A/R Edumication

[DrBrown]

I have read TONS about A/R's and compressor flowcharts. The one thing I still dont get out of all of it is what to use hehe. I dont have a i4 Dsm, but a 2.5L mazda V6 rather. I have a T3 (48 hot/60 cold) on it now and this thing just spools WAY too fast for my engine. I max out peak power around 4700 rpms and on the freeway its even worse how fast it spools up. So I am looking into buying something like a hybrid T3/T4 with a 63 AR exhaust housing with a stage 3 .63 turbine wheel and a T4 50 A/R compressor. I know that this thing will outflow my current turbo 10 fold. But I just wondered if you guys have used a high flow stage 3 turbine wheel yet because I am thinking I wwouldnt be able to get much boost until after 4k RPM where now I am almost at max by then. Have any of you used a turbo this big and do you think it would be a bit too much for a 2.5L high compression high flowing 24-valve engine? Only reason I post here is because you turbo guys know 20 times as much as the probe community since there are less than 100 or so turbo PGT's in the US Thanks ahead of time. All comments welcome and appreciated!

Dan

 

[DSMJim]

I have that turbo on my car now. T3/T4E 50Trim .63A/R Stage 3 exhaust wheel. I get 20psi by 4000rpm at the very latest in the worst conditions. My car is a 4cyl 2.0L so your car would still spool that turbo quickly, but would not max out the power like you are now. You would probablly with proper tuning get full boost by 3500rpm but you would be able to hold whatever power you want all the way to redline. This turbo is rated to over 400 WHP on a DSM so I'm sure it will suit your needs nicely. It will make a whole heep more HP from the start of boost until redilne compared to the turbo you have on your car now, no problems.

One thing you will need for a turbo that large is more fuel. I'm not sure what size injectors come on your car probablly 230cc or less but a set of 310cc from fuel injector clinic and a APEXi SAFC would do wonders for the fueling on your car.

The 50Trim will pump double the CFM at the same PSI and RPM that your little turbo is doing now. You have whats called a T3 Super-60 which is a great turbo for low HP small displacement engines, not great for a 2.5L motor.

Hope that helps a bit.

 

[DrBrown]

This is EXACTLY what I wanted to know. Thanks a bunch! If you can spool yours that quickly my high compression and bigger displacement should carry this turbo to MUCH more power than my T3. As far as fuel I have a 255l/hr fuel pump and a 12:1 FMU. My car is safe to run about 7-8.5psi w/out worrying too much about detonation or running lean. I will most likely run it at about 6 psi to be safe. I know dick about those s-afc deals. Can you actually control how much fuel the computer dumps in the engine?? Cause that would just be awesome to adjust teh a/f on the fly like that.

Thanks for all the info. BTW, nice looking eclipse you got there Jim

 

[a351must2]

A lot of the 2.3L Ford guys run the stage III 0.48A/R turbine wheel with the 50 trim T04E compressor and claim the same spool-up as a .63A/R T03 with the .60 T03 compressor without the loss of high rpm exhaust flow. We're only talking in the range of 400rwhp though out of a 2.3L 4cyl though...

 

[DrBrown]

Yes I agree for a low compression 2.3L 4 cylinder thats most damn impressive! For its time the 2.3 engine was pretty cool in stock form. Bod I love boost. I dont know if I can ever own a N/A car ever again!

 

[DSMJim]

Originally posted by DrBrown
This is EXACTLY what I wanted to know. Thanks a bunch! If you can spool yours that quickly my high compression and bigger displacement should carry this turbo to MUCH more power than my T3. As far as fuel I have a 255l/hr fuel pump and a 12:1 FMU. My car is safe to run about 7-8.5psi w/out worrying too much about detonation or running lean. I will most likely run it at about 6 psi to be safe. I know dick about those s-afc deals. Can you actually control how much fuel the computer dumps in the engine?? Cause that would just be awesome to adjust teh a/f on the fly like that.

Yes it does control the amount of fuel dumped into the engine. It tricks the signal from the mass air flow sensor or MAP sensor and makes the car think there is less or more airflow causing the comptuer to add or take away fuel accordingly. Your FMU is good 12:1 is a good rise, good about the 255lph pump. Have you ever put your car on a wideband to see what your AF really is? You will likely notice that it needs a bit of fuel here and need to take some away there to make the AF smooth across the whole RPM band. That is exactly what the SAFC does, just add a few percent here and there and away you go. It's best tuned on a dyno but street tuning is totally possible and works well.

Originally posted by DrBrown
Thanks for all the info. BTW, nice looking eclipse you got there Jim

It's a Talon but thanks non the less!

 

[DrBrown]

Well I checked with my other fellow probe community ppl and they have confirmed we cant use the AFC's. Reason being our cars dont have a MAF, we have a Vaccum Air Flow sensor and our ECU is programmed to provide 6 different signals for the fuel. One individual signal to each injector, so I would have to buy 6 AFC's to get my car to run smooth on a dyno plot . This is why you shouldnt turbo cars that were never meant for this kind of thing I really hate Ford & Mazda sometimes!

