to MBC, or not to MBC?

[KMOSES]

Hey fellow DSMers,

Mods are listed in profile, but for your convenience : HKS SSQV BOV, HKS Cat-back Exhaust, Injen intake hard pipe.

Here is my dilemma, a MBC is the next step for me in the stage 1 upgrade path. (Yes i realize that the exhaust comes after an MBC in the upgrade path. it was on the car when i bought it.)

However I'm already hitting 15-16psi of boost(on occasion i'll get fuel cut), the purpose of the MBC is to turn the boost up, I can't really turn it up any higher on the stock fuel system without getting consistent fuel cut.

My current goal is 300hp, essentially the stage 1 upgrade path. The guide say's that I wont be turning up the boost past 16psi at this stage, and if I'm already getting 16psi what would be the point of a MBC?

so my question is, should i just get one to be safe and use it keep everything at or under 15 psi, to avoid the occasional fuel cut(not sure how damaging fuel cut is). or skip the MBC at this stage, and continue on with things like a hi-flow cat, downpipe, exhaust mani, ect.

thanks!

 

[housegsx]

You will need the mbc with a new turbo. You won't be at 300hp with the t25.

But I would look into tuning, like ecmlink, before all the other bolt on parts you have listed.

 

[XiKeiyaZI]

You shouldn't be hitting fuel cut at 16PSI, especially on a T-25. I have a GST sitting in my carport running 18psi with 20psi spikes with absolutely no fuel cut or hesitation until redline, and that's on a 14b, not a T-25.

Have you attempted to rewire your fuel pump so that you achieve a constant and steady flow of fuel? The GST I am speaking of was lacking fuel and hesitating at 15PSI until we rewired the fuel pump. Now, it holds those boost levels all day long with no ill effects. I would look into doing a rewire if you have not already, I know that my experience on a rewired stock Fuel Pump was sold the moment we tested it out.

 

[KMOSES]

You will need the mbc with a new turbo. You won't be at 300hp with the t25.

But I would look into tuning, like ecmlink, before all the other bolt on parts you have listed.

thanks ill go with the mbc.

Ecmlink looks real nice, I was also looking into ECUflash/EVOscan.

Do you think I could get away with maybe just a safc for now? or are you recommending i get ecmlink for all the other tuning features and not just fuel tuning at this stage?

You shouldn't be hitting fuel cut at 16PSI, especially on a T-25. I have a GST sitting in my carport running 18psi with 20psi spikes with absolutely no fuel cut or hesitation until redline, and that's on a 14b, not a T-25.

Have you attempted to rewire your fuel pump so that you achieve a constant and steady flow of fuel? The GST I am speaking of was lacking fuel and hesitating at 15PSI until we rewired the fuel pump. Now, it holds those boost levels all day long with no ill effects. I would look into doing a rewire if you have not already, I know that my experience on a rewired stock Fuel Pump was sold the moment we tested it out.

Are you running a wb or anything to check your AFR? just because your not hitting fuel cut doesnt mean your not runing very very lean.

although you do have a rewired fuel pump to allow for constant fuel, someone correct me if I'm wrong but I was under the impression that anything over 15psi is bad for the stock system. The stock injectors can only push enough for 15psi at WOT no matter how much fuel the pump pushes. and after 15psi boost the afr will start leaning out.

I'm not trying to be defensive or offensive, just saying you may want to check your system out.

although im not really interested in increasing the boost, untill i get more supporting mods like bigger injectors, fuel pump, and some tuning device. thanks for the tips, and i'll look into a fuel pump rewire and what its all about.

 

[FLASH1970]

You have a 99 so your ECU is flashable. You do not need ECMLink. Just get a Tactrix 2.0 cable with a flash plug, get EVOScan and use ECUFlash. Ceddy has done a lot of work on the flashable ECU's in the 98-99 cars. Just search "Ceddy" and the threads he started should pop up.

Use EVOScan to run some datalogs and see what your injector duty cycle is when you hit fuel cut. If it's below 100% then try rewiring your fuel pump. Get a wideband too so you can monitor A/F ratios while datalogging. Then get your downpipe and high flow cat. Then get the MBC. Or get the MBC before the exhaust stuff but get your engine management things first.

 

[Boomdeeze]

You have a 99 so your ECU is flashable. You do not need ECMLink. Just get a Tactrix 2.0 cable with a flash plug, get EVOScan and use ECUFlash. Ceddy has done a lot of work on the flashable ECU's in the 98-99 cars. Just search "Ceddy" and the threads he started should pop up.

