Injector Sizing Opinion/Help

[WikdTSi]

In my quest to run the smallest injector for my application, I am unsure what to step up to now.

Current Mods:

2G Pistons
Heavily ported/polished head with SS Valves w/3 Angle Job
Heavily Ported 2G Exhaust Manifold
VP 2.5" 02 Housing w/ Ext. Dump
3" Turbo-Back
2G Mas *honeycombs in* w/ stock 2G Snorkel
Big 16 in 6cm housing *also very ported*
Spoolinup AFPR @ 43PSI
RC 550's
Walbro 255 RE-wired with #10

Through previous logging, It was determined I am running out of fuel
550's are 98%+ by 15-16PSi

I can turn up the FP to ~50 as a band-aid I'm sure..but I plan on running 20+PSI and would like to do it right.

Also, going forward the car should be consuming NOTHING but 100 oct.

Giving the fact that it will be a race-gas (100, haha) only situation what would be the mininum injector size needed.

I saw Pavo had 720's but they seem like a huge overkill.
Perhaps 605's-620s ?


Logical input greatly appreciated.

-Shawn

[Iwishiwascool]

i have almost the same setup minus afpr and i believe ill be running 660s... though my injector duty cycle will be a complete guess. 2g bliss.

I would log it with the 550s using the 100 octane and leaning it out to your comfortable knock value and checking your duty cycle then. I cant imagine that youre flowing that much air to max those out at just 15 psi.

[biglipps66]

Ya I still dont think something is working rite over on your end. You shouldnt be using all of 550s at 15psi. When I had my 16G and supra sidemount setup and a 190.. I was able to run 22psi without any problems at all on my 1G motor.

Hell I dont even use all of my 650s at 23psi with a HUGE 3055 turbo. If you end up with 720s, your going to need a dsmchip to help correct the sizing and dead time of those huge things. You'll be at -50s on the afc and still need help :D

I think tuning seriously owns you man. Get to a tuesday meet and have some one help take a look at it for you. :thumb

[BlackEclipse]

I use 550's and I think they are overkill for what I have. I run 20PSI every day and let it creep to 23 -24 PSI on those colds days and I still don't go lean. I have my AFC leaned WAAAAY back to like negative 39% at the top end.

maybe fuel lines are smaller on a 1G...maybe you got a kink or restriction in your fuel system?

[biglipps66]

Ya another thing as well.

Ashley was able to run 450s on her 16G and 255 setup, she ran 17psi all day without any issues at all, and hell, it ran rich as can be.

You just need... tooninated :freak

[WikdTSi]

Not entirely sure...
I know since it got opened up..*DOH* forgot to list mod:

2.5" IC piping with
Supra SMIC.


The car felt 100% better before.

The car now @ 9psi felt MUCH better than it did at 16-17psi when it ran the 12.93 and trapped 106.

No clue, it would appear to be sucking in a massive amount of air.

The AFC, Untouched.. was seeing nearly 2000hz *again unadjusted*
From a 2G mas :eek at 15psi

Guess I'll have to pick it apart..

[Iwishiwascool]

PS. 2g responses.

1Gs naturally run leaner than 2Gs.

PSS

Shawn has been tuning since before any of us owned a DSM. (Minus MB)

[biglipps66]

The AFC, Untouched.. was seeing nearly 2000hz *again unadjusted*
From a 2G mas :eek at 15psi



My 14B seen that exact air when I was 99% stock, and during 4th gear pulls I hit fuel cut. Only mod at the time was a 14B and an air filter.

Bust out the tuning skillz :)

[WikdTSi]

PS. 2g responses.

1Gs naturally run leaner than 2Gs.

PSS

Sean has been tuning since before any of us owned a DSM. (Minus MB)

Sean?
Shawn.. I wouldn't get carried away Ken.
I just always kept the car very conservative and safe is all..

Perhaps a steve-tek system is in order.
:bow

[DQ Driver]

last time you pressure tested?? are you seeing spikes in boost and then leveling out?

Maybe you got a dank poopra smic that is bleeding that boost away, and causing an extreme rich condition. The turbo is being overrun, the car will feel better initially and then enough pressure builds and escapes?? since the logger only records up to 1600hz.. i try would monitoring the karmen readings in the graphical mode with the afc, maybe your just spiking it


in case you were wondering.. i know NOTHING

[BlackEclipse]

I know nothing as well. My car gets me to/from work and that is what matters most.

[WikdTSi]

Boost is not spiking..whatsoever.
Never has, hopefully never will.
Car builds boost as fast as ever, and again feels fantastic. (even with 2.5" piping/smic I usually have full boost before 3k)

I very slowly raised the boost up from 9psi.

I know logically this condition shouldn't exist. Perhap my FPR is not doing its job 100%, and as above suggested perhaps I have a restriction in the fuel delivery.

Might have to invest $100+ in a FP guage to check its functionality under boost.

Thanks For You Help.

-Shawn

EDIT: Supra MKIV was tested..and has both tanks sealed tight with epoxy for extra insurance. No leaks there.

[v8etr]

I am a big fan of making the fuel pressure work for you. I dyno'd 411 hp on stock 450cc injectors, and 538 hp on 550cc, both with a 60-1 T3/T4. I would definitely take a look and see if something else is affecting your readings. Maybe something like a clogged fuel filter or something that is keeping the fuel pressure from raising under boost. I actually had a problem once on a 90 Laser FWD where the wire leading from the connector to the pump had gotten old and brittle. Under boost I was down to 10.2V at the pump and my fuel pressure dropped off to less then 30 psi. At idle it had the normal 40 psi though. After hot wiring the pump I was back up and running. It always turns out to be something weird.

