Stock LT1 24# injectors, support 350rwhp?
 

Title says it.

94 LT1, believe stock injectors are 24#. Collecting parts, LE head heads flow 270/185 at max lift (purchased CC502). Guessing somewhere between 325-350rwhp once all together. Fuel pump and injectors are original. My plan was to have the injectors cleaned/benchmarked by FIC. Planning on mail order tune. Am I better off going to a larger injector? The stock fuel pump is healthy on my stock-ish combo - presuming it is not failing, is it up to task? Believe many have run stock pump/injectors on cammed combos with nothing more than a tune, unsure if with headwork the stock hardware is still capable.

Yes, I ran a similar combination in my 94 with stock injectors.

Also turned up the fuel pressure and ran 375 rwhp with a different combination, still using stock injectors.

Instead of guessing, why not get a dyno tuner to tell you what his experience is and what he suggests you get as a COMBO instead of you sticking this cam with that intake and that head. Have someone work you a SYSTEM and not a great cam in this car mated to a great set of heads from that car, etc, etc. Really wouldn't bother with "guess a tune". Never had one work better than when a tuner sat down with a dyno and made improvements till no more can be had.

Easy answer... no one dyno tunes these things anymore or want a prohibitive amount of money to do so. They’ve moved on to newer platforms.

Mail order tunes have been successful, these aren’t exactly new combos anymore. It might leave a little power on the table... fine by me, street car/weekend toy.

Glad to hear stock pump/injectors worked for others. Planning on going this route unless there is a failure.

Even with mail order tunes like Ed Wright, I'd still talk to him about what he feels the necessary fuel injector size will be for the combination.

starting point - https://www.onallcylinders.com/2012/...injector-size/ -

this should get you in the ballpark - :rock:

What is the definition of "prohibitive"? From what I have seen it is about 3 or 4 hours of dyno time which includes having to strap it down and take it off and put wear and tear on the equipment and later on having to drive it around to make sure it works all over besides at WOT.

It will either leave some power on the table or the tuner is reckless. Neither is a positive in my book. That said, there is yet another issue. Assuming I am not racing, much of the time is NOT at WOT so I need it to have street manners. For example, my Powerstroke seems to run well with the tunes. That said, I still had to datalog and go back and forth to get the DD part where it isn't jerky or isn't responsive enough. Fine balance which requires fine tuning. The reason "Guess a Tune" has been successful is because it is cheaper and people are not able to be picky when they want to pay less.

If the stock injectors are Multec, you have to stay away from any gas station that isn't having 100% pure gas. You have to be around familiar stations. Even if I was at stock size, Multecs would be the first thing to hit the trash can because of the limiting factor.

I get that your are passionate about a dyno tune, but understand that the success rate of mail order tunes is proven for a pretty standard combo like this.

Yes, dyno tune better - no one is denying that. But to crap all over the track record of mail order tunes and blanket label them as “guess a tune”, well it’s kind of unfair.

Here is why many have gone mail tune:

1) it’s convenient
2) the cost is far less
3) you can still datalog/refine with the tuner
4) you don’t have to go hunting for a tuner that is willing to touch a 25 year old car
5) proven track record, lots of LT1s running around with these tunes

Wouldn't be fair if I didn’t list some of the drawbacks:
1) some power/efficiency left on the table
2) every car different, some small margin of error
3) no local support if things go wrong
4) you need the hardware and software to flash your pcm (I have both) or you are forced to physically mail your pcm to the tuner and face extended downtime

I believe the 94 injectors are of Bosch design and not as susceptible to ethanol as the Multecs (thought that was primarily an L98 issue).

Also, the aim of this thread was really to see if others have successfully used stock injectors on mild heads/cam cars. Answer: yes they have.

FWIW, When my car was stock, other then headers, hot cam and a set of ported LT1 heads, I made 362 RWHP on stock injectors, 22's on a 93...... That being said they were maxed out.
Tune was by PCM4Less of NC.... His mail order tune made within 5hp of what his dyno tune did. Yes I had both.

I pretty much agree with jmgtp, but would like to add, your tune, being dyno or mail order is only as good at the tuner.... Just like mechanics. They are not all equal.

You mentioned sending your injectors out to be cleaned-tested. I have one suggestion,

Talk to your tuner first.
Consider the cost of having them cleaned vs upgrading to 30's
You may never need them, but it gives you room for growth not to mention you will be running at max capacity for the stock injectors.
Also consider that GM put 28's in the LT4.

Just my 2 cents worth.

Hi 93ragtop - thanks for the reply. I’ll certainly ask the tuner about that before spending on cleaning the 24# injectors.

Not telling you what to do, but really you should consider contacting Alvin at http://www.pcmofnc.com/ I cant say enough about how good he was to help me. Especially after I had got burned by another so called tuner.
IMO dyno tunes in some cases are not needed.
If you have a common combo. that they have dyno tuned before, it should work on your car.
The factory, dyno tuned 1 specific corvette. Then they used the same tune in many......
Basically, its the same thing if your combo is one they have tuned before.
Just my opinion

How about a ranking/recommendation of mail order tuners?

I've heard good things about Ed Wright (from my F-Body days) and I think Lloyd Elliott recommends Moe Bailey
I've also heard a guy that was really good left PCM4less

I agree with you except for 3 and 5. I don't know how they data log. So while they can, I don't hear much of it being done, do you? Mostly I hear "just fine" and I am not sure what to think about it. Unless you have a laptop with software to log, it does seem like a SOTP guess on the owner's part and another guess of what to do based on some facts you give me. Again, if cheaper but imprecise is fine with you, I'd definitely go cheap and easy.

IF being the operative word

PCM of NC was great to deal with in my case.

When I was in your position I went with a hotcam because it was a common combo, knowing I could trust a mail order tune. No one around here touches Gen2 LT1 stuff, so I was nervous going the mail order route with a less common cam.

However, if I were to do it again i'd prob go with a more modern cam as PCM of NC was great to deal with. I data logged the initial tune which looked to be spot on, and they confirmed after looking at my logs. I'd have no problem going back with a combo that would take a couple rounds of back and forth.

How long ago was that?

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Originally Posted by aklim (Post 1599283636)

IF being the operative word

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Well lets look at the OP.
1. LL ported heads with flow numbers
1. Comp cam. CC502.

To me, that is common, and is probably something that Alvin has already dyno tuned. Again, I would ask him.

Data log with what? Eons ago, I had Jim Formato using Diacom. He sent me the cable and we had to make several goes at it. Lingenfelter who designed that combo had to make several tweaks. This is why I wonder how anyone is so good that they can get it down with one shot. Hitech custom ground the cam and 383 combo and it took them a while to get it perfect which includes driving under different conditions to get the low to mid range just perfect. It was very close as an initial offering but may I am just more picky about how the car performs when I am on the street as opposed to a WOT run they got pretty quickly.

I’m planning on using Datacat for logging. I’ve had tons of success on other GM cars with TunerProRT but it just doesn’t want to jive with the LT1. I have pulled the bin from the PCM and made tweaks in TunerPro but real-time logging just won’t work.

I’ve reflashed the PCM a few times for things like wheel size, gears, fan temps. That works no issues with TunerCat.

Also just to add... I think a big part of the success is that it has all been done before. A small part of the reason I went with an off the shelf cam over a custom grind was that it is guaranteed that mail order tuners have seen and tuned this combo before.

Last summer

It’s a PITA but ive had success with datamaster which is what I used. It’s the only program they will work with as far as I understand.