Fuel Injectors

palermocorey90 wrote:

that should work check the ZZP site and see what that says, im almost positive that you need a XP cam to run the 3.0

no offense to you palemocorey, but I hear everyone say you MUST HAVE a cam to run those lower pulleys, but guys have proven that wrong.

the lift on my rockers is like .490 or something, the cam is like .510 (a measurable difference but probably not huge performance differences) - and you cant go much higher than that with stock heads. And Im not buying new S2 or S3 heads!

turtleman wrote:

you can put the biggest IC on it you want but if you have a bunch of boost and no fuel, youre in danger again and probably not making the power you want.
.

true, but with much cooler intake air temps, you wont need as much fuel.

98riviera98 wrote:

AA wrote:

With an intercooler, you'll get a machined LIM, which should help flow if I'm correct. Do you agree, Derek?

I think the IC is your best bet. Go with ZZP's best core. The 3.0" should be easy to run, but also install the bigger injectors just in case.

go for the 60lbers over the 42.5lbers you'll like it much better

As for 60lbs injectors, I want to go with 42.5lb because they are said to be easiest to tune (except for stock injectors of course).

98riviera98 wrote:

AA wrote:

Quote :

go for the 60lbers over the 42.5lbers you'll like it much better

Why?

when more people in the 3800 modding scene switch to E85........... 42.5lbers just cant keep up

there are FOUR E85 places in D/FW area (from what I hear), so I could care less about running that.

deekster_caddy wrote:

Quote :

my ported SC doesnt have an intercooler outlet.

Please explain this. The outlet is the same as any other SC isn't it? I have installed many ICs and never had any special SC.
.

lol, I cant explain this, cause Im not exactly sure what an "intercooler outlet" is.
So is a ported intake manifold a must too? and would the intake gaskets be reuseable after a year? I did a top end replacement not too long ago and aint really looking to buy all new gaskets, that would add $100+ to the deal.

deekster_caddy wrote:

having larger injectors than you need will hurt your idle/gas milage. Depends how big you go, 42.5s will get you a long way. They are also very resalable should you prove to need 60s.

I didn't think this would necessarily be the case. Doesn't the PCM use a shorter pulse width a higher pound injector? If not, there would be no way to tune 60lb'ers for cruising throttle. That can't be right..

To use larger injectors, you need to modify the IFR table. The stock table is as follows:

kPa000 = 210.97 mSec/Gram
kPa010 = 210.36 mSec/Gram
kPa020 = 209.94 mSec/Gram
kPa030 = 209.36 mSec/Gram
kPa040 = 208.51 mSec/Gram
kPa050 = 208.08 mSec/Gram
kPa060 = 207.78 mSec/Gram
kPa070 = 207.48 mSec/Gram
kPa080 = 207.23 mSec/Gram
kPa090 = 206.50 mSec/Gram
kPa100 = 205.84 mSec/Gram

For 42.5# injectors, divide 36 / 42.5 = 84.7%
For 60#ers, divide 36 / 60 = 60%

Multiply each number in the table by the appropriate % to find the correct value for your table.

turtleman wrote:

deekster_caddy wrote:

having larger injectors than you need will hurt your idle/gas milage. Depends how big you go, 42.5s will get you a long way. They are also very resalable should you prove to need 60s.

I didn't think this would necessarily be the case. Doesn't the PCM use a shorter pulse width a higher pound injector? If not, there would be no way to tune 60lb'ers for cruising throttle. That can't be right..

Yes, BUT the larger the injector, the worse atomization at small flow rates. It won't be a huge difference, but I was just trying to help the argument for 42.5s. If you give a crap about idle/low throttle tuning or passing emissions it would be harder to do with the 60s.

Rule of thumb is not to use larger injectors than you need to.

Oh, and just to get back on topic

I think a cam is better bang for the buck than an IC. IC is a different approach, but a cam opens up more possibilities, plus you can IC later.

I know quite a few 12 second cars with cam but no IC. I don't like IC because of the mess it adds, the lack of easy heat exchanger placement on the Riv, and the general unreliability of most IC pumps (although the new GM pump makes that argument lesser).

deekster_caddy wrote:

the larger the injector, the worse atomization
at small flow rates. It won't be a huge difference, but I was just
trying to help the argument for 42.5s. If you give a crap about
idle/low throttle tuning or passing emissions it would be harder to do
with the 60s.

Rule of thumb is not to use larger injectors than you need to.

