On hard acceleration at WOT, at around 5000rpms the engine will suddenly lose power for 1/100 of a second then pick up power right after. It feels like I lost boost all of a sudden. This happens again at around 6000rpms. I'm wondering if the injectors are maxed out, or its just the timing kicking in. It feels really weird. Any ideas?

 

Sounds like the traction control system.

 

yeah thats what it feels like. But this is on 4th and 5th gear.

 

What boost are you running? I have heard if you run over 6psi, your fuel pump isnt sufficient. I would think of replacing that first.

 

8psi at 6k rpm. I have an auxilary inline fuel pump.

 

It's the timing being taken out, I'm pretty sure of this. I have the same feeling in my car with the J&S installed.

 

5th gear at 6000rpms?! That may be why I don't feel it. The only time I've ever hit 6000rpms in 5th gear is on a dyno at 132 miles an hour.

--Steve

 

Steve, go do a pull in 4th and you'll feel it. Better yet, I'll cruise right next to you and we can punch it

-Bill

 

I got my car running last night. I haven't pulled boost or rpm above 4k. My car needs to be tuned but even at these rpms and boost levels in 3 & 4 gear I feel something simular. Let me know if you can help with getting my car tuned locally. I really need a place to do this late in the afternoon or on a saturday.
Thanks,
Mike

 

Mike,

I will e-mail you later on and we will talk, I'm at a friends right now.

Bill

 

I was told right before you shift our car drops FP too, I would up your injector size, but I may be apples to oranges because you have a 7th injector steup?

 

I researched this it's pulling timing like Bill said.

My timing is perfect and the timing is changed at the ECU level so I don't feel it. I bet your timing signal is being intercepted and adjusted?

Whhile mine is programmed right it. Technosquare.

Is the split second box just like the J&S?

Peas!

 

Right Max. It's being intercepted and changed and sent off I believe. The Split Second box does both A/F and adjust timing. I haven't seen the software but I'm sure it's like the Greddy E-Manage, where you tell it x amount of timing for this RPM, I think it's every 500 for the Split Second. The J&S you retard by RPM or PSI, or both, but also will retard if it detects knock which the Split Second does not do.

 

Sounds like a good deal all the way around. Should be an interesting Spring Season!

Edit add just saw the last line, sounds like this J&S does more than Split Second and should sell well.

 

J&S doesn't have the ability to adjust A/F does it?

--Steve

 

I think most people running the J&S on my kit have the Aeromotive for that, they use the J&S maily for timing/detonation and warning via a light or something, I don't have it just read from others.

Like I said all kits seem to be working well, haven't had any booms so we are on our way to a much happier year than last year right? Timing is everything!

 

No, the J&S does not adjust A/Fl, it is just for timing and knock retard, but it will have an effect on your A/F when you change your timing, so you will have to adjust your A/F after taking timing out. I have the J&S along with the Aeromotive, the combo is great, but honestly I need to fine tune a little bit more, so I'll be using a Greddy E-Manage for that, I'll ditch my SAFC. The LED on the J&S is for when it retards timing because of knock. Mine hasn't lit up yet, I'm just taking out 8 degrees at redline with 2 switches that John preset for us and all is well with it. He's got all kinds of goodies on that box

 

Dollar99,

Do you have a Procharger or Vortech? If it's the Procharger, I'd think that it's your DFMU switching between different sliders for fuel pressure. Possibly becoming overrich at the beginning of the slider causing it to hesitate and leaning out towards the end. I experienced exactly what you're describing when I started my engine up for the first time with the Procharger. It was like a stepped power band. It would bog every 1000 RPM or so because the sliders were waaay too rich. It was definitely more pronounced at the higher RPM range also.

If you have the Vortech, I don't know.

Do you have the J&S? I don't remember. If it is in fact pulling too much timing then you might need to adjust the sensitivity of the J&S unit. It is extremely sensitive and if not tuned properly, it could be hearing what it thinks is knock but is just a loud engine.

If none of the above applies to you, then I'd start logging my engine parameters (Timing, A/F ratio) to see if there's anything amiss at those RPM's.



Edit: Looks like there are others that experienced the same thing with the J&S unit.

https://my350z.com/forum/showthread....548#post637548

 

So let's summarize for everyone.

Vortech (above) uses "Split Second." Does it too correct timing after it senses knock? I haven't read anything about it. Does it include something to fine tune the A/F like E-Manage like Bill is gonna do?

Is pulling timing *after* it senses knock sort of like throwing your hands up for a block move after getting smacked in the face?

If you bump some heavy bass it may think that is knock and pull timing?

I think the better solution would be to pull timing before knock. Is the only way *currently* to do that via reflash?

If this is the case then I would think all of these SCer makers would be addressing this??

On my car timing is corrected just as Jesse says to a max level of boost, he is correct in his safety warning there. My car pulls timing and adjusts the A/F up to 9lbs, that is why I am changing pulleys for yet a 3rd time to be at a MAX of 9 lbs, but mine is done before knock not after.

I guess we should have a thread that lists all the FI products and then what they use for A/F and timing so we could look at all of them in one thread, then others can determine what works best.

To me it would seem that the GReddy E-Manage if hacked in there (not the stock map one with password) would work good enough to pull timing, add fuel AND pulse larger injectors without the other two items wouldn't it? Lots to learn I guess.

 

Well, it depends on the level of knock. For peak performance you want to be on the threshold of knock/no-knock. Most knock retard units can detect knock long before it's a damaging situation. It can hear knock that is totally undetectable to humans and to most stock ECU's. Knock/detonation isn't one of those all or nothing things. There are varying levels of it that are acceptable and expected in your engine to maintain peak performance.

The knock sensor listens to the engine. It doesn't care about outside noises and listens for a specific frequency. Most knock is in the 5khz-10khz range depending on the bore and stroke of the cylinders. I suppose if you had a world class sound system that could vibrate your engine at that frequency it might cause a problem, but for 99.9% of the users, I can't see how it would be an issue. I'd think your ears would be bleeding before the engine pulls timing.

AFAIK, Split second boxes don't have a knock retard mechanism. It's a tune it and forget it. So, if it's not tuned correctly in the beginning, it's not going to protect your engine if knock suddenly develops like the J&S box would.

Split Second makes boxes that can control A/F ratios, but I don't know which one is used in the Vortech SC kit.