I have a 2005 evo VII

mod list:

arc air box
hks 272 cams
1000cc injectors
GT35R turbo with tab-fab header
38mm tail wastegate
50mm tial BOV
3" downpipe and HKS exhaust
greddy profec b spec II boost controller
stock ecu
stock mass air
255 walbro fuel pump
vivid racing fuel rail

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I have tuned timing and fuel on the car....

i think that the turbo is flowing so much that the mass air cannot keep up or read the amount of air that is flowing through it.

The problem is that around 6500rpm and 20psi the engine shuts off(big jerk)....its like hitting a brick wall. Thats the best way i can describe it.

How could i retune the stock mass air if thats the problem?

has anybody else ran into this problem?

 

I'm assuming you raised load limit? Sounds like fuel/spark cut issue due to load over shoot or boost over shoot. Something like that.

 

ya sounds like a fuel cut.. if im not mistaken a stock evo8/9 maf can read up 600hp worth of air . correct me if im mistaken. and im assuming a gt35r isnt making that 600hp @ 20psi... what rom are you using btw and does anyone have and idea of what the maf hz would look like logged on a maxed out maf? maybe that would help.

 

i can try to raise load limit. how would i do that on my stock rom? i have ecuflash and evoscan for logging. using a lc1 wideband as well to log a/r

 

If you haven't raised it yet, you're almost certainly hitting it. It's defined in different places in different roms. Look either in boost or fuel settings for something called "Max Load Limit" or similiar. It's a 1 column table with values like:

235
235
235
225
225
200
200
200

If you go over those loads, which you will with any bigger turbo, it cuts fuel.

d

 

i think it is boost cut load under Turbo Boost single Solenoid...is that right.

i just upped all the values to max which is 319. what do you think?

 

you should have a limit just in case boost spikes up but its up to you

 

That's not a good idea. The limit is a safety feature. I protects against overboost conditions by cutting fuel. Imagine if the vacuum hose slips off the wastegate. Now you have no way to controlling boost. Boost will just climb and climb until a) something leaks b) the pressure simply forces the wastegate open c) your engine blows up. In all three cases you're operating the car well outside of the load ranges it is tuned for.

EDIT: However. 319 might not be high enough for a 35R. There are also mods to increase that limit.

d

 

so how would i increase the load limit? do i just increase the max value in the edit table? please explain further.

 

Theres a definition patch to raise the load limit to 600 something. Search and you will find...

 

got it....is there anything else i would need to change if im running around 350 load? i know fuel and timing for sure but anything else that people generally miss?

 

Rescale your load axis so you can edit those higher tables. LoL be careful