msp+mbc= boost spike! wtf

[1FASTMP5]

ok i have a msp turbo kit on my p5 now for over 8 months.
mods are : fmic,cold plugs,cams,full custom exht,shrt ram,turboxs ds mbs

for some reason i cant get rid of my DAMN boost spike!! if it was like 1-2 psi that would be fine but it's not.

if i start out slow bring the rpm's to about 2500-3000 and punch it.....BOOM
boost spikes to 12 psi for a split second while turbo spools and falls off to 7 psi and holds to red line. wft??????? is this normal??? anyone else got any feed back on this?

i checked everything over and over....no leaks and a good vac source. wtf
i also use the shortest route to the mbc to the weaste gate.

i also did many searches and found no REAL answers on this. i did read about drilling out the mbc to get rid of the spikes.....anyone do this???

any feed back would be greatly appreciative!!!!(thumb)

 

[ForceFed]

DUDE!WTF!

Get a better boost controller
You must not have a very nice one....
Matt
I suggest a hallman....2 psi spike at reletively high boost setting.

 

[dominoy2k1]

maybe its that gay wastegate. or maybe its the mbc.

 

[Riles]

Electronic boost controllers really arent that expensive. I just picked up a Blitz Dual SBC for 200 bucks on ebay. Electronic controllers pretty much eliminate spiking. Why spend 1-3 grand on a turbo kit and then skimp out on the boost control?

Manual boost controllers spike. Thats pretty much a fact. A better one won't spike as much, but they still spike.

Also, it doesn't seem like it is the wastegate, because the stock wastegate seems to work fine, unless its dirty/stuck. Sometimes carbon deposits can build on the wastegate flap, so that could possibly slow down the wastegate reaction. But, MazdaSpeeds haven't been around long, so I dont think the turbo has enough miles to have this problem.

 

[1FASTMP5]

DUDE!WTF!

Get a better boost controller
You must not have a very nice one....
Matt
I suggest a hallman....2 psi spike at reletively high boost setting.

bro, i have the turboxs d/s mbc....brand new too. i even tried the joep mbc and got the same results with it.:'(

 

[Riles]

Its still a manual boost controller, meaning it will still be a victim of boost spike.

A way that we used to fix boost spiking and creeping on my friend's car was to put a softer spring in the wastegate actuator so that it has less force to fight against to open. This only works with a boost controller, but I think even a manual boost controller would be fine for this situation.

I might recommend trying that to make sure the wastegate is opening fully every time.

 

[505zoom]

...i did read about drilling out the mbc to get rid of the spikes.....anyone do this???

any feed back would be greatly appreciative!!!!(thumb)

You can port the bleed hole, but if you drill it too big it will not be good. That IS one of the ways that MBC's are tuned for spike though. You can also play with spring stiffness. If you are going to port the bleed hole, I would suggest drilling it out in VERY small increments.

 

[ForceFed]

bro, i have the turboxs d/s mbc....brand new too. i even tried the joep mbc and got the same results with it.:'(

I wouldnt sweat it!
Just turn up the boost so it spikes at 12 and falls to 10...The spike is the fun tire breaking,spinning balls to the wall scarin the s*** out of your friends when you mash the gas stuff!
Gotta love it!
Or you could just buy a hallman or an EBC...And be done with it.
Matt

 

[1FASTMP5]

You can port the bleed hole, but if you drill it too big it will not be good. That IS one of the ways that MBC's are tuned for spike though. You can also play with spring stiffness. If you are going to port the bleed hole, I would suggest drilling it out in VERY small increments.

ok, thanks..... i think i will try that for now. but damn, 5 psi spike that seems super high to me.

 

[CustomMSP]

Try adjusting the MBC for a little more boost and see if it still spikes like it does. Just be careful not to adjust it for too much boost.

 

[505zoom]

ok, thanks..... i think i will try that for now. but damn, 5 psi spike that seems super high to me.

That is.

If you can't get rid of it, sell that and get in on my GB that starts on the 21st. I have max 1psi spike with my BoostSciences DSBC, even at 14psi.

 

[1FASTMP5]

I wouldnt sweat it!
Just turn up the boost so it spikes at 12 and falls to 10...The spike is the fun tire breaking,spinning balls to the wall scarin the s*** out of your friends when you mash the gas stuff!
Gotta love it!
Or you could just buy a hallman or an EBC...And be done with it.
Matt

hell ya! on the way home from the track last weekend i kept mbc @ the setting i had for the track cause i still have some 100 oct left in the tank. it would spike to 16.5-17 psi and hold at 12-13 at red line.......DAMN this s*** PULLED like a mofo!!!!! i mean sick hard!!!! if i would just punch it in second gear @ 2500-3000 rpm's it would spin the **** out of my tires like nothing. s*** was awsome.(yes)

 

[Rich24km]

mine spikes to like 10 or so and drops back to like 7, and if i go over ten with my Turbo XS dualstage, it will not spike really at all. Under 10 it spikes to 10 no matter what.

 

[jflo]

mike, i think what that your open exhaust and FMIC have to do with it. people have experienced increased boost while adding on an FMIC and downpipe partially to the fact that the FMIC has less pressure loss and the downpipe allowing the turbo to spool much quicker

 

[1FASTMP5]

thanks for the help! (headbang)

 

[DiscreetSpeed]

wrd dude id invest on a better bc...i used to have the turbo xs dsbc and at rpm punches like that shows how good one(boost controller) can be.

good luck

 

[celdridge]

bro, i have the turboxs d/s mbc....brand new too. i even tried the joep mbc and got the same results with it.:'(

Thus my point about MBCs is made. Get a EBC and you will not have this much of a problem with spiking. You will get a little spike if its not configured 100%... but we are talking like .5 - 2 psi. Which is nothing in comparison to your issue. ********** is selling them for 299.00 with free shipping right now.... thats a hell of a deal.

 

[1FASTMP5]

Thus my point about MBCs is made. Get a EBC and you will not have this much of a problem with spiking. You will get a little spike if its not configured 100%... but we are talking like .5 - 2 psi. Which is nothing in comparison to your issue. ********** is selling them for 299.00 with free shipping right now.... thats a hell of a deal.

cool,thanks bro....ill look into it

 

[BOOSTR]

You guys must have defective TurboXS units. There is nothing wrong with their products. I have them on both of my turbo cars. Getting the DSBC is the best $239 that I have ever spent!

Try contacting them for assistance. They are very helpful.

 

[1FASTMP5]

You guys must have defective TurboXS units. There is nothing wrong with their products. I have them on both of my turbo cars. Getting the DSBC is the best $239 that I have ever spent!

Try contacting them for assistance. They are very helpful.

just talked to turboxs a few mins ago. right now im running the first boost setting completely closed, and the second setting 3-4 turns. because i only wanted 5psi(stock) for low boost, and 10-12 for high setting. -turboxs said the first setting needs to be open a couple turns or it will cause a spike. he also said i could drill out the brass nipple with a 1/16 bit to reduse the spike also. just thought i would share that info with you guys.

i will try out these tips tonight and post my results in this thread later tomorrow. thanks for all the feed back!!! (friday) peace