Turbo questions..Map bypass valve, fmu's, etc?

[Inagawa]

Hey, so i'm turbocharging the 4afe "first Gen", and was reading about our map sensors not going past 8-10psi of boost and issues with the gm map sensors.

so i was wondering would it work with a Map bypass valve? "Blox",

according to the ad: "The BLOX Racing MAP Bypass Valve is designed for use with forced-induction applications.
The MAP Bypass Valve completely blocks boost from reaching the MAP sensor, thus simulating a wide-open-throttle reading at the vehicle's ECU. The vehicle is then prevented from running in "limp" mode so that no check-engine light appears. The end result is protecting the MAP sensor from being damaged.
MAP Bypass Valves are available as internal or external units."

i have a 38mm wastegate with a 8psi spring, does this mean that i can't go past 8psi of boost without changing the spring out?

will 8 psi be too much with a T3/T4 .63 trim turbocharger on the 4AFE?

i have 450cc injectors, is it too much fuel? max boost i want to run is 12psi...

is a 14point7 piggyback controller a good fuel controller? i don't have money to afford MS, Greddy, and barely enough to buy a used SAFC.. i do plan to get it professionally tuned though.

could i use ARP rod bolts from a 4age for first gen 4afe's connecting rods?

should i run a wideband/egt especially for tuning or it's not that necessarily needed?

is a walbro 255lph fuel pump overkill? even if i use a fuel pressure regulator?

Thanks in advance, i just wanna make sure i'm not screwing up my pride and joy car, lol..

[Evo_lucian]

For "protecting" your map sensor just get some check valves from your local aquarium supply place and place it inline with your map sensor vacuum line.

8 psi wastegate spring means your wastegate will open at 8 psi so to run more than 8 psi you will need a high pressure spring or a boost controller.

I think you have your numbers mixed up . The .63 you are referring to is the "AR" of the turbine wheel. If you ever had a "63 trim t3/t4" you will almost never spool that on a 4afe. Find yourself a t3 from a ford thunderbird or dsm t25 , it will suit your 4afe better.

450cc injectors will give you about 280 whp before it maxes on stock fuel pressure.

The 14point7 uafc looks good on paper if you are on a budget.

No idea if 4ag rod bolts will work, but I can tell you stock bolts will be fine.

A wideband and egt guage are useful tools but if yo intend to have the car professionally tuned then its not a necessity but the wideband is useful to have.

255 or 190 lph pump will be fine on your set up.

If you on a budget I would just do a t25, 14b, or small t3 turbo on stock injectors with a fmu and walbro 255 lph pump and keep boost under 10 psi

[bakwoods]

Originally Posted by Evo_lucian

A wideband and egt guage are useful tools but if yo intend to have the car professionally tuned then its not a necessity but the wideband is useful to have.

If you on a budget I would just do a t25, 14b, or small t3 turbo on stock injectors with a fmu and walbro 255 lph pump and keep boost under 10 psi

I hate to disagree, but a wideband is a MUST when tuning. It's a lot easier to see your A/F ratio on a gauge then guestimating by hearing the car running. You can street tune a car yourself. I've done it and it's not hard to do. TunerStudio is a fairly straight forward program that works with most piggy back or standalone ECUs.

For that small motor, a 50 trim would probably be best. Obviously FMI, fuel pump I'd upgrade and 450cc injectors would probably be more than enough. High impedence injectors would be required for this. I know Subaru has good 450cc ones, I think they're the light blue ones.

Keeping boost under 10 psi is a good idea because you're not sure what to expect. Start off with a low wastegate spring 8psi probably and get a manual boost controller and turn it all the way down. Once you get a good base tune, then increase the pressure.

[Evo_lucian]

Originally Posted by bakwoods

I hate to disagree, but a wideband is a MUST when tuning. It's a lot easier to see your A/F ratio on a gauge then guestimating by hearing the car running. You can street tune a car yourself. I've done it and it's not hard to do. TunerStudio is a fairly straight forward program that works with most piggy back or standalone ECUs.

OP already stated that he wants to have the car professionally tuned. No need to buy a wideband if you not gonna be doing the tuning yourself. Disconnect charge piping to intake manifold, and drive the car to the tuner so he can tune it . Street tuning is not rocket science but some people just prefer to leave it to a pro.

Originally Posted by bakwoods

For that small motor, a 50 trim would probably be best. Obviously FMI, fuel pump I'd upgrade and 450cc injectors would probably be more than enough. High impedence injectors would be required for this. I know Subaru has good 450cc ones, I think they're the light blue ones.

50 trim would spool really late on a tiny 1.6. 48 trim better suited IMO. High impedence are not mandatory. You can always add a resistor pack if your injectors are low impedence . I agree, Subaru injectors are really good. They can be decapped to flow around 750cc .

[bakwoods]

Only reason I suggested street tuning, is because it's a cost savings. I know those tuners charge over $500 to do a dyno tune. At least in my area they are uber expensive which is why I learned to do it myself.

While high impedence are not mandatory, are the stock injectors high impedence? Hence why I figured it'd be less work to stick with something that is less work.

Agreed, Subaru injectors can be 750cc, but aren't those the pinks which are 620cc to start, but decapped run 750cc. I'm not certain, I'm just pulling at straws. I figured a 48 trim might be a good size, but there's a turbo calculator online that you can use to figure roughly the right size. I know 50 trims are run on 2.0L DSMs but I figured the 1.6 is pretty peppy and will spool up just fine. I think it all comes down to trying it out and seeing the difference.

My logic was always running a slightly larger turbo just because as you build the block, you have wiggle room. I ran a 60 trim on my 2.0 and it spooled pretty good. Hence why I figured 50 trim would be good on the 1.6...who knows lol.

[kwint]

Couple threads for ya.

http://forum.9000rpm.co.za/viewtopic.php?id=7888

190whp 4afte!

http://www.6gc.net/forums/index.php?showtopic=51572

Good luck

[Evo_lucian]

I agree with you and I am a strong believer in DIY especially when it comes to tuning. Even if you don't fully tune the car yourself , you should at least be able to get it to idle and drive around. That way if for whatever reason something goes wrong with the map you can do a lil till you visit a tuner.

01-07 pink sti injectors flow 565cc stock IIRC and Light blue wrx injectors flow 440cc both of which can be decapped to flow 750-800cc.

50 trim t3/t4 spool in the mid to late 3k rpm on our 3sgte's, when you take into consideration the smaller 1.6 4afe with the 6300 rpm redline, you looking at a 2-2.5k rpm powerband. The dynograph will be peaky and the turbo will surge. I agree that you should buy a turbo with a lil wiggle room but in the end after you build the block it will still be a 1.6 with a shitty flowing head. Picking a turbo that suits you goal is a wiser choice than buying too big of a turbo and hoping to grow into it IMO. Even a 46 trim is on the bigger end of turbos for a 4afe IMO.

Take it from a Gen 3 3sgte owner , lagg is over rated. I make 17 psi (full boost) some where in the early to mid 3k rpm but power feels sorta flat after 5k and I find myself shifting at 5500 most of the time . I will happily trade 1k rpm of lagg for some more top end.