Use EVOScan to run some datalogs and see what your injector duty cycle is when you hit fuel cut. If it's below 100% then try rewiring your fuel pump. Get a wideband too so you can monitor A/F ratios while datalogging. Then get your downpipe and high flow cat. You don't list a boost gauge so get one of those on there (I didn't look at your profile so maybe I'm wrong). Then get the MBC.

I thought not all 99 ECU's were able to be flashed? Make sure you verify the numbers on the ECU itself and the ID number on the board.

 

[XiKeiyaZI]

Are you running a wb or anything to check your AFR? just because your not hitting fuel cut doesnt mean your not runing very very lean.

although you do have a rewired fuel pump to allow for constant fuel, someone correct me if I'm wrong but I was under the impression that anything over 15psi is bad for the stock system. The stock injectors can only push enough for 15psi at WOT no matter how much fuel the pump pushes. and after 15psi boost the afr will start leaning out.

I'm not trying to be defensive or offensive, just saying you may want to check your system out.

although im not really interested in increasing the boost, untill i get more supporting mods like bigger injectors, fuel pump, and some tuning device. thanks for the tips, and i'll look into a fuel pump rewire and what its all about.

I'm going to do the best to state this without sounding like a complete prick as I can, but certainly this must be clarified. You are asking questions that I had researched and answered for myself or sought direction with quite some time ago. Having taken the time to look into my profile, you'd be able to see that I am not the type to simply toss on a turbo, close the MBC and take off down the street slamming into brick walls (fuel cut) the whole time and then wonder what's going on.

In the case you are unaware, the stock fuel maps for these vehicles are rich to begin with, so, upon hitting an area where the fuel begins to thin and the air begins to overtake things, it is HIGHLY unlikely that you're going to destroy anything by increasing your boost levels on a rewired fuel pump by 2PSI. This is also assuming that you have a healthy engine and are doing so on an engine that isn't, say...pieced together with improper torque specs. To date, that GST, which as stated is under new ownership, hasn't developed a hiccup, ill symptom, or loss of compression and has been at it's current boost level for quite some time. Of course there are monitoring tools and procedures in place, it would be absurd to not have a way to observe things.

In any instance, if you want the most technical explanation and answer to your issue possible, buy a wideband, don't install an MBC until you get the WB02 installed, rewire your fuel pump, and keep the boost down to stock wastegate levels until you have the ability to monitor and tune. IE : Link, as many of us own and utilize daily.

I didn't get these chiclets for helping people blow their vehicles sky high.

 

[KMOSES]

Just search "Ceddy" and the threads he started should pop up...

Sounds good! thanks for the advice. Ill do some research on "Ceddy" and see what i can pull up.

I thought not all 99 ECU's were able to be flashed? Make sure you verify the numbers on the ECU itself and the ID number on the board.

pardon my ignorance, but what do I verify these numbers against? is there a list of ECU ID numbers that work somewhere or what?

I'm going to do the best to state this without sounding like a complete prick as I can, but certainly this must be clarified...I didn't get these chiclets for helping people blow their vehicles sky high.

Obviously I was misinformed, I do apologize... As you are, I am also not one to "take off down the street hitting brick walls" Which is why i questioned your statement as it didn't line up with what I had previously known to be true. And in my case I currently do not have any monitoring devices, so it wouldn't be in my best interest to rewire and increase boost without being able to see how it's effecting my system. I suspected the same for you, but now you have clarified things up and I see were more prepared than I am. thanks again for the advice.

 

[XiKeiyaZI]

No problem at all. I would, however, still recommend a rewire of your fuel pump so that you have constant voltage running to it. It's a must-have for the future anyhow and takes little to no time.

 

[KMOSES]

No problem at all. I would, however, still recommend a rewire of your fuel pump so that you have constant voltage running to it. It's a must-have for the future anyhow and takes little to no time.

Sounds good, I'll definitely look into that as one of my next steps

 

[Boomdeeze]

pardon my ignorance, but what do I verify these numbers against? is there a list of ECU ID numbers that work somewhere or what?

There is a thread on here that give the number of the ECU's that are flashable. Let me see if I can get a link for it.

Here you go, read away.

http://www.dsmtuners.com/forums/tun...rst-flashed-dsm-ecu-98-99-flashing-faq-6.html

 

[97gst_spyder]

Fuel Cut = Boost leaks. Fix them and re-wire the fp. It will be a whole different car...

 

[KMOSES]

thanks for the link boomdeeze!

Fuel Cut = Boost leaks. Fix them and re-wire the fp. It will be a whole different car...

Did a boost leak test not too long ago, ill do another and let you know how it turns out.

 

[Dylan0123]

KMOSES, when you do decide to get a manual boost controller I suggest this one: Link
It's extremely cheap (you can make an offer on there for $15-$17), and from what I've read, it works great. Then you'll just need $2 worth of vacuum line from an auto parts store.

