Controlling some wild boost, ideas?

Russ

Club Member
Hi all,

Ok finally bored of not being able to just floor it lol.

I've got an Apexi boost controller, generally it's pretty well behaved. I have four programs I can set up, idea being you chose the one for the day. This is crap though, my lowest setting is useless most days, and too high on the old cold day. I regularly spike to something silly and then the boost is dropped in a panic, then up, down up down. I'm overtaking very fast, not fast, very fast, not fast lol.

It can take an external input for the control though, which sounds interesting.

Is there a product that takes say air temp/pressure, and I can plumb this in to keep my controller in check. I'd pay (almost) anything for it to hit 13psi and sit there, but instead I see 11, 12, 13, 14! 11, 14, 11.

At 13.5 it's really pulling well, 11 is no where and 14 is too much.

Help!! :D
 

SRRAE

Well-Known Forum User
Strange, my AVCR works very well ( When my car was working )

I put it on self learn, floored it about 3-4 times and it got it, I can set the duty and the boost stays within 0.5psi.

Check for air leaks etc to start.
 

Mr.F

Inactive
AVC-R is a superb piece of kit and gives very stable results plus fuzzy logic learning. Something wrong - check the install and details of the set-up...
 

Russ

Club Member
RIGHT THAT'S IT!

If I can fix it I'll bloody never drive the car again.

Last night I was nearly out dragged by a frickin bright red cherry bomb shitty Astra. The chav in it must have loved it. I know it's childish but the thought of him saying to his mates "my car is as fast as a 300zx" makes me want to self harm!

http://www.blitzperformancesales.com/techsupport/pdf/sbc_i-d_iii.pdf

Thats my boost controller. I also have a ID meter. I really liked both bits until I cannot consistently not fly through the boost then the car is just surging and I don't get anywhere.
Here are my settings

SET - Boost ratio or boost pressure setting

Now these when I bought the car were set to 48 and 50 (chan 1 or 2) and seemed to work well last summer (50 by day, 48 by night). Last night I was on 28, I ended up going down to 13 when testing before it'd stop going mental, which made me think "Hang on, is this actually the PSI I'm trying to set??". It'd never work aiming to hit 50psi though would it???

GAIN - Usually between 5-15%, gain controls the boost response.

Currently on a 5 on the slow setting, and bloody slow. I'm thinking I'll try SET 13, GAIN 15 when I get home and see how that goes.

I just want a car that runs the boost I want consistently/reliably. If anyone has the answer to that (I'll buy a AVC-R if I have to but my Blitz setup was about £600 new I think so kinda loathe to change it)...

Please help!! :(
 

Mr.F

Inactive
I'm not that familiar with the Blitz controller, but a skim through the user manual shows one important comment - "WARNING - Auto mode will not work properly on any twin turbo, sequential turbo, or high boosting vehicles."

In manual mode, the boost figure you dial in is a ratio or (I'm guessing) percentage of the maximum boost attainable by your system, so a car capable of reaching, say, 30psi unlimited and set to "50" should reach 15psi when controlled by the SBC.

The GAIN determines how the boost is delivered. This word of warning is given:
"Stock turbo charged vehicles with actuator type wastegates will usually use a gain setting of 5-15 percent. External type wastegates usually requires higher gain setting.
WARNING - High gain setting might cause boost spikes.
Note: Each channel can be set to each individual gain setting"

It is recommended to set the warning function which will let you know by buzzer and red display when you overboost. The LIMITER function pulls boost back towards standard in the case of overboost. Recommended setting 7 - 10 (0 gives no reduction; 99 pulls back to stock).

Additional control by vehicle speed for example can be set if you have the Blitz Power Meter i-D.

Do you have Auto Peak set ON or OFF?
Have you set wastegate type correctly? Should be set to AC for actuator type. External wastegate has different behaviour characteristics.
 
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Zed2k

Well-Known Forum User
I just use an actuator set to 15psi/ 1bar and it's rock steady, but on a twin turbo I'm not sure how the actuators are balanced out, maybe better to just have them set to 1 boost setting. Although I am quite interested in due setting using a boost controller and 2 fueling maps, say 1 bar and 1.2bar.
 

Russ

Club Member
ALL SORTED! :)

Thanks Mr.F.

I actually didn't bother to check any of the settings knowing they were right when i bought the car and the countless times I've messed about with it. However it appears whilst driving and fiddling with the controller I accidentally set it to AUTO :( lol. Back up to 15% gain which feels pretty good in the car.

Now it does a pretty good job at being at the right boost, provided you tweak it for that days conditions :) What I really need though is something totally automagic, so I say "13 psi please, give it everything it's got to get there" and something intelligent does all the tweaking for me :)

Thanks again!
 
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