EATON M90 vs 1FEFZ ENGINE

[SUMOTOY]

So what is wrong with using a SMT6 with a MAP sensor do to the the tuning. Not good enough either? Yes, it would be nice to tweak the factory ECU, but MR T decided we are not going to do that. MR GM likes you to do that. So good for them.

Hey even the audi application derived 034EFI would work. No knock sensor input on either tho.

I don't think piggybacks are the way to go, but that's just me. I thought hard about going bonkers and putting in the 034EFI stuff and just starting from scratch with dual turbos. Then reality took hold, and I remembered inmy cae it's a frickin work truck that needs a little extra sumptin under the hood. I have audi turbo quattros with lockers to play with for fun.

Christo, I have no interest in making some 500hp LC, I'd venture neither do 95%+ of your customers that could afford it. Give me power to haul my trailer up to Estes Park and home without playing leap frog with a microbus. I'm good with that.

I've already got all the calculations done in terms of what I need for injectors, fuel pressure and intercooler. I'm quite happy that for under 2large and 6hours in, I'm halfway to the potential power at 1.5PR and I can enjoy what I have until I choose to install the other half. And I didn't need to do any fabricating or sizing, and can show even if I did, the M90 is a really tough to beat fitment.

As a turbo guy, that just tickles me silly.



SJ

 

[parabola]

So what it really boils down to ST, is that you and I mostly agree on the technical differences, we just don't agree on what the argument should be about.

Regarding your assessment of MAF metering: MAF sensors measure air flow. The ECU corespondingly provides the fuel for that flow. The density of the air inside the manifold doesn't matter. It's not a perfect way to meter air in an FI setup but it is more than adequate for our purposes. I agree that fueling based on manifold pressure is a better way to do it, but likely unnecessary for 7psi. Not to mention the emissions implications of using MAP.

Apparently TRD agrees with me and didn't see the need to convert the system to MAP with the SC kits.

 

[parabola]

I don't think piggybacks are the way to go, but that's just me. I thought hard about going bonkers and putting in the 034EFI stuff and just starting from scratch with dual turbos. Then reality took hold, and I remembered inmy cae it's a frickin work truck that needs a little extra sumptin under the hood. I have audi turbo quattros with lockers to play with for fun.

Along the lines of baby steps:

Maybe someone who already has FI should get a hold of an old school HKS VPC, associated MAP and IAT sensors, some supra injectors, and give it a go? I can scrounge up my old stock supra injector ROMs. Heck if I had my old VPC still I'd donate it to the cause.

 

[SUMOTOY]

So what it really boils down to ST, is that you and I mostly agree on the technical differences, we just don't agree on what the argument should be about.

Regarding your assessment of MAF metering: MAF sensors measure air flow. The ECU corespondingly provides the fuel for that flow. The density of the air inside the manifold doesn't matter. It's not a perfect way to meter air in an FI setup but it is more than adequate for our purposes. I agree that fueling based on manifold pressure is a better way to do it, but likely unnecessary for 7psi. Not to mention the emissions implications of using MAP.

Apparently TRD agrees with me and didn't see the need to convert the system to MAP with the SC kits.

I'm comfortable with the exercise as given, stick with 1.5PR. As such, I don't see any disagreement. I'd encourage you to stay there, it's a much tougher exercise than rehashing a lot of accepted turbo theory. One of the main reasons I got into all this hubbub on SC vs Turbo. GIVEN: Low Pressure Ratio. I have a very solid resume of turbo theory and application already....

A couple of points to the above, technically MAF's measure the air mass entering the manifold (hence Mass Air Flow meter). Density of the air inside the manifold, not only mattters, that's the exact and primary function of a MAF. What you speak of is an AFM (Air Flow Meter - like what's in my 94) that measure air flow, and use air temp to calculate mass. After either enters the tables as air mass, the ECU adjusts the appropriate fuel for that mass. The MAF is much more accurate to calculating mass, since it's directly measuring it, and it really doesn't need any altitude compensation.

MAP sensors were used in Audi turbos with AFM in every production turbo engine 1982-1991 at 7psi factory delivered boost pressure, so I'm not sure I agree with 'unnecessary'. It's a more accurate input to tabling boost parameters. There are no emissions implications of MAP, it's only a input parameter to tables to 'recognize' boost and/or engine load.

TRD doesn't agree or disagree, they found that a bolt on kit can run without installing a new ECU. We can take a look at the fuel curves under boost, or Christos dyno numbers and see that not seeing boost is a problem. The fuel fix doesn't have to be in the ecu, but it sure would be much better.



