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Discussion Starter #1
Cooler weather is here! :rolleyes:

Driving the last few days I've noticed a bit of a spike in the boost. It only seems to do it in second gear. If you keep high revs (around 5k) and then put your foot to the floor for an overtake etc, there has been a spike. Doesn't seem to do it in other gears, just 2nd. If the boost builds from say 3k in 2nd it doesn't do it.

I'm running a Blitz SBC-ID which is set at gain of 9 (turned down from 12) and ratio of 42. I have the warning enabled and set at 1.04 bar so that if it goes above it cuts back the boost, but it doesn't do it long enough for this to kick in. With those settings the boost is holding about 0.92-0.94 bar.

Mods are decat, trust power extreme exhaust, apexi intake, hks plugs, abbey 1 (or poss 1.4) bar ECU and the blitz sbc-id.

Any thoughts?

I could knock the gain down a bit more so the spool up isn't quite so fast, but much lower really effects spool and response time, or do I just need to live with that?
 

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i've got the same problem with that controller, it flashes red for a second or so. Its happening to me in 2nd, 3rd and 4th at the top of the rev range. Its bugging the hell out of me.

Any ideas greatly appreciated
 

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Discussion Starter #3
Yeah, its always at the top of the rev range, mine doesn't do it any other time. It doesn't even spike long enough to go red (from what I've noticed anyway!). What setting for gain/ratio do you have yours on (albeit a different turbo looking at your profile? mines on standard r33 tubbies)

I'm running standard turbo's so interested whether this rare spike is ok or if it will kill them........
 

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I've got a Blitz Dual SBC.

Mine does it in all low gears as well (i've seen 1.25bar on the peak recording - i've got a Blitz TT as well and this also confirms the high levels). Cars is a 33 GTR, Stage 1 350 @ hubs.

Settings are

Ratio : 47
Gain : 10
P : -5
C : 0

Warning set at 1.00bar. What I need to know is (what I worry about is). Will the standard turbos be ok with this and how long its staying at such a high boost.

On the other 3 settings i've got ratios of, 38, 26 and 17. Most of the time the car lives on 17.

On some spirited motorway runs 130 - 170mph the car was "plusing" (best word I can think to describe it) as it accelerated due to the car being on and off the boost limiter.
 

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Discussion Starter #7
So by the sounds of it my boost spike isn't all that high.......

Lee - with a ratio of 47 what boost are you holding? I guess just under 1bar if your warning is set at that?
 

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I think it has to do with the amount of more oxigen in the air at cold temps.
Its the same when you live in higher regions. Where the air gets thinner.
HKS has a built in pressure balance control to prevent such boost spikes.
That´s all I know bout that.
 

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Mine dosent seem to hold at a particular level, like I said earlier the car pulses along even in high geras as it hits the boost limiter.





The above shows the ratios of 47, 38 and off. I realise it totally contradicts my "not holding a level" statement above, but I dont actaully keep an eye on my blitz boost gauge needle. All I can feel is the car pulsing, I hear the boost alarm go off and if I flick my eyes down the dispalay on the DSBC is often red.

If anybody can explain that i'd be a very happy bunny :D
 

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Discussion Starter #10
That'll be why the boost is pulsing, if you have the warning set which you do and the controller see's boost over the warning (goes red), it reduces boost by whatever ratio you have set, and then once low enough lets the boost back again, hence the pulsing!

Interesting to see the graph with the different levels though :) I tried driving mine in the off mode a while ago - OMG, how slow and sluggish is the car then! :eek:
 

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Discussion Starter #12
I tried it this morning, and had exactly the same thing as you - pulsing boost. I had it set on 48, gain 7 and warning set at 1 bar. When I looked at the controller it was flashing red on between 1.05-1.07 peaking and being reigned in by the controller and thus the pulsing. My defi gauge showed 1.1 peak but that reads in Kg/cm. At the next lights I turned it down to 45 and 5 gain, turned the warning up to 1.02 (new settings the peak was 1.00 or 1.01 so not long enough to reign back) and I had no more issues with pulsing boost!

I'd say that in this weather those settings are just a little to high with the controller warning set at 1.0 bar before it starts to reduce boost. Seems to be quite a fine line in the settings!
 

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Discussion Starter #14
Thick mode engaged - P & C? Mines an SBC-ID, same solenoid etc, guess its the same........

It was 2nd and 3rd, hard acceleration, then had to ease off in 4th. However I've found 4th and 5th to be not so bad anyway as the turbos don't spin up so quickly.....
 

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lol. Guess you dont have those modes on yours? One is a boost reduction / increase onces limiter is hit, and the other is how muh it changes it for in seconds.*











*I think.
 

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Discussion Starter #16
Ah - yeah - I have that, you can set how much reduction and how long for with it under the warning settings so I'll have a look!
 

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Discussion Starter #17
Right - had a look :)

There is no time duration as such, it just keeps doing it while it is over the boost figure you set. The reduction is set at 10 (it recommended 7, but I increased a little for safety).

One thing I have noticed is since reducing the gain to 5 the boost spikes are much less - 1.02 now instead of 1.07ish witht he same ratio setting......
 

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Discussion Starter #19
Doesn't seem to be much noticable delay in spool with the lower gain either, still getting strong boost around 3.5k
 
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