Awesome. I have decided to do delteq and will have ECU take care of timing when i finish my turbo 383..

 

I solved it with a PRO-M Maf.. granted i haven't installed it, but it will read from 0-900g/s from 0-12000hz

 

when do you plan on installing it? I'm curious to see how the ECU responds to it. That would let us still keep the 1bar MAP sensor for resolution and tune things on a curve to approximate boost. It wouldnt be "dead nuts" accurate, but at that many CFM, once you give it a good baseline, most likely it wont ever be too far off, and will be able to better respond to partial load/low spool and overboost responses.

 

This pro-maf sensor, from what you are saying it will never max out...but even with the 900g/s the pcm only go'd to 500 g/s how is the extra 400g/s add in there, is there any other tuning that you have to do,m to get this to work..

At the level of power you are going to make why not just get DFI you are going to have the same money into all the add on's ..

 

A frequency divider would do the same thing and cost alot less that the Pro-M and voltage to freq converter. Cheap alternative, Just not sure how to tune it yet. Change the injector constants?

 

an aftermarket pcm doesn't have near the same tables that aid in driveability that i want... granted they have more feautures for WOT... but for part throttle its always a bit more difficult... i am not willing to make the sacrifices.. or i would have to spend around 5k for a motec which would be the only pcm i would use.

a frequency divider will not work correctly.. the pro-m maf is CALIBRATED for those ranges... from what i've read the limit is 12hz, etc because the sensor is not accurate above 480g/s 12hz resolution, yet the pro-m maf solves that since it has it own converter to change from 0-5v to frequency... its also tuneable, etc etc etc...

Dividing the injector constant in 1/2 will also permit me to change the VE Tables to 1/2 and more or less tune in boost. also, since i will be using a 2 bar map sensor, even if i loose resolution i'll try to tune with boost the pcm and the timing tables.. in the end i will get it done... im sure... still.. we will see...

The only way i see of the stock maf working for heavy HP is if you use either 2 MAFs or have the same sensor put into 4" tubing so you can lower the frequency output. since there are no mafs from GM that are 4" or so... well... i think its a viable option to go with the Pro-M maf sensor...

 

Why can't LT1 Edit or TC add,change the maf tables or the map sensor so we can put in a 2/3bar sensor

HPtuner has it for the LS1....they are tuning with a 3bar map now...why can't we get this?

 

Because it is code change...actually.. IIRC Ken from HPT did a code change for the 2 bar much like they did for the ls1... ask him to see if he can release it.

 

Cant just increase the maf size - you'll have dramatic velocity drops which will throw everything out of whack. Same with the twin MAF idea.

I too want the part-throttle and "daily driver" ability that the stock ECU has. Honestly you spend $2000 on a standalone, but then you spend another $2000 getting it tuned by a pro so it starts properly and idles right around town. Thats the issue I have with standalone setups.

I'd love to see the twin maf idea work, but again, there's the issue of packaging and the like.

We can use a 2bar or 3bar just fine. downside is you loose resolution for part throttle cruise and idle... That is my biggest issue. I'd use a 2bar and not be out much, but if I ever go over 14psi of boost, the sensor is a waste. Not to mention my maf will max out long before then as well.

My thought was leave the 1bar MAP sensor. If the MAF keeps reading and sending to the ECU, then you're getting somewhere. Tune all the tables for max load and you'll just run a little on the rich side otherwise when in boost. The only time that would cause you to run rich is partial throttle and in boost, which doesnt happen often. So its not an issue really.

Why bother at all then? Cause I'm paranoid. If I loose the vacume line to the wastegate for some reason and boost creeps from say 14psi up to 18psi. Without the car reading something in some way shape or form (MAP is pegged and MAF is pegged) if the tune is for 14psi, then it will add fuel for 14psi. If I had 18psi of boost in there I'd be running very lean and risk killing the motor. I'd like to have some form of "insurance" or safety measure to prevent that. Thats why this interests me.

 

I am not tuning pro at all, and it will show. here is my take:

Geoff, I am not sure if you want to run the stock 1 bar because of the timing it controls. If you look at the stock table, MAP versus rpm, you will see what I mean. Lets say the MAP sensor gives a 0-5V reading. If you use the 1 bar sensor, then as soon as your boost gauge reads 0psi (5V), this could be at 1600rpm WOT, then your timing will be whatever was in the last cell (100kpa). This means at 0psi you have two options:

1. You'll have to have the max timing without knock at 0psi and then use a timing retard to pull out timing as boost builds.
2. If you dont do a timing retard, you'll essentially want to set your timing for full boost in your 100kpa (0 PSI) cell which will have the same low timing thru all boost ranges (which will sacrifice all the low and mid boost #'s since they should be higher then the final timing at full boost).

