Gunny Highway

iTrader: (1)

I'm just curious as to why the price is jacked so high for 65 / 68# injectors over everything else. It's one thing if it was a simple relationship of more #'s = more $, but it's not.


Per Turbo City's page

36#'s = $73

46#'s = $73

55#'s = $73

61#'s = $73

68#'s = $131

75#'s = $73

My 350 has arrived, and this is the last thing I need for my swapping out parts. It's an LO5 w/ a Crane Cam, Trick Flow heads and a bored out Edelbrock intake and throttle body. I was looking for "Cop Car" injectors (65#) since my motor is more beefy than even the cop car motors were, and I've got a cop car chip to get things to atleast run while I datalog.

Should I just go for the 61#'s and turn up the pressure?

Brent

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75's

va454ss

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Just like anything else, what's most popular is the most pricey.

Get the 75's..............

Ronny

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gmpartsdirect.com

BronYrAur

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If you really want the 65's check ebay. I just picked up a whole TBI setup off a 9C1 Caprice with the 65's for I think 25 bucks.

Gunny Highway

iTrader: (1)

Really?? I look on there all the time and I can never find anything but 45 and 55#'s. What phrase did you use for the search? I always use: "TBI injectors" or "Cop Car injectors"

I used to get hits all the time, but now that I need them, I hardly get any hits.

BronYrAur

iTrader: (1)

I just do a search for "TBI" you'll get a bunch of hits, you want to find the ones not listed as cop car injectors or something because the ones I found I'm sure the guy didn't know what he had. Look for that. Or if you have a good fuel pump just get any of the truck ones with the 55#ers for like 20 bucks and turn up the pressure on them.

Gunny Highway

iTrader: (1)

I've got a Walbro 190, but I'll be running a "cop car" chip to atleast have the car running while I'm datalogging so I want to use the "cop car" chip's preprogramming for 65#'s to make it less complicated.

I did a search for TBI today, but I got nothing after going through like 4 pages of stuff.

BronYrAur

iTrader: (1)

Just get some 75's or 55's and either turn down or up the fuel pressure to be equivalent to the 65's then the calibration will work the same as if you had 65's.

Gunny Highway

iTrader: (1)

Really, that works? That won't mess w/ the atomization process at all?

Maybe I'll just go with the 55# since I can get those on Ebay all day long. . . I'm still worried about the chip functioning correctly.

BronYrAur

iTrader: (1)

That straight up "cop chip" is going to be way off wiht a cam and trick flow heads. That chip was also set up for a very heavy car so its timing will be set up differently than it should be for your f-body. It's a good starting point, but it will need a lot of work; you'll need datalogs most definitely so make sure you have that capability.

There are equations out there to calculate pph flowrate from psi that could tell you exactly what psi to set a pair of 55's at to attain 65 pph. Although, honestly, that may be a pretty decent motor and you may want some 75 pph injectors to keep the pressure down and give more room for expansion later on, just a thought.

Gunny Highway

iTrader: (1)

Well, I'm thinking I might have some idle issue with the 75's, so right now I'm leaning towards the 61#'s.

As for the motor, it was both DD2000 and Engine Analyzer Pro'd at 330 HP and 430 lb/ft. I'm thinking I can get the 61's to work better than detuning the 75's.

Opinions?

BronYrAur

iTrader: (1)

That's a stout enough motor that I woudln't think you'd have idle fueling issues with the 75's. I think with a motor like that I'd go bigger injectors before smaller. You can turn pressure down on the 75's but you can only go so high on smaller injectors.

I think you should look into a much bigger cam though for that motor, it would really like a bigger cam I think. I remember you were looking at one in the 204/214 range right? I'd go more towards lt4 hot cam territory with those heads.

I think at WOT you're going to want big injectors though; it's going to need a lot of fuel.

Gunny Highway

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Cam Specs are:

204/214 .429/.452 116

Yeah I know it's a tame cam, but this is a daily driver, so it has to be very dependable and get decent gas milage. I've done the all out super street thing, and I paid dearly for the low MPG.

I figured it this way, when I get it running, and i I turn out not to be happy with the performance, I'll just put some 1.6 RR's on there to pick up some more ponies. Cam specs would then be:

204/214 .458/.482 116

So I have some room to work with here.

BronYrAur

iTrader: (1)

You would want some more duration though too, I think at least go a little bit bigger. It'll be easily driveable for daily use. But that's a tiny cam for a 350.

Ronny

iTrader: (1)

idle issues? i have the 90's at 12 lbs and idles nicely. 350 cid.