Ahhh yes, I can see that. Bigger pintle/seats don't spray small amounts
as foggishly. having boost in the jug I'd think makes that less of a
problem at least than an atmospheric car.

dual injectors might be a pretty sweet idea, mr Turbocharged400smc... jk but not. he seems like the one, if anyone, to do something like that lol

AA wrote:

To use larger injectors, you need to modify the IFR table. The stock table is as follows:

kPa000 = 210.97 mSec/Gram
kPa010 = 210.36 mSec/Gram
kPa020 = 209.94 mSec/Gram
kPa030 = 209.36 mSec/Gram
kPa040 = 208.51 mSec/Gram
kPa050 = 208.08 mSec/Gram
kPa060 = 207.78 mSec/Gram
kPa070 = 207.48 mSec/Gram
kPa080 = 207.23 mSec/Gram
kPa090 = 206.50 mSec/Gram
kPa100 = 205.84 mSec/Gram

For 42.5# injectors, divide 36 / 42.5 = 84.7%
For 60#ers, divide 36 / 60 = 60%

Multiply each number in the table by the appropriate % to find the correct value for your table.

little problem here, my 96 IFR only has one box with one number. It doest have variables based on kPa.

deekster_caddy wrote:

Oh, and just to get back on topic

I think a cam is better bang for the buck than an IC. IC is a different approach, but a cam opens up more possibilities, plus you can IC later.

I know quite a few 12 second cars with cam but no IC. I don't like IC because of the mess it adds, the lack of easy heat exchanger placement on the Riv, and the general unreliability of most IC pumps (although the new GM pump makes that argument lesser).

I understand and agree about your cam comment, but if I do a cam it will be big. Big enough to need new heads. That was one of my options above. I could sell/trade the 1.9rr's for some 1.6's and slap a cam in. But it wouldnt be a mild one. Stage 2 or 3 with matching heads.

yes, an IC would be more plumbing and potential failure of additional parts. That was my #1 reason for not really wanting to go intercooled. But I want to be able to jump in this car and take a road trip on the whim without worrying about reliability. I still have that now.

let me add, nitrous was a factor in me reaching that goal of 12's. But I dont want to run a huge shot to acheive that. I want the nitrous to me like 50hp maybe. Again, reliability.

Great discussion and hopefully I can add to it.

The mention of a machined SC for intercooling, sounds like taking out the "great wall" this is the wall between the outlet and the bearing cavity area. By removing this wall, you end up being able to use a 4"x8" area of intercooler instead of 4"x5" area, and enhancing the overall cooling ability.

Derek makes an extremely good point about injector sizing. Think of the 36's we have as a small mist bottle, 42's as putting that bottle on stream instead of spray and 60's as dumping the bottle directly into the intake port. Atomization helps greatly. Another good point is brought up that if E85 is a future option, why spend twice.

Pulley sizes: You can run any size pulley as long as you don't get KR and blow up. If you intercool, you add a restriction to your intake and must lower your pulley size to maintain the same boost levels you had pre-intercooling. Overall though the pulley size you run should be relational to what your motor can flow.
Let's not confuse a cam and rockers as being close to the same thing. They both help flow, but do it differently. Rockers open the valves further while following the cam profile (assumed stock), meanwhile a cam is usually ground with some timing advance, different lobe profiles to keep the valves open further and longer. This usually makes a cam a better performer in the overall, while rockers are easier to install. Cost wise..they both run about the same before labor to install. One other consideration is timing chain stretch, the cam will usually be a fresh timing set due to it's removal and the rockers will be using a slightly stretched chain. In the end though, it's all about how much air you can process while staying on the high octane table for timing.

do LS7 injectors work in our cars if so how big are they? lb an hour wise?


http://forums.corvetteforum.com/showthread.php?p=1565092113

would these work?

BillBoost37 wrote:

Great discussion and hopefully I can add to it.

The mention of a machined SC for intercooling, sounds like taking out the "great wall" this is the wall between the outlet and the bearing cavity area. By removing this wall, you end up being able to use a 4"x8" area of intercooler instead of 4"x5" area, and enhancing the overall cooling ability.

.

well, my SC is machined as you describe, so perhaps they included that? They never charged me for the EGR hole fill either and it wasnt even an option listed online.

I think I will go with the intercooler idea, and probably do injectors at the same time. I dont even think I will port out the intake manifold. I will just wait until I chunk a piston or need other major rebuild work and then drop in a cam, new heads and intake manifold, timing chain and maybe some diamond forged pistons.

Just an update here, I took Derek up on his offer and took his old injectors, had them cleaned at CODY per his suggestion and now have them installed. I have 135k on my old ones and they obviously needed cleaning because my idle is now perfectly smooth and my Kr is completely gone. I was worried about my fuel pump but now with some clean and calibrated injectors I can eliminate that job from my list. My old ones are going to another member. Highly recommend cleaning and flow test/balance on your high mileage injectors. Ive been unable to properly tune because of this, now I can start fresh.