The way i am would like to do it, now i havent so i dont know how hard it will be or if its feasible, is to use a 2 bar map for 14.5psi of boost. I will then rescale my timing tables so 0-2.5V will be vacuum - 0psi, and 2.5V-5.0V will be 0psi-14.7psi. That way I can play with the timing on the dyno and input each individual cell. Will I lose resolution when not in boost, yeah, but I am worried about making power under boost

I feel like you will sacrifice more by using the 1 bar map and using the 2 ways i described.

I dunno, correct me for mis info guys. Thanks.

 

Once again I will ask: Anyone ever hear or know of the "Mass Airflow Massager" part number MA001I-1 from procharger for 1996-1997 LT1's w/obd2? I am not familiar with it, all i know is that it comes with a supercharger kit and is somehow related to the maf.

 

[QUOTE=The Highlander]Because it is code change...actually.. IIRC Ken from HPT did a code change for the 2 bar much like they did for the ls1... ask him to see if he can release it.

HPT are they out for the LT1? There has to be a way to add on the maf and map sensor LT1edit or TC...with a code change i am sure every person with a FI LT1 eng would love this ...

Geoff with DFI what tables do you think that they are missing for daily driving over the stock pcm..with gen7,BS3 and with the wb02 and dial in your AFR, it just looks like every thing you ask for is there even safy .....yes $$$ is a big thing you ask people for help on here for tuning why not ask people here to help out with tuning....

 

[QUOTE=Schurters LT1][QUOTE=The Highlander]Because it is code change...actually.. IIRC Ken from HPT did a code change for the 2 bar much like they did for the ls1... ask him to see if he can release it.

HPT are they out for the LT1? There has to be a way to add on the maf and map sensor LT1edit or TC...with a code change i am sure every person with a FI LT1 eng would love this ...

QUOTE]


Jeremy, with the stock pcm tuning, I dont think you can add onto the tables. You can scale the table in half. If the timing table is 0-100kpa (vacuum to 0psi), that heading cant change. However, if you use the 2 bar map, then essentially the cells under 0-50kpa are for 1 bar and the cells that are under 50-100kpa represent the 2 bar (boost portion). I have yet to change mine, but i am pretty sure thats how it works. Anyone have any input?

 

Everything is there in DFI and all the stand alone setups.

Stock ECU isnt as efficient at max power, that is very true. However at partial load, the stock ECU does a good job of adjusting and tweaking itself for idle and cruise. On a DFI/FAST, those need to be all tuned, where the Stocker really only needs a lot of hassle at WOT. It's more time on the dyno and more fighting with it for average use. Thats just how it is.

My car has several interesting things for a "355". I'm using a water/air intercooler with 3gallon reserve tank, a lightning intercooler pump, 2 heat exchangers 12"x12" (roughly) and the intercooler core is about double the size of the vortech intercooler core. I have a 255 fuel pump for non boost inside the gas tank and 83# injectors.

When I step on it, the controls system has two permissives. One is a Hobbs switch (I will have to figure out where its best to be set at from 2-5psi). The other is a WOT switch. When I hit WOT and start to go under boost, the 2nd in tank fuel pump kicks on and the alcy injection also kicks on.

Do I have a timing retard box? No, but I have considered it, though I'd prefer not to (k.i.s.s). Hence my use of alcy and an air/water intercooler in hopes of not needing it. Also I have the ability to run ice in my air/water when I feel like it as well. How would I be able to take those advantages? Thats a very good question.

I see your thoughts on the 2bar map sensor. I agree with you 100%, but for my purposes, the added accuracy without boost is where I am more concerned. If I sacrifice 10hp-15hp on top end because I have a more conservative tune I'm really not that worried. Even 20-30hp. Not a big deal. The car is a street car and will almost never see the track. I'm also using a 3" downpipe with the full 3" Corsa exhaust. For the power levels I'm at, I should consider a cutout, and I will of course, but not immediatly. That will be costing me power a lot of power as well - but again I'm not worried about it. For a quiet unassuming street car that was built as such, I think it will do just fine. But we'll see when its done in a few weeks.

Trying to get 500rwhp to hook on street tires is a joke. Trying to get 600rwhp on street tires is worse! Again, I'd like to see how all this plays out.

And just to throw another wrench in the works, I know the 3rd gen guys have been working with the Syclone/Typhoon ECU.

Any thoughts on that, as that ECU reads boost?

 

Should I be worried about maxing my stock Maf out? I have a stock LT1 with about 9psi. Obd1 and tunercat. I see the updated Tunercat version but I haven't downloaded it yet.
I am hoping for 420-440 rwhp.