Highlander944

Hey Ahmet, what boost are you running in your car? Here's why I ask. I'm a bit of a nut when it comes to KNOWING the car is running 100% perfect. Any little noise I hear, any little vibration I feel.. I want to know about... For example, when I started the car after several months of sitting, I felt more body rock when in idle and I pressed the accelerator. This rock would go away within a few minutes... I later was told that the motor mounts are some kind of oil/hydraulic filled device, and that slight rocking after longer periods of sitting is exactly what you should feel, along with the stiffening as the car runs a bit.

So.. now that I've established that I'm a bit anneal about making sure everything is running just right, fast forward to today. I have installed the Guru Racing, version 8.0 chips on my 1986 944T. My car has 56k miles. My father was the original owner and he put on about 46k miles. The car is in excellent condition.

The version 8.0 Guru chips which I received last week run very well. My boost is right around 15psi. There is absolutely NO, that is zero stumbling at idle or through a VERY slow rolling take off. In fact, as I recall, from the day we got the car, back in 1986, the car NEVER liked running at sub 2k rpm levels. If you hit the gas at this low level it felt as if there was almost no response! The car feels pretty much identical with the Guru chips or stock chips when ACCELERATING through 1-2k rpm.

Now trying to drive the car VERY slowly in 2nd gear, like through a school zone or in stop go traffic is a different story. WITH STOCK CHIPS, the car would tend to 'buck' if in 2nd gear and trying to 'cruse' in slowly. I recall HATING traffic jams for this very reason. I have only had the Guru chips in for about a week. We've had a significant amount of snow this week. So I've been driving the car at slow speeds. To be 100% honest, I'd estimate that the Guru chips are a touch smoother than the stock chips in this extreme bottom end. As I recall several times once the bucking began, I could not steady my foot enough to keep the car from oscillating in this condition! I actually had to pull the car out of gear and cost to remove this condition, and this was with the car being ALL STOCK.

If the choppy response is felt as a 'bucking' I would recommend putting the stock chips back into the vehicle just to make sure your not being extra sensitive to the new chips. I know I'm that way. I am 100% for sure confident that my car used to buck with stock chips FROM DAY ONE, when running at very low rpm and very low speed. I can also say, without any doubt, the car is as smooth or better in slow speed cursing and easy acceleration with the Guru chips over the stock chips.

Perhaps there is another issue and these chips are simply the catalyst that exasperate the problematic condition?

Peter.

Sam Lin

Peter, the situation you describe (low speed, second gear), sounds like you're lugging the engine.

Sam

JustinL

Peter- I agree with Sam.

The problem many of us have is moving the throttle to quickly (even free revving) will cause the RPM to dip before it rockets up. I've learned to drive smoothly with the new chips, but if I'm a little too agressive with the throttle there will be a brief deceleration before she takes off. Any agressive shifts over 4000RPM and I get a big pop from the exhaust if it's hot. Danno had said that the stock chips have a compensation for the AFM lag built in and this might be responsible for the stumble for those of us with MAP kits.

Justin

Highlander944

lugging the engine?? What I'm saying is that the car drives the same with the Guru v8 chips as it did from day one, when it was driven off the lot of Paul Miller Porsche in NJ. It takes a VERY tender foot to run smooth at low speed in 2nd gear and low to mid rpm. 1st gear is even more difficult to drive smoothly.

Now that dip. That dip has been observed since day one as well. The car has ALWAYS acted like that. In fact the mechanic I used yelled at me when I did that... he told me that revving the engine is bad bad bad for the injectors. With stock chips, if you were at low idle or below say 2k, and you punched it, there was a dip... I am 100% sure of this.

The only difference between the Guru chip and stock chip when revving then complete let off is the Guru chip makes a louder pop, but rest assured, the stock chip mad a pop as well.

On your high rev topic. I have only heard this once or twice... I will do more testing. I recall changing from 1st gear at about 5k+ rpm and got that loud exhaust pop. This is not consistent. I will try to reproduce to see if anything is different.

I would say that the Guru chips act nearly identical to the stock chips in the low RPM range, weather your revving or driving.

Peter.

turbo944

Revving is bad for the injectors? Did he ever explain to you how and why it was bad for them Peter? I'd like to know.....that sounds like an old wives tale to me. Same with things like leaving a battery on concrete and it would get drained.

Well, I just about have my battery cable installed, leaving work early today to finish it up, so hopefully by about 6:30 tonight I'll know how these Guru chips run in my car, swapping over from Autothority Stage II/Weltmeister chips.

Blueman33

Three QUESTIONS about GURU CHIP

1. is 18psi considered safe? i had heard anything over 15psi was risky.

2. how do i set my LBE to the appropriate setting? I already had it before the chips so didn't need Reliaboost. It comes set for 10psi i believe and i haven't touched it.

3. Will the chip start screwing up if I go from stock WG to Tial?

I want to set it/forget it. I don't want to fool and fiddle.

26/6
LBE
guru chip
test pipe
93octane
100k mile

Thanks for responses

Danno

Blueman33, did you get your updated chip yet?

"It takes a VERY tender foot to run smooth at low speed in 2nd gear and low to mid rpm. 1st gear is even more difficult to drive smoothly."

I think that's what the offset throttle-cam on the 944NA is for. It results in smaller throttle-plate changes for the throttle-pedal change and makes more easier modulation at low speeds in the 1st half the pedal travel. Then at the 2nd half, the throttle-plate changes increases faster with the same amount of throttle-pedal increase. Kinda like an accelerating throttle-plate while the pedal motion is constant.

