MightyMouse

I've been using this forum for about a month now and it seems at some point or another turbo owners more or less go through the same growth pattern before finally ending up MSPNP'ing their cars. Well I'm at the point where I've Uprgraded my 1.6 Fuel pump to a 255lph, upgraded my injectors to the 1.8 stock injectors, 2.5 Intercooler, Bipes, AFPR, BOV, 16g turbo, 2.5 Down pipe, dual exhausts and in a couple of weeks an Old Guy O2 clamp, all of which I've learned about from this very forum (Thanks All)......My question is this Can 10psi be a realistic goal with this set up?

Braineack

iTrader: (62)

read my faq in diy section.

wes65

iTrader: (7)

heh, how did i know that was coming?

Saml01

iTrader: (9)

Turn up the boost and find out for yourself.

FHS

iTrader: (2)

Don't do it.

MightyMouse

I have to say though I've received sound advice and information off of this forum, there are many who are for a lack of a better word present themselves as obtuse.

MightyMouse

FHS why do you suggest I not?

Saml01

iTrader: (9)

Probably because you don't have enough fuel.

FHS

iTrader: (2)

...because you don't have enough fuel.





















Trust me.

Saml01

iTrader: (9)

For a second I thought you had the stock injectors. Those are only good to like 8psi with a AFPR.

So just do it, or whats the problem?

samnavy

iTrader: (7)

I ran 130psi of fuel pressure on 1.8's and was rich at 12psi. Of course it's not recommended to run anywhere near that much fuel pressure on old-*** fuel lines, but the injectors don't care. I don't know what the 255lph specs out at, but I've gotta assume it's good to 100+psi at least... which should be enough for 10psi on 1.8's.

I think he's got plenty of fuel if he can stomach the pressure.

Mightymouse, you need a fuel pressure gauge so you can do the math and tune your AFPR appropriately, or you need a wideband. It would also be a good idea to upgrade to 300+cc injectors so you can get the fuel pressure down.

What are your Bipes settings? With 93octane, you should be fine with 14* base, pulling 6-7* total.

FHS

iTrader: (2)

I guess I couldn't stomach the fuel pressure so it didn't take me too long to upgrade my injectors. Then, I couldn't stomach the crappy gas mileage.

Braineack

iTrader: (62)

i didnt write the faq for nothing.

paul

iTrader: (21)

bigger injectors don't give you crappy gas mileage, poor tuning does. i run 460s in my 271hp 94 and the mileage is the same as it was before it was turbo'd and same as my other 94 NA, 27mpg

ApexOnYou

iTrader: (10)

Dude you'll be fine at 10psi, I ran 12psi with bandaids on tan tops with no problems. Just be careful, step it up slowly and pay attention to everything

MightyMouse

Braineck I was actually not referring to your reply, though in the past your responses can often carry an air of elitism. Yet I suppose if you get the same questions time and time again one get's irritated.

Newbsauce

iTrader: (2)

Your supposition is correct. You should be good to go, just keep an eye on your air/fuel. Don't end up being stank nasty rich.

samnavy

iTrader: (7)

Mightymouse, you can get only get away with ZERO tuning tools for so long. Most guys on bandaids simply install a fuel pump, and turn their AFPR up all the way and drive... and run retarded rich. That's fine at 5-6psi Turning up the boost will only raise your fuel pressure more, and while there's more air, it's still playing with yourself. You're giving up power by running rich... and if your AFPR isn't working properly, or your fuel pump isn't up to spec, you might be running lean already and the move to more boost will simply blow your motor.

BUY AN LC1!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!
or at the very least, get a fuel pressure gauge. It's super easy to tap one into your fuel feed line, especially if you've gone dual-feed.
https://www.miataturbo.net/forum/sho...1&postcount=24
Here's the way I did it so I could see the gauge while I was driving and tune that way. If you leave the engine bay, you've gotta put it on a dyno to check your pressure under boost... which isn't a bad idea anyways if you're not buying a wideband.
Here's another thread:
https://www.miataturbo.net/forum/showthread.php?t=9645

Here's my original "removable" fuel pressure gauge and instructions on how to tap the rail:
https://www.miataturbo.net/forum/showthread.php?t=4948

brgracer

iTrader: (14)

Band-aids will work, but you are taking a risk running such high fuel pressures. I did it with my old GReddy, AndyFloyd did it with his setup, Braineack did it with his old setup, and lots of others have done it as well. It's not a question of can it be done, but how long can it be done safely.

Aside from locking an injector, running lean, and blowing the engine, your next biggest issue with AFPR/fuel pump/stock ECU is that you will be following the stock fueling curve that once in open loop goes very rich so I hope you like a black rear bumper. Some peeps have used the RX-7 AFM to try to adjust the fuel curve up top a little as well. YMMV.

FHS

iTrader: (2)

You are absolutely correct. I just couldn't figure out how I was supposed to tune my Bipes, AFM, and FMU to run 10 psi with 305's and get decent gas mileage at the same time. So, I ran out and picked up an EMB instead. My last roadtrip running at 10 psi, before I stripped my set-up, I got 34 mpg.

I suppose I could have just suggested dumping the band-aids at the start, but that wasn't his question. Having done what he wants to do now, my suggestion is not to do it.