 

[DSMJim]

Hmm. Never heard of that. I know we use AFC on other Mazda cars with no problems...

 

[spac3y]

Well I checked with my other fellow probe community ppl and they have confirmed we cant use the AFC's. Reason being our cars dont have a MAF, we have a Vaccum Air Flow sensor and our ECU is programmed to provide 6 different signals for the fuel. One individual signal to each injector, so I would have to buy 6 AFC's to get my car to run smooth on a dyno plot . This is why you shouldnt turbo cars that were never meant for this kind of thing I really hate Ford & Mazda sometimes!

I'm kind of confused why one would need 6 afc's. The afc modifies one signal coming in (from the maf/map/etc..) and sends that to the ecu so it thinks more/less air is flowing through the engine. On a DSM ecu there are 4 outputs for injectors (one output per injector). I'm guessing this is what you're talking about when you say the ecu provides 6 different signals. The number of injector outputs should have no effect on the afc other than you will need to set the number of cylinders on it. You will only need one afc, but you need to find out if it supports the type of airflow sensor you have, or if there is a way to convert to a maf/map setup to use an afc with it.

Exactly what type of car do you have? I'll see if I can dig up some info on the sensor issue...

 

[DrBrown]

Basically what they are telling me in a nuttsehll is the afc works wonders for you gus and other stock turbo engines. But on our ECU's nobody knows how to reprogram them for boost applications. There is no way to make our ECU's understand the extra incoming air along with positive manifold pressure. Even when the afc can modify the fuel sent our ECU's are designed to take over and go into a default"dunny or safe" mode and then just runs strictly off of the o2 sensor readings. Which is not good because the computer will then continue to incredibly lean out the mixture to compensate. Most of the HP boost ppl in the PGT community say they work great on like 3 psi or spraying but 6+ psi is too much for our ECU to comprehend and there is only one other way to trick the computer. And thats running off the TPS and making it dump fuel in accordance with the VAF and how much the spring inside moves. Cause this is what tells our ecu what amount/volume of air is coming in. Its just not a good design to start boost with. All I can hope for is there is one guy who custom programs KL03 ecu's for big money. But I am a budget racer . :shrug: Thanks for the help though! God this was long....soryy

 

[kpt4321]

You can never have a turbo that spools too fast. I think your problem is that the turbo cannot flow enough air at higher rpm's, so power is tapering off where it should not.

DSMJim, a 50 trim will not flow twice as much air as his turbo. No way. Not possible. I don't know where you came up with that, but it is not going to happen, unless his turbo has a maximum flow of something like 25 lb/min, and he is flowing that much at every rpm and boost level.



....Kyle T.
93 TSi AWD "TURBO4"

 

[spac3y]

Ahhhh....My head is stuck in turbo land where my dsm ecu is meant to be boosted, and doesn't fight (too much ) with having the boost turned up. In a situation like that you would be looking into some kind of stand-alone ecu, but I'd find one that has some kind of base map to use, and make sure you have some free time and money to spend with it.

 

[spac3y]

You can never have a turbo that spools too fast. I think your problem is that the turbo cannot flow enough air at higher rpm's, so power is tapering off where it should not.

That makes sense.

(although for us fwd dsm guys I've heard a fast spool can lead to traction problems...)

Oh well, a reason for a bigger turbo!

 

[DrBrown]

Originally posted by spac3y

Oh well, a reason for a bigger turbo!

WERD! The 2nd Gen Probes were still FWD and mine has terrible traction cause I get full boost by about 2300-2500 rpms which I am only running 8 psi. SO it spools way too fast and its out of power by 4500. A stock 48 turbine in a smallish 48 housing is too small for a 2.5 V6.

I somewhat agree that I could have more top end with a huge T04E 60 compressor but its not detremental! I am not trying to get a great dyno car, just an all round fun fast car for the track and the ocassioanl ricer in his b16 waiting to be blasted! So as long as I get into the 13's with full interior I will be fairly happy, then I can pull a few seats & carpet out and get mid 13's. FUN FUN. Thanks gents!

 

[ItsStockOfficer]

Dr....You can use an AFC on anything. It has setups for 4 different air mettering systems...Karman Maf, Hotwire Maf, Flap and Speed density(Map sensor). This includes your car. You only have on air flow signal and thats what it modifies. The pre ecu signal, not the post ecu injector signals. Dumb probe community


And you will pick up about 50 hp when you ditch your fmu. They ####ing are garbage. Think about this: 40 psi base pressure + 8psix12 =136 PSI! You think you injectors are giving you a qaulity spray pattern or consistent results at that kind of fuel pressure? You NEED to get big enough injectors to flow the fuel you need at under 60 PSI fuel pressure for a smooth a/f and good numbers/driveability.

