I'm planning an engine swap soon (check sig for details) and I'm basically just going through my stock bin and modifying some things to try for a good base tune to get the motor running. So far I've taken the timing tables out of a 350 TPI bin and worked them into my 305 tbi's bin. Then I took the VE tables from the ANLU (caprice 350) bin and put them in my bin.

Now when comparing the 305 bin to the 350 bin I see that the pump shot values are considerably less in the 350 bin, but I've always heard guys swapping to 350's having to up the pump shot very much. I've also seen that at the high KPA levels and high RPM values the VE drops. I assumed this was GM figuring the TBI engine couldn't flow much at those rpm so wouldn't add more fuel. With my better flowing heads and bigger cam should I alter this "top" portion of the table to have more fuel in the top end?

Also, the BPW constants are very similar (305=134, 350=135) why are these values not further from each other since the injector sizes are much different? I've also heard a lot of problems with IAC and noticed that the "Max IAC Throttle Follower Steps" in the ANLU are 96 and in the 350 axkw are 80 should this value be changed up to the 96 or what?

Now this isn't anything I can just test, I'm just hoping to achieve the best possible tune to get the engine running on so I can then datalog and change things based on that. Also, sorry for the long post but I figured I'd throw everything in one. Thanks for any replies.

 

The pump shot (AE) is dependent on a number of things. Best to finalize it once the SA & VE is closer. A lot of GM tuning is based on EPA & CAFE requirements.

As for the VE tables I would change the 80 to 100 KPa drop off to a slight increase. Wasn't the LO5 (ANLU) a swirl port head? The L98 set up will have better VE characteristics at higher loads. As for more VE at higher RPM, good possibility. The L05 Caprice also came with a 20 foot long single 2" (2.25"?) exhaust. That will also kill VE. It is better to start rich and lean it down as you go.

The BPW is a ratio of injector flow to engine displacement, hence the simliarity between the 5.0l & 5.7L engines. The 5.7L has a larger injector.

As for throttle follower (TF) steps, hmm, general consensus puts 0 as a good number. May want to do that for the start of tuning, then change the max TF & gain later on. On flow limited TB's I like a high max TF with a gain setting that gives max TF at max TPS%.

Are you staying with the '8746?. May want to disable lean cruise and setup the rev limiter patch prior to tuning.

Of course don't forget a decent fuel pump and some injector to go with it.

RBob.

 

Yes, I'll be staying with the '8746 and be adding probably either 65lb injectors or 55's with some added pressure.

Max Iac steps is set at 191 for both bins stock. What value for IAC should I be setting to 0 like you suggested? Also, where is the lean cruise set? I'm using Tunerpro 3.06.

A rev limiter patch sounds like a good idea too especially since the car is a manual gearbox. Can you direct me to some sources of information on this patch please? I'm not too familiar with everything yet but I think I have a decent handle on how to do this stuff.

edit: just thought I'd add that this prom came stock on 9C1 Caprices, so an LO5 with the swirl port heads and an L98 cam.

 

Set the TF steps to a low value. Here are the parameters:

The TF factors are the ratio of TF steps to TPS%, low them for less action. Max TF steps can also be set low. At least while tuning in the SA & VE.

For the rev limiter patch and another great patch, code_43, see this thread:

https://www.thirdgen.org/techbb2/sho...hreadid=108380

The code_43 patch (down near end of thread) eliminates the forced knock test while also enabling hiway & PE spark.

RBob.

 

Ok thanks for the link RBob I'll look into that. As for the TF step parameters you listed, I can't find all of those in Tunerpro where would I find those codes? I'm still pretty new to this and have only made a few changes in Tunerpro.

 

IIRC TunerPro uses an ecu file. If those parameters are not in it they would have to be added. Push comes to shove use a hex editor and just zero out the max TF steps location in the bin. As much as folks hate the TF I'd figure that maybe the max TF steps would be in the ecu.

RBob.

 

Ok, yeah I'm using Jon Prevost's ecu file. There is a value for the max TF's, I found that one that was set at 96 but I couldn't locate the other parameters you listed. So, as long as I'm ok just zeroing out the Max TF steps then I can do that. Thanks.