TurboXS MBC install

[jersey_emt]

Got a barely used TurboXS standard MBC from a friend, and put it in today. The stock (pretty hard rubber) tubing did not fit on the MBC, so I bought a 1/8" -> 3/16" converter thingie. Everything fits good and seals good.

With the MBC set for the lowest possible setting, I'm getting spikes of 9.5psi-10psi in the lower gears, and steady boost at 8.5psi (my target). I'm just concerned about the spikes. They're only there for a fraction of a second, and then it drops back down to 8-8.5psi. Higher gears seem to be fine, they hold steady at 7.5-8.0 psi the entire way.

I always use 93 octane gas, and I'll be switching to 94 if the gas prices go down soon (it's not worth paying $1.85 a gallon for 94 when I can get 93 for $1.75).

Any forseeable problems? I haven't heard any detonation or hit fuel cut. Colder plugs are on the way.

I ordered a JoeP MBC the other day, still waiting for that one to come so I can compare the two.

 

[Striker187]

i doubt there'd be any problems. a lot of members are boosting 9psi+ with no problems. colder plugs would probably be a good idea anyways though, just to be safe.

 

[jersey_emt]

Yeah, I'm pretty sure I'll be safe, especially with the colder plugs. I'm still pegging the A/F meter on the rich side most of the time.

It's quite a difference @ ~8.5psi. The higher gears feel more or less the same, but 2nd and 3rd pull noticeably stronger. I haven't pulled through all of 1st gear yet. The turbo spool-up and whine is noticeably louder, as is the turkey.

The mod bug is cured for the time being. I'll probably catch it again next week

 

[KyRaceFan]

all MBC's spike a little bit..
My Joe P MBC spikes about a psi or so, then drops down to where i want it.... damage occurs when you overboost for too long and get detonation.

 

[2K3 MSP]

Don't worry about spiking to 10psi. I had mine set to 10, spiking to 12 before I put my DP on. A few others were running even higher than me.

 

[jersey_emt]

Yeah, I figured that this was normal from what I've read on the boards. I think that the reason why the lowest setting on the MBC is spiking @ 10, holding at 8.5-9 is because of the adaptor I had to use to attach the wastegate hose to the MBC (it's an additional restriction).

After I get my intake and exhaust, I'll probably upgrade to the Greddy Profec B.

 

[jersey_emt]

Well, I exchanged the TurboXS MBC this morning, because from reading the boards, I should be able to set the MBC lower than what it is.

This one's much better. Spikes @ 9-9.5psi, holds 8.5 steady. So far, I'm happy.

 

[turboge]

boost spike is inherent from the wastegate. We aren't using external units here, only the factory internal one. It is slow to react so thats where you are seeing the spike come from.

With a better boost controller like the SBC-R or the Profec B you can make it "sense" that spike and drop the solenoid duty cycle enough to prevent it.

 

[ND4MSP]

was the install the same as.. say a joe p mbc install, or any other mbc. Just wanted to make sure. I've got a xs standard mbc going on today. Thanks

 

[ND4MSP]

other than the line fitment probs

 

[turboge]

Yes, same install. 2 vacuum lines to run.

 

[ND4MSP]

thanks.

 

[prospeed]

i have the turboxs high performance boost controller set to 9psi with very little boost spike. but the bleed off almost makes the car stall somtimes.

 

[ND4MSP]

Is it because of the high boost recomendations for running it?
BTW have you looked at the site for install instructions for the hi po controller? It shows an alternate way for install:

(Pasted from site www.turboxs.com)
When increasing the boost pressure to higher levels (15 psi or higher), you will get more accurate, responsive and stable boost pressure by using a pressure supply line directly from the engine inlet manifold after the throttle body housing instead of the pressure line from the pressure side of the turbo as stated in step 3 above. By supplying the pressure directly from the engine inlet manifold, pressure effects due to air being forced through the connecting pipes and intercooler are eliminated from the operation of the wastegate actuator system. Ensure any previous pressure supply lines after the turbo are appropriately
blocked

Not sure if this can be useful to a speed or not. Could be benificial to those toying with the engines limits

 

[WeldingHank]

Profec B all the way. never spikes! i highly recomend it.

 

[DiscreetSpeed]

hit 12psi spiking 13psi, youll love it more.

 

[WeldingHank]

nah, i like 16 psi more

 

[DiscreetSpeed]

yah me too...^^^