Im planning on getting my hallman mbc in tomorrow...

My currents bolt on is TBE, o2, cone Filter...no tune.


Whats the safest I can turn the boost up to just on that basic bolt on?

 

Make sure you have a boost gauge to monitor your boost.

 

Yes I have a boost gauge.


I also have some cams coming in next week..

But as of now im wondering how much is the max on just the basic bolt ons...Im thinking 21 lbs

 

I'd keep it at stock boost until you get a tune, in my opinion... especially post-cam install... better safe than sorry, right...

Once you get your tune.... ball the eff out!

 

Yes keep it at stock boost levels until you get a tune. Once you get your cams you'll need to get tuned anyway so just hold off on increasing the boost till then. Get a Walbro 255 fuel pump before you get the tune aswell.

 

OP - When you are getting tuned, your tuner should be looking for knock and base the boost advice on your specific car, setup, and gas. I believe IL. has 93 octane, so assuming you have an 8 turbo, running 93 octane, and get a good tune, you should be in the 22 psi range peak tapering to ~16/17 psi redline. Good luck !

 

^ why taper the boost down I believe that the point of getting a boost controller is to to increase and control boost level and to have it hold at the same level all the way to red line.
just my .02.

and YES, get the walbro 255, and keep your boost as close to stock until you get it properly tuned. C

 

The boost will taper on its own, its not something you will tune for in this instance. In order to tune specific boost numbers into the car and have it follow the values you program you need ECU boost. With an MBC you are basically saying this is the max boost value I want, get me there. The turbo will either lose efficiency that high and taper down, or the boost control source will start to bleed and let some of the boost off...

 

PV=nRT....Sure you could FORCE the turbo to push tons of hot air and maybe it could hold 22 psi at redline, but it would be really HOT, cause tons of knock, and not produce anymore power....

Per buchner's answer, the taper is just natural with the stock 8/9 turbos. You can hold a bit more with a 9 turbo than an 8 and if you are running e85, race gas, or Meth you can push the turbo harder (the higher octanes resist the knock).

 

With a tune, you shoud be able to push 22 - 22.5 psi but ensure you upgrade the fuel pump at a minimum. should be safe at 22.5.