Hey everyone, I am the proud new owner of an xB (well, in about 2 weeks when it comes in).
I have some experience installing turbo's on VW's and Ford Escorts. My problem is all those cars had return fuel lines. One the newer Toyota products, they don't which means I can do what I have been doing for fuel.... installing vacuum/mechanical FMU's.
So my question is how is the extra fueling accomplished on the non-return line cars like our Scions. Do I need to get an AFC computer deal, I forgot exactly what they are called? I also imagine I need to get bigger injectors, or a 5th one like I did on earlier VW's.
If anyone could help with these questions, it would be great. I know how to do everything else, I just don't know how to work this non-return line fuel system. And I dodn't want to pay $2500-3500 for a turbo kit when I have a turbo and an intercooler from a previous project to use here.

 

Generally the same way as those with fuel return lines, except the fuel pressure regulator is at the tank rather than the end of the fuel rail, this started on all cars back in 1995 with the release of OBD2.

Being that its a mass air system, it should compensate for certain modifications up to a point. The japan version of the trd turbo uses the same injectors. Not 100% positive, but I'm pretty sure it has 440cc stock, good enough for over 160hp. I honestly cannot imagine going above that without going to a stand-alone EMS like a haltech or similar.

A super AFC would work, if you went to a larger injector than stock. You can then lean out the mixture so the factory computer doesn't go into limp mode. Other than that, there is little use for them, I honestly consider them a band-aid when stitches are needed. If you've ever seen a car with three or four piggyback's present you know what I'm talking about.

Mike

 

Agreed. SAFC only for big injectors to lean out the mix.

Extra injectors seems like what everyone is using however.

 

i doubt this lil ol 1.5l engine uses 440cc injectors...especially since its an economy engine. im thinking the injectors are around the 250cc area. ive seen hondas with 440 cc injectors dyno at 300+ hp. once i see what kind of fuel setups other xb w/ turbo kits are using, then ill start planing on putting together a turbo setup since i have experiences with honda turbo systems. otherwise...if revhard or greddy kits become street legal, then ill go that route. but who knows when those turbo kits will be out....theyve been working on them for a while now.

 

I know what you are saying about how it can compensate for some mods. but I'm looking for serious power. 160 would just be for starters.... lol If you are right about it working similar to return line cars, then I think I can figure it out.

By the way Mike, when we gettin our cars... lol

Chad

 

if i remember right i think they were 200cc

 

yeah, I don't know what car board I was thinking I was posting on with that one. 200cc injectors would be the correct size, good for about 170hp.

Mike

 

Returnless isn't a big deal....

There several ways you can fab up a return style system. I don't care for them, but for those seeking alot of power on a budget are welcome to try these methods.

Otherwise you can use a piggy-back system like the PSC-1 offered by Split Second, being used on several other forced inducted project on Toyotas floating around the net, including superchagred Matrx and Toyota pickups and 4-Runners.

www.splitsec.com

With that you can run larger injectors and replace the MAF sensor with a 2.5bar MAP sensor and that will allow you up to 20+psi of boost.

You need a larger pump...

With the PSC-1 you'll be able to lean out the injectors enough to run 48lbs injectors (500+cc) and with a decent amount of rail pressure, have enough fuel for 300hp, even with the smallish 1.5L engine.

Walbro should be able to provide you with the in-tank pump you need.

Injectors from RC engineering should cover that part.

PSC-1 goes for $265 and since the Scion is tuned to run on 87 octane you most likely won't need any igntion retard as long as 91 or higher octane fuel is used.

 

hondas that do custom turbo kits, most of the time use 440cc DSM injectors form the turbo talons or eclipse's. I wonder if a set with fit on the scion motor.

What fuel pump would work?( from a diff car or aftermarket)and sam question for FPR...