Scott Justusson

 

[sleeoffroad]

We can take a look at the fuel curves under boost, or Christos dyno numbers and see that not seeing boost is a problem.

? We do see boost and the truck is tuned on a fuel map to add fuel where we need it. Not sure what you are seeing on the dyno curves? Or am I reading this wrong?

 

[SUMOTOY]

? We do see boost and the truck is tuned on a fuel map to add fuel where we need it. Not sure what you are seeing on the dyno curves? Or am I reading this wrong?

Christo, what I refer to is the SC dyno chart vs the turbo. You have fuel compensation incorporated into your boost profile, the SC exactly doesn't. What I see on the dyno curves (especially as rpm increases) is the lean condition causing an early power drop in the SC curve.

Peak power in terms of A/F ratio we know to be .86 lambda (12.6:1 A/F ratio). Above this you are lean, below this you are dumping fuel thru the exhaust. This is quite noticeable on the power curve on the dyno IME. Under boost the SC drops out of fuel almost immediately, so a lot of power is lost. As boost stays steady ( a known in a SC) and rpm's rise, this will result in even more lean condition.

What might be interesting is to just test proper fueling vs 7psi and then add IC with proper fueling vs 7psi. I'm trying to get some calcs going as to what I see that actually doing before I take the actual measure. Too many audis with bigger problems right now.

My curiosity regarding your dyno numbers will get more intense as I work thru this. I see something going on in both charts that makes me think something is happening at high rpm's on the boosted trucks. The flutter at the top of the turob, indicates either a turbo boost profile problem, or some sort of fuel/VE thing happening.

Just nerdin away while I wait for (audi) turbo parts to arrive....

SJ

 

[sleeoffroad]

Christo, what I refer to is the SC dyno chart vs the turbo. You have fuel compensation incorporated into your boost profile, the SC exactly doesn't. What I see on the dyno curves (especially as rpm increases) is the lean condition causing an early power drop in the SC curve.

Peak power in terms of A/F ratio we know to be .86 lambda (12.6:1 A/F ratio). Above this you are lean, below this you are dumping fuel thru the exhaust. This is quite noticeable on the power curve on the dyno IME. Under boost the SC drops out of fuel almost immediately, so a lot of power is lost. As boost stays steady ( a known in a SC) and rpm's rise, this will result in even more lean condition.

Actually the SC truck ran a rising rate regulator and bigger fuel pump. If anything it ran rich, way to rich. This is the fuel curve of the turbo vs supercharger for the 1993 truck that we did last year.

The fuel regulator is tunable a little, but not enough for what we wanted to do.

So not sure how you saw the lean condition, when it is really way to rich.

Blue - SC / Red - Turbo

My curiosity regarding your dyno numbers will get more intense as I work thru this. I see something going on in both charts that makes me think something is happening at high rpm's on the boosted trucks. The flutter at the top of the turob, indicates either a turbo boost profile problem, or some sort of fuel/VE thing happening.

Any analisis is welcome. Just remember the charts for the 1997 truck were not the finall tuning charts. What do you mean with fuel/VE?

 

[SUMOTOY]

Actually the SC truck ran a rising rate regulator and bigger fuel pump. If anything it ran rich, way to rich. This is the fuel curve of the turbo vs supercharger for the 1993 truck that we did last year.

The fuel regulator is tunable a little, but not enough for what we wanted to do.

So not sure how you saw the lean condition, when it is really way to rich.

I remember that chart, Either side of the equation, you have a fuel problem. At 3500 it's drowned, dude, you killed it by 4k, I can't even keep quattros running below 11:1!

Any analisis is welcome. Just remember the charts for the 1997 truck were not the finall tuning charts. What do you mean with fuel/VE?

I'll work those charts vs your dynos a bit Christo. What injectors did you use on the two trucks? Might be interesting to see what the SC would do with the same fuel curve. Normally, we should see the torque hump and the HP hump. Given the torque and HP are really close, they might not be so easy to isolate, especially with software smoothing. The breakup of the hirpm on the turbo indicates to me that either you have surging of the turbo, or choking of the turbo (I suspect the former). This might be helped by a boost controller, but that's a whole bunch of turbo to try shutting down. What sometimes happens IME, if you use a really big turbo, it starts to ramp, the wastegate is open max, and the turbo starts surging boost (boost flutter) on the intake side because of it. This can also manifest itself in part throttle problems with big turbos as well.

