evo/3g mas on 2g?

[byebyev8]

I have a 16g evo560's evopump with rewire and fmic that I'm going to put on my car soon.

I don't have a tuning device but from what I've herd I"d be fine running the evo8 or 3g mas with the 560cc injectorson a 2g. I herd that it would compensate for the bigger injectors and it be just like running a eprom chip with no safc. Is this right?

 

[snowborder714]

http://www.dsmtuners.com/forums/151091334-post2.html

 

[byebyev8]

I've never heard of anyone doing what you have said, running a 3G/EVO MAS with the EVO 560 injectors and a stock ECU, but here is a graph I made that shows the difference between a 2G MAS and a 3G/EVO MAS compensation:
http://www.dsmchips.com/~keydiver/MA...N_1G_2G_3G.xls
The EVO injectors flow ~30% more fuel than the 450's. As you can see from the bottom graph, the 3G #482 MAS needs to have ~40% more compensation at idle than a 2G, so you will be rather lean at idle. The fueltrims *should* be able to correct for that. At higher airflows, the 3G/EVO MAS needs to have 25% more compensation, so you will be 25% leaner, but the injectors are injecting 30% more fuel, so I would guess that you will be 5% richer than the already rich stock 9.3:1 maps.
The other BIG downside to this idea is that the ECU uses the airflow Hz to calculate how much load the engine is under, to decide what maps to use. With a 25% lower Hz from the 3G/EVO MAS the ECU will be using more aggressive timing maps, which *might* cause knock issues, depending what octane fuel you are running.
Jeff O.
dsmchips.com

Just letting people know this is just like the people running 550's on 1gs with a 2g mas without anytuning or a safc almost zero'd out.

 

[DSMunknown]

Thought about taking this project up to see the +/- effects, but it's not worth the risk on my only DD. Plus finding a MAS off an Evo 3 will be a little tough. I haven't looked into it, but I would imagine the 2G harness may need some hacking to properly adapt to the Evo MAS. Just my initial thoughts.

And with Link v3 coming my way, this suspending "project" is virtually null.

 

[byebyev8]

This thread is about the #482 mas found in the evo,v6 eclipse's, motero's etc...

The more research i do on this the more it seems like a good idea. It really would make a great basic tune with the evo 560cc injectors depending on how much they actually flow. If they flow around 575cc they'd be flowing exactly 25% more than stock 450s making it a almost perfect match for the 3g mas which runs 25% leaner than the stock 2g mas. If it ran to rich or you just wanted to lean it out about 5% more you could throw on a 1g fpr. The agressive timming might be a issue with the 8.5.1 compression though but if you have a 6bolt with 7.8.1 compression you should be fine.

I'll update this thread when i get a new tranny in the car.

 

[JayRolla]

What are you actual afr's before the swap and after at idle, cruise and wot??

 

[byebyev8]

j/w if i put the 3g mas on and some 750cc injectors on e85 would it be a good baseline tune. seeing that you need 25-30% more fuel with e85 and the 750's and 3g mas would put it right there with a afpr and 255. Wouldn't it put it at or around a 11.5 afr using the e85 conversion and have pretty agressive timing?

 

[twdorris]

Running 560 cc/min injectors on gas with a stock 2G ECU and an EVO8/3G MAF would be a nearly perfect match. Based on ECU data from both the EVO8 and 2G, I'd guess you'll run about 5% lean at idle (which will be easily compensated for with fuel trims) and about 4% rich at WOT. Cruise should be nearly dead on.

To run pure E85, which has a stoichiometric ratio of 9.8526:1, and still maintain stock ratios, you would need closer to 835 cc/min injectors:

560 / 0.670 = 835.8

A little more E85 data can be found on the following page.

e85fuel [ECMTuning - wiki]

You can run smaller injectors on E85 to get a leaner ratio at WOT, but you'll be pushing the trims pretty far out during idle and cruise. 750s are about 10% leaner than the theoretically "perfect" 835s. Combine that with the 5% lean you'll be running at idle just from the MAF swap and you're definitely pushing the limits.

Thomas Dorris
ECMTuning, Inc.

 

[dsm-onster]

The compensation going from a 2g maf to a 3g maf is fairly consistant, about between 22% and 31% difference at all hertz outputs. Most of the flow outside of closed loop sits right at 27% difference. You will need 616cc injectors to compensate for the this 27% difference. Idle is 31% difference and it dips down to 22% difference as you're going into the edge of closed loop hertz counts. So I recommend 650s if you want to try this.

