Noob turbo ?'s

[meathooker]

Just got my sled up and running. 800 cfi motor with a diy turbo kit. Using a 2860, attitude controller, hallman mbc, 2:1 rising rate fpr.

1. we just got it fired up and running it on the stand this weekend and it is only pulling 4 lbs of boost. i messed with the mbc and am able to lower it; but not raise it. Is that common since there isn't a large load and should expect to pull more boost on the snow?

2. what are you guys reading for vacuum at idle? i am reading no vacuum; the boost gauge came out of a car so i am pretty sure it is reading accurately.

3. has anyone tapped into the compressor housing to get a boost signal or is everyone going off of the charge tube/air box?

 

[turbolover]

I could never get it to produce anything more than very minimal amounts of boost on a stand. Under load it jumps right up but you have to load it.
My boost guage is plumbed right to the air box.

 

[devilrmk]

I get full boost on the stand, however I do have to hold it open for a bit to get it there. Start looking hard for boost leaks. The richer you are running the less boost you will get and the slower it will come up. You may either have boost leaks or probably just a bit fat.

You will see no vacuum on the 2 stroke, may get just barely noticeable amount when first cracking the throttle, none any other time.

 

[meathooker]

devilrmk,

are you running a bov? i have been wondering if there would be enough vacuum in the TB to actuate it???

thanks for the input

 

[POLARIS600cc]

where are you getting your pressure signal for the boost gauge? If you want it to show vacuum it needs to be after the throttlebodies, or in the tb's but after butterfly.

 

[devilrmk]

devilrmk,

are you running a bov? i have been wondering if there would be enough vacuum in the TB to actuate it???

thanks for the input

Yes I am running a BOV. Plumbed between the carb and reeds. You have to use a very light spring, or shorten one so its real light.

They don't see much vacuum.

 

[JET FUEL]

Just got back from test and tune with meathooker. had a few issues, finally got it to quit cutting out at wide open and we need to re think the oil tank for the turbo, it wouldn't drain very well and smoked like an old pinto..but wow that thing is fast, still need to dial it in some more, its laggy off the bottom. the BOV wasn't hooked up and we have a mess of wires we still have to hook up(IQR w 800cfi).
On a side note my naturally aspirated 797 didn't skip a beat

 

[meathooker]

The bravo didn't skip a beat either

Just got back from test and tune with meathooker. had a few issues, finally got it to quit cutting out at wide open and we need to re think the oil tank for the turbo, it wouldn't drain very well and smoked like an old pinto..but wow that thing is fast, still need to dial it in some more, its laggy off the bottom. the BOV wasn't hooked up and we have a mess of wires we still have to hook up(IQR w 800cfi).
On a side note my naturally aspirated 797 didn't skip a beat

 

[turbolover]

full boost on stand??????

I get full boost on the stand, however I do have to hold it open for a bit to get it there. Start looking hard for boost leaks. The richer you are running the less boost you will get and the slower it will come up. You may either have boost leaks or probably just a bit fat.
.

I don't have leaks but I am running it a bit on the rich side. I haven't had the guts to hold it open long enough to get more that just minimal amounts of boost (3-4 psi) on the stand and the speedo says over 80 MPH!!!!! on the snow it will jump to 9 psi quick enough to do wheelies.

 

[devilrmk]

I don't have leaks but I am running it a bit on the rich side. I haven't had the guts to hold it open long enough to get more that just minimal amounts of boost (3-4 psi) on the stand and the speedo says over 80 MPH!!!!! on the snow it will jump to 9 psi quick enough to do wheelies.

Yea it gets moving pretty fast by the time it boosts.