Who makes the best, what are most people using? They are for a 350, cam, AFPR, headers, ported plenum, other than that, stock.

 

Think most are using Accel or SVO. Any good quality injector would do.

 

A Few things to Remember....

Stock LT1 Injectors are 24# - Suitable for a warmed up L98

Stock Ls1 Injectors are either 26# or 28# - Suitable for a pretty Hot L98

Ford Motorsport SVO injectors are rated at 38PSI, and as a result flow on the average 2# More at TPI pressure.

Any Injector Flow Rating Change from Stock Will require a Corresponding Change of the injector Constant in the PROM.

Slight Changes in flow Rating can be fudged for with a AFPR, but beyond ~2# Don't Count on it.

If I was Buying New Injectors for my L98, I would personally Go with 28's or 30's.

Small enough not to have Minimum PW problems at idle, Large enough to Not break a sweat on all but the most radical street builds.

 

Bort62, a little correction needed here.

When quoting what a specific fuel injectors flows, you have to know the fuel pressure for what it is rated for.

The factory '99/'00/'01 injectors flow the same amount as our L98 injectors,,,22#/hr rated at 43.5psi. My '99 LS1 injector is said to flow 26#/hr,,, but that is at 58PSI. The injectors in my '87 L98 IROCZ and my '99 LS1 SS are the same injectors if flow rated at 43.5psi.

The earlier LT1s do have 24#/hr injectors (at least some of them, I think the '93s and '94s). Later, someone can correct me here, the LT1s had 22#/hr injectors.

SVO injectors are rated at about 39.5psi. So a 24#/hr SVO injector in my '87 car with a stock fuel system (43.5psi fuel pressure) will actually flow about 25.2#/hr. In my '99 SS, these same SVO injectors will flow about 29#/hr.

Injector flow rates can be very misleading if you dont know the base fuel pressure used to flow rate the various injectors.

If you have a nice highly modded L98 still at 350 cu in., the SVO 24#/hr injectors is a good choice. The SVOs at higher fuel pressure should have no problem making up to 450Hp.

 

24's, SVO. Use the AFPR (bad idea) or change the injector constant in the prom (good idea.)

With 30's, you have a real good possibility of having too low of an injector pulse. I wouldnt do it on a mild 350, and I'd question it on a somewhat more radical than mild 350.

 

Can anyone else confirm this or can you point me to where you got this data? I currently have 22# injectors on my 383 set at 52PSI. I may waiting on a set of 26# LS1 injectors that I just bought. If what you're telling me is true I just wasted my money because they won't flow any more than my current ones. How do I determine my current flow rating? If stock injectors flow 22# @ 43.5PSI then what do they flow at 52PSI? Or am I missing something? Thanks

 

I may Be wrong, But I don't think the LS1 Injectors are Rated at 58PIS.

Kevinc Would be the guy to ask.

That Was a little brain slip on my part, however. I forgot the LS1's Operate at a Higher pressure.

Madmax, 30's are about the limit without having min PW issues at idle. At least from what I have seen.

 

From my Corvette Fuel Injection & Electonic Engine Management book...

L98: 34-40psi (1985)
L98: 37-42psi (1986-1987)
L98: 41-47psi (1988-1991)
LT1: 41psi
LT4: 41psi
LT5: 49-55psi
LS1: 55-61psi

 

On occasion when warm at idle, I've seen the PW's drop below 1.5ms, the threshold in the prom I have was 1.49ms. I wouldnt exactly call the engine they are on a mild engine.

 

DannyT,

Very sorry to say but I think that you wasted your money. Sell those LS1 injectors. I have both cars, '87 and '99, I am 99.99% sure of what I say is dead on correct!

For a 383, you could install 24#/hr SVO injectors. I am running these in my highly modded '87.

Here is an equation for you to estimate the flow rate of an injector at other fuel pressures other than what they are rated at:

new flow rate = (rated flow rate) * square root of(new fuel pressure/rated fuel pressure)

example: (24#/hr SVO injectors, rated at 39.5psi) but now fuel pressure is 52psi

new flow rate = 24 * sqrt(52/39.5)
new flow rate = 24 * sqrt(1.3164)
new flow rate = 24 * 1.147
new flow rate = 27.5#/hr

This is a well known equation and gives you a very good estimate of the flow rate at other pressures.

