Car somtimes feels like it hits a wall for a brief second around 3000rpm?

[Heatmakerz]

So my car has developed a weird issue some times, its starting to do it more often lately is when i take off it feels like i hit a brick wall for a brief second then it drives fine.

It usually happends in 1st gear the odd time in 2nd but mostly 1st.

Any input would be awsome! Thank you.

Also those of you who have polyurethane engine mounts do you get pretty good viberations?

 

[6A13TT TYPE S]

Sounds like boost cut. Does it have an aftermarket boost controller on it

 

[Heatmakerz]

Yea it has a greddy profec b spec. Ill have to keep an eye on it next time. But yea its weird and it doesn it when im not even wide open throttle so thats what made me not think it was that.

 

[Heatmakerz]

Im even curious if its the shitty stock intercooler charge pipes that collapse because there so weak an flimsy.

 

[Wakaba]

Do you have a tune?

Do you have a boost gauge, if yes, what is the gauge showing when it happens?

Air density is increasing with the season change, makes sense a high boost issue would happen more often now.

 

[Heatmakerz]

I was the ecu is already tunes but i probably not tuned to what i have upgraded. And i the gauge would spike pretty high!

 

[6A13TT TYPE S]

The stock ecu uses "load" as an axis on the fuel map
Load is an air mass (air flow meter reading)
For a given boost pressure the load may be 180 at summer temperatures. In winter because the air is colder and more dense to start with, and the cooler temps make the intercooler more efficient that load may go up to say 200. Which is likely above the fuel cut value.

If you have an aftermarket boost controller it doesnt care what the ecu wants itll just do what you tell it to which is usually to jam more boost in.

The better method is to wire a 3 port boost control solenoid into the stock solenoid wiring and tune the boost via reflashing the stock ecu. As that way you can match the fuel cut load tables to your boost desired engine load tables

 

[Wakaba]

The stock ecu uses "load" as an axis on the fuel map
Load is an air mass (air flow meter reading)
For a given boost pressure the load may be 180 at summer temperatures. In winter because the air is colder and more dense to start with, and the cooler temps make the intercooler more efficient that load may go up to say 200. Which is likely above the fuel cut value.

If you have an aftermarket boost controller it doesnt care what the ecu wants itll just do what you tell it to which is usually to jam more boost in.

The better method is to wire a 3 port boost control solenoid into the stock solenoid wiring and tune the boost via reflashing the stock ecu. As that way you can match the fuel cut load tables to your boost desired engine load tables

That’s where I was going with my questions. I’m not much south of him, and my car is really happy with the air density and IATs. But I’m tuned on a 3 port so I’m not spiking too much.

If he’s on a EBC with stock’ish fuel cut, I can easily see that as an issue. Big spikes on boost could be a control issue though.

 

[6A13TT TYPE S]

Yeah in this day and age i dont know why external boost controllers are still a thing on flashable efi cars.
Distributor or carburettor turbo stuff sure but when you can make the OE ecu do it all why not

 

[Wakaba]

Yeah in this day and age i dont know why external boost controllers are still a thing on flashable efi cars.
Distributor or carburettor turbo stuff sure but when you can make the OE ecu do it all why not

Price of admission and relative “ease” for quick easy boost.

 

[6A13TT TYPE S]

The saying "the poor man pays twice" rings true here.
Along with the one "buy once cry once"in terms of buying a tactrix cable to reflash your shit. yeah it may be cheaper up front to put a boost tap on but the ability to do diagnostics, AYC bleed, reflashing etc is so worth the extra money.

 

[Heatmakerz]

Awsome thanks for the info guys i really appreciate it and i think i will go this the route you have suggested!!

 

[Wakaba]

Awsome thanks for the info guys i really appreciate it and i think i will go this the route you have suggested!!

Sorry if we sounded catty, was not my intent. This community has helped me a ton and is a true asset for these rare cars.

The stock ecu allows for only a little extra boost to be added by an external boost controller (electric or manual) before it starts throwing a fit. We’ve all gone down the same exact path and all found tuning the FL ecu (or standalone) to be the most effective path. Problem right now is the Tatrix 2.0 has been discontinued and the prices are obnoxious in NA (don’t know what you in AU/NZ are seeing).

As above, the stock ECU looks at engine load and adjusts boost from there to reach the goal on the ROM. Load too low, add more boost, load too high, back it off. Load way too high, boost cut! That’s why you see boost ratings on these cars as a band. This is because the amount of “too much” boost pressure is variable based on lots of different factors, mostly air density (more on that below).

Your Profec adjusts based on desired pressure in the system. Pressure too low, add more, pressure too high, back it off.

Because the air now is more dense (more o2 per liter of air) you can achieve the same engine load with less air. That is, equal power to the wheels with a lower volume of intake/boost air. To compensate for the higher air density, the stock ECU will reduce boost to maintain the desired engine load. The more dense the air, the lower the boost pressure is needed for target engine load, and by extension the lower your boost cut becomes.

That said, there could be other issues happening right now. But, give this a try, set your Profec for a target pressure of .1-.2 bar below where it is now, and take it for a rip and see if you hit that same boost cut. If the symptom is resolved, then your car doesn’t have any issues, tweak your Profec as you wish to compensate for this amazing turbo friendly air.

While the best method would be to tune the ECU, there is a price of entry. Running the Profec will just require tweaking as air densities fluctuate based on seasonality, weather, air pressure, altitude, etc.

 

[Heatmakerz]

No worries bro i didnt take it in away, im just happy to have you guys and your knowledge because otherwise id be lost! Haha i really appreciate all the information! I just want to do it right the car came with the profec ill try adjusting it for now untill i can find a tactix.

Its just so weird because even at like half throttle it will do it always in first. Just didnt make sense it just started happening. And again like you said awhile might be my coils fried because they are the cop kit. Could be a variety of things.

 

[Wakaba]

No worries bro i didnt take it in away, im just happy to have you guys and your knowledge because otherwise id be lost! Haha i really appreciate all the information! I just want to do it right the car came with the profec ill try adjusting it for now untill i can find a tactix.

Its just so weird because even at like half throttle it will do it always in first. Just didnt make sense it just started happening. And again like you said awhile might be my coils fried because they are the cop kit. Could be a variety of things.

Which coils are you running with the COP? I think I missed that part… too focused on the trees to see the forest.

I’m wondering if your dwell tables were changed to suit, or are you seeing the results of coils dying. I’ve been down this rabbit hole for weeks now.

Have you pulled your front plugs to see how they read?

Thankfully I [reluctantly] put the car and truck in storage yesterday, so Legnum efforts have shifted to parts accumulation until late April. Spouse is excited that I have no more excuses to not work on the Mini.

 

[6A13TT TYPE S]

Yeah well put wabaka . The annoying thing with external controllers is to get them not to spike and ride that "load limit" to get as much out of the car without reflashing the ecu is very hard. Especially if you get it running great in summer then winter hits and the load goes up so you have to retune the boost controller.

Obviously if you wanna run more boost than the factory load table allows you need to reflash the ecu, at which point your silly not to just tune the ecu to control the boost.

 

[Heatmakerz]

So after along time ive been putting off taking out my cop kit and putting my stock coil packs and wires in! It fixed my issue car runs like completely different than i have ever felt before! So thanks to all of you who guided me and helped with information!