Prophet7000

I've read a lot/searched about this. I'm in the process of tearing apart my car (mods in sig) to replace the notorious FPD (I had fuel pooling on the top of the engine) and my LIM gasket. Since I have to go through everything and its grandmother to get down there, I'm considering going non-sequential. My question is: While non-seq can apparently be run with the stock ECU with resistors in place of the solenoids, a lot of people say that its a bad idea. Why? If I run my current exhaust setup (I am aware of the lag ramifications) tuned with an MBC to 10 psi max and the fuel map is based on mean air pressure, shouldn't the AFR stay the same or am I missing something? Plus, who's had good or bad luck with non-seq on the stock ECU?

Thanks in advance. P7k.

CantGoStraight

As long as you maintain 10 psi you should be fine. The car really doesn't care if it's sequential or not. Since your sig doesn't show I have no idea if you'll be able to keep the boost at that level.

NissanConvert

iTrader: (1)

The engine doesn't care if you're non-sequential or not. The computer will figure it out. The 3k hesitation will make you want to shoot yourself though.

4CN A1R

iTrader: (6)

but when you punch it...its insane

Prophet7000

Since the stock cat is still in place, I should have sufficient back pressure for the stock wastegates to regulate to the 7 psi set by the springs (without the pills). Then I'll just use the MBC I have sitting around to increase it to 10 psi. At least that's the plan.

Prophet7000

Are you talking about turbo lag in general or the 3k hesitation? If the latter, why would switching to non-seq make it worse? I thought the cause of that problem was still up for debate (grounding issues etc etc etc). Thankfully that common problem hasn't plagued me. Not busting your chops, just curious.

jeff p

the stock ecu is good up to 11.5-12 psi from what I am being told by very respected people in the rotary business. the stock maps have a lot of room built into them to avoid damage by the average Joe and low octane fuels. now that being said I would not run above 10 psi. this gives you room for cold days and spiking . I also would not run a midpipe on a stock ecu ( I know a lot of people do) I think you should have a stock cat or a highflow converter to prevent boost creep and always run good 91 or better fuel if you can get it to avoid detonation.

Jeff

NissanConvert

iTrader: (1)

Both at the same time... I bought a car that was ready to blow at any moment. street port, poor mans non-sequentials, stock computer, no cat.

When i punched it i'd half spool hit the hesitation (look like a retard) then take off like a bat out of hell until i hit about 10psi where i had to lift (and usually shift).

Lag and 3k hesitation is not fun. I'm so happy i have a PFC.

as for you: safe yes, fun no.

Prophet7000

@ jeff p - I've got no plans to go midpipe as I don't have the tools to port the wastegate or the money to buy a high flow (for now, I'm looking at getting an SMB) so I'll be sticking with the stock cat to prevent boost creep. As far as gas goes - 93 or better.

@ NissanConvert - Hmmmm. I wonder if that's a common problem. I haven't personally read about anybody complaining about 3k hesitation due to a non-seq conversion. Is it possible that the hesitation was a product of the shape of the car at the time (I'm sure you've got it squared away now) and not the poor man's?

CantGoStraight

Should be a doable plan. I'm not sure why people are mentioning the 3k hesitation as this is typically things related to grounds, when the fuel pump goes from low to high voltage and the time the turbos go from primary to both. The going to non sequential should eliminate those issues since transition is gone (the reason most go to non-sequential) not to mention simplification and lag won't be that bad if you keep the car in a slightly higher rpm level, other wise a lower gear will be needed to over come this.

CantGoStraight

If the stock ecu's were good to that level why would people need to up grade to a re flashed ECU or a tunable stand alone, and when has any octane other than 93 (min) been a choice for these cars ?

Prophet7000

Yeah, even though I didn't have a 3k hes problem, I redid all of the grounds with 8g monster grounding cable (cost me like $16) the first week I got it. I guess what's nice is that when you're puttin' around town you can stay out of boost more easily, but when its time to go its not like your rpms are dipping into the lag range anywho.

NissanConvert

iTrader: (1)

Yeah, i put the PFC in and got rid of the 3k hes. Got a cat to comply with the law and not overboost. Looking to buy some new turbos and port the wastegate so that i can bypass the cat on race days. I'm still on poormans because every time i have money put away for block off plates i have to buy something else.

I usually downshift to pass anyhow, i wasn't aware that there was a solution to 3k hes, other than buying a non-stock ecu.

jeff p

the stock ecu will support mods up 12 psi then you will hit fuel cut. anyone running higher boost 12 psi and up will need a re chipped ecu or stand alone. in california we can only get 91 octane so if you can get 93 in other states use it. a lot of people buy things they don't need because of hype and being in with the crowd. the 10 psi rule has been proven . if you set your boost at 10 psi the stock ecu will handle spikes up to 12 psi then you will hit fuel cut.

Jeff

Prophet7000

Block off plates from rx7store were like the first thing I bought for my car. I used removal/blocking of the AWS, double throttle, wax rod, fast idle cam, and throttle body coolant reroute as my first attempt at getting familar with the engine bay. I think his comment about the downshifting was tossed out as a coverup for lag issues.

Thanks for all the comments guys. I feel better about the whole process now. Hopefully this thread will help somebody else in the future.