boostin_7

Hi guys,
Im after some advice on the tune of my jap spec s4 rx7. I have just had it tuned to run 14psi with my new 800cc injectors running in the secondary positions.
The main problem is that it seems to be way to rich. I have drawn this conclusion from the fact that my economy is through the roof (like 1/2 a tank for 100kms of sedate driving) & the fact that it idles lumpy & backfires with any slight decceleration when hot.
Basically ive been told on an aussie forum that my AFR's are all over the place, but nobody will elaborate on what is wrong with them so i can go back to my tuner with the info i need to get it fixed.
Here is my dyno graph:

P.s its a stock port engine.
Any help would be greatly appreciated,

Regards
Greg

junito1

i dunno anything really. but see if you can get that AFR 11.5 across the entire rpm

Its rich i know. but better than near 14. U might need 680 in your primaries injectors....

Or just take it to a microtech/rotary tuner

boostin_7

i got it tuned by a rotary mechanic who specialises in microtech systems, but its running too rich. Its impossible to drive when the temp outside is above 25 deg celcius bcos it backfires constantly on decceleration

rotarydelight

It Actually Looks Kinda Lean On The Low End At 14 Psi You Definetly Need To Be In The 12's To 11.5 On Top End. The Tuner Might Have To Adjust Injector Duty Cycle Or However The Injectors Are Controlled On A Microtech

Sideways7

iTrader: (7)

If you have to come on a forum to get advice on what to tell your tuner, then you need a new tuner IMO.

junito1

Dude. you think it might be ur tuner? Dont let idiots tinker with your ems. Make sure you know other peoples rx7 he has tuned. Never know with people these days.

Cause if my graph looked like that after it came out the dyno session. And it wasnt my car acting up. I would be pissed.

RETed

You don't post your mods, but if we're talking about a stock turbo'd FC, that power output is actually about right.

Yes, the AFR's are a big ragged, but the power curve looks okay.
Even if you get the AFR to smooth out, you won't get that much power gained.

Lastly, I dunno who the hell is touching your EMS, but it's obvious they don't know what the **** they are doing.


-Ted

Aaron Cake

iTrader: (1)

Sounds like you "tuner" only tuned the boost map and left the other settings alone.

Find a new tuner.

Basically you'll want the ECU switched to Matrix mode as a first step. This gives the familiar MAP vs. RPM table that every tuner should be familiar with. Most of the work will take place in the vacuum screens where it's probably the stock Microtech base map (VERY rich). You will find the Decel setting in screen 30. Turn it on and set it for 19" as a starting point. That will cut fuel when the throttle is closed and vacuum is 19" or higher.

junito1

dude he said this was on 14 psi. SO no its not normal numbers...

NZ_87_TURBO

neither is a 180kw. I think he probably read that. Get a new Tuner. Take it to PAC or dyson. You'll be happy you did

My5ABaby

iTrader: (7)

Isn't the tuner the person you go to when you need this type of thing fixed?

RETed

I run 14psi on the stock turbo, so what's the big deal?


-Ted

Sideways7

iTrader: (7)

Yeah, thats exactly what I am thinking.

boostin_7

Hmmm interesting. I got a tune done by this rotary workshop b4 on 8psi & made 147rwkw's it ran fine & got ok fuel economy for a rota.
Then i returned it to the workshop to get a FMIC & tune for the aftermarket FPR & larger secondaries running 14psi. Do you think that maybe all the tuner did was change the boost map & thats it?

Thats exactly what im ticked off about, i paid a reputable rotary specialising workshop here in adelaide for a matrix mode tune & this is what i get. Obviously it pulls harder than 150rwkw's but i had better driveability & better fuel economy then.
Here's a map of my tune for 8psi @ 147.8rwkw:

Aaron Cake

iTrader: (1)

Ah, the secondaries were changed. It all makes sense now.

With the Microtech if you change the injector %stage it effects the PRIMARIES and not the secondaries...It's a bit hard to explain but here's a link to how it works:
https://www.rx7club.com/forum/showthread.php?t=182032

Once you know how it works and have experience tuning it, you will see that it is a brilliant setup. You can smoothly stage nearly every injector combination and even forget that staged injection is even turned on...

HOWEVER if the tuner increased the %stage this means that your primary pulsewidths are now increased by that number. So you will need to retune the portion of the map when the primaries are firing for lower pulsewidths.

boostin_7

I just check my staging settings. REVstg = 1380, MAPstg = 02", % stage 75%

boostin_7

with my secondaries coming on at 1380rpm, would this be the cause of my off boost bad fuel economy?

Force Fed

Well I'm still learning these cars myself, but 1380 rpm sounds very low for the secondaries to come on, that's barely off idle.

Aaron Cake

iTrader: (1)

In theory no. In order for the secondaries to fire both conditions must be met. So the RPM must be 1380 or higher and the vacuum 2" or less (or greater? You know what I mean....vacuum above 2").

That's a very odd stage value though. What injectors are you running primary and secondary?

Can you post a screenshot of your Matrix table? Just the off-boost numbers will be fine I think.

boostin_7

My tuner said that he likes to stage the secondaries pretty low in the rpm range so that you dont get any hesitation when they kick in under boost.
My injectors are 500cc primary & 800cc secondary.
I wish i could checkout the screen shot of the matrix table, but i dont have the laptop adaptor, just the cable that goes to the dash unit.

snowball

im pretty sure the cable that goes to the dash is a serial cable, same as used for laptops.

RETed

I think the OP mentioned 800's in the secondaries.
I'll assume stock 550's in the primaries.

Even if your "tuner" insists on staging them that low, it's a really stupid idea due to the fact that intake velocity isn't high enough to induce proper atomization, especially in the secondaries.

I'd stay away from whoever this tuner is.


-Ted

Aaron Cake

iTrader: (1)

Good in theory, bad in practice. As mentioned you are just going to be flooding the secondary runners with fuel. Really, you should be staging at 3000 RPM minimum. If you run out of fuel before then, upgrade the primaries.

Oh, that sucks...My only complaint about the Microtech is the current inability to save maps. But they say they are working on that, and I'm currently working on decoding their communications protocol so I can write my own Microtech tuning software.

Long story short is that my guess is your off boost pulsewidths are simply too high for the %stage value used.