Awesome! Pay it forward everyone!

deekster_caddy wrote:

......... I was thinking I should have my old injectors cleaned (having them cleaned out of the car on a separate machine has no equal), then sell them to somebody else in the club who still wants stock injectors, so they can do an injector swap with minimal downtime (have nice clean injectors on hand), then they can send theirs on to be cleaned and send them on to the next person who needs them, rinse, repeat, continue.........

Cool, there's incentive for me to install my cleaned/flowed injectors from Bill.

Quote :

I have 135k on my old ones and they obviously needed cleaning because my idle is now perfectly smooth and my Kr is completely gone.

I had nearly the same results. Additionally, my torque/HP increased roughly 10% I estimate. This WOT acceleration graph doesn't lie:



Yellow curve is from a year ago, red is from a week before new injectors, and blue is after the new injectors. All of the runs were done in the exact same location, 3.4" SC pulley, same tune, and 75ºF ambient temp.

from: https://rivperformance.editboard.com/series-ii-engine-transmission-f4/engine-swap-gen-v-t5778-120.htm#84649

AA wrote:

I've stayed away from 42.5# injectors because I fear they would decrease my fuel efficiency.

Properly tuned in they won't

Is that a fact? Does a 42.5# injector atomize the fuel as optimally as a 36# injector during idle/cruise?

98riviera98 wrote:

AA wrote:

I've stayed away from 42.5# injectors because I fear they would decrease my fuel efficiency.

Properly tuned in they won't

If that's the case, I've got some big time tuning to do because my gas milage sucks!

Maybe Travis can help you. He's getting great economy on 42.5# injectors, but he's properly tuned.

It's amazing how quick a study Travis is. Isn't it.?
He's already become the resident expert.
I'll have to pay more attention to every word he speaks......NOT !!!!

Dumb Ass #1 wrote:

Maybe Travis can help you. He's getting great economy on 42.5# injectors, but he's properly tuned.

I never put the 42.5's in... After some trading and selling off all my injectors I'm waiting on a flow matched set of 65's... You can tune the 42.5's in on the IPR table and make them so that they are putting the same amount of fuel as 36's

Dumb Ass #2 wrote:

It's amazing how quick a study Travis is. Isn't it.?
He's already become the resident expert.
I'll have to pay more attention to every word he speaks......NOT !!!!

turtleman wrote:

98riviera98 wrote:

AA wrote:

I've stayed away from 42.5# injectors because I fear they would decrease my fuel efficiency.

Properly tuned in they won't

If that's the case, I've got some big time tuning to do because my gas milage sucks!

Ya bro.. Or you need to lay off the gas..

Dumb Ass ??

You don't really want to go there do you?

Dumb ass #1 here - Hey travis, I found this statement at 3800Pro forums regarding injector upgrades. What do you suppose it means?

Quote :

don't go too big, the injectors have a hard time at low pulse widths causing you to have issues with low speed drivability. Only go as large as you HAVE to have.

I found this at the fullsizechevy board. What do you think of it?

Quote :

You don't want too big, because small pulse width performance will suffer badly. Injectors don't like to try to get below 1-1.5 mS, they can't manage themselves well there. So we shoot for keeping the PW higher and the only way to do it is properly sized injectors. Remember, we are dealing with mechanical injectors, and it gets hard to manage as accurately as we need to when we get down to the low PW's.

Here's one I found at 60DegreeV6, regarding 36# L67 injectors in a N/A V6:

Quote :

They are a bad idea on batch fire (MPFI) motors. The minimum pulse width recommended for high impedence injectors is around 1.8ms. Tha means that 1.8ms all the way down to 0ms will deliver the same amount of fuel because the fuel injector just cannot open and close any faster then that.

At idle I was seing around .9ms (1000 rpm) A 800 rpm idle was down around .7ms. At a 70mph cruise 1.4ms was about average.

Whats this mean? You will get a horribly rich and rough idle and it will be cruising just sucking down the gas. Tuned the best I could the most I could get was 21mpg highway driving, probably due to the injectors.

Travis would have to read and comprehend all that data.
He's proven he's incapable of doing that and just not willing to.
So it's just not worth it to try and help him out.
All he want's is for someone to tell him what to do, not figure it out on his own.
And if he try's to figure it out alone..... well we've seen the results.
Someone told him to go the 65# ers and now he'll be whining for help with tuning, guaranteed.
And if no one told him to use 65# injector's and he came up with that conclusion on his own then it just further justify's the argument that he can't read and comprehend technical data.
Be sure to remind him about the Dumb Ass comment when he comes whining for noob help... as he has been since getting tuning software.