TurbomanKnight

I searched but didnt find a straight answer.


I have a 88 L98 with headers, no cat, and soon a ported plenum and intake. I also need injectors. I found a post for LT1 24lb injectors. And I was wondering if they would work and if it would be too much for my car? I'm worried about running rich.


Need some advice!




Thanks!

Fast355

iTrader: (2)

They will work great assuming the injectors are good. You will need to do some fine tweaking in the prom to make the engine run the way it ran from the factory. The increased flow will make the engine run rich in open loop before it warms up. You will need to file down the stands on the manifold where the fuel rail bolts by about 1/8"-1/4" each. The LT1 injectors were about 1/8" shorter than my stock 1986 Multecs. Otherwise when you lock the injectors into the fuel rails with the clips the injectors will not sit fully into the intake and you will have 8 vacuum leaks.

irocuroc

been there done that. 24's are to big for a l98.. the early lt1's 92 93 used 22's/ only the 94,5,and 6 use 24's because they have spfi not batch fire. i had probems up the *** trying to get the blm off 110.. go to FIC and get their design 3 bosch for the corvette. They are modified so you need not file any thing down on your engine to make them fit. Plus you won't have the crummy multecs that can't handle e10.. Too much work to change twice.. the whole set of 8 is like 169.
www.fuelinjectorconnection.com

Fast355

iTrader: (2)

I'll stick with the LT4 injectors (28#) that I am running in my 305. I even run 50 PSI. I am a DIY tuner though. IMO the GM LT1/LT4 tips (5 small holes) are of a better design than the bosch ones you speak of.

jamon8

iTrader: (3)

stock motor

stock injectors

why program a prom and buy a afpr when its not going to help you if you cant get more air and fuel into the combustion camber

formula_novice

iTrader: (1)

You can run 24# injectors on a stock L98... I've done this. The car will run fine. However I do agree that, in order to run optimally, you should program the PROM to adjust for the larger injectors.

Hope this helps.

Abubaca

iTrader: (3)

I ran 24 pounders on my ZZ4 cammed L98 with no problems for several weeks. Eventually I had it tuned.

They ARE in fact a little shorter, as are several other manufacturers injectors. You do NOT need to file anything down. If mounted correctly, the 1/8" distance is still down inside the intake manifold, and doesn't actually effect anything. 99% of the people (and there are a lot of us) that are running various shorter injectors have had no problems. While I can't be sure of course, my guess is that those who HAVE had issues with leakage where due to improper installation.

......I just re-read the OP. I'm assuming you need new injectors due to some issue with the stockers, right? If everything is working fine, keep what you have. Typcially the swap is done when the original 22 pounder take a crap. The reason 99% of us go to 24 pounders is because it's cheaper, they CAN be better quality depending on what brand you buy, and they are a LOT easier to find.

Fast355

iTrader: (2)

I could easily tell that when the fuel rail was bolted down there was no way they were going to seal properly. I could see light entering the intake port from around the injector o-rings (which were correct and new, btw). The injector bosses in my TPI lower intake (both stock AND Vortec) were tapered and would not seal until the injectors were inserted deep enough. It was a requirement of mine to run the injector to fuel rail clips.

Abubaca

iTrader: (3)

Well yeah......

That's kinda what I mean by "installed correctly"

....without the clips the injector can slide up into the fuel rail a little. On stock injectors, which we all agree are longer, it's not an issue. With shorter injectors, they're too short.

While I don't doubt the filing the posts works just fine, using the clips just seems to be so much easier.

Fast355

iTrader: (2)

Even with the clips in it would have still caused 8 vacuum leaks!!!!! I had NO OTHER CHOICE but to grind the posts or get longer injectors. Since I already had 8 low mileage LT4 injectors that had been cleaned, I decided to use them.

jv9999

iTrader: (1)

If you run a three wire (heated) O2 sensor it will always be in closed loop. The ECM will adjust the pulse width to keep the mixture right with 24lb injectors.

irocuroc

who writes your material. the lt4 first of all runs 26lb injectors. they are multec 2's part number 17124251 .the original documentation that was printed on the lt4 was for a much higher hp engine using Bosch design 3 28. Before production gm closed the ports a little to reduce HP. If you look at the casting of a lt4 head you can see where they filled it. They did this because they had the new highly tauted LS1 coming out in the 97. They did not want more HP from the lt4. at the same time they used in production a 26lb injector. Again a multec. The lt1 in years 94,-96 used 24lb multec. The replacement SVO (ford 24 is actually 25.2lbs at 43.5 psi.. Its too big for a l98. You will have low BLM's and the o2 will not compensate unless you tune ands then still you will have a air problem.. I know all about the lt4 because my dad has two 96 Corvette lt4's. Both have the orig injectors and both are never driven. What a shame. 1 more point the LS1 uses Bosch design 3 28 injectors. If the predesessor Multec was better why did they switch to Bosch. Maybe because Porsche uses the same one. Anyway, the Bosch 3 that you can get for the TPI from FIC is a direct fit at the same height as the multec, this way you don't have to cut the manifold down which is so mickey.

Fast355

iTrader: (2)

I don't need to read it when I had the injectors on a flow bench. 28# @ 43.5 PSI. You can run 30# injectors on a stock L98, NO PROBLEM AT ALL, IF you are DIY TUNING. You can go on about having an air problem, but if you are tuning its not a problem in the least degree. I could run 40+ on a stock 305 and still have it idle smoothly and not flood it out.

If you knew what you was having to be cut-down on the manifold you would know it is an easy 10 minute procedure.

The LTX multec injectors are vastly different than the plastic tipped early TPI garbage. THe later multec injectors are better than the bosch, BUT the bosch are cheaper which is why they are used now.

irocuroc

don't want to argue with you but you are comparing a Multec to a Bosch.. enough said

Abubaca

iTrader: (3)

Well, I certainly can't speak as to what exactly you had going on, and I'm not saying you're wrong. What I AM saying is that several people, run LT1 injectors with no problems. I had a set that I didn't want to use, but I compared them to my new Ford24# injectors and the dimensions were the same.
I would suggest that anyone doing the swap see for themselves and proceed accordingly. BUT, doublecheck before cutting your manifold. "most" people haven't had to do this.

the blur

if you can tune your prom, and have an AFPR, what is the difference if your running a 19, 21, 22, or 24 lb injector ???
AFAIK: NOTHING
you need to make adjustments for your injector sizing. the end result is still the same. your either adjusting your FP and/or PW to make the injectors work properly for your motor. I don't get why people are so hung up on injector sizing.

Kevin91Z

iTrader: (1)

But it will still run too rich in open loop, and at wide open throttle. The O2 sensor and the computer can only adjust so far. With stock heads and cam, larger injectors are NOT required and will only cause it to run rich.

Abubaca

iTrader: (3)

Your motor needs the proper amount of fuel. Can't be too rich or too lean.

Dale

iTrader: (12)

Agree. And while playing with the pressure and pcm can make a difference. You need to be in a reasonable range, then fine tune it with the pressure and pcm work..