Fuel Cut Rev Limit vs. Spark Cut Rev Limit

SON240sx Automotive
1

What are some of the pros and the cons to Fuel Cut Rev Limit and Spark Cut Rev Limit?

Copy and Pate List as we discuss adding in what you think fits each column.

Fuel Cut Rev Limit
PRO:

CON

Spark Cut Rev Limit
PRO:

  • Sounds Cool

CON

  • Unused fuel washes away oil on cylinder wall’s
2

Fuel Cut Rev Limit
PRO:
Less chance of flooding the engine? :dunno:

I mean it’s already there in the existing system (fuel cut @ ~180km/h)

CON
:dunno:

3

Fuel Cut Rev Limit
PRO:
-no flams out pipes to make cops angry

CON:

  • hard on engine, causes momentary lean condition

Spark Cut Rev Limit
PRO:

  • Sounds Cool
  • big flames out exhuast pipe

CON

  • Unused fuel washes away oil on cylinder wall’s
  • big flames out exhuast pipe
4

But if you’re hitting some kind of cut near a cop car, aren’t you already doing something to make them angry? False?

5

Didn’t you say spark cut is hard on cap and rotor?

PRO to spark cut is it spools the turbo, fuel cut does NOT

ideal cut for engine life is both spark and fuel cut I think

for launching it is ignition retard

for launching and having a lasting turbo its spark cut

6

LOL.

Hi officer…bye officer! <fire-breathing car>

Take a look at http://www.importintelligence.com under Performance Electronics/launch system - they even have a test vid w/ an SR20 launching…kinda neat.

7

How can it be lean with No fuel?

Word on the street is spark cut kills caps and rotors.

8

I have heard that a hot engine without fuel revving high is bad for it, but it doesnt make sense since surely an EXPLOSION with fuel at high rpm is hotter than NOTHING

could the jerking of the on/off of fuel/spark be bad for the engine itself?

9

Sorry for sounding arrogant, How does spark cut work? And why would you change whats already in the system (fuel cut) To spark cut.

Dont flame me im just an idiot :smiley:

10

I will not flame you but agree in regards to you calling youself an idiot. :wink:

Why you’d change it?

You don’t but when you have the choice of you do…

11

hehe i love how this discussion only applies to us

12

spark or fuel cut, there is still the same amount of air leaving the cylinders to spool the turbo, I don’t see how one would spool faster than another?

13

fuel cut causes some burn in the turbo when its hot spooling the turbo

I’ll try it on my car hold both at 6000rpm and see how much boost each one produces with the exhaust hot and cold

14

Fuel Cut Rev Limit
PRO:
-no flams out pipes to make cops angry
-stops dumbasses from driving at excessively high speeds

CON:

  • hard on engine, causes momentary lean condition
    _ fuel cut has and i have seen it get so hot momentarily that it has burned a hole in the piston, u need to remember that the car will lean out cuz there will be fuel still in the engine from just before fuel cut and will still be unspent fuel pushed back into the cylinders from the backpressure of the turbo, back pulses and all that yadda yadda yadda, the turbo doesnt stop pushing air in just cuz your computer say “no fuel for U”, fuel cut is bad for turbo charged engines

Spark Cut Rev Limit
PRO:

  • Sounds Cool
  • big flames out exhuast pipe
    -no lean conditions produced

CON

  • Unused fuel washes away oil on cylinder wall’s
  • big flames out exhuast pipe

your best bet is to run both if u can have spark cut come in and then have fuel cut come in about 30ms afterward

15

It’s not time based its RPM based.

16

Both is the best.

there is also a person on FA who has snaped his rockers 2 times from using his 2 step at 6500 rpm

17

mm id rather see big flames and sound like a rally car…

but thats just the ricer inside me

GT

18

And inside of me… :wink:

Guys you are mistaken Ignition Cut with Ignition Retard (Rally style Anti-lag thats what shoot’s the flames)

19

Rally Anti-lag “Bang-bang” system is a nono for street vehicles… unless you don’t mind your exhaust system exploding within a few hundred km’s.
I’m pretty sure your turbo/manifold wouldnt enjoy it either.

Just install a sparkplug in your exhaust whilst running rich and with no cat. You know you want to do it.
:twisted: