Jeff Oberholtzer's 1G EPROMs

keydiver · Oct 20, 2003

Stage 1:
Eliminates fuelcut
raises rev limit (if desired)
boost gauge becomes O2 or knock sum gauge
octane reset at startup

Stage 2:
All of Stage 1 plus:
Stutterbox and clutchcut (includes diode kit)
or simple 2-step for launching that doesn't require kit
A/C cutout above X TPS

Stage 3 (coming soon!)
All of Stages 1 and 2 plus:
Injector size compensation
Injector deadtime (risetime) compensation
MAS compensation (for 1G with lower honeycomb removed or 2G)
Highspeed Closed-loop operation (maintains closed loop at higher rpm's/throttle position)
Higher idle speed (for you guys with BIG cams)

Stage 1 is ~$30, Stage 2 is ~$45, and Stage 3 will probably be about $70 because of the hundreds of R&D hours I have into it.
Thanks for the great reviews, guys! I'm trying!
Jeff O.
#1886/2000

Rodman · Oct 20, 2003

Don't forget the all important thing for us 90 guys.

Complete 91 code, which has better A/F and timing maps

keydiver · Nov 10, 2003

Guys, I have a new 2G chip I've been working on. I actually started it in February, but all this 1G stuff kept me too busy to work on it. If you, or anyone you know, has a socketed '95 ECU I would like them to beta my chip for me. But, it has to be a '95 or '96 car, because it doesn't compensate for the inverted CAS signal (yet). Please have them contact me directly at keydiver@yahoo.com.
The chip has the fuelcut removed, higher rev limit, bigger injector compensation, and a higher idle speed.
Someone with a DSMLink would be ideal, since they already have the socketed ECU.
Thanks,
Jeff O.
GVR-4 #1886/2000

Lurker · Nov 12, 2003

I just got Jeff O chip installed on my GVR4 about a few hours ago and just finished some basic tuning.

For those folks who got way too much timing because you're substracting too much airflow ( either via MAFT or SAFC or other piggyback system ), you now have a solution.

I got Jeff's 660cc injector compensation.
I went from MAFT base setting of 8 ( -40% ) to around 2 (-10%).
My timing curve is much better, and where I used to get large count of knock, I don't anymore.
I can even floor it on 5th gear, going slight uphill on freeway without getting knock. Plus, my 5th gear is the TRE 10% taller.

I also would like to mention that, sadly, I am not really sure what injectors I have. It was installed by the previous owner, and he said it is ND 660. I even cross-reference the band-color, and it seems to be ND 660. However, whenever I'm tuning for good trim values, I always found that my injectors are more like 750cc.
I bet if I really had a 660cc injectors, then I would be able to run Jeff's chip w/ my MAFT setting to all zeros.
Since I can still tune the car, I'm not worried too much.

My fuel-related mods are:
MAFT, 190lph rewired, AFPR set to stock fuel pressure, SAFC, and four injectors that seems to be bigger than 660cc.

Oh yeah, the launch studderbox rpm feature is awesome

mhavel · Nov 12, 2003

Lurker said:
I just got Jeff O chip installed on my GVR4 about a few hours ago and just finished some basic tuning.

For those folks who got way too much timing because you're substracting too much airflow ( either via MAFT or SAFC or other piggyback system ), you now have a solution.

My fuel-related mods are:
MAFT, 190lph rewired, AFPR set to stock fuel pressure, SAFC, and four injectors that seems to be bigger than 660cc.

Oh yeah, the launch studderbox rpm feature is awesome

Awesome, I was just about to ask if we could run a MAFT setup with Jeff's EPROM. Nice. I think I'll have to pull mine and send it out to Jeff.

Hey Jeff, can we get a $2 discount if we send you our own replacement caps?

(Just kidding... I'd send the caps w/o the discount in graditude for your time and hard work.)

Mike

edged1G · Dec 4, 2003

website

has he posted his website yet?

kpz11 · Dec 4, 2003

do a search for "keydiver chip"hes got a link posted there

KP

DRW · Dec 5, 2003

Ha, that's funny "do a search for keydiver chips" and the website that pops up is www.keydiverchips.com That wasn't too hard!

The same site can also be reached at www.dsmchips.com

AWD92TalonTSi · Dec 10, 2003

{9) I always try to encourage people to get the ECU socketed locally if at all possible. TMO's site has some nice instructions for the do-it-yourselfers, or any TV/VCR shop can usually handle it. I have a fulltime job that sends me out of town often, a house that keeps me very busy, and I'm trying to avoid burnout like TMO, so I hope you understand when I'm reluctant to take on your ECU repair. }

What do you mean by this? have somebody else remove/install the eprom on the board?
bryan

mhavel · Dec 10, 2003

Not so much install the chip as remove the old chip and install a socket for the new chip to 'plug' into. The reason Jeff asks that its done locally is because it takes time to do it right. He has to heat up the old solder and suck it out so that he can remove the old chip and then solder a socket back in. The taking out is the hardest part...

Besides, that is time better spent on him working on updating the code that makes the chip so sweet.

16g-95GSX · Dec 10, 2003

In addition, if your board is socketed then all he has to do is send out the chip, you dont need to send in your ecu, as the chip will pop right in.

bastard1g · Dec 14, 2003

Hows the chip coming along?

