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Seems To fast?

D

DaRiceRipper

New member
Joined
Nov 20, 2002
Location
North Jerzy
LOL
I know this is going to sound stupid but, My car seems to fast.
I just recently bought a 82 245 turbo, witch from what i understand only has a 6-7 psi fuel cut off switch.
Now ive installed an itercooler a 2 1/2 inch down pipe with a 3 inch exuast and a ford 60/63 turbo. NOW OMG WHAT A DIFFERENCE.
Ok now here is my question the car is so much faster but yet my fuel cut off switch hasnt kicked in yet that ive noticed and ive been getting on it real hard.
One thing i did notice is that my boost gauge isnt going any higher
{about 3/4 of the way threw the yellow} then it did befor its just getting thier alot faster with me pushed into the seat alot harder. But no fuel cut off. Is it realy possiable that im not hitting over 7 psi yet?
 
You are still boosting 7psi but the intercooler and the larger turbo allowing you to do two things at the same time that increase your efficency(sp?)
-Intercooler
The intercooler it cooling the charged air now. Before you were shooting the charged air from the turbo straight intot he cylinder. Without the intercooler that air tended to be rather warm from the compressor. The Intercooler cools things down and allows for a cooler, denser, charge to be put into the cylinder.
-Larger Turbo
The larger turbo flows more air that your stock turbo does. If the B21FT turbo's are anything like the B230FT turbo's I've delt with they do fine from 0-4000RPM or so but then they tend to drop off. The larger on you have lags a little more but is able to hold a steady boost all the way to redline.

Hope all that makes sense and if anyone wants to chime in and correct something I've said or add to it go right ahead.
 
thank you for replying


I understand how the intercooler and everything works, like i said i knew it was a stupid question. I just couldnt belive this was only 7 psi. Im starting to understand how big of a difference this is GOING to be. Im going to home depot and making and mbc. I cant wait to see what 12 feels like.

Now ive found several pressure switches ranging from 10-25 psi and some adjustable.
I know the fuel cut off switch shut down the fuel pump when it hits its max psi. But how does it do it. Does it cut the ground or positive to the pump.
Or is thier more to it.
 
Hello ... The fuel cut-out is a vaccum switch near the brake assembly under the dash. I think its set at about 14 psi and when you hit it you'll hate it. It's immediate fuel pump turned off, you freak out and let off and its back on. You should crank up your boost until it just enters the red zone. Shorten the rod on the vaccum actuator. When you intercool you get a different wastegate actuator!! If you need the part # I'll try to find it.
As you turn up the boost listen carefully for ping/detonation. Death rattle as its called is too much boost for the situation. Causes could be too much carbon buildup, too little fuel, spark/timing issues. etc. Happy Boosting - Later Gary
 
One more thought ... I assume the fuel pump ground is broken at over boost situations. You should be able to shorten rod on wastegate to up your boost to top of yellow/bottom red. Are parts available for a MBC(manual boost control) at home depot? If so please let me know, OK? Thanks Gary Ggaryboy@aol.com
 
Its a vacum switch?

Ok first its set to 6 or 7 psi on non intercooled cars. So thats what mine is.
Seconed i know what it is and what it does like i said befor i need to know how it shut the fuel pump off. Does it send or send a power or ground. And if so, does it do it to the computer the relay or directly to the pump.
 
If you're going to be messing around with your boost, I would highly recommend getting a calibrated boost gauge. It's always good to know exactly how much boost you are running.
 
On my 242 I just plugged the vacuum line going into the fuel cutout, and no more fuel pump cut-off. I run 12 lbs of boost with a a/f gauge, mbc, and a boost retard on my ignition with no problems. Dan242tic

EDIT I presently have a cockpit adjustable ignition controller (MSD) which varies ignition timing a total of 15 degrees, will be replacing that with a MSD BTM as soon as I get one of them roundtoits.
 
Dan242tic said:
On my 242 I just plugged the vacuum line going into the fuel cutout, and no more fuel pump cut-off. I run 12 lbs of boost with a a/f gauge, mbc, and a boost retard on my ignition with no problems. Dan242tic
Click to expand...

boost retard.....aftermarket ignition?? please elaborate
 
[quote:e161b3e809]boost retard.....aftermarket ignition?? please elaborate[/quote:e161b3e809]
240's have a mechanical boost retarding distributor. It isn't exaxtly sophisticated, but it works. It is possible that he has aftermarket, but it is possible to the tweak stock distributor or just run stock.
 
Thats what i figured but some one in this thread called it a vaccum switch, but then again that was the same guy who said my switch was set at 14 psi.
Thanks again doug.
 
They are both pressure switches. In automotive circles anything that is triggered by manifold pressure (where negative pressure- vaccum, or positive pressure-boost) is often called a vaccum switch, since it's triggered by a vaccum signal.
 
Hi,
The original non intercooled overboost switch is set to 10psi. That's
why you haven't hit the cutout. It removes ground from the fuel
pump relay. The intercooled version is set for 14psi. I've hit that with the stupid boost creep problem my car has. I second the suggestion to get
a numbered boost gauge. You really don't want to guess when it comes
to adjusting what you set boost to. I wouldn't recommend running without
some type of overboost switch. If you plug it and the motor goes into
some kind of high boost condition it could save the motor. Get an adjustable Saab one like what is used for the Terminal 11 trick. Or you
can cut out the sealer crap on the stock one and adjust it higher.

Dave 82 242ti
 
Would it be worthwile to just tee off the vacuum line going to the boost cutoff?...when your running 15 psi, the cutoff switch would only see 8 or so, depending how big of a tee you are using to bleed the pressure....Sounds right in theory, but has anyone tested it? The one problem would be that what your creating to do this is a vacuum leak, no? Just a thought...thoughts? experiences?
 
i was deffinitly going to get one i just wanted know exactly how it worked so i could get the right switch. Im going to get an adjustable one for a mini compressor it got a nice dial that will mount in one of the switch plates on the center console.
 
hey, does any one have a idea how to bypass the fuel cut off for tha 740 turbo? and where the system located, i dont have too much experience with the fuel system on the 740s










87 740 Tbi
 
Ok this is my idea,
I have a way of testing an mbc befor you install it on your car.
Take a vacum pump just like you would with the saab fuel cut off switch.
with a small gauge on the other side of the mbc and just keep adjusting it till desired amount off psi. now could i just adjust one to where i would want the fuel cut off to kick on and put it inline befor the switch? That way as it progresses i could just adjust it easily.
 
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