You will be running richer than stock in the higher airflows because 650s are larger than 616cc. But because you are fooling the ecu with a lower hertz count with the 3g maf, you will be leaner on the fuel map for most of the airflow curve. So you should be ok. Your light cruise and midthrottle fuel will take the biggest hit and be the richest as you only need 577cc fuel flow per injector to comensate for the difference of the 3g maf at these flows (22% difference in hertz count). . . So you'll get fairly bad gas mileage. It will be like running 550s with the stock maf at these times.

 

[twdorris]

The compensation going from a 2g maf to a 3g maf is fairly consistant, about between 22% and 31% difference at all hertz outputs. Most of the flow outside of closed loop sits right at 27% difference.

This depends on which set of numbers you believe and/or trust. The numbers you're referencing are the original numbers from Mitsubishi documentation. But the ECU (both 2G and EVO8) provide adjustments to those numbers, presumably based on empirical results from testing the final configuration in an actual car. I trust those numbers more personally.

FWIW, the 1G ECU does not have this separation in the code. The 1G ECU simply has as single compensation curve that's the final result. Both the 2G and EVO8 ECUs have two separate tables. The first lists out data according to documentation, the second which is applied on top of the first, is the adjustment I'm going to guess the engineers deemed necessary based on real testing in the car. Those are the numbers my figures will be based on.

Thomas Dorris

 

[dsm-onster]

AH! thank you for clearing that up Thomas.

 

[twdorris]

Not a problem. If you want to see what this compensation roughly looks like once the ECU compensations are taken into account, it's listed here:

evo8mafsettings [ECMTuning - wiki]

EDIT: BTW, Tom is fine.

Thomas Dorris

 

[byebyev8]

So basically a set of 780's or 750's with a higher fuel pressure should be able to work. The afr wouldn't be as rich as with the 835's it'd be almost in like the 11.5 afr right.

 

[dsm-onster]

No. My references were higher than they end up being in real life. As the wiki article Tom posted shows. For much of the hertz range the difference is only 19% between the 2g maf and the 3g maf. This comes to 556cc where 450s are stock.

Per his wiki article, you will be VERY lean at idle. As there sitll is a 30% differnce in the idle and light cruise airflow readings. You will need 650cc flow (-30%) for these conditions which is closed loop; and 550s (-22%) for conditions on boost which is open loop. You'll likely need an safc to get a decent drive out of this. . . You're looking at either running too lean in openloop for decent driving or running too rich in openloop and making low power.

 

[twdorris]

He may be asking about 750s on E85. Which still isn't a great option, IMO, but might work OK. You're not going to find 835s anyway. Maybe do 750s and raise the base fuel pressure to 53psi, assuming your pump can handle that base pressure plus whatever boost you're going to run.

Thomas Dorris

 

[jking29]

I have been trying to find as much info I can about the the compensation between a 1g and 3g mas. I intend on running a 3g mas with 1000cc injectors and e85 this year. I want to get it as close to a base tune as possible before starting with the afc. What kind of base fuel pressure would you suggest with this combination?

 

[twdorris]

I have been trying to find as much info I can about the the compensation between a 1g and 3g mas.

It's not pretty. Expect to find between about 50% and 65% adjustment.

What kind of base fuel pressure would you suggest with this combination?

Hard to say for sure because the MAF compensation is even less "static" in this case. If we just pick a point, say 57%, then the 1000ccs on E85 nearly cancels the MAF compensation.

MAF adjustment = 1 / 1.57 = 0.637
E85 1000cc = 450 / (1000 * 0.670) = 0.672

The difference between the two is only about 5% (0.672 / 0.637).

The problem is that we're just "picking" a point for the MAF compensation in this example. So it's sorta close at 57%, but it's not so close at 65%...

Still, I bet it'll fire up and run sorta OK just slapping 1000ccs in with E85 and a 3G MAF on stock base fuel pressure in a 1G.

Thomas Dorris

 

[byebyev8]

Yea I don't know how you guys do the math for these conversions. To my undestanding every 55 cc gets about a 10% correction. If the 3g mas runs 20% leaner and as a results needs 110cc which means 560s even it out. But on e85 you run 33% leaner and 33% more fuel is about 180cc which is total about 740cc. Thats why i thought with e85 on the 3g mas 750's would work the same as the 560s would on pump. Am i doing the math wrong?

 

[twdorris]

But on e85 you run 33% leaner and 33% more fuel is about 180cc which is total about 740cc.