For your 22#/hr at 52psi:
new flow rate = 22 * sqrt(52/43.5)
new flow rate = 24.0

Does this help?

 

What's up, fellas? This is my first posting on this site and would like to say "hello" and tell you that I'm quite impressed with all the info floating around here.

After having owned quite a few 2nd gen and 1st gen firebirds - I (finally) purchased my first 3rd gen GTA with a TPI 5.7 and found that it is a completely different world. After having owned Jap/German cars for awhile the old American fire came back and I decided to pick up a couple of cars to play around with. One is a 70 Formula 400 which was fun, simple and almost finished, and a 87 GTA which I am totally lost with.

The GTA is a TPI 5.7 w/700R4 and bone stock at 57,000 original (unmaintained) miles with the only modification a flowmaster 80 muffler on it. When I brought the car into my friends shop to check out, he told me it would probably be a good idea to change the injectors as he suspects that some are dripping.

The very first things I'm thinking about doing to the car is to help it's breathing so...I plan on porting the manifold, plenum, and get new runners (slp/siamese or arizona speed/semi siamese) port the throttle body 52mm and do up the exhaust.

Here's my question - since I am driving this car on a daily (now) what kind of injectors would you recommend I get right now that will add performance, but will be compatible with the performance upgrades that I'm planning?

I found this company (fiveomotorsports) that sells slightly used test injectors off of Fords for about $160 a set rated at 21. Can I put these in or higher flowing ones without playing around with anything else?

Any input would be appreciated. Thanks!

 

One option is to have the stock 22# injectors cleaned and flow checked. Call Rich at www.cruzinperformance.com


I have used Rich in the past, I highly recommend him.

 

Well, I realize im out on a limb here with no evidence on hand to support My Claims, But I still don't think Ls1 flow rates are measured at 58 PSI.

And I find it hard to belive that 28# Ls1 Injectors are the same as our 22# units.

Would be good if somone with more knowledge than I could clear this up

Apart from the, Most motors radical or not are going to have similar fuel demands at idle Christian. We never saw less then 2.0 BPW on the gta, but then again BLMS were a little low.

 

I thought that I said that:

L98 22#/hr injectors are same as '99/'00/'01 LS1 26#/hr injectors.

and

LT1 24#/hr injectors are same as '98/'02 LS1 28#/hr injectors.

Well, call Rich at www.cruzinperformance.com, he is a very knowledgeable person concerning fuel injectors. Rich should be able to answer many of your questions about fuel injectors, he does not sell them the last time that I called him, so dont be worried, he will not try to sell you fuel injectors.

 

I was going to send mine to Rich but he told me mine were some of the worst ones ever made and I would be much better off to spend the money for new ones.

 

Im just wondering where you got that information. If your right, your right.

Im just being skeptical as I have heard circumstancial evidence that would indicate otherwise

 

Not sure what you mean my "same" but visually the L98 and LT1 injectors bear no resemblance at all to the LS1 pieces. Same flow rate?

 

Not sure what you mean my "same" but visually the L98 and LT1 injectors bear no resemblance at all to the LS1 pieces. Same flow rate?

 

I think he meant approximately the same flow rate

 

Yes, I mean same flow rate at 43.5psi.

I have no doubt that the actual '87 and '99 fuel injectors are different units with different part numbers. And that the '99 fuel injectors are of a better design as far as the pintel and electronics is concerned.

But they have the same flow rate if rated at the same fuel pressure.

And there is a side issue that we have not addressed, batch fire vs SFI.

Because my '99 car is SFI, 100% duty cycle is reached at 6,000rpm when the injector PW is 20msec. However, for my '87 batch fire car, 100% durty cycle is reached at 6,000rpm when the PW is 10msec.

This I think is an interesting point if someone is calculating the size of injector for a specific engine based on a batch fire or SFI car.