Yey everyone

i have a 1991 350 with a stealth ram 58mm tb
afpr , i just ordered 1.6 roller rockers and underdrive pullies i also have a crane hi6 ignition system with lx 92 coil performance wires plugs and exhaust everyhting is noted on the sig.

I am wondering if it is about time that i concider buying some bigger fuel injectors. if i am understanding right my car has 19 lbs on there stock, so what would i up grade to 24,30lb or what. i would like to be able to continue busting power and not have to change the in jectors again but i also want it to run to its peak performance now too,

Thanks for the input

Eli Jacobson
Raptere@aol.com

You should have 21# injectors stock (19# were for 305's)... Do you have any PROM editing hardware?? If not, I would get it before anything else, as you can't be getting all you can out of that combo without custom tuning.. Plus, some datalogging software can tell you the duty cycle of your current injectors (how much your current injectors are being utilized to supply the current fueling)..

If anything, buy a set of Lt1 injectors for like $40. Their #25. Or LS1's can be had for $70 or so and I think they are like 27 1/2 #

Could some one please elaborate on PROM editing hardware.
I dont have anything done right now accept turning my tps sensor up a little bit and having my fuel pressure set up a bit.

Do you mean do i have a chip or something or is there software you can use to burn new chips or re burn the one you alredy have. as i said i dont know a whole lot about this part of tuning but i would love to learn, pleas teach me or at least send me in the right direction, to where i can get the info. and ill take thoes injectors into concideration.

-Eli

Check out the DIY-PROM forum right here at TGO... You will benifit more from tuning at this point then probably most anything else...

Get new injectors. I don't think you're pushing the flow rate of your current ones, but if they are 14 years old, they should be replaced. I had 1995 LT1 injectors on my car and it ran like crap until I got new ones. Not to mention the LT1 injectors were a less than optimal design even if you get a new/remanufactured set. At L98 fuel pressures LT1 injectors are 24 lph and LS1 injectors are 25. A new set of LS1 injectors can be had from slp for $99. Whatever you do don't go used, because new ones are cheap and much more likely to do the job right.

My injectors are fine.....

You probably got a really bad set.

You have several options to 'burning' a chip. You can buy the hardware and burnable chips, then burn them, and install them. A great alternative is the prominator, which you plug into your ECM in place of the 'chip'. It has a ribbon cable coming off of it that you can just hook up to your laptop and upload your data to the prominator, instead of having to burn chips and replace them. https://www.thirdgen.org/techbb2/sho...ght=prominator
http://misterbill.homeip.net/aboutprominator.asp
For about $200, it is cheaper or comparable to buying a custom chip from someone like Ed Wright. http://www.fastchip.com/

Yeah they were garbage. Rochesters aren't the worst you can get, in my case it could have been age related. On that note if you're still running your original injectors, I would recommend replacing them.

Already going to, gonna get some 30# for the cam.

I wouldnt waste any money on bigger injectors. Technically there isnt any real mods to the car. Now if you get heads or cam then maybe look into bigger injectors. But if the 22lbs which are stock in your car is running fine then I wouldnt worry till those are maxed out. I had a LT4 cam and TF heads on my 350 with superram and I was just about maxing out the stock 22's now with the 383 I have 28lbs.

Im trying to make sense of that prom stuff kindof confusing...

But with the injectors i am interested in in getting some new ones even if they dont need to be bigger they are 18 years old and the engine dosent run as smooth as i think it should be able and dosent idol so well either.

I'm interested in the slp ones #25 they are a hundred bucks and i am just wondering if they would be ok or would they be over kill and hurt performance or idol or something.

The whole PROM thing is simply changing a single number in your ECM. That number is the injector constant which stores the flow rate of your injectors in pounds/hr. If you have your eprom injector constant reset to 25 lph, it will probably run better than it is now. 25 definately is not overkill, they're probably cheaper than you will find replacement 22's and they will give your engine some room to grow

I bought the 25's and in order to get my BLM's up to 128ish I had to use a 28 constant. And this was on 383, 219, TF, and SR combo.

Was this on stock pressure? My car is still set at 24 lph from the LT1 injectors, as soon as I can meet up with my PROM burning friend I'll change it. It still runs a million times better even with the constant a little off.

Also is this prominator something any one can do or do you need other experience with car oriented things.

I am a 18 year old high school student. i have been working on cars for years now done all my own work and am very good with computers not much with coding though. Do you think i will be able to properly tune my car?????

