You are correct, I'm confusing the FMU with the superfueler. Don't know why I confuse one with the other. I have done so B4.

What are all these varying levels of boost and loads that your referring to on turbo cars? You floor it, you get max boost rather quickly and it stays there.

I don't recall stating a condition of 'varying levels of boost'. I DID however agree with the statement that boost is load dependant, and not rpm dependant. Some with turbo setups do/also operate with the throttle less than floored. You stated you tune for max load/WOT. I realize this will make you safe as you put it, however I don't consider this good tuning for partial load/boost. This is what (in part) I was referring to in regards to good driveability and consistant A/F ratio metering. I trust your wideband is reasonably accurate when used to monitor boost applications. Some aren't you understand, and shouldn't be trusted, especially the lesser expensive models. Not all wideband monitoring devices are equal.

I routinely see boost at partial throttle, but like I said the MAF is far from maxed out and is adding fuel as the airflow increases. All the MAP sensor does in closed loop is pretty much tell what timing to run, which you can't change past 100kpa, which really isn't that big of a deal.

Well, my memory isn't good enuf to recall the boost level you are attaining, however, I don't consider applications that do not max the MAF, as serious boost unfortunately. As for as the MAP is concerned, if you are running a conservative timing curve, then timing beyond 100 kpa may not be as big a deal. However, if the correct (spelled optimum) timing is desired for any given condition, in addition to the correct fueling when experiencing 12-15+ # boost, then without question, (to me) the ticket is an ecm that will recognize boost. The less boost one chooses to operate with, the less a boost sensitive ecm is necessary, or, a worthwhile option, in regards to both timing and fueling adjustments.

At any rate, in your case, if your setup is working well for you, IE, you have it adjusted to your satisfaction, there is obviously, little desire to option out to an alternative ecm.

 

I'll start off by saying I agree w/arnie (except about the FMU stuff (((whacko)))??

As far as part throttle tuning goes, I never go WOT on the street... EVER. It just doesn't work unless all I'm trying to achieve is a smoke show. Therefore, I've "trained" my right foot for a couple different throttle positions, one equals about 5# boost and is my normal style of leaving stop signs and what not...

The next throttle position my foot is trained for is about 10-12# boost, this is about all the drag radials will stand, I use this throttle position to scare off anyone who is wondering what I'm about..

The next throttle position relates to about 16-18# boost. This can't be utilized from a stop, but I can roll into the throttle and increase boost between shifts, shifting @ 18# boost = tire spin, I have to back off the throttle unless I want to spin.

WOT = 22-24# boost and isn't usefull on the street. (but it sure is fun on the strip)

OK, you're saying Why in the bloody hell doesn't he get a boost controller??? I'd like to have one, but I've never received an adequate answer on which model would work best. I've trained my foot to be my boost controller, so I'm not too worried about it..

If your stock PCM wil do that, and maintain your desired Air/Fuel ratio, I'll eat my hat.

Brady <--- w/FAST

And Yes, LJ is running a stock PCM, but ask him what he's doing to his spiffy new motor right now, and why? (Not taking anything away from Jeff, he's the MAN)

 

Just wait till you get old and senile.

 

Well Its pretty obvious that your 800+ Hp Twin Turbo probably does require a FAST or other ECU. If your running 24 psi of boost on any LT1 its pretty obvious you have lots of bucks in your setup. A guy who bolts on a turbo and runs 10 -15 psi will run fine as long as the issue with maxing out the MAF is dealt with. Is an aftermarket ecu NEEDED? NO.... Would it make tuning the engine more precise, YES. would it be better, Probably, but not a total necessity.

 

it was never my intent to get into a horsepower "battle" but the thread originated explicitly on 900-1000 hp setups..

 

FWIW if you convert over to a higher flow rated maf (calibrated Pro-M univer +, etc) then you can meter whatever range you want. Run the impedance converter and you can run whatever injectors you want. Run a BTM and you have full by boost timing control.

Assuming you don't want over 7k the stock pcm should be able to handle things fine. Of course you have also probably spent enought to pay for a good aftermarket EFI

My main issue is drivability/tuning - you can definitely get a SD system tuned well and running well, but it takes a ton of work - and most people will not get it running near as well as a stock pcm is capable off (After all GM has invested tons of time/money in ensuring the stock computer can give you good drivability).

The MAF approach I think is superior to the SD approach - you *know* how much air is coming in rather that having to try and calculate it from static tables.

I believe MoTeC has an option to support MAF input, but aside from them I don't know if anyone else does.

 

Who sells the Pro-M maf?

Thanks

 

Chris B made an excellent point. It's easy to wire up an aftermarket ECU and get the car to run. It's also pretty easy to tune for max hp/WOT. But if you are building a street or street/strip car it's a whole 'nother ballgame. Tuning for drivability and starting is neither easy nor fast. Most people end up needing a pro to do the fine tuning, and that is not cheap. Nor is it easy to find someone who knows how to do it. A good part of a friends business consists of helping people who bring in their cars after installing an aftermarket ECU. Many of these cars will barely run. A week and a couple of thousand $$$ dollars later and they are good to go.

Arnie also makes a good point, as usual. Ideally, you want to be able to tune for boost across the entire range. That's one reason I have used the Superfueler. At least I can tune fuel according to boost with it. Practically speaking though, this is not so important as it seems. With an MAF car, you will seldom max out the MAF except at WOT. And since when at WOT there is basically a fixed relationship between boost and rpm, it is still possible to tune using the stock PCM. Since getting LJ's impedance converter I have been using 90lb injectors and have not been using the Superfueler. Though I may play with it this year a bit.

Rich Krause

 

Superfueler for sale here.

 

I know of someone who did modify the code in the pcm to overcome the maf limit Hz and that has extended the timing tables to reach 190kpa AND added a table for fueling based on map for the lt1 pcm...

Is it available?? sadly no... or not yet.. he wants to get it to a magazine first and be the first to use it, have it, etc.

He is a real brain.

 

Not to drag this up too much from the dead (Again) but that does sound like it atleast has some promise - just like converting over to a 2bar or 3bar MAP sensor and adjusting the tables... I'm trying to sort through the piles of threads on this as I'm working on building the rest of my turbo car setup. I'm heading for a 355 running 12-14psi on pump gas - so no doubt there's going to be some fun there...

My original intent was to get a good E-BC and go from there. One that will let me progressivly let the boost on, and have different levels. To this effect I was looking to run ~8psi to the street and not max out the ECU on a regular basis. Then click it to 14psi if I'm having more fun... but having the ECU more powerful and able to account for all this would make things much better.

Only reason I stay away from FAST and the like is the partial throttle/cruising/starting. I've dealt with it before on DSMs- and it sucked.

 

It has been done.. the sad thing.. its not available.. he is a good and knowledgeable guy with the ASM code.