All right, enough OT posts from me. Time for some stupid newbie questions. My first one is about boost controllers....

I've read about gaining 30-40 hp* by simply installing a $20 MBC and raising the boost to 15 lbs. I'm curious what the downside is of doing this? Does it create reliability issues? A needless strain on the engine? If there's no real downside, why wouldn't everyone do it? I also see people suggesting not increasing psi beyond 14 (with everything else being stock). Is that right?



*Numbers I saw were an extra 10 hp per pound. This is on a 2nd gen.

_________________
"Well-weathered leather, hot metal and oil, the scented country air,
Sunlight on chrome, the blur of the landscape, every nerve aware..."



meastie beastie

I always thought that the MBC free boost mod was for the 1 gen cars to bring there boost levels up to the second gen levels (9 lbs to 11 lbs, don't quote me on that...) I also remember hearing somewhere that some cars develop knock as low as 13 lbs of boost, and some are fine running up around 15 lbs, so to be safe they don't puch the limit with out a datalogger. Probably depends on how everything has been taken care of, milage, and how the cars are driven in general, along with little deviations that will occur from car to car, even in mass produced situtations. Hope this helped, and wasn't to far from the truth...

_________________
Bad decisions make good stories.
Look at it! LOOK AT MY @SS AND TELL ME IT'S PRETTY!

The free boost mod refers to 1G cars only. It does not however involve an MBC to do it. Basically it involves removing a small ring in the boost control solenoid (small restriction) which allows 1G cars to boost to about 12psi like 2G cars.

"Safe" is different for all cars. Typically our cars can run 14psi or 15psi on 93 octane safely, however, it's possible your car can run only 12psi safely, or maybe up to 16psi safely. You do generally gain 10hp her psi with a near-stock config, but those extra ponies are generally only available to about 5k rpms anyways because after that, the stock turbos cannot quite pump out enough air to maintain that higher levle of boost. What you see is, 14psi up until about 4600 rpms or so, and then 13psi, 12psi, 11psi down to roughly 10psi by redline. Only way around that is bigger turbos.

So. For a 2G car, you have to debate with yourself whether the extra 20 or 30hp (for a small section of your rpm band) is worth the $ for a boost controller. It's hard to justify the $450-$500 for an EBC (electronic boost controller) on a 2G when you don't gain nearly as much as you would on a 1G car. Another option is an MBC (manual boost controller) along with a boost gauge. Total cost is about $150 instead of $450-500.

Reliability issues? Eh. Well, anytime you increase HP, you're taking a chance at reducing the amount of life in a motor. How much is dependant on so many factors: health of the engine, care/maintenance, and amount of extra go-power. A properly maintenance vr4 with basic performance upgrades (BPU) can be just as reliable and long-lived as a stock car.

As to why not everyone does it... -> $$

_________________

Best in Show - NG07
2010 - 6G74/3.5L E16Gs - 688awhp/679awtq (Race+Meth)
2011 - 6G74/3.5L 68HTAs - 740awhp/762awtq (Race+Meth)
2013 - 6G74/3.5L MTC Stage4 - 908awhp/832awtq (Race+Meth)

I have a Mbc and I will replace it with a electronic one. More money but I just don't feel safe with a mbc. Don't use one with a stock boost gauge!!!

_________________

So I take it it's not advised to do only the MBC upgrade without also hooking up an after-market gauge? Why? Just so that if the boost controller is failing and allowing 20+ psi, you'll know it before it's too late? Is it needed for tuning?

Silly me, I thought you could just install the $20 thing and dial-up 14 or 15 and be good to go....

_________________
"Well-weathered leather, hot metal and oil, the scented country air,
Sunlight on chrome, the blur of the landscape, every nerve aware..."



meastie beastie

BTW, due to your screenname, all this time I thought yours was an NA.

You will need an aftermarket gauge with an MBC. 14 PSI is said to be the safe limit because after that the stock fuel system can't keep up and it starts to lean out.

