i actually hit boost cut

[bobiseverywhere]

Well i was out crusing the other day and i did a nice pull in third gear, Boost went up and then started to creep a bit with some hgher rpm's around 5K i think. The boost started to rise from .7 or .8 bar up to 1bar, then the car hickuped since i hit boost cut and cut the fuel to the engine. The Ambient air temp out side was about 22C - 24C i believe. I was a bit shocked since i have never hit boost cut with my engine before.

I have not really changed anything on it and the creep did kind of make me concerned obviously.

Mods are not much. stock Y pipe, Trust DP, no CAT, HKS Sport CAT back, and HKS Muchroom filter on just the rubber portion of the intake piping.

I saw all this on my elec boost gauge.

This was done in Third Gear.

I did try to push the car again to produce the same results. I did see the boost creep up again, but did not hit boost cut?

is it just a fluke?

 

[OneJoeZee]

No I wouldn't call it a fluke. The stock turbos like to creep up with full exhaust. Sometimes you might bang off FC, sometimes you might not. Usually redlining in a higher gear like 3rd of 4th at WOT you'll have that happen sometimes.

If you dyno'd the car and logged the boost pressure, you would probably notice your boost rising quick to your target boost then creeping up a psi or two until you shut down.


Just hope it doesn't happen while you're racing someone.

 

[honestabe]

I feel your pain bro. I'm boosting about 14 PSi right now with just a cold air intake and 3" catless exhaust. I can only go about 3/4 throttle before I hit boost cut. Pisses me off every time I do it too. Then again, I'd rather hit the fuel/boost cut then blow my turbos/motor.

Adam

 

[HIDPLANET]

Yea, anytime I have the boost controller set at 14psi, I can hit FC at high RPM. I set it to 13psi and it stops it. I tried to set it to 12psi but the power loss was fairly evident so I like the 13 setting best so you can still get on it without hitting FC. Ive hit FC while playing around on the freeway and it really does ruin the moment.

Im just surprised you've never hit it in the past. Since day one when I got the car back from DriftMotion, I hit FC because I was at 14psi. When I install my Stealth ECU it will get rid of FC/BL/SL but I dont wanna blow anything up so i'll have to keep an eye on things.

 

[bobiseverywhere]

Ya i am not sure why i have never hit full cut either, and i have driven the car when it has been cooler out. go figure???

Funny thing is my throttle cable has some slack in it so i am never even at WOT 100%

I do not have a boost controller as of yet maybe soon but not yet

 

[bobiseverywhere]

Also forgot to mention i was able to keep pace with an Lexus IS350 on the highway the other day

 

[Yotaholic]

It must be nice to say it's rare to hit it , I can't drive my damn car without hitting it in any gear , I finally bought a Greddy bcc but find it hard to remove that safety feature. I would be quite happy with 13 or 14 :1zhelp:

 

[kwnate]

Also forgot to mention i was able to keep pace with an Lexus IS350 on the highway the other day

Keeping pace? Turn up the boost

 

[suprahero]

Keeping pace? Turn up the boost

Josh, you should be setting the pace...............:evil2:

Good luck with the boost cut issue. I haven't hit it once with my single turbo, and I'm running 20psi...........knock on wood.

OOOPS, didn't mean to say the word knock in a supra forum.............:biglaugh:

 

[str8_6]

since we're on subject and no one answered my thread on this question...if you have safc would you still need a boost cut controller? stock injectors by the way.

 

[OneJoeZee]

I would be wary of boosting much higher than factory boost cut on stock injectors if I were you. Especially considering you're single turbo.

It's a shame the 1J didnt come with larger injectors stock. Trying to make power on stock injectors is playing with fire, IMO. Ask me how I know.


But to answer your question, an AFC can raise your boost cut

 

[str8_6]

thanks!...guess i better throw those 440's i got laying around. and damn i hate your sig.... gets me every time.

 

[7Mboost]

Are you saying you hit boost cut at 1 bar? or it crept past 1 bar?

 

[OneJoeZee]

thanks!...guess i better throw those 440's i got laying around. and damn i hate your sig.... gets me every time.

ya dude. If you've got 440s laying around, go ahead and use them.

 

[suprahero]

Are you saying you hit boost cut at 1 bar? or it crept past 1 bar?

I think he is hitting boost cut at .8 bar. I'd have to reread it to make sure, and I"m way too lazy for that.:icon_bigg

 

[OneJoeZee]

Nah he described it as hitting boost cut at 1bar, where it should be.

 

[str8_6]

i'm hitting boost cut at 18psi.. anything less and i'm okay. i dont know if the 2jz map makes a difference...i heard it doesnt...but i do have that.

 

[foreverpsycotic]

i have heard 2 things, that the 2jz map is good for 18-20PSI and that the 2jz map is the same as the 1jz map (14psi). im hoping that stock injectors, 12v mod, emanage (or mapecuII) and a 2jz map will help me hit over 325 wheel, although i doubt the injectors will support it.

 

[bobiseverywhere]

last i checked the 2J Map is a 2bar map sensor as the 1J is a 1bar.
There are differences and it does matter putting in the 2J map with out anything else will cut back on some of your fuel, since it is then giving your ECU false info.

And in answer i am hitting boost cut at 1bar

For the moment i am just happy to have a running supra that i can take to work everyday

 

[str8_6]

i have heard 2 things, that the 2jz map is good for 18-20PSI and that the 2jz map is the same as the 1jz map (14psi). im hoping that stock injectors, 12v mod, emanage (or mapecuII) and a 2jz map will help me hit over 325 wheel, although i doubt the injectors will support it.

i did 348rwhp with stock injectors...do i recommend..highly no. but according to my aem wideband...i was at 11.2-11.5 afr all the way till redline. 440's are so cheap now though its better if you get a set less then $100.00 and have them flow tested/cleaned...good insurance.