I searched the site for this one, but couldn't find it. Anyone know when the stock ECU on an sc400 stops the engine from reving , from a fuel cut or cutting the ignition timing or however. I know the redline says 6500, but we all know it will do more than that, just curious of the limitations of the ECU. My interest is in cams, as with the stock ones there is no point in goin over 6000 anyway. I don't recall which member it was, but he made 70+ extra rwhp from cams that were pretty mild, so I imagine there is potential with rpms. thanks
SC400 Fuel Cut
- Thread starter WDoherty
- Start date
The 1UZFE EGR Delete Kit is available for sale here.
When it gets to the rev limiter it will not go any faster and you will know all about it. I had a commodore motor in my truck and connected the computer to the toyota speed sensor{twice as many pulses as the commodore sensor} and when it reached an indicated 110kph the motor would literally turn off as if you had turned off the ignition and would not turn back on until the speed had dropped by 10 kph. The rev limiter on my lexus motor holds the revs on maximum.
sorry to bring this back up, but does anyone know the fuel cut for the stock ecu as it would be good to know and i'm assuming its unchangable. I'm thinking about doing a 1uz swap (after i get rid of the sc400, probably another project after that too) in my 1st gen celica eventually and the determining factor on that would be know if a stock ecu could handle cams that would need around 6800 to 7k to breath, otherwise i'm considering an ls1 with t-56 swap because the pcm is programable (stand alones are not cheap).
UZZ30-Québec
New Member
why not just try it? you won,t blow the engine!
i'm uncomfortable forcing it, if it pulled like it wanted too i wouldn't mind, but it doesn't plus i don't know if will just shift at a set tranny point or what, plus i don't want to hold my car on 1st and rev the piss out of it to see where it stops revving, i just figured someone of this forum would know.
UZZ30-Québec
New Member
well, if someone can answer you, it'll be someone who'd have tried what you said.
put it on the pwr mode then do a burn out on 1st gear, you'll hit the cut-off, for a good reason
put it on the pwr mode then do a burn out on 1st gear, you'll hit the cut-off, for a good reason
The ignition cut is usually at 7,200rpm.
Bigger cams will not work with the stock ECU as they will flow more air than the ECU is programmed to handle.
The engine does start to run flat after about 6,500 as the cams are way past thier peak at that point.
My advice would be improved cams combined with improved exhaust and a Link or simillar aftermarket system.
Bigger cams will not work with the stock ECU as they will flow more air than the ECU is programmed to handle.
The engine does start to run flat after about 6,500 as the cams are way past thier peak at that point.
My advice would be improved cams combined with improved exhaust and a Link or simillar aftermarket system.
madmont: that's interesting that it will not go past 6300, so i guess the majesta ecu is different than the U.S. sc400 ecu.
Zuffen: so the ecu won't cut until 7,200, that's good news. I know that the ecu is not programmed for aggressive cams, but i was hoping a piggyback could handle cams, permitted the stock ecu would allow the engine to reach these revs. This could be goo news. Do you think a piggyback could compensate?
Zuffen: so the ecu won't cut until 7,200, that's good news. I know that the ecu is not programmed for aggressive cams, but i was hoping a piggyback could handle cams, permitted the stock ecu would allow the engine to reach these revs. This could be goo news. Do you think a piggyback could compensate?
Peewee
New Member
My UZZ30 ecu around 6500.
I'm not sure how accurate the tacho is up there, so it could well be 6300 that it cuts.
Speed cut is a dead accurate 180kph.
Fuel cut (its rarely ignition cut), is very violent.
Speed cut is very sedate, it took a couple of seconds to work out what happened.
Only the modded ecu's (HKS, Mines, etc) can raise the rev limiter.
No piggyback can do that.
Speed cut is easy to get around.
I'm not sure how accurate the tacho is up there, so it could well be 6300 that it cuts.
Speed cut is a dead accurate 180kph.
Fuel cut (its rarely ignition cut), is very violent.
Speed cut is very sedate, it took a couple of seconds to work out what happened.
Only the modded ecu's (HKS, Mines, etc) can raise the rev limiter.
No piggyback can do that.
Speed cut is easy to get around.
right i know piggyback's can't raise the rev limit, but i thought zuffen was saying it wouldn't cut until 7200. Is the UZZ30 the soarer code. I know i've seen my sc400 zoom past 6500, i guess i might have to give it a try myself, do you think this is totally safe with no change of causing engine damage, hold it in 1st and rev it until the fuel cut, i don't want to do it, but if there is no chance it is harmful, then i'll do it.
bansheebuzz
New Member
This is good info and very good questions....So my understanding to this point is when operating the SC4's and Soarer's (1UZ-FE) in combination with the stock ECU there are 3 cut off points...
Speed cut - 160mph?...
Igniition cut - Violent but rarely occures regardless of Cams and rpm's...
RPM's cut - 7200...regardless of what cams you are running...
Also, no piggy backs have the ability to raise the rev limit? None? How about this king of piggybacks, the SM 6 and 7's..? Wow, these stock ECU's are very restrictive in more ways then just the A/F ratio....Unbelieveable, never had cut off limits in my older mod'd Chevy's...things would just start breaking on me and that would let me know the cut off point.......:redface:
So when upgrading to an aggressive type cam and lift setup, it is a good idea to get A Stand Alone ECU to go along with the cams? Is this correct? Such as the 40- 45hp gains which the Kelford cams claim to do?
I just learned something new about the stock SC400's today...thanks fella's....for me that doesn't happen too often anymore!!!!:slaphappy
Speed cut - 160mph?...
Igniition cut - Violent but rarely occures regardless of Cams and rpm's...
RPM's cut - 7200...regardless of what cams you are running...
Also, no piggy backs have the ability to raise the rev limit? None? How about this king of piggybacks, the SM 6 and 7's..? Wow, these stock ECU's are very restrictive in more ways then just the A/F ratio....Unbelieveable, never had cut off limits in my older mod'd Chevy's...things would just start breaking on me and that would let me know the cut off point.......:redface:
So when upgrading to an aggressive type cam and lift setup, it is a good idea to get A Stand Alone ECU to go along with the cams? Is this correct? Such as the 40- 45hp gains which the Kelford cams claim to do?
I just learned something new about the stock SC400's today...thanks fella's....for me that doesn't happen too often anymore!!!!:slaphappy
ok, finally remembered to test it. Indeed it cuts right at 6500rpm. I think the one time it went over was due to a downshift to 2nd when i floored it at 80. jibby, you can still use cams from Kelford designed to work with the stock ECU and you would still probably pick up 40-45hp. Notice this graph ( http://www.a1turbos.co.nz/images/graph_large.jpg) from the car a A1 turbo that made 330rwhp at 6880rpm with their reground cams and 8 throttle-body. So if you take a 15% drivetrain loss that is a 390hp n/a 1uz, not bad. You"ll also notice that its making 320rwhp (375hp crank) at 6500 rpm. Now it doesn't say if they are using 89-94 engine with 10 to 1 compression or a 95-97 with 10.4 to 1. So do you guys think a 95-97 1uz with those or similiar cams minus the 8 throttle body set-up could make 340-350hp with a stock ecu and a piggyback at 6500rpm (of course it would suck bouncing off the rev limiter shifting gears while the motor is still pulling strong). What hp would you account to the throttle body set-up 25hp, more? Also this engine would have full headers, exhaust, and cold air intake (this is a possible set-up for my 77 celica liftback, 2500 pounds pre-lightening, w50 gearbox, as my sc is to heavy for an n/a 1uz).