_________________
'94 vr4- Now with extra slowness

BTW, due to your screenname, all this time I thought yours was an NA. [/quote]

B-29 Stealth Bomber dropping 9b's on Honda's Stock boost gauges are highly inaccurate, it's more like "are you stepping on the gas" gauge. If your going to up the boost you need to know exactly where you are raising to, to make sure your safe. I run mine at 10 to twelve pounds to be safe incase the MBC should malfunction and spike a bit that way I have some room for comfort. Also, you will have to constantly check your adjustment of the MBC to make sure to compensate for changes in air temp, etc. A electronic one will do this for you I believe.

_________________

The boost control unit itself is only $20-$30, right? Are you saying that you'd have to spend $100-ish for the gauge?

And I've been meaning to ask, instead of purchasing an additional gauge and installing it, how come you can't just change what the stock gauge is hooked up to so that it's reading actual boost instead of whatever it's reading now? (Not that I have any clue what's involved in installing a boost gauge or what it's "hooked up to" compared to what the stock gauge is "hooked up to".) If possible, it seems like it'd be less work and give you an option of maintaining the stock look.

The boost control unit itself is only $20-$30, right? Are you saying that you'd have to spend $100-ish for the gauge?

Yes.

And I've been meaning to ask, instead of purchasing an additional gauge and installing it, how come you can't just change what the stock gauge is hooked up to so that it's reading actual boost instead of whatever it's reading now? (Not that I have any clue what's involved in installing a boost gauge or what it's "hooked up to" compared to what the stock gauge is "hooked up to".) If possible, it seems like it'd be less work and give you an option of maintaining the stock look.


Because the stock gauge is a electric gauge and is not tapped into your vaccum lines. Hooking up a boost gauge is fairly simple. Installing it in the dash in the stock location is another story. I did it, it took six hours to get that center cluster of gauges out and six weeks to get it back together. Actually, the gauge at the top of this page is out of my car. Your car is a second gen though so I'm sure it will be easier for you with you having the pass airbag. If your interested in doing it in the stock location then I would recommend swaping all the center gauges with some autometers or greddy's since your in there. Then you can also arrange them how you want in order. Another option is to go with a piller pod. Whatever you decide if you have a garage and a little notice I'm sure more than a few of these guys would join you in a install party and get you set up properly. BTW, When you up the boost to around 14 psi that car will really get moving in a hurry compared to stock.

_________________

The stock boost gauge is connected to the oil pressure and the water temperature guage in a three gauge set. You can not seperate them as the strip of wiring that runs all three gauges is connected together, and they have more than one common wire lead. You may be able to remove the gauges and use that plasitc peice as a bracket for the replacement guages. Even with the air bag in the passengers side it took me a week to change the center gauges. I recessed(sp?) them back in the stock location, which kept the stock look, though. If you wanted to you could just set them in the three holes in the dash. I believe that you would want the 60 mm gauges then instead of the 52 mm. You would still probably want some sort of mounting bracket for the back side, which you will only be able to fabricate once you are looking at what you want to do, ei the gauges in your hands and your car half torn apart so you can see how you want to mount it. I wish I would have taken pictures of my bracket before I put in in. Not that it was pretty, but then I could have thrown it up as a picture for you to see. I made it out of a plastic lumber 2 by 4. If I had it to do all over again I would mount the boost gauge closest to me instead of keeping every gauge in it's stock location, but I DO NOT want to rip it out again and switch it, which should give you an idea as to how much of a hassle it is. I personally don't believe that the stock boost gauge is quite as bad as everyone says it is, but they are all 100% correct in saying that you cannot tune a MBC by it. It's not that accurate. If you do switch the gauges out I would get a gauge that converts the pressure to an electrical signal before going through the fire wall. Something like a GReddy or Defi gauge. I believe that the Defi gauges read in PSI, which is nice. GReddy reads in atmospheres, or Bar, or kg/cm^2 which ever sounds like less people will understand it... .