It will take a while to get the fuel and spark stuff down, but a sedated monkey could change the injector constant, and you can change other things quite easily like fan turn on temps, rev limiter, etc...

LS1 injectors are rated at a much higher PSI than our regular injectors, I think its like 55 psi. So a 24lbs injector at 42 lbs would be a 27 lbs injector at 55 psi, know what I mean?

Also, underdrive pullies are not great for daily drivers. You slow the alternator down, add in high power headlights and a kickin' stereo system, and suddenly your battery is dead.

Lastly, I dont notice new heads in your huge signature, so I hghly recommend you replace the stock valve springs with some better units when you put those 1.6 rockers on there.

Well for the pullies i was sure to get the special alternator kit that has a smaller alternator pullie looses you like 2 horses but brings power back up. Also, if my upgrades look random and inifficient let me know what you would suggest. i am basically just trying to find the things i can afford that i also have the capability to install my self, and that have the greatest wow factor as well as hp to dollar ratio.

Please, let me know what you suggest

-Eli

HSR on a stock engine is kinda wierd. Did your car run faster, the same, or slower after switching from TPI to HSR?

How is it wierd on a stock engine?? The 350 needs the air and he will probably pick up 20-30 to the wheels over 4k...

Sk Pressure. NO afpr. With the constant set at 25 my BLM's were maxed out at 108 everywhere.

In the TPI shootout, HSR was putting out less power than factory TPI up to 4300 RPM on a 383. On a 350 it would be even higher. I just think that he would be sacraficing a lot of his useable revs on a stock engine. There are definately engines that would benefit more from it than his. It just seemed odd to me.

Yea... mabe kind of wierd but i actually noticed a lot of power with it i also turned up fuel pressure and put on the new throttle body at the same time so that may have effected something. Please let me know what you would suggest for me to do if i am going in the wrong direction as far as performance parts.

for the persone that suggested putting in new springs at the same time how would i go about doing this. i work at a toyota dealership and the tech i work with has done it before with hooking a compressor line up to the spark plug whole but i dont remembe exactly how he did it , any ideas and wht if i were to skip the new springs would that cause problems?

Yup, completely understand. Same reason buying ford SVO injectors that are 30#'s are 32#'s at 42PSI in the LT1 since they run at a lower PSI in the fords.

So are 19 SVO's 21-22lbs GM?

Yea, you hook the compressor up to the spark plug holes like you said to keep the valves from dropping and use one of these type vavle spring compressors to get the springs off.

Can't you just turn the engine and make sure you're on the compression stroke of the cylinder you're working on?

I'm no pro here and I've never done a spring change with the heads on the engine, but do you think that it will hold pressure in cylinder long enough, or do you think it will leak down too much?

We did it this way, me and Texas LT1. Basically, spin the harmonic balancer until the arrow is TDC, so you know you can do the valves on the #1 & #6 cylinder. Basically go by firing order and you can do 4 valves at each o clock....12,3,6, and 9. thats looking at the cam gear. not sure how it is on the harmonic balancer. basically go by firing order. The piston will keep the valve from dropping.

- so i can just use the piston to keep the valves from moving at all, and does that method work for removing as well as installing the springs. Also that tool you mentioned is that available at any automotive stoor or is there something i might alredy have that should work, or can i just fabricat a simple tool?

-if you suggest new springs what weight and do i want singel or doubble ones?

-thanks again every one for all the help,

Eli-

o also with the prominator, what things would i be able to change/ tune, and what things would i need to for my set up or to squeese more power out of the engine, push it to its full potential?

You can get a valve spring compressor from any store, also the air chuck bit if thats what you were talking about. Yes the piston will keep the valve from falling, if your unsure if you got the right piston, just comress it slightly and if the keepers move down with the spring, your piston is not at TDC. Its actually pretty easy once you get the rhythm going.

Spring suggestions please!!!!!!

o and i am glad you can just use the piston insted ouf pulling the spark plugs because with my headders it is really difficult.

thanks, later

-ELi

anyone?

Call combination motorsports, they will hook you up and tell you what springs to get, thats what I did. Great service and these guys race like us, they know what their doing. They suggested Comp 612's for my CC306. Its got about 15 more lift capacity then what lift im running. You don't want too much pressure on your springs but you want about 15-20 more pressure capacity than the lift your gonna be running.