I think that's the misconception/error there. E85 has a stoichiometric ratio of 9.8526:1. Which compared to gasoline's 14.7 would require 49% more fuel:

14.7 / 9.8526 = 1.49

To convert injector size for gasoline to injector size "equivalent" on e85, multiply by 0.67:

1 / 1.49 = 0.67

So running 750s on e85 is like running 502.5 cc/min on gas:

750 * 0.67 = 502.5

To go the other way, divide by 0.67. So to find the e85 equivalent of 560s on gasoline, you'd use:

560 / 0.67 = 835.8

I'm not sure where the 33% number came from, but quite a few people seem to use it. Maybe because 1 - 0.67 = 0.33. I'm not sure. This page has some details. Read through it and see if you agree with what it says.

e85fuel [ECMTuning - wiki]

Much of that is based on the wikipedia page here:

E85 in standard engines - Wikipedia, the free encyclopedia

Thomas Dorris

 

[JayRolla]

Man there was some good info in this thread. This is where a crappy safc would come into play just perfect. Just a little compensation for the difference in airflow.

 

[DSMunknown]

Just thought I should share this relative info about certain 560s.


http://www.dsmtuners.com/forums/151500768-post14.html

 

[DSMunknown]

So I'm jumping into this project head first.


Cost:

Evo 8 MAS - 80
Evo 9 560 Injectors - 103
Evo 8 MAS Harness - 15

Total - 198


So hopefully With about 200 bucks I will be able to throw on a larger turbo (I only have a 14B in solid shape at my disposal right now) and up the boost a bit with no worries. And of course, I have my PocketLOGGER right by my side too.

FTW, most of the MASs I saw for sale were around 100, but a couple people were going as low as 50. The injector price ranges from 100-150, at least from what I saw. And I could have used my existing 2G harness connector, but it would have gotten really messy and ugly.

So there you go. Larger injectors without a tuning device (but I highly advise a monitoring system). We'll see how it works out. I will also be sending out the injectors to FIC to have them cleaned and tested. At 20 bucks a pop, that adds up to an extra 80 on my bill. Hey, at least I'll be able to add a few more parts to this thread. And if this works out the way it should, then that's a much more cost effective and cost efficient way to up the boost than preceding with my previous plan.


Old Plan & Cost:

DSMLink v3 - 595 new
Used Laptop - 150 to 250 used
FIC 850cc Injectors - 275 new, ~200 used
AEM Wideband - 220 new
PLX Wideband Controller - ~175 new

Total - ~1450


The only thing I'm losing with my current plan is the forced knowledge to learn, understand, and know the system (Damnit!). But it's a price to pay in the face of the real cost in this downward spiraling market. I would love to be a part of the Link community, but I cannot ignore the dollar savings here. And don't forget the ease of installation, more fuel immediately available, and the start-up-n-go aspect. All good stuff.

 

[byebyev8]

Yea that sounds good. Only thing though is that your most likely going to run a little rich around 9.1 afr which would make you lose power but the timings going to be alot more agressive so it might even itself out. Dsmlink or a chip would definently make more power though.

On the e85 setup with 750's the wot afr would be somewere around 10.3.1-10.6.1 with stock 2g fuel pressure (43psi) and be between 10.6.1-11.1 with 1g fuel pressure(37psi). If my math is correct.

The lean idle and cruise can be offset a little by runing the stock fpr and letting the 255 overun it.

I'm going to experiment with this setup and see if its works ok. Its kinda crazy how all of these problems can cancel each other out though. I think using this setup would be equal to running a safc without a wideband. But i might just get a eprom and keydriver chip depending on how it runs.

 

[DSMunknown]

I haven't logged anything yet, but there is no trouble so far with my Evo 8 MAS and injector swap. I simply keep turning up the boost on the 14B and have fun.

 

[habitatguy187]

Wow what a thread! I 've learned so many new things here, and still have lots of questions. Even more so I have worries now....


Right now I'm running 550s and 2gmas in my 1g. I just bought a set of 750s and I was going to throw them in and run straight e85, but now it looks like I can't. I still don't understand the math, from everything I've read before today e85 requires ~30% more fuel, which would make 750s a little rich (30% bigger than 550s are 715s) So I figured I'd be rich and fuel trims would help for it at cruise, and I'd be rich under WOT rich would keep me safe for now.

What I don't understand is exactly how much more fuel do you need for e85???

What is the stock afr for a 1g at WOT - I know it's super rich and maybe I would be safe because of this?

Worse case scenerario how would it react to a 1g auto fpr with the higher base pressure?