A manual boost controller is just an tap into the stock controller to let it bleed off extra psi before the stock controller opens the wastegate. You adjust the amount of air that is being let out(1~2~3... PSI) by opening or closing an oriface. As you go to winter, or summer, or change in elevation(not so much in flat-lander-ville) the density of the air changes and it becomes necessary to recalibrate the manual boost controller, where as the electronic boost controller, for the most part only cares about the intake pressure of your car, not the atmosphere outside the car.

Either way, let me know if you want to swap gauges, and I'll help. I can get you more info if your going to tackle this job also, like pictures of the stock gauges in there cluster, and what tools you will need, and what knuckles you will be scraping. Don't cheap out on the gauges, either, as this is something you do not want to do more than once. It's not hard, just takes lots of patience. oddles of patience...

_________________
Bad decisions make good stories.
Look at it! LOOK AT MY @SS AND TELL ME IT'S PRETTY!

The stock guage gets its signal from the ECU which calculates the boost based on RPMs, throttle position, and the stock MAS. It isn't accurate at all and the guage itself is not of high enough quality to hook up into a pressure sensor.

An Autometer gauge is less than $50 so there is no excuse not to have one.

Besides an aftermarket gauge anyone lifting the boost should be datalogging to make sure the ECU is not seeing knock. Faulty fuel componets like dirty injectors or a weak fuel pump can be okay at stock boost but once the boost is cranked up the problems could be enough to not allow the ECU to compensate and the engine will be damaged.

_________________
1992 3000GT VR-4
-----------------------
3SI Member 0660, 1753, 2038
W3SI Member 15

EBC's are nice because they all have boost gauges right on the display (with a peak hold function meaning you can see how high the boost was during a run), they give you cockpit control (meaning you don't have to pop the hood to adjust the boost), and most have a safety feature which cuts the boost should it spike too high (protects your motor).

b.t.w. The BSC mod (pulling the little rubber ring out) can be done on a 2G sellenoid, and you get an additional 3psi just like the 1G cars.

The answer to your question of "how much boost" depends on a few things. The real answer is "get a logger and find out". I like to run as much as I can without knock. On other cars, guys have found 14psi is the average of what most motors can handle with the stock feul system. BUT your car may be different.

_________________
06 Blue EVO 9

Thanks everyone. Great responses. I hate to keep the questions coming, but such is my nature. So, two more things...

Are there any opinions on this gauge?: http://www.machv.com/spwsicafibog.html ... I like the fact that it has illumination color options that would look closer to stock. The only one I've seen like that. Seems cheap, too. (Too cheep?)

Also, can you do a manual boost controller but have an digital boost gauge? (just to take advantage of a peak hold feature) I don't think I saw any digital gauges when I was looking around last night unless it was an EBC package. Then again, I may not have known exactly what I was looking at....

Thanks again!

_________________
"Well-weathered leather, hot metal and oil, the scented country air,
Sunlight on chrome, the blur of the landscape, every nerve aware..."



meastie beastie

Manual boost controller and boost gauge is two seperate things.

You use your intake(be it taping a new hole, using an existing hole, or splicing into an existing line running to somewhere else) pressure to give the boost gauge a reading. The electric gauges have a sending unit that gets mounted in the engine bay (or not, I suppose) and then have wires running through the firewall to the gauge. the peak hold feature is then in the gauge. The mechanical gauges usually have the vacuum line running through the firewall to the back of the gauge. be careful not to crimp the line. I believe that both G Ell and DJauggie(us3s) have told me that the length of vacuum line and the size of the line may affect the validity of the gauge reading, and response time.

Gauges in qustion seem a little cheap...

_________________
Bad decisions make good stories.
Look at it! LOOK AT MY @SS AND TELL ME IT'S PRETTY!