Ashitaka

pls help. i just did a dyno on my car yesterday and it seems that i am running a bit lean before 3000rpms. is this normal? or i need to get a fuel controller and start tuning my injectors? pls input, thanks.

here's my mod list:

1. cone filter (pepboys ~40bucks)
2. airbox (out of cardboard)
3. n1 dual catback
4. g-force chip pre-programmed for intake, catback and a hi-flow cat (which i dont have a hi-flow cat)

car is 89TII, with 87000 miles on original motor

Thanks a lot
George

Ashitaka

second sheet

Ashitaka

also, the guy who did the dyno put the wideband O2 sensor from my exhuast.
he said it'll suck exhuast into the "sucker" and the sensor takes the reading. he also said it'll be about 100rpm delay, "not a big deal" he says.

George

Ashitaka

bump bump bumpady bump

Ashitaka

where did all the acknowlegable (spelling?) guys go?

Scott 89t2

206hp / 220lbs to the wheels with a cone filter and cat back? dam LOL... you're making all the N/A guys upset

do you know what boost you were running at?


so you still have stock cats in? that will throw the 02 off. if you have cats you really need to put it into the down pipe before the cats.

looks like the A/F is decent once the secondarys kick in at 3800. maybe you primarys could use a cleaning.

edit: the air pump is probably screwing the readings up too since that stays on till 3800 or so as well...

Blowtus

that dyno run looks pretty crazy... power seems to come in very late and tail off very early. Very interested to know what boost you were running too...

Charlie

Ashitaka

no scott, i had the g-force chip messing my fuel and timing.
could the timing be the problem besides the injectors and the airpump?
will a new air pump filter help?

thanks for the input.

Tec

I havent seen a stock airbox in a long time for a turbo II! But i'm pretty sure the air pump inlet comes out of the air box?

The chip sounds kinda weak! my turbo II with the same mods of catback and cone filter mad 219hp and 222 torq @ over 5,000 feet of elevation

Ashitaka

yea, there's somethingwrong with the a/f. i have to do some adjustments to it? maybe the ignition has to do with it. Tec, what chip did you use?


george

Ashitaka

oh yes, the boost that i was running at was about 10.5 psi.

Tec

No chip! Just a FCD that i built from radioshack, my boost was around 9-10 psi with the stock cat and precat.

If i where you! Get rid of the chip, buy a Safc of greddy emanage along with a exhaust temp gauge and tune you A\F that way! double check with the wideband when your on the dyno.

The mr2 community has nothing good to say about the gforce chips! lot of blow motors, i didn't even know there was one for the fc!

Ashitaka

apparently, i cannot turn back....
well, i'll just have to tune the car with the g-force installed, but now, i need to know what the problem is.

Tec

running lean before 3,000 rpms? whats your A\F as you start building boost to redline? I would think as long as you rich'n up under boost you'll be fine.

Ashitaka

i dont know how to say, at
3.0k -- 14:1
3.5k -- 13.5
4.0k -- 12.7
5.0k -- 11.5
and it stays around there till redline.

my dyno is posted about at the 1st post.

thanks for the help tec

Ashitaka

bump

Blowtus

won't the air pump be confusing any exhaust gas analyser that is in the line after the air pump...??? Ie, making it appear a lot leaner?

Charlie

Ashitaka

bumpbump

fellow rotorheads... help out pls...

Henrik

I assume your still running stock injectors so here's my thoughts. The really high A/F ratios you see below 2700 or so are as Scott said, likely from how the wide band is placed (ie in the tailpipe after your cats) - have it installed in the O2 sensor bung instead and that should go away. In the range of 3k-3.8k or so, you see a plateau in your A/F ratio around 14 which is way lean for the boost your running - likely your maxing your primary injectors as the secondaries don't open until 3800 or so on a stocker - I don't know if G-force modifies this point or not (a good question for them and also a good reason to be very careful with chips unless you know exactly what they're doing). Remember your pushing about the same rwhp on the primaries only as a stocker does on all 4. After 3800 it seems much better as your now running on all 4 injectors. What happened on the second run above 5500? - there you're A/F is climbing again.

I would suggest bigger injectors. A fuel computer won't help if you are already maxing the primaries until you upsize. A fuel pump upgrade wouldn't hurt either.

Henrik
87TII

Ashitaka

thanks for the reply Henrik
I am waiting for the new fuel pump and a fuel computer to come in. i am still looking for some used 720 injectors for the sec. what would you recommend for the primary ones?

George

ColumbusTurboTwo

iTrader: (7)

the dyno sheet is wiggin me out LOL

Ashitaka

wiggin?

Ryde _Or_Die

I'd stay stock with the primaries, they should do you fine for the stock turbo. I also suggest you just get new secondaries, I had a bad experience with used ones. One had to be rebuilt which meant the other had to be as well because they have to be the same. The cost to have that done was alot more expensive than getting 2 new 720cc injectors.

Ashitaka

wow, bad experience... maybe i should get new ones. i was hoping to run into someone getting 720cc, but then changed their mind, and that i can get them at a very good price
i'll just have to wait till i get my car tuned andsee what the duty cycle is at for the secs. if they're working too much, i will get new ones instead. thanks for the input ride_or_die, much appreciated

George

P.S: do you (or anyone) happen to know how timing works? i want to retard it at lower rpms, and let it stay the same in mid-high. is that possible?

Ryde _Or_Die

I have actually never messed with timing. I haven't had a reason to. I think your chip is causing you to lean out if any, but the air pump is definitely fooling the O2 sensor. I've never heard of anyone leaning out with just an intake and catback, but haven't seen someone running 10# with those mods either.