SaabCentral Forums banner
1 - 20 of 76 Posts

·
Registered
Joined
·
723 Posts
Discussion Starter · #1 ·
fluxuation of floridian air humidity and tempature is starting to bother me

i am constantly readjusting my mbc to avoid fuel cut, but stay at around 14.5 psi


how harmfull is fuel cut?
how dangerous is it to bypass fuel cut?
 

·
Registered
Joined
·
386 Posts
fuel cut is there to prevent the engine from starving, so its not bad for your car so to speak, because it cuts out before it can be potentionally harmful.

as far as bypassing, there are going to mixed reviews. I have mine bypassed to 20psi, had it set that way for almost a year, and i havent had any problems, but long term abuse...ie heavy foot non stop, there will more than likely be damage.

the air fuel mix is going to be running lean if you bypass the fuel cut, thats about all i know.
 

·
Registered
Joined
·
2,219 Posts
Saabrunner05 said:
fuel cut is there to prevent the engine from starving, so its not bad for your car so to speak, because it cuts out before it can be potentionally harmful.

as far as bypassing, there are going to mixed reviews. I have mine bypassed to 20psi, had it set that way for almost a year, and i havent had any problems, but long term abuse...ie heavy foot non stop, there will more than likely be damage.

the air fuel mix is going to be running lean if you bypass the fuel cut, thats about all i know.
How did you bypass the fuel cut?
 

·
Registered
Joined
·
723 Posts
Discussion Starter · #5 ·
crystal beach, which is in palm harbor, which is in pinellas county, which is in tampa bay area

near clearwater/saint pete

the outside tempature has been fluxuating between 80-40

i guess i want to have my car set to about 15 psi without having to worry about fuel cut ever again
 

·
Registered
Joined
·
949 Posts
The "best option" is to install a zener diode on the map to give you the headroom that you need.

I am in Florida also that's why I asked.

I am unwilling to take the time to fight the battle of whether the diode is safe or not on these forums. (BTW, it is.)

I have significant experience and will be more than happy to share my findings with you. Simply PM me and we'll talk.
D-
 

·
Registered
Joined
·
2,059 Posts
David in Tallahassee said:
The "best option" is to install a zener diode on the map to give you the headroom that you need.

I am in Florida also that's why I asked.

I am unwilling to take the time to fight the battle of whether the diode is safe or not on these forums. (BTW, it is.)

I have significant experience and will be more than happy to share my findings with you. Simply PM me and we'll talk.
D-

Has there been a dyno run with logged A/F?

On a saab?
 

·
Registered
Joined
·
949 Posts
Palmer1980 said:
Has there been a dyno run with logged A/F?

On a saab?
Nope...and if you need one to build a decent car you don't understand enough about internal combustion engines to be building your own.

Again, I'm not going to debate. If you're interested, PM me, if not, let it go.

D-
 

·
Registered
Joined
·
949 Posts
Saabrunner05 said:
david

with your set up boost are you able to get?
In my set-up the overboost protection (otherwise known as fuel cut) is completely eliminated. IE, I can achieve whatever boost levels my turbo and boost control are capable of providing. Right now my MBC is set at 24PSI. You can also view my car in the "MODS" sticky. I'm about half way up on this page...

http://www.saabcentral.com/forums/showthread.php?p=1118493#post1118493


Here's a thread from a while back that will give you some good info on my "fuel cut" journey.

http://www.saabcentral.com/forums/showthread.php?t=109637&page=1&pp=20&highlight=bypass+fuel

Enjoy!

D-
 

·
Registered
Joined
·
723 Posts
Discussion Starter · #13 ·
i think i get it now ;)

correct me if i am wrong.........nicely...

If one were so inclined, one could use w/m injection to safely raise boost pressure past fuel cut to yield hp comparable to a stage 3 tune for slightly less cost.
:D
 

·
Registered
Joined
·
949 Posts
doorcheese said:
i think i get it now ;)

correct me if i am wrong.........nicely...

If one were so inclined, one could use w/m injection to safely raise boost pressure past fuel cut to yield hp comparable to a stage 3 tune for slightly less cost.
:D
Yes, you could certainly do that. I am simply running VP MS 103 unleaded fuel.

The key to the original question is that additional fuel is available to cover the "headroom" necessary to avoid overboost with a manual boost controller with or without a staged tune.

D-
 

·
Registered
Joined
·
2,059 Posts
David in Tallahassee said:
Nope...and if you need one to build a decent car you don't understand enough about internal combustion engines to be building your own.

Again, I'm not going to debate. If you're interested, PM me, if not, let it go.

D-

Ok, bigshot.:roll:



It was an honest question. You cannot make inflammatory, rude statments, and not expect questions.


Sorry for not memorizing all your posts. Perhaps you could PM them to me, so I can have them for refrerence in case I somehow miss one?


That would be great.
 

·
Registered
Joined
·
949 Posts
Palmer1980 said:
Ok, bigshot.:roll:



It was an honest question. You cannot make inflammatory, rude statments, and not expect questions.


Sorry for not memorizing all your posts. Perhaps you could PM them to me, so I can have them for refrerence in case I somehow miss one?


That would be great.
You're right. I apologize. I am a little defensive due to some ridiculous arguments that I've gotten myself into.:(

Please forgive me.

D-
 

·
Registered
Joined
·
5,905 Posts
A stage 3 ecu does more than just up boost. In fact the ECU Dip was running on his late 'vert was only set to 15. Fueling and timing are large parts of the re-map.
 

·
Registered
Joined
·
4,857 Posts
I think you can safely do a map hack, but I would think knowing you're a/f is a big part of "safely" upping the boost.

When you use a bleed on the map sensor it is seeing less manifold pressure than what is really there and that can lead to lean conditions.

If you run a wide-band, you could safely increase the boost until the a/f mixture gets to the "marginal" range and that would be perfectly fine, but to just up the boost and have the map sensor see less manifold pressure than what is really there without knowing the a/f is a little bit risky in my opinion.

Put a wide-band on that thang!!!

John
 
1 - 20 of 76 Posts
Top