[biglipps66]

. I dyno'd 411 hp on stock 450cc injectors, and 538 hp on 550cc, both with a 60-1 T3/T4.

The most amazing thing Ive ever heard.

WTF, Im wondering how you managed such a thing

[M 4 L k i 3 R]

I think you're best bet would be to log it and see what is going on with air and fuel and boost. If you've got a log, post it up. If not, try and find someone with a logger and get a log of whats actually going on.

$0.02

[WikdTSi]

John,

Ont he 411Hp run,
What kind of BSFP were you running? 50+ PSI I presume?

I was always under the impression that I should avoid 75 and above PSI on injectors as it caused adverse affects on the durability, spray pattern, and ability to not leak during off-cycle.

-Shawn

[biglipps66]

Maybe he was running like 150psi base fuel pressure to squeeze 400hp out of stock injectors? Ive never heard of stock injectors achieving such a number, but Ive been told you learn new things everyday, maybe today I will learn something new!??

[Iwishiwascool]

could it be possible!!!

;)

[v8etr]

John,

Ont he 411Hp run,
What kind of BSFP were you running? 50+ PSI I presume?

I was always under the impression that I should avoid 75 and above PSI on injectors as it caused adverse affects on the durability, spray pattern, and ability to not leak during off-cycle.

-Shawn

It has been a few years now since I did it, but I seem to remember running 55psi base pressure without vaccum. A lot of this was to compensate for the 550cc chip in the VPC. It ran really bad with the stock injectors on the bigger chip without rainsing the fuel pressure. Since I did it on 15psi of boost, the fuel pressure never went over 70psi. The only reason we tried it was because I sold my 550cc injectors in favor of some 660cc ones from Buschur. I had to wait because they were back ordered, so we threw in the stock injectors just to play around. I never thought it would crank out those kinds of numbers on 15psi of boost on pump gas. It took about 15 pulls to get it over 400hp though. A 9:1 motor down here knocks a lot on pump gas because our gas sucks. Since Houston is the smog capitol now, we have tons of extra junk in our gas to help emissions and kill power.

[WikdTSi]

John,

Ont he 411Hp run,
What kind of BSFP were you running? 50+ PSI I presume?

I was always under the impression that I should avoid 75 and above PSI on injectors as it caused adverse affects on the durability, spray pattern, and ability to not leak during off-cycle.

-Shawn

It has been a few years now since I did it, but I seem to remember running 55psi base pressure without vaccum. A lot of this was to compensate for the 550cc chip in the VPC. It ran really bad with the stock injectors on the bigger chip without rainsing the fuel pressure. Since I did it on 15psi of boost, the fuel pressure never went over 70psi. The only reason we tried it was because I sold my 550cc injectors in favor of some 660cc ones from Buschur. I had to wait because they were back ordered, so we threw in the stock injectors just to play around. I never thought it would crank out those kinds of numbers on 15psi of boost on pump gas. It took about 15 pulls to get it over 400hp though. A 9:1 motor down here knocks a lot on pump gas because our gas sucks. Since Houston is the smog capitol now, we have tons of extra junk in our gas to help emissions and kill power.


Thanks for the input.
I may try and get it tune it on 50psi. Probably be sufficient with race gas.

Thanks
-Shawn

[biglipps66]

400hp = 15psi + 450s + pump gas?

[v8etr]

400hp = 15psi + 450s + pump gas?

Well it was on a full built motor with every part known to man and a huge turbo. 60-1 stage 5 can pump out a decent amount of air. I have a link of some pics of the car and some of its parts. A lot of things have changed since these were taken but you might still get a kick out of them. The white Laser was the dyno queen. I tore that one up to make the blue AWD Talon. :)

http://www.imagestation.com/album/?id=4290864413

[biglipps66]

Yup I just find it totaly amazing thats all :)

[WikdTSi]

I think lippy thought you had a 14B or something

;)

[biglipps66]

I think lippy thought you had a 14B or something

;)

Nah, just amazed that you can squeeze 400hp from 15psi and stock 450s.

[Mike C]

What amazes me is that he made that kind of power on that turbo at that boost level. I've never heard of a 60-1 making anything like that at such a low boost level. Do you happen to have a scan of that dyno pull so we can see the curve?

[v8etr]

What amazes me is that he made that kind of power on that turbo at that boost level. I've never heard of a 60-1 making anything like that at such a low boost level. Do you happen to have a scan of that dyno pull so we can see the curve?

I dyno'd those numbers almost 3 years ago. I have no idea what happened to the printout's since then. If you are really interested in the curve, check out the dyno link below and you can see a similar curve that Buschur did with the same setup. Mine was nearly identical except the 400hp mark was about 500 rpm's later than his run. When I turned up the boost to 26 psi for the 538 hp pull, the manual controller stayed shut longer and my curve was almost exactly the same all the way up. At the time I made those pulls I was running the Crower 414's. Since then, I have swapped to the HKS 272's. I actually noticed better midrange power with the HKS.

http://www.crower.com/cat/import/mitsu/camshafts.shtml