J-Rat

iTrader: (2)

Got a few questions that hopefully you all can help me with. Here goes:

First off, I SWEAR my car is pinging at 5500-7000 RPMs, but nobody can hear it but me. I am only hitting 10 PSI (actually I am falling off to 10 PSI). Is pinging very loud and noticeable? I have 720cc secondaries, and I am running the SAFC at nearly 50% at 6000-7000 RPM.

Second, I am looking for a good source for injectors. I would like to get some larger ones. Where is a good place to purchase them?

Lastly, my mods are in my sig, and I am hoping that maybe someone has some SAFC settings I can use until I get to the dyno.

Thanks in advance!!

Jarrett

NZConvertible

With your mods I seriously doubt you even need the 720's, let alone bigger ones. 10psi at high revs on the stock turbo is within the capacity of the stock injectors.

What do you mean by running at 50%? With those secondaries I'd expect you to be running around -15% to -10%.

Pinging can be very hard to hear over the noise of the engine. To give you an idea, I've seen dyno tuners use headphones attached to an amplified piezoelectric microphone attached to the engine to listen for detonation during dyno-tuning.

Josepi

That's the quiet "popcorning" sound...It's easier to feel than it is to hear. I've had it so extreme it sounded like two midgets hitting the engine block with ball hammers.

J-Rat

iTrader: (2)

thats precisely the sound I am hearing!

J-Rat

iTrader: (2)

I hear its possible to cause pinging with too much fuel.. Is this probable?

Jarrett

Husemoller

Is pinging usualy caused by not enough fuel?

J-Rat

iTrader: (2)

Yes it is, but somewhere I read that it can be caused by too much fuel. I have GOT to have enough fuel. At 5500-7000 rpms, I am setting the SAFC at +40%.

I am obviously in a little over my head here, and could really use some advice. I was thinking of changing to 720 primaries and 950 secondaries (tuned down of course), as I am purchasing the T04B upgrade soon.

Help! What is a good injector combo!!

Jarrett

ERAUMAZDA

too much fuel will cause carbon deposits and allow for pinging.

J-Rat

iTrader: (2)

Now that I have someone else that has heard this... Do you have the article? Or is this just word of mouth.

Jarrett

ERAUMAZDA

This is what I have learned.....I don't know if this can happen in a short period of time. But yes this can happen.

J-Rat

iTrader: (2)

Hmmm...I am starting to think that I am hearing things... I DEFINATELY had a low rev ping, and with the addition of the SAFC, I have eliminated that ping. Maybe I just need to turn the Injector settings back down above 3800. It sounds ALOT like pinging, although I am GROSSLY overfueling.

Another setting question...Anyone got a good setting for flames....

ERAUMAZDA

buy some doctors ears

J-Rat

iTrader: (2)

and do what? The car only pings at 5500-7000 under load. Unless I can find a dyno, those ears are worthless to me.

NZConvertible

Why so high? You'll be running massively rich like that. With those bigger injectors you should be reducing the flow, not increasing it. To get back to stock mixtures with 720cc/min secondaries you'd use a -13% correction. You should be somewhere around there, and you certainly shouldn't be in the positives.

Rich mixtures do cause carbon deposits that can cause detonation. I don't know hoiw long this takes to occur, but your mixtures are currently so rich it wouldn't surprise me if this is the cause. You need to get to a dyno soon.
Those injectors are enough for ~450hp. What's your target?

J-Rat

iTrader: (2)

Not that high...I would be happy with 325-350. I am not trying to go crazy, but I would like some ponies. I am trying (as we all are) to balance performance with reliability. I figured that my parameters would give me some reliability and performance (I am not deluded, I fully expect things to start breaking at 325). I was thinking the Stage 2 or 3 BNR turbo.

So you think that I should go -13%? It would make sense, as my previous problem was a LARGE ping right around 3000-3500 I had NO ping at 5500-7000. My car makes boost like no other, I can free rev to 6 PSI. So I turned up the percentages around this area, and the ping went away. So I will turn down the percentages after 3800 to either baseline or -13 or so.

Thanks for the help sir, and I am DEFINATELY getting to a dyno, SOON! I just installed the SAFC last night.

Just gotta find one in Tucson....

Jarrett

NZConvertible

You only need the correction after 3800rpm, since before that only your stock primaries are firing.

Four 720's would suit your power goal perfectly. Even a full set of GLS-SE 680's would do the job.

$150FC

if you've been "pinging" this long and your engine is still alive, are you sure it's detonation?

J-Rat

iTrader: (2)

There was a DEFINATE ping at or around 3200-3500. It was heard by 2 people (I only did it 3 times). My theory was the primaries couldnt keep up at low revs because I was making 10+ PSI at 2800 or so.

But I am definately starting to question myself...... Maybe I am hearing things?

Hey NZC, where is a good source for the 720s? RCE?

IRISHMAN

I HAVE THE SAME BASIC SET-UP THAT YOU ARE RUNNING ON MY 87 TII. I WENT TO PETTIT RACING TO HAVE KAMERON DYNO AND TUNE MY SAFC. I'M RUNNING 10PSI AND STOCK INJECTORS . AN HOUR AND 8 PULLS LATER, ALL THAT NEEDED TO BE DONE WAS TO LEAN HER OUT A LITTLE AT 5500. BY LEANING HER OUT AT 5500, WE PULLED ANOTHER 20 HORSES. YOU NEED TO CHECK YOUR SYSTEM BEFORE YOU START SPENDING AN ASSLOAD OF MONEY.

ERAUMAZDA

maybe your secondary injectors are clogged and when they kick in its not a steady stream. Do u still have the PD on the car.

J-Rat

iTrader: (2)

PD is still installed, most of the fuel curve has been turned down also.

Just checked the fuel pump. Not a walbro. I always thought it was. SO thats been ordered.

Jarrett

ERAUMAZDA

ok

1987RX7guy

iTrader: (3)

Jarret I think your hearing things bro. Wankel7 on the forum was runing 8-9PSI IIRC with 720's in the secondaries with a highflow cat and APEXi duals and he had to lean it out a lot. How many miles on the engine? Maybe it has some carbon build-up?

The way that TOO much fuel would cause ping would be if you run too much it begins to make too much carbon deposits in the engine and this raises the compression ratio of the rotors which in turn makes you ping when you lean it out.

Also I am not sure about this but don't they sell Knock sensors? Do they sense ping? Maybe you could try hooking one of them biatches up to your TII.

Good luck at the DYNO.

Santiago

PS- I want to see how many Ponies the Rat can pull.

ERAUMAZDA

what kinda fuel you running. Try boosting the octane and see what happens.

J-Rat

iTrader: (2)

I always run 91 octane. I just retarded the engine a few degrees. I am going to make some pulls. If I keep hearing this noise, I am going to assume that the noises I am hearing are something else.

I also turned down all mixtures after 3800 to at or below 0%.

God I need a dyno!