Has anyone with the stage 3 chip using nothing but a maft for tuning getting some postive results from the injector size compesation? What about the extended closed loop operation? just to clarify, Does that mean that the ecu will never see open loop again or does it mean that it ups the closed loop operation a lil higher for better gas mileage in cruising speeds? I like that idea cause when i first learned about how fuel systems worked, I was wondering if anyone made a device to mointer the ecu's open/closed loop opertation for cruising (gas saving) speeds.

Bohrn · Dec 14, 2003

I'd also like to know what each of the mods does. I understand some of them, but others are a bit beyond me.

DRW · Dec 15, 2003

Bohrn, which mods would you like to know about?

There is a simple way to see when the ECU goes from closed to open loop; watch the O2 volts. In closed loop the O2 volts cycle up and down approx .20 to .80v. In open loop O2's hold steady , usually .75v and higher, depending on how it's tuned.

The stock ECU switches from closed to open loop mode around 3700 rpm or 77mph in top gear. With the Keydiver chip mod the threshold is upped to 4k rpm, or about 90 mph. This helps gas mileage now that many freeways have abandoned the 55 mph speed limit. (remember that?!?)

Bohrn · Dec 15, 2003

I guess the only one I really don't get is the Dead time compensation. I don't fully understand the Octane value reset either.

A full explaination of each mod would be useful as some people might not get much of it at all.

EG; Eliminate fuel cut - In stock form, our ECU sees a certain amount of air flow at a certain barometric pressure and a certain tempurature. It then calculates the needed amount of fuel and injects it. But when we flow more air due to more boost, larger exhaust, bigger turbo etc, the ECU will see that it cannot supply enough fuel for that amount of air. So it shuts the fuel off completely to avoid internal engine damage. We can add a bigger pump, higher pressure and more , but the ECU doesn't know it, and it shuts down once a certain airflow is reached. So we have eliminated this part of the ECU's programming.

DRW · Dec 15, 2003

I don't quite get the injector deadtime compensation either, but I think it's because really big injectors take more time to open and close?

Octane reset is a nice feature. It's not very well known, but our ECU has an ignition timing trim. That's sort of like a fuel trim, but it's used for ignition timing. It's there so that we can run different octane, even crap 87 octane in an unmodded car, and the ECU can keep the knock down to safe levels. I guess you already knew that the ECU pulls timing when there is knock, but this is a long term value. What if the ECU sees knock all the time? That's what the Octane trim is for. What happens is when the ECU detects consistantly high knock counts and has to constantly pull timing it will reduce the timing trim, or octane, so the ECU won't give so much timing to start with. Rather than pull the timing after getting some knock, the octane trim lets the ECU hold back the timing before it starts.

The problem with that is when you go to the track and add some nice race gas. There isn't any knock, but the timing is still crap! WTF?!? With the octane reset feature you get full timing, it's reset everytime the car is turned on.

But the problem with that is; what if the area you live in only has 91 octane gas? With poor gas it's nice to have the timing pulled back to what the gas can tolerate.
Choose your mods wisely.

91eclipsegsx16boy · Dec 23, 2003

DRW said:
I don't quite get the injector deadtime compensation either, but I think it's because really big injectors take more time to open and close?

Yes that's true - bigger injectors have less response.

Octane reset is a nice feature. It's not very well known, but our ECU has an ignition timing trim.

Hmm, afaik 1g's octane value only affects the stock BCS to cut some boost. I believe 2g's affect the ignition timing.

-aaron

Smoothbodyman · Dec 24, 2003

Well I have been driving the car for about 3 days now with the new
Keydiver chip in and I am extremely pleased. The ease of tuning and
the window of finding the sweet spot is much better now. Idle is also
much improved. I had everything tuned in about 5 minutes and the car
is running smoother and faster than ever before. Unfortunately I dont
have hard numbers to show any acceleration or power improvements, but
I'm a very happy camper. Im talking about HOLY CRAP Im doing 120 already where are the brakes.

The stutterbox launch setup is lots of fun, but I think I need better
tires than the Khumo 711's to really take advantage of it.

Jeff was also able to upgrade the code to the 91+ to get extra fuel
trim range and what I was told are better timing tables.

Im only running 660's and saw a major improvement so I imagine an
even greater difference for those running 720's or more.

MAFT is 5 clicks lean on base and 1 click richer on idle and wot.

91TSiGuy · Dec 24, 2003

Smoothbodyman said:
Im only running 660's and saw a major improvement so I imagine an
even greater difference for those running 720's or more.

MAFT is 5 clicks lean on base and 1 click richer on idle and wot.

So you did get the eprom with the 660 injector size compensation? I'm struggling with too much timing with my MAF-T at lower boost going into high boost causing knock that I can't tune out. Were you able to log knock before and after this chip?

Smoothbodyman · Dec 24, 2003

I used to have problems tuning out knock, but since I lowered my base timing from 5 to 2 I havent had any problems with knock, and run 21 psi on 92 octane pump. But yes I did get it compensated for the ND 660's. Idle is much better, throttle response, everything. I dont really understand how deadtime works, but it seems to make a huge difference in drivability. I think I may try experimenting with raising my base timing now that I'm not taking away so much of the airflow signal. I still had to lean the base from 0 a bit on the maft, but it could just be the maft, my 41 psi base fuel pressure, or Jeff just setting things on the safe side.

Jeff Oberholtzer's 1G EPROMs

keydiver

Rodman

keydiver

Lurker

mhavel

edged1G

kpz11

DRW

AWD92TalonTSi

mhavel

16g-95GSX

bastard1g

Bohrn

DRW

Bohrn

DRW

91eclipsegsx16boy

Smoothbodyman

91TSiGuy

Smoothbodyman

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