SJ

SJ

 

[sleeoffroad]

I remember that chart, Either side of the equation, you have a fuel problem. At 3500 it's drowned, dude, you killed it by 4k, I can't even keep quattros running below 11:1!

We knew that on that truck. Then we looked at what it will take to tune it, possible do a custom intercooler etc etc. The customer then decided he would rather have a turbo and we pulled the sc and replaced it with a turbo.

I'll work those charts vs your dynos a bit Christo. What injectors did you use on the two trucks?

Stock injectors, but the turbo truck has 2 additional ones. It is pretty obvious that the stock ones can drown the truck, the catch is that you can not really control them (cant get into the ecu).

Might be interesting to see what the SC would do with the same fuel curve.

I assume you mean the corrected one.

The breakup of the hirpm on the turbo indicates to me that either you have surging of the turbo, or choking of the turbo (I suspect the former). This might be helped by a boost controller, but that's a whole bunch of turbo to try shutting down. What sometimes happens IME, if you use a really big turbo, it starts to ramp, the wastegate is open max, and the turbo starts surging boost (boost flutter) on the intake side because of it. This can also manifest itself in part throttle problems with big turbos as well. SJ

SJ

So far we have not experienced it.

 

[SUMOTOY]

Stock injectors, but the turbo truck has 2 additional ones. It is pretty obvious that the stock ones can drown the truck, the catch is that you can not really control them (cant get into the ecu).

The reason I asked is that many times we get fooled into thinking a stock injector 'works' when in reality it went static or semistatic (sticks open), which mimics out of control injectors. I doubt you can add 50% to the flow of those stock injectors with any fuel pressure regulator. IIRC, I believe Dusty shows "plenty" of fuel as well. I don't believe that to be true, that's a lot of extra injector capacity. Anyone remember or have the stock size injector rating?

My bet is that you put in bigger injectors, then the FPR could do it's job. I don't think you need to crack the internals of the ECU for that.

Seen this too many times on the turbo cars I work on. Usuable duty cycle in a disc type injector is better than a pintle type, but after about 80%DC they are almost impossible to control.

SJ

 

[Kenso]

My bet is that you put in bigger injectors, then the FPR could do it's job. I don't think you need to crack the internals of the ECU for that.
SJ

What would you do to keep the truck from running too rich off-boost with the larger injectors, assuming you weren't running some type of piggyback fuel controller (or was that the plan?) Just wondering what you had in mind.

 

[SUMOTOY]

What would you do to keep the truck from running too rich off-boost with the larger injectors, assuming you weren't running some type of piggyback fuel controller (or was that the plan?) Just wondering what you had in mind.

I don't think off boost is the problem, a rising rate fuel pressure regulator should take care of that under vacuum, since it will sit at stock fuel pressure. I don't believe in piggy back fuel computers in EFI. Most of the fuel can be addressed with fuel pressure regulator and proper sizing of injectors IME.

I also am quite intrigued by that fuel pump resistor. I'd like to get rid of it myself, we'll see. I generally don't like them, tho it may be necessary to keep it.

SJ

 

[Kenso]

I don't think off boost is the problem, a rising rate fuel pressure regulator should take care of that under vacuum, since it will sit at stock fuel pressure. I don't believe in piggy back fuel computers in EFI. Most of the fuel can be addressed with fuel pressure regulator and proper sizing of injectors IME.

I also am quite intrigued by that fuel pump resistor. I'd like to get rid of it myself, we'll see. I generally don't like them, tho it may be necessary to keep it.

SJ

What year model is your 80? I was thinking the 96-97's, being OBD2, might set fuel metering DTC's with the bigger injectors. I don't have any first hand experience with these trucks yet, just wondering how finicky the ecu is when it comes to this sort of thing. I'm coming from a honda background, not used to dealing with MAF setups really. I wonder if you could set the base fuel pressure on the FPR slightly lower than stock to offset the bigger injectors in low load conditions. I suppose you'd need to completely eliminate the original fpr in order to do that though.

I'll be interested to see how things go for you, if I can ever find an 80 of my own, I plan to add the SC as well and I'm sure I'd be looking to improve things beyond what TRD provides.

 

[Rookie2]

Not being highly educated on the subject, does methanol/water injection make-up for some of the untapped potential of the SC, versus trying to work out an intercooler setup, or are you still leaving a lot of horse in the stable?

Be interesting to hear some feedback from Dan regarding his experiences with the meth injection.... pros, any problems/issues etc..


Rookie2