardless, the ECU monitors various parameters; calculated load, max MAP voltage, max MAF voltage, boost curves, power curves...basically a crap load of stuff. The more modded (heavily modded) you are the harder it will be to pinpoint the exact trigger.
For the member that did not want to lose the safety feature of boost cut, TurboXS has a MAP clamp that allows you to "raise" the boost cut limit.
I just order TurboXS's FCD-5V Fuel Cut Defender and will be installing it this weekend. Hopefully that will solve my boost cut issue. This MAP clamp supposedly has a knob to clamp the MAP voltage and another knob to set an max boost cut voltage.
I hope this helps and clears up some things.
Fuel Cut and Boost Cut are two different beasts...but at the same time similar. Let me explain:
Boost Cut occurs when you are WOT and all of a sudden, it feels like someone just slammed on the brakes and instantly released it. It can happen once or multiple times through out the RPM band. The cooler the ambient temps, the more pronounce the cuts are...
Fuel Cut occurs in the same WOT condition, but feels differently, more like a rev limiter where the engine stutters/bounces.
Boost cut is a lot more violent...
Boost cut happens for a few reasons, the ECU will trigger its safety mechanism when it sees higher than stock boost (peak base boost), a higher boost curve (maintaining a higher boost profile throughout the RPM band), and increased flow throughout the intake tract.
Fuel cut is simply running out of fuel; fuel pressure loss, a lean condition, and/or the MAF sensor reading high air flow rates (beyond threshold value).
Boost cut and fuel cut both share the same safety mechanism that the ECU employs. But feel different when they occur. There are also a few other triggers that may result in cuts, MAF reading too cold of temperatures and to high of a flow rate. Thats why the StandBack or some other programmable ECU is a much better solution for these cuts...all depends how far along your mods are.
For the average modder, a MAP clamp will solve the boost cut issue, while an upgraded fuel pump with solve the fuel cut issue.
Regardless, the ECU monitors various parameters; calculated load, max MAP voltage, max MAF voltage, boost curves, power curves...basically a crap load of stuff. The more modded (heavily modded) you are the harder it will be to pinpoint the exact trigger.
For the member that did not want to lose the safety feature of boost cut, TurboXS has a MAP clamp that allows you to "raise" the boost cut limit.
I just order TurboXS's FCD-5V Fuel Cut Defender and will be installing it this weekend. Hopefully that will solve my boost cut issue. This MAP clamp supposedly has a knob to clamp the MAP voltage and another knob to set an max boost cut voltage.
I hope this helps and clears up some things.
AutoXRacer
Member
Careful, there have not been many MS3 (none that I know) that have installed these. There was one MS6 guy that installed it successfully with no issues and I heard another had a CEL...
I should have gotten the Splitsec unit better due to its easy install; but its just a basic clamp.
But I will try to install the TurboXS and see how it works out and let you know. I really hope I don't get any CELs...
AutoXRacer
Member
Yeah, this whole fuel/boost cut had my head spinning!! They all call it a Fuel Cut Defender/Clamp/etc...anything that attaches to the MAP sensor is a MAP clamp. TurboXS Fuel Cut Defender is a MAP clamp.
I wish the people who made these named it right...but the line that separates fuel cut and boost cut is blury.
Stick with the Splitsec or any other MAP clamp. Just make sure it modifies the MAP signal.
Here are the instructions for the Splitsec and TurboXS:
Absolutely correct. The stock turbo takes off once it begins spooling due to increased flow. I will have the car tuned before next season with the ems ihave in hand. As I mentioned friend ran the wide band02 on the car after all mechanical mods then again after the replacement fuel pump. Much better, but I have one of the early build dates. Fuel was an issue for sure
I hope it works. As long as you can monitor the boost , will you be able to adjust boost up and down? And will you have the same maximum boost in every gear? thanks
AutoXRacer
Member
No, I want to stay with stock boost until I get some kind of EMS/ECU and do it electronically.
I have no idea what the results will be... I just want to get rid of the boost cut that I have due to the Full Throttle Flash keeping my throttle plate open 100%, thus changing the stock boost curve. I'm holding boost till redline; it slightly decreases, but not as much as before...
Before the Full Throttle flash I did not have boost cut, even with all my mods...but having that throttle plate open 100%, the car is a totally different beast. It just wants to keep going...while the ECU is expecting it to die after 5500 RPM...
Yes, i recall you speaking of the full throttle flash. Thank you for the clarification about the fuel / boost cut. So do you consider the flow increase, creating a little more boost to be the problem. or maybe more of a combo of signals referenced by The sneaky Mazda ecu Thanks hope this is not a terrible question.
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