Gunny Highway

iTrader: (1)

What did the 75#'s come in? Or if anybody has a correct part number for 75# injectors, that would make my life a little easier. I searched the threads, but I got 3 numbers for 75#'s, but those threads were like 3 years old, and never gave a definative answer.

I'm pretty sure that the 75's came on 93- and earlier 454/7.4L motors that came in 3500's pickups. Anybody else confirm?

BronYrAur

iTrader: (1)

I think you're safe with any BBC injectors whatever flow rate they might be. Just go with the earlier ones because I think later model ones had low PPH but were at a high psi. I found this info:

Blue/Black
Late big block pickup
80 lb/hr
GM 1708430 *RPD


Dark Red/Dark Blue
big block pickup
90 lb/hr
GM 5235231 *RPD

Then I found a thread that you actually started a couple years back that has some numbers in there too:

Here

Gunny Highway

iTrader: (1)

Wow was I ever a newbie when that thread was started.

JokerRS

BronYrAur mentioned that the cop car chip really wont be very close and he is right on. I used it for a baseline when I put heads and a ZZ4 cam in my LO3 because I was using 65 PPh injectors. The timing chart in the LO3 bin was better. You need to spend alot of time on the timing chart to get the most out of your combo.

Is that cam a roller cam?

DM91RS

Would it be better to start with the LO3 bin instead of the LO5?

DM

BronYrAur

iTrader: (1)

With my setup, I'm starting with the VE tables from the LO5 bin wiht a little extra fuel up top to smooth it out. Then I took the timing tables from an L98 TPI bin and put them into my bin. All of this went into my stock LO3 bin and most other things are the same as they were. Just a suggestion for a starting point, I think it might work ok.

DM91RS

BronYrAur that sounds like a good way to come up with a baseline bin. Then change the BPW for the different injector sizes? I can't remember offhand how much they varied from the LO3 to the LO5.

On your 350 what cam are you going to run? The stock L98?

BronYrAur

iTrader: (1)

Looks like I'm going to be just keeping the stock L98 cam in there for now. It's an 89 so its the biggest stock cam they came with too, so we'll see how it goes.

As for the BPW, since its related to the displacement as well the difference between the LO3 and LO5 constants are about 2 points. Doesn't seem like a meaningful enough difference to even need a change. I did a lot of smoothing out on the timing table though for starters because its really choppy from the factory with a lot of peaks and dips in the curve.

Brent

iTrader: (1)

Did you guys miss this thread?Here
There ain't any room to add any fuel up top as dimented24x7 clearly shows. You're just gonna end up running the injectors static.

Cobbling bins together from different cars seems to me, to be a BAD strategy. After all the cutting and pasting you don't know if the bin will run the injectors static or what other problems you've just created.

If you can resist the temptation to cut/ paste some tables and do testing instead, you will end up with a much more optimized tune.

JokerRS

The BPW constant in the cop car chip was 135 , if anyone was intrested.

DM91RS

Good link Brent...I missed that one.

On the bins and looking at it from your perspective it does seem to be setting oneself up for unknowns especially for tuners with low levels of experience like myself.

And....low levels of time.

That being said which bin would be better to start with for a 350 TBI the LO3 or LO5?

And thanks Joker...I found my ANLU bin since the last post.

Brent

iTrader: (1)

The engine is only part of the question

IMHO if you've got an 350/Automatic trans then start with the L05 bin.

If you've got a 350/Manual trans then start with a L03/T5 bin. (since there aren't any 1228746 350/manual trans bins)

I don't care for the way an auto bin, installed in a manual car, drives.

BronYrAur

iTrader: (1)

Brent, I definitely agree with you on testing and making the changes, but if I'm swapping in an L98 longblock with much better heads and bigger cam I figured starting with the LO5 VE tables would be the best bet. I didn't want to chance starting up the motor with the LO3 fuel tables and work them out from there in case it fires up and is incredibly lean right away.

Since my car is a T5 car I have the original bin only with the fueling tables implanted in it from the LO5 and the timing from an L98 car since my engine is going to essentially be the same as an L98 only with TBI on top.

Brent

iTrader: (1)

My experience has been the exact opposite of your fear. They end up being WAY rich at idle and part throttle if you've increased the injector size and/or fuel pressure to match the HP of the new engine.

BronYrAur

iTrader: (1)

I could see that actually Brent. I never really gave it that much thought that the VE shouldn't change all that much if I'm changing injectors. I figured back when I was making the bin that I'd try it first and see how it runs and then try the stock bin and see how that runs and just go off of what feels better as a starting point. So, we'll see when the swap actually happens.

JokerRS

Especially with a larger cam!