 

[KMOSES]

KMOSES, when you do decide to get a manual boost controller I suggest this one: Link
It's extremely cheap (you can make an offer on there for $15-$17), and from what I've read, it works great. Then you'll just need $2 worth of vacuum line from an auto parts store.

Very nice find! I've been looking at a hallman mbc and the cost of this is MUCH less than a hallman. And if the quality is there this will save me some cash to put towards other things.

Thanks!

 

[gst96spyderman]

yeah, but the hallman is not only better looking, but easier to use and intergrate into the cockpit of the car... Just saying. Cutting corners leads to being DSM less. I had a home depot MBC and it ended up playing a huge part in my engine failure... Hallman Pro evo w/ incabin control is the way to go man.

If you are still wondering if your ECU is flashable, from what I've read, the black ecu's or the one;s with black housing are flashable...

 

[KMOSES]

I had a home depot MBC and it ended up playing a huge part in my engine failure... .

Awesome I'll Look into and see if i have the black housing.

Could you explain to me more on how a MBC can contribute to engine failure, and how a hallman mbc helps prevent vs the HD mbc. I would love to take your advice I just don't fully understand and wouldn't want to go in blind.

 

[gst96spyderman]

The MBC I HAD was a simple locknut typical design. Pain in the ass to operate. I was getting boost spikes because it was not functioning properly or installed. Anyways, that lead to me running very rich, ended up melting a spark plug into the head, causing an exhaust valve to melt onto the piston, and actually through it, causing the TB to snap and having to replace the head...

Although the MBC was not the complete reason for my rebuild, it did contribute to the outcome due to the boost spikes... It was not functioning properly. I'm having boost spike with my hallman MBC, but thats more than likely a pinch in the vaccum line and my WG flapper not working as it should... I actually have a bnib Turbo XS mbc...

 

[KMOSES]

Sorry to hear that, sucks..

Definitely appreciate the advice, the NXS one linked above has a 30 day money back, so ill try that out first and see how that goes, and if im getting bad spikes, or anything weird i'll return it for the hallman.

 

[KMOSES]

Fuel Cut = Boost leaks. Fix them and re-wire the fp. It will be a whole different car...

Sounds like i have a major boost leak, pretty loud hissing on the back side of the throttle body towards the firewall, I'm guessing shaft seals...

its gonna raining all week/weekend here, once the weather clears up ill work on getting that fixed. Never done one before, hopefully VFAQ will be a good enough guide and i don't screw anything up.

 

[Fightclub66]

Do you have hard pipes yet? I found myself in the same situation a while ago, but with SEVERAL boost leaks. Fixing them all was not very fun, but hard pipes make a big difference!

 

[KMOSES]

Do you have hard pipes yet? I found myself in the same situation a while ago, but with SEVERAL boost leaks. Fixing them all was not very fun, but hard pipes make a big difference!

Yeah, I definitely want some hard pipes, but I'm planning on a FMIC so i"m just going wait on those and get one that comes with hard pipes

 

[1 FAST TSI]

Sounds like i have a major boost leak, pretty loud hissing on the back side of the throttle body towards the firewall, I'm guessing shaft seals...

its gonna raining all week/weekend here, once the weather clears up ill work on getting that fixed. Never done one before, hopefully VFAQ will be a good enough guide and i don't screw anything up.

i just fixed that same spot on my 1-g..its the trottle plate shaft seals.behid the throttle cable springs..I SWEAR IT WAS LIKE A 20WHP GAIN after fixed..spooled ten times faster also.
extreme psi sells them. but make sure to pick up gaskets also and mark your idle controll motor well or will get idle surge..

 

[KMOSES]

i just fixed that same spot on my 1-g..its the trottle plate shaft seals.behid the throttle cable springs..I SWEAR IT WAS LIKE A 20WHP GAIN after fixed..spooled ten times faster also.
extreme psi sells them. but make sure to pick up gaskets also and mark your idle controll motor well or will get idle surge..

Awesome! how time consuming was the job? im pretty new to dsm, well cars in general, seems like the hardest part of this is just putting everything back together right.

 

[1 FAST TSI]

Awesome! how time consuming was the job? im pretty new to dsm, well cars in general, seems like the hardest part of this is just putting everything back together right.

not to bad..the hardest part was prying out the old ones.
on a 1-g they are like rubber with a copper case around them. you will need a sharp and strong xacto knife.

just make sure you mark your icm.
honestly getting the springs back on correct was royal pain in the arse...was like a needle on my fingers..i wrapped my thumb and index finger with duct tape to stop the pain.

2 hours..BUT i took my sweet time. drinking a few while working.