Hi!

For the last season I have been experimenting with the ARAP code in my car.

I just got myself an ATI Procharger which I am going to install before summer, and my question is, in order to still be able to use the ARAP code, could I simply copy the spark tables from my original chip to the ARAP chip and use it as a starting point?

(ATI Procharger manual says I have to use my stock chip, because a chip with a more advanced timing curve could cause detonation).

Any suggestions from any of you who has been making your own chips for use with a blower would be very welcome....

 

Wrong ecm for doing a S/C correctly.
Look at the 1227749 try www.syty.org and look aound for info on it. You can edit it to use with a v8 and then just use a 1227730 memcal, for the Limp home stuff

I run 17d timing at WOT in my GN at WOT.

 

I concur with Bruce that currently the 1227749 ECM used in the turbo SyTys is the best swap at this point. Neither the MAF 165 or SD 730 can properly deal with boost applications.

For SD and MAF, one "cludge" is to use the "PE %Chage AF Ratio vs RPM", but this only addresses WOT. It is possible to have boost that causes the MAF to exceed 255 or max the MAP sensor to 104 Kpa while you are NOT in PE mode. Thus you have no fuel correction.

The SD 730 offers as second "Cludge" where you basically half all the MAP comparisons so the ECM thinks 200 Kpa is 100 kpa etc. But this can cause a problem at the lower limits of the VE tables as the lowest MAP reading on the table is 20 kpa which would now really be 40 kpa. This can cause problems with idle and deceleration.

If someone was to "disassemble" the SD 7730 and then redo the tables and code to work truly with a 2 bar Map sensor, then you'd have something - but no one (who may have done this) is sharing. So you are on your own if you are not prepared to go the 7749 route.

 

For the moment, I'd just like to know if I can safely use the ARAP code if I copy some of my stock tables to it. Or if I am better off running the stock code until I have gotten the blower kit installed and done some logging with a computer?

The blower kit included a Fuel Management Unit and an extra inline fual pump, which should give the needed fuel correction when in boost mode. (Works by giving a higher fuel pressure when needed by sensing boost level and blocking off the fuel return line momentarily).

But, as both you and Bruce pointed out to me, it might really be a good idea to get another ECM and do everything "right" from the beginning!

 

What people often forget is the instant you mention non normal aspiration you VE jumps from like 80s to 110s. There is a big jump when you go from having the atmosphere try to fill the sylinder to there actually being pressure.

I can start spinning the tires on my GN with 4 PSI of boost with a 231 CID engine. Needless to say what they're doing at 24 PSI.

And done right you can get to 150 VEs without too much work.

 

So you guys are basically saying, that if you run a blower you should obtain a 1227749 stock SyTy setup, and edit it for use with a V8?

If this is what your saying, does that mean that this is the "way" to go, or can you get buy with say a 730 and mods (to the PROM, of course).

The reason I'm asking, or trying to confirm is because in the near future I'm going to be doing a 355 with blower, and some of the stuff I'm trying to do a little research no is how I'm going to start out PROM wise. Like, do I do the rebuild put the motor in with out the blower and tune, then put the blower on and tune again. Or do I get the whole thing setup (motor and blower all in one shot) and start tuning from a stock PROM (which would be the 730 (I'm a 91 SD))?

 

It's really up to you but your prom burning experience should probably dictate the decision. If you're really good at it, jump in with the blower and all. If not, maybe wait and tune without the blower. Who knows, by the time you get to be a great tuner someone may have come out with a patch to be able to run a 730 with a 2 bar map and you won't have to do a conversion to the 749. Or more will become available on using the 749 code in a 730. Either way, this is pretty much off topic from the original post so if you still have more questions I would start a new topic.