why is max boost limited?

[Dabigguy]

Put all of your parts on and take it to test n tune night at your local track and have fun. Get a notebook and take notes on EVERYTHING. Log all changes to the car,air temps, barametric pressures, humidity......and the times your car runs. Every car is different with it's likes and dislikes with tuning adjustments. You will just have to see what your car likes.

Don't be in a hurry to make a 10 sec. run take it slow. If you get in a hurry, you WILL break parts.

Most of all.....enjoy.

 

[Dabigguy]

There are adjustments that you can fine tune the chip for your car. Read the instructions that come with your TT chip. Take some time to digest everything that you have been told about these cars. These cars are very sensitive to tuning and when you change too many things at one time, you really don't know what has actually helped you.

One more thing, someone mentioned your exhaust system. Do you still have the stocker? If you do, that is something that needs to be addressed before you go any farther.

 

[corsair231]

LIke Razor said, get aluminum heads, a front mount, drop your timing and you can hit 20 on the street. If you are running 25 in your DSM then it is probably with a front mount and a larger turbo to go along with the low timing. When air is compressed it heats up. Anything that takes heat out helps with knock supression. Aluminum sheds heat faster than iron, a larger intercooler takes more heat out, and alky takes alot of heat out. :biggrin:

 

[Razor]

LIke Razor said, get aluminum heads, a front mount, drop your timing and you can hit 20 on the street. If you are running 25 in your DSM then it is probably with a front mount and a larger turbo to go along with the low timing. When air is compressed it heats up. Anything that takes heat out helps with knock supression. Aluminum sheds heat faster than iron, a larger intercooler takes more heat out, and alky takes alot of heat out. :biggrin:

What he said

 

[notacarlo]

What they said

 

["Turbo-T"]

but what do you mean tuning?

what else can i manually tune after the chip

Best way I can describe it....and someone correct me if I'm wrong....pop in your new TT chip. It should be set up to like 20/18 timing on 92 octane and 16-17 PSI.

Go to your local drag strip. Turn the boost down to like 12....make a pass. Watch for knock. Don't worry about how fast the car can go at this point, your main concern is ensuring you have an adequate fuel/air ratio. If you see ANY knock at this point stop and figure out why.

If none comes up then up it another lb....make another pass...if no knock then up it to maybe 15 and maybe add a little fuel if needed. Make a pass. If you're doing it right each time you add boost you should be going a little faster thru the traps.

Now if all checks good and by the time you hit 16 you start seeing knock, then back off. You can try adding fuel via the chip and Scanmaster and seeing if that helps. if so, proceed. if not then back off.

What you want to do is shoot for the highest mph you can go thru the traps w/o any knock. And also the highest boost you can achieve w/o any knock. If you have more air than fuel you'll go lean and that's where knock starts happening. That's why it's important to start off small, so you can see where it's weaknesses are.

Now if anytime you make a pass and knock is detected, you need to let off the pedal and figure out why. Could be false, could be real. At the top of 3rd gear the Scanmaster should be in the 780-800 range. If the Scanmaster reads anything lower than 780, let off the pedal.

I don't know if you have upgraded your fuel pump and hot wired it or not but if not then now is the time. Your engine needs a good fuel supply to keep up with adding boost. The stock pumps were crap and are probably worn out by now, plus the voltage drop in the stock wiring is what warrants the need for the hot wire kit.

As a final thought I myself have always been told if I wanted to run any boost over 15 I'd need an alky kit or race fuel but some here have claimed they've gone more than that on pump gas.

 

["Turbo-T"]

When air is compressed it heats up. Anything that takes heat out helps with knock supression. Aluminum sheds heat faster than iron, a larger intercooler takes more heat out, and alky takes alot of heat out. :biggrin:

That must be why they went to intercooled cars in 86? To cut down on knock? (and make power)

 

[Rell87]

I wonder how much boost I can run on 91 octane? I never ran more than 15lb.

 

[Razor]

I wonder how much boost I can run on 91 octane? I never ran more than 15lb.

You can run 30 PSI.. but not for long as bad things can happen quick when you dont support with octane.

 

[DIAZ 87]

their is alot of good info here,im learning just by reading what every one is saying.Read and listen to what guys are saying here.
I have my car setup where she pulls hard and only 18 psi.Once again it's about tuning her right

 

[DIAZ 87]

Maybe post what town you live in for some one can look over your car and help you get it tuned properly.It would'nt hurt at all.

 

[notacarlo]

We are here to help and keep eachother in-check so you do not get bad information.....which I am full of.:biggrin:

 

[liv4gnz]

lol from nj passaic county and without this board i wouldnt know where to even start

 

[bison]

Build the engine to run high boost and you can run it. The one im building now will run low 10's at under 20psi and a lot quicker at 30psi:biggrin: . Its GN1 headed, 9.3:1, 224/218 cam and will rev to 6400 no problem. I havent seen a DSM that will run anywhere near that that is over 3300 lbs under 20 psi. Boost pressure doesnt mean dick unless its actually making more power. You could retard timing and reduce inlet air temps and run 20psi on a nearly stock engine but it wont make anywhere near the power of an application like the one i am putting together right now. Like a 200+hp difference at 20psi. 1500 rpm increase of engine speed and over 1 point in compression does a lot for hp with the right combo of parts and a good tune. It will be about a 500 hp difference vs a nearly stocker at 20psi when running 30+psi with this combo. A lot of $ are always required to go fast but dont guarantee you will be fast:tongue: