rberry951

More report from the NA tester:


Yesterday I received the 944MAX chip for 1988 and on 944s (10.2:1 compression, non S, non S2, non turbo) and installed it. First I would like to point out that Russell has been nothing but helpful in this endeavor and informative to as much detail as possible.

So here are my first impressions of this chip:

- Fixes the NA shudder.
- Much better acceleration from a dead stop. I could roll on to the clutch at 1200 rpms without the engine hesitating.
- MUCH better acceleration from idle to 3000, instead of the power suddenly "starting" at or around 3000 rpms it's constant from idle to redline.
- Throttle response is improved, no hesitation so far when going from a high gear to a lower gear (or next lower gear) and punching the throttle.
- Fuel economy... No idea, I just filled up and I'll have a mileage count by next wednesday or friday.
- Constant power up to redline (I stopped at 6k).

Now, the best improvement IMHO:

4th and 5th gears used to be a real bear before, having to downshift into 3rd from 4th, or 4th from 5th to get some useable power for passing on the freeway or getting up to speed. I can put the car in 4th at 2000 and still have the car pick up speed and not slouch nearly as much as it did before. in 4th or 5th, if I were below 3000 rpms I couldn't go up a hill, I would have to downshift. Now the car will maintain speed and/or accelerate from lower in the rpm range, instead of leveling off or dropping on slight inclines. This chip brings a lot "oomph" into the lower RPMs, and gives you useable power right off the line.

These are just my driver's seat perceptions. Overall this is a VERY good improvement over what the stock mapping does. I bet I could beat a well-tuned 911SC from a dead start, now. Before I'd have to keep the RPMs high so I'd have useable power to keep up. Now I can probably upshift sooner rather than later.

I'm going to do three dyno runs two weeks from tomorrow (weds.) to quantify what the overall improvements are in HP/TQ. But so far, this is a very worthy investment for $175-$200

Also, I've just sent a chip to test in a 87-88 924S. It seems they are the same engine/electronics as the late NA. I'll get a report from him next week.

El Commandante

Did you bump up the rev limiter or is it at the stock level?

rberry951

Right now the rev limiter in the beta chip is still set to 6480, I'll bump it up to 7K in the production chip, or whatever anyone wants, it's a quick change.

Regards,
Russell

Whitt944

For the love of God, please do not tempt me with a 7 grand rev limiter. I already routinly shift gears at around 6 grand, I don't need that kind of temptation.

rberry951

I'll set yours at 4000...

Whitt944

Ha! funny, thanks for the concern man!

El Commandante

is 7000 perfectly safe?

rberry951

Truthfully a higher rev limiter is just to 'move it out of the way'. If you track your car as some do you find yourself hitting the rev limiter at the worst possible moment, in a tight corner where you need power. I wouldn't spin these engines up to 7K on a regular basis. By the same token, many have done modifications to their engines and the engine can indeed withstand 7K rpm on a regular basis. But even then there's not much reason to spin it that high as you have diminished your usable torque by that point. I raised the limit to 7K on my original turbo chips because I wanted the ability to hold higher RPMs on short tracks with lots of turns. Without the above stock rev limiter I would be shifting more and overall slower.

Having said all of that, the stock chips are designed to run out of steam around 6K rpm. The dynos on the 944S chips and the S2 we've seen so far the torque curve holds out increasingly higher above stock as the revs go up. So you are still building power right up through 6500 rpm, which is already above the stock rev limiter.

I'm anxious for the dynos on the NA chips so I can start making more power in the next iteration. The first version is always 'smoothing'. I'll even show you what I mean by 'smoothing'. I'll attach two images, they are the stock partial throttle timing map, and the V2 timing map for the 944S2 chip that is currently in beta testing. The final maps will look different still, but this is where you spend most of your time driving is in the partial throttle maps. In the first image you'll see the timing map is actually quite 'jagged', and the second is not only visually smoother, but you can feel the difference when you drive the car. I do the same with fuel, and with the WOT fuel and timing maps. And to date, the first iteration of smoothing has always had a side effect of making more power when we go to the dyno.

I just like to let you guys know what's going on as it happens, I want you to understand exactly what you are getting from me.

M758

With respect to the rev limiter.

7k rev limit is nice in race car. I have a chip that I believe hasa 7k limit or no limit at all.

I shift at 6000 ro 6200 RPM in most all cases, however there is still a bit of power at 6400 RPM there can be times to "over" rev a bit. The last time I did this was in mad dash for the finish line in my last race. I was chasing first place and right on his bumper. Instead of making the normal shift to 5th I simply stayed in 4th right to the finish line trying to get a tiny edge. I my competitior shifted to 5th and I actually pulled 2-3 feet by holding 4th. Nice to not have a 6400 rpm limit and worry about hitting the limiter. Plus an accidental overrev in heavy traffic like at start is nice to be able to rev a bit more rather than hit the limiter and then lose all momentum.

rberry951

UPDATE:

I now have a '89 2.7L tester testing the chip for that car... results soon...

Could still use one to dyno it.

Regards,
Russell

rberry951

We finally have a dyno chart of the V1 944NA chip. Once again, in smoothing, we made power, and a broader torque curve over stock. The 4500-5500 RPM range looks very good. The down side to this read out is I called the shop he took it to prior to his visit and told them I HAD to have an A/F reading and to start at 2000 RPM so I can see the whole curve. Well, I guess they don't like to be told what to do.

They did not use the tailpipe sniffer that they said they would to take note of the A/F, and started the chart at 3500. I'll salvage what data I can from it, but there's not a lot here to work with unfortunately. Hopefully the run of the V2 chip next week will have better data.

This is not Brandon's fault, it's the dyno shop, I spoke with them myself to insure this did not happen. Thank you Brandon, V2 will be coming to you in a day or two...

Yummybud924

how much would the NA chip cost?

from what I've read (about other 944 na chips) is that they don't really add any power at least it won't be noticeable in a street car. I usually shift below 4k rpm.

rberry951

It'll be 175.00, but when released I'll do a 30 day Rennlist promotion at 150.00

Shooting for mid Dec as my testers had issues come up that set us back a couple of weeks. Was looking at Dec 1st. Still might make it, I'm working on V2 as we speak/type and it's going out overnight to another tester tomorrow to dyno hopefully by next week.

This was just the first round of tuning above a stock chip, may take 3-4 to make the most out of it I can. I can't just make it all out all at once when working with volunteer testers for obvious reasons. I don't know them, I don't know the health of their cars, etc. It's slow going at first. But I like to keep people informed on the development process. Full testing results on all products are always on the maxhpkit support forum on every product where you can see various phases of product development.

Regards,
Russell

robertocarlos

hi all. my name is rob and im new to the 944 scene. i just had a question for russell regarding the chip for the 944 na. do you think the chip would be fine for a australian delievered 944 2.5L (1988)?

rberry951

Hi Rob,

Welcome to the 944 world, and Rennlist.

The original Bosch Motronics were designed so Porsche could ship cars all over the world without making very many changes. There are different sets of fuel/timing maps in the chips that are selectable by the regional coding plug and impedance adapter connectors on your wiring harness. If you look at your harness near the computer you'll see one or two plugs. Probably 2 where you are. So the same computers/chips that ship to one part of the world are the same as another, with a different (ROW) map set selected. My line of MAX chips currently set all maps the same, so these plugs don't have to be changed and will have no effect on the function of the chips. So yes, they will work fine on your car.

Regards,
Russell