Blitz SBC Help..

[jay1300]

Update 25-08-10

I think we have found the problem, my intake manifold gaskets are completly destroyed... I think there was a major leak which probably is why I could'nt boost past 0.8 / 0.85

I have read the previous threads about the blitz sbc spec r on a Skyline GT-R 1990 RB26DETT (I got twins not single).

I have checked all the lines, from the 2 wastegate to the "OUT" and the Intake Manifold to the "In" (the line goes under the plenum near the 6th cylinder.. // UPDATE : Which I was told was the best place when theres an aftermarket Boost Controller)

Then I checked the harness for the Boost Controller and it goes inside the car to the control unit.

I have theses mods :

HKS 2540 Turbos (I think... // UPDATE : It is written HKS on the turbines..)
555cc Injectors
Mines Intake Filters
3" Downpipe to 3.5" Muffler
HKS FMIC
Apex'I Boost Gauge (I think it's connected to the Stock boost Sensor on the left side of the EB)
The previous owner had a dyno sheet of 425 rwhp at 1.3 bar..

My settings are :

Gain 5
Ratio 68 / 80 / 100 I tried those 3 settings with almost no change to the boost..
Warn : 1.3 bar

Here is my problem :

I can't boost higher than 0.87 bar... I don't know what to do.. Thanks

Jay


Threads Ref :

http://forums.gtrcanada.com/gt-r-tech/37792-blitz-boost-controller-settings.html

[TW]

Did you try turning up the gain? from what i remember, the gain function on greddy bc's controls the boost pressure.

[TW]

unless gain controls response time.. what other options do you have ?

[jay1300]

Ratio is supposed to control the boost.

For example, if ratio is at 50%, it means the turbo will work at 50% of it's capacity. Meaning if it's at 100% it will work like the wastegate was always closed (or something like that) which shouldn't be my case since im only supposed to push 425 rwhp.

If I unplug my wastegate hoses, I will see if it's the turbos or the SBC that is the problem right ??
I know it's not a good idea but for 1-2 test runs to see if the boost goes higher than 0.9 ?

Thanks alot..

Jay

[GTR-Dad]

Jay,
Your diagnostic plan will work fine. You can do as many test runs as you want as long as you don't let boost run away as even once can be fatal to your hardware.
Pick 3rd or 4th gear and gradually roll throttle on with a friend watching your boost. This way you won't get it spiking to 2 bar etc.
Dan

[TW]

X2^
let your foot do the limiting, just be careful

[jay1300]

Small Update :

I have checked the Boost Controller by unpluging my wastegate hoses with NO RESULT.

The car is boosting 0.85-0.87 bar at full throttle in 3rd / 4th

If im correct, this would mean that my wastegate stays open for some reason.

It's not the boost controller, it's not the turbos...

Is there a boost restrictor somewhere that locks boost past 0.85 ??

I can't seem to understand why the previous owner was running 1.3 bar and I can't go past 0.85..

[jay1300]

I have also had an issue for the third time.

When I start the car (on random occasions) the car won't let me rev past 2500-2800.. (Like a rev limiter) I've searched on the forum and most answer are a bad maf. I just wanted to confirm this.

After a few tries and some time it always go back to normal (loose connection ??)

[jay1300]

Anyone ??

[klys]

Have you checked for a boost leak?

[needavdub]

X2

Check for leaks, with the wastegates unplugged you should be hitting crazy high boost levels.

[jay1300]

Could a boost leak make me loose like .5 bar of boost ?? that would be a huge leak IMO. I will check further in the engine bay because I can hear a hissing noise coming from the charge piping on the right side of the car (turbo side).

Can a wastegate get stuck open ??