danny951

Can't remember if I already asked... I called Majestic Turbo in Waco and asked about getting a k27 turbo using my k26 core. He said due to the expense of the k27's he'd recommend using Garret parts (57 series??) on my exhaust core. He said for $850, he could do the job and I could expect 325 - 350 RWHP!

Asking some other turbo (non P-car) friends, they mentioned that my fuel system probably couldn't handle that kind of air and I'd run very lean. So I am turning to you guys... What, if any, mods would be required on my fuel system to balance the extra air from the new turbo. Things I've thought about are:

-new chips.. custom or ??
-adj fuel pressure regulator.. how much can I go on stock injectors?
-piggy back type air/fuel controller (I think I'd go with the Apex'i S-AFC)

Would I HAVE to change the injectors? I mean, sure we would all probably benefit from it, but would I have to do it to keep my motor from predetination since I'd have a higher volume of air coming into my motor?

Thanks for any help! I am very excited about getting this much HP from this...

Luke

our 37lbs injectors are rated kind of funky and i understand that they actually vary in size quite a bit. I was told that some are more like 45lbs, so it will depend on the car. I dont think you'll be able to maintane a decent A/F ratio past 310rwhp on stock injectors. You'll need an adj. FPR to do that, im sure.

danny951

So I could keep the stock injectors and just use an adj FPR? (is it true??) Those are cheap right?

what about chips? A necessity?

Jeremy Martin

if you want 350, you'll need alot. new turbo, a MAF, new (or shimmed) wastegate, new injectors, a 3 BAR fuel pressure regulator, and some kind of adjustable boost controller (although an electronic boost controller would be the best bet). if you do it right, you're probably looking at at least $4500 in parts alone. and make sure your engine is strong... you dont want to run that kind of boost all day, particularly if your engine is going on 100,000 miles since a good rebuild.

Jeremy Martin

oh yeah, and chips, but that goes without saying. the best bet is to have some palace like speed force racing burn you a set of chips that's tailored to exactly what you've done to your car... and if you can dyno it and keep tuning the chips it's even better.

danny951

Why would I need an MAF? I think lots of people think they need all this stuff, but I'm not going for the fastest car in town, just fast enough

If this new turbo can give me enough air, I don't see why I couldn't get 350 HP, the only question is how do I get .. or will I have enough fuel to run with that much air? Say 15 psi.. which isn't much more PRESSURE, but with the new turbo.. would be a lot more VOLUME of air. then get one of those guages like on ebay that measures the fuel pressure using the adj pressure regulator.. seems like it should work.

Just wondering if I'll be okay with the stock injectors.. Can anyone tell me how much fuel you can push through our injectors?? 86 model specifically if it matters.

Instead of chips though.. I think I'm gonna get the S-AFC. It's got much better resolution than the ARCII.. Then hopefully I'll catch a local dyno day and get it all smoothed out and tuned properly.. See if I can get over 325 at the wheels.. <img src="graemlins/bigok.gif" border="0" alt="[thumbsup]" />

adrial

I'm pretty sure you'll need bigger injectors...but hey why not try it, start with the boost cranked WAY down (like 7psi) and see how it runs. You could pick up a wide band O2 sensor for $350 or something these days..(same thing the dyno places use).

Danno

Yeah, I ran out of injectors at 12psi and 290rwhp. This is roughly about where a lot of people hit the limit of the stock injectors as well. There are some that make more than that. I suspect that the stock injectors actually came in different sizes, although they have the same part# on them. I've seen two flow-charts from RC-Engineering, both showing the same part#, but the flow-rates between the two sets was different by about 50% ! Bizarre....

Luke

yeah, I have seen 290 on stock injectors and I saw a 330 on stock injectors. Both maxed out?!?!?

Ahmet

Remember what year cars those different injectors came from?

If indeed the flow rates are different, perhaps they were higher in 86 (would make sense with the con-rods being stronger and the tranny cooler standard, etc.), or with the turbo S and 89 model year cars, which would also make sense because of the larger turbo, different DME mapping etc.
Ahmet

Danno

No, I'm talking about with ALL the variables being the same, or ALL the variables removed, the injectors are still different. The case I'm talking about are with two sets of injectors that's been removed from the cars and tested by themselves. In this controlled environment, they flowed vastly different amounts of fuel:





Notice that the Bosch part# is the same for both sets. Sure the test pressure is different, but let's re-calculate what Tony's injectors would be at 43psi:

Which doesn't come close to Tom's 366cc/min.


Or if we reduce the pressure in Tom's test to 36.25psi we get:

Which again, isn't anywhere near Tony's 262.8cc/min rating.
No one has been able to decipher this riddle and the empirical field-data appears to support this inconsistent injector sizing as well. Some people (Ian Manning, Russ Murphy?) ran out of fuel at around 290rwhp like me. Other like Luke or John Anderson have gotten much more (400rwhp in John's case). Luke doesn't count because he's got a special one-off top-secret-agent car that defies all logic...

Ahmet

That's really interesting... I'm shooting for about 300 hp in the short run but my injectors aren't in the best of shapes. I don't plan to ever pursue over ~370hp (crank) can't decide if I want to buy new/larger injectors or not.

With the wastegate disconnected, I recorded a 5 second run to 60, and to 100 in about 9.6. Car has chips and a 3 inch turbo back open exaust (muffler goes on this week). I must've been running quite lean, because with all the vacuum problems fixed, and the wastegate connected I'm only making about 9.5 psi. I just put in an air/fuel gauge, and boost gauge. Disconnected the wastegate, and I will see what it does then. I will probably end up jetting the banjo bolt, and shimming the wastegate, and getting an adjustible FPR. Will probably track it a lot with that set-up for at least 6-8 months, and see what I want to do then...

ANYWAY, I'm sure you've noticed the differing information for the 'injector type' field. Wonder the significance of that? How'bout the field for 'SDTF'?

PS: Yeah, I agree with you on Luke's funny car...
Ahmet

danny951

I guess I can only hope I've got the "bigger" injectors.. we'll see. On my list of do's is the new turbo, adj FPR and 3" turbo (downpipe) back straight through exhaust.. oh and the S-AFC so I can get an idea of my AF ratio.


CANT WAIT!

Luke

[quote]Originally posted by danny951:
<strong>I guess I can only hope I've got the "bigger" injectors..
CANT WAIT!</strong><hr></blockquote>
Same here

David Floyd

Why take a chance with stock injectors, if you are investing in upgrades ( Turbo, MAF ) new injectors 52,55 or 72 lbs are only $360, good insurance IMHO

<a href="http://www.injector.com" target="_blank">www.injector.com</a>