Sean

 

[DrBrown]

From my experience FMU's dont raise the the base fuel pressure 12:1 in my case. Originally teh base fuel pressure was 40 psi and I was getting 5 psi when I first started out and I was only running around 90 psi of fuel. As far as injectors, there is only one real upgrade for our engines and they are only 280cc mazda millenia injectors. As far as the AFC it wont work because you have obviously not tried to reset a probe computer When our ecu see's something unusual like a mass amount of air it over compensates by changing the o2 readings, which then makes the car dump more or less fuel in accordingly. The afc is great for N/A probes because the readings the computer sees are not all the different. Whereas my ecu is saying WTF????? And it actuallly worked on some of the turbo probes until about 4500 rpm's then the ecu ignores the afc and still chagnes the fuel map. So there is not much I can do other than use an FMU because I have no alternate way of adding more fuel I hate probe engines

 

[idt512]

how about adding auxillary injectors such as an SDS EIC or Haltech F5? those dont tie into the factory management and wouldnt disturb it all.

 

[a351must2]

I vote SDS at that point...it sounds like the Mazda computer either is a Ford EEC, or operates like a Ford EEC. Either way, the computer uses tables and therefore cannot be tricked into doing good things without burning a new chip for it. The SDS has become pretty popular among 2.3L Fords as well...easy to tune and very effective, plus you can ditch the "Vane Air Meter".

After looking at the rest of the responses on here, I would say that a .63 Stage III exhaust turbine with a 50 trim would probably be about right to keep it from spooling too early (for the sake of traction)...the .48 Stage III sure seems to handle the big T04 compressors well though. I'd get someone that can read compressor maps or has experience with your application to choose your compressor though.

BTW, I run a stock 0.63A/R turbine with a GN compressor (about equivalent to a 46 trim T04) and to me, it spools late with only 10psi at 2800rpm and 20psi by 3800rpm on a 2.3L Ford with some major porting. I know of guys with the 50 trim being full spooled around 3000rpm with the .48 Stage III.

 

[DrBrown]

This is some really great info, thanks!

BTW, what does SDS stand for? I know there have been like 2 or 3 turbo PGT guys use it but they never commented about it on our forums. So I have no idea what it really is, and searching on probetalk got me ZERO results. Thanks again - Dan

 

[ItsStockOfficer]

Originally posted by DrBrown
From my experience FMU's dont raise the the base fuel pressure 12:1 in my case. Originally teh base fuel pressure was 40 psi and I was getting 5 psi when I first started out and I was only running around 90 psi of fuel. As far as injectors, there is only one real upgrade for our engines and they are only 280cc mazda millenia injectors. As far as the AFC it wont work because you have obviously not tried to reset a probe computer When our ecu see's something unusual like a mass amount of air it over compensates by changing the o2 readings, which then makes the car dump more or less fuel in accordingly. The afc is great for N/A probes because the readings the computer sees are not all the different. Whereas my ecu is saying WTF????? And it actuallly worked on some of the turbo probes until about 4500 rpm's then the ecu ignores the afc and still chagnes the fuel map. So there is not much I can do other than use an FMU because I have no alternate way of adding more fuel I hate probe engines

If the ford comp was seeing 10% less ar, or more air, how would it know?

 

[kpt4321]

Agreed. A properly used AFC should work fine. The ECU does not know that you have an AFC.

All you do is, for example, get 40% larger injectors, and then decrease the airflow signal 40%. The ECU stays happy, and you retain the A/F ratio you want.

However, I would wonder where the flow limit of the flapper MAF is. You do not want to reach that point, because then air metering would become non-linear.


.....Kyle T.

 

[kpt4321]

Agreed. A properly used AFC should work fine. The ECU does not know that you have an AFC.

All you do is, for example, get 40% larger injectors, and then decrease the airflow signal 40%. The ECU stays happy, and you retain the A/F ratio you want.

However, I would wonder where the flow limit of the flapper MAF is. You do not want to reach that point, because then air metering would become non-linear.


.....Kyle T.

 

[DrBrown]

You can count the number of people that did a vaf to maf conversion on one hand and have fingers left. Its just too much work because these damn ecu's are so stubborn. They constantly overide and update the signals. For example you will see my fuel pressure change within 1-2 psi after driving around for a while. And the A/F ration changes a lot on long drives as the o2's start leaning out the mixture.

Anyway I know of 3 or 4 people that are the true pioneers in the probeland and they all had afc's at one point then sold em and bought better turbos and injectors cause they weren't working out. And some of these guys had their cars/kits tuned professionally. Yet they still werent able to get it to work. For my purposes I dont care I just wanna get more power with a reasonable amount of boost, and w/out injectors of some sort I am stuck on 7-8 psi. Till then I will be slow and run my 260 whp probe down the road . I mean how much power do I need in a daily driver????

 

[ItsStockOfficer]

Then they were doing it wrong, and how can your ecu affect fuel pressure?

Sean

 

[DrBrown]

I think it changed the fuel pressure because the ecu leans out the O2 sensors to even the a/f mixture. In turn the ecu forces the FPR vaccum sensor thing to change which allows more fuel to enter the rails. I think thats it in a nuttshell.