Volt Boosters and alchy

K

KEVINS

Post count: 24,375
Joined
May 24, 2001
OK, I've been sifting through many, many, many threads on these pieces but nothing came up that is recent so hopefully this won't bug anyone too much.

Scene:
I roll into the throttle in second gear and just after the TPS hits max voltage at around 40-45mph Direct Scan shows 7* of KR at max boost of 25psi at this particular time then nothing more the rest of the run. Ialso have a audible knock detector so I can tell when it's getting knock.

I can't tell what's causing the KR. O2's start around 830 after I floor it (I know this is rich) then drops right down to 810 and I'm still getting KR. At the exact time I get the KR (which lasts about 2 seconds), the alternator goes from 13.3 to 12.5V and stays at this voltage throughout the run....no KR after this point.

Once in high gear the O2's start to fall from 810 down to 770 but I never get any more KR. I'm guessing that the XP fuel pump (hot wired) isn't handling the volume due to the low voltage drop so I'm thinking this could be part of the problem.

I've read soooo many things good/bad about the VB's but again these were old threads (2008-2010).

So what's the take on these VB's from Caspers on a car with alchy:
http://www.casperselectronics.com/store2/product_info.php?products_id=614

If you hate them or they cause too many tuning issues then how do I get my alternator to maintain the voltage? What have you done to solve this issue? There was mention in a thread about changing a diode in the alternator but nothing else was posted on what was needed.

Just to summarize:
I roll into the throttle in second gear around 40-45mph and as the throttle is opened all the way the boost hits 25psi and I get 7* of KR for about 2 seconds. After this 2 seconds - no more KR even through high gear.

I'd really like to get the voltage up where it should be before I really start pushing the boost more.

tia
ks
 
Have you tried priming the system with the test button right before rolling into it? Line could be partially empty causing the short term knock
 
Hell, I just remembered that I installed an electric vacuum pump and it has a hobbs switch that is triggered at 4psi. Could I hook up the Volt Booster to that switch then the alchy is set to spray afterwards.
Julio?

KS​
 
The Volt booster i havehave works off boost anyway not sure what you gain there...btw i have heard all the horror stories as well, but i have been using both a vb and alky for years...only problem i have had with is once i drove through a torrential rain and water got thrown up under the hood and got the vb wet, voltage spiked for a few minutes but it quit before any problems arose.
 
How are you reading voltages at the pump(s)?
 
bison said:
How are you reading voltages at the pump(s)?
Click to expand...
I'm just reading what Direct Scan is tellimg me. Red's XP fuel pump is hotwired to the back of the alernator so I don't know exactly what the pump is seeing but I do see the O2's dropping throughout the run from 830 down to 770..

It's hard to tell what is causing the 7* of knock because everything starts to happen at the same time and only last about 2 seconds according to Direct Scan so I'm starting with the voltage drop.

ks
 
I run Alky an vacume Voltbooster on single XPR1 intake hotwired, No Issues....(But i have XFI)
Only thing i dont like is at night, when you stab the gas,your Headlights get brighter...lol

(read your other post on boost issue,Get a bleed-off valve,RJC racing as one)

Enjoy!
 
False knock.

If your system is primed and you get knock, then its false KR.

Knock that comes up fast and then disappears is false. Knock that climbs.. 1,3,5,7,10 etc is real.

Bad motor mounts, bad tranny mount, exhuast banging, etc.

Its not a voltage problem.
 
Razor said:
False knock.

If your system is primed and you get knock, then its false KR.

Knock that comes up fast and then disappears is false. Knock that climbs.. 1,3,5,7,10 etc is real.

Bad motor mounts, bad tranny mount, exhuast banging, etc.

Its not a voltage problem.
Click to expand...

Thank you sir, that's comforting.
Now to find where the false knock is coming from and to figure out the O2's dropping.. Sounds like a new pump will be in order..:(

ks
 
the volt booster makes the alky pump spin faster i would guess right?

so we would be spraying more at the same settings after installation of a volt booster?
 
kidglok said:
the volt booster makes the alky pump spin faster i would guess right?

so we would be spraying more at the same settings after installation of a volt booster?
Click to expand...
Correct.
The biggest issue I can see is that you don't want the extra voltage to come on after the alchy is already sprying. If the voltage is already being applied then the alchy starts to spray then the system should be able to be tuned as normal.

I was looking at the volt booster from Casper but I hate the installation of it. They say to just stick it under the IAC/throttle body on top of the manifold. They go through all the trouble to design it with good connectors, etc then they want it to lie on the intake manifold...WTH..?

ks
 
O2's will always fall on a Buick. Thats normal. Typically you should see low-mid 800's when you punch it.. as the MPH goes up it will drop. At 80 MPH you'll see 790's.. at 110 MPH you'll see 770's.

You want steady.. get a wideband :eek:
 
KEVINS said:
Thank you sir, that's comforting.
Now to find where the false knock is coming from and to figure out the O2's dropping.. Sounds like a new pump will be in order..:(

ks
Click to expand...
You need to systematically go after things that "ding/bang" or make sharp metallic noises. Anything from a MAF pipe hitting the alternator, to downpipe hitting upper control arm, to TQ converter, timing chain, valve springs, etc.. Typically its bad motor mounts.. tranny mount.. IC hitting sway bar, etc.

My buddy chased a knock issue for 6 months. His ended up being the exhuast would bang on the rear axle.

HTH
 
Razor said:
O2's will always fall on a Buick. Thats normal. Typically you should see low-mid 800's when you punch it.. as the MPH goes up it will drop. At 80 MPH you'll see 790's.. at 110 MPH you'll see 770's. You want steady.. get a wideband :eek:
Click to expand...

I don't know what my fuel psi did on that run but what causes the o2's to go down if the fuel psi is steady? Will/won't the injectors try to maintain a constant O2 reading?

Hell, maybe mine is fine then.. I'll make some more pulls later this week and review the data and see what I come up with but I'm getting leary now that the boost will get raised even more. I just want to make sure everything is working as it should before the boost gage starts to get pushed..

ks
 
The longer you put heat on the stock O2 sensor.. the lower it reads. Just an "is what it is".

I'd be concerned if you punch it at 55 and its 750 by 80 mph.
 
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