There are many changes in the v9 chip too numerous to list, but here's a quick list:

1. fuel mapped for 18psi boost, ignition-map revised acordingly
2. FQS igntion-retard changed from 2.0 to 2.7 degree retard, allows for 21-22psi boost
3. off-idle zones re-mapped with additional fuel, I might have scaled it down too much earlier to compensate for 3-bar FPR
4. adjusted low-rpm/high-load zones that can only be hit by the MAP-equiped cars. AFM cars can't even hit those zones because by the time the flapper-door moves open far enough, the RPMs will have increase, thus moving you horizontally over one cell on the maps.

On the MAP kits, badcoupe reverse-engineered some settings that we typically program into the MAP boxes before they go out. Apparently some of the computers went out in their default factory-reset conditions. If you need to know what those settings are, please send me a note, or do a search for the thread where those settings are published.

Ahmet, Jeremy, you guys are on the list to get chip-updates this week, so no need to contact me. No charge either since you've been having problems.

P.S. everyone, please send back your old chips after you've installed the upgraded ones, I'm getting low on supplies.

Jeremy Himsel

Danno,

Mine are out of the car already (put APE's back in). Send me an address and I'll get them in the mail ASAP. Both Chips or just the DME?

Highlander944

Turbo944,
Well the mechanic that told me this was watching me as I pulled the car out of the garage. I revved the car a bit before putting it into gear then I kind of revved it while releasing the clutch. He waved his arms a bit at me, then explained that this type of acceleration was not recommended and that a steady rpm was better for the injectors. I would imagine the injector pulse changes with rpm/throttle position, so it seemed reasonable. I mean constant fluctuation vs steady increase seems less stressful.. but sometimes what seems reasonable may translate directly to practice. Anyone know for sure? I kinda trust the guy, I mean anyone who owns his own shop and people travel 50 miles to have him work on their Porsche has got to be doing something right.

Danno
Seems reasonable about the over comp for the 3.0 FPR. The only reason I say this is because I was told that my car came standard with a 2.7 FPR not 2.5. Perhaps if the 2.7 FPR were used in calculations, the projected adjustments would be just right? Anyway, just a thought.

Peter.

sm

I have this "bucking" as well, and read that it's caused by the fuel injectors being shut off by the DME as the RPMs dip below ~1650. They are then turned on again, when revs drop to ~900 (or something like that). This is done by Porsche for emissions reasons.

So, I have the "bucking" when the injectors are shut off, and feel a slight "surge" when they are turned back on. Is that what your car does?

EZRider

Well, I am no expert at any of this stuff. When I am in a hurry from a stop light I rev it some just before it turns green. But I don't smoke tires not even chirp. Seems to me with an engine like ours, almost dead below 2k, RPM revving is beneficial when you are in a hurry.

O' yea I should mention I am still driving stock chips

morefun

I havn't had any issues the my 8v chips that have been in my '87 for nearly a year now. I can idle away from a stop sign (the Rhode Island Slide) in second gear w/o any stumble. Otherwise it just goes goes like stink and sucks gas like I have friends in OPEC.

cheers

Highlander944

sm.. that feels about right.

The revving that I was told not to do is an on/off rev, not a hold at 2+k and release clutch rev. I am used to driving my old Z-24 Caviler, I used to pump the gas and let out the clutch, made for very easy starts and felt like I didn't use the clutch up so fast. I continued this trend when I began driving the Porsche... the caviler died after many years of good service.

So it's more of a pumping of the gas peddle not a constant rev that I was told not to do.

Sorry for any confusion.

Peter.

Blueman33

Danno,

I did recieve my new chip and took my car in yesterday to have sway bars, speakers, new dash, steering wheel, p/s pump, new instument cluster dash reflectors, etc etc fixed. So I have not driven the new chip, and will promptly send back the older one when i pick up the car.

I still don't know what to do with the LindseyBoostController. Just leave it alone? I think it comes set at 10psi, will that work well with the 18psi chip?

Also i was thinking of putting on a new WG, but one person's opininion was that you have to redo your A/F ratio, which means 'get a new chip' for guys who have no way of adjusting A/F ratio themselves.

Thanks.

Danno

"Well the mechanic that told me this was watching me as I pulled the car out of the garage. I revved the car a bit before putting it into gear then I kind of revved it while releasing the clutch. He waved his arms a bit at me, then explained that this type of acceleration was not recommended and that a steady rpm was better for the injectors. "]

"The revving that I was told not to do is an on/off rev, "

Strange... I don't know about the injector stuff or where your mechanic gets the idea that revving the engine is tough on the injectors; just think about them opening & closing 100-times per second at 6000rpm!!!

But I think your launch technique may be tough on the clutch. My sequence is as follows:

1. release clutch to point of initial grab, you can feel the car move a little and the RPMs drop
2. add a little gas
3. release clutch a little more while simultaneously adding gas, balance it so RPMs are around 1200rpm
4. when clutch fully disengaged, give it more gas

It's a 3-4 step process that occurs when shifting gears and matching RPMs, there's that little pause at the point when the clutch 1st engages that allows the synchros and gears to get up to speed. During that time, I find it's best to not give too much gas when starting from a stop, and during shifts, I rev up or down to match the RPMs in the next gear before releasing the clutch. I suspect this has something to do with the OEM clutch on my Supra lasting 254k-miles.

Good practice on feeling this clutch engaging point is to start your car from a stop without using any gas at all. It can be done, and smoothly. This will give you an idea of what the left-foot motion is like. Kinda like dancing... step one... two.. three... four...

"Seems to me with an engine like ours, almost dead below 2k, RPM revving is beneficial when you are in a hurry."

All this launch technique stuff is so confusing! Just floor it and sidestep the clutch when the revs fly past 4000rpm and you won't have any problems with injectors or stumbling!!!