I'm installing LT1 injectors in a L98. (with a Super Ram intake)

I did a search and found the impedence difference to be OK, but I didn't see a clear consenus on if the fuel rail towers need to be shaved or not.

When I installed the injectors in the fuel rail, I pressed them all the way in. When I installed the injectors/rail assy into the intake and tightened the 4 bolts, the injectors don't go all the way into the intake. I looks like the O-ring went in far enough to seal, but I'm concerned that the injectors will get sucked down by intake vacuum and possibly pop themselves loose from the fuel rail.

Also concerned that if the injectors don't pull down into the intake, will the spray pattern hit the flange at the bottom of the inj cavity or will the spray pattern be tight enough to spray through the hole and into the runner.

 

the clips that hold the injectors to the rail will prevent the injectors from getting "sucked down" away from the rail.

I run the LT1 injectors first on the stock intake and now on an accel intake. Are they a bit shorter? yup. Does it seem to matter? nope. Have I had any problems? nope.

 

I run the SVo injectors which were a tad shorter than stock...mine leaked so I shaved down the fuel rail posts...problem solved...I'd say install, prime and look...if they don't leak...the probably never will...but If u want to be sure shave a little off the posts....

 

Oops, forgot abt the clips. Got the ones off my old injectors. With the clips installed, the injectors are a little further into the intake. Looks like it will work.

Now all I got to do is figure what sequence to install the remaining TPI parts. Everything is aftermarket and nothing seems to fit..
Can't tighten the runners without looseneing the fuel rails.
Can't install the plenum without looseing the runners.
Can't tighten the fuel rails with the plenum installed.
Good grief....
Screw it, I'm going to bed..

 

I run the LT1 injectors with stock rails and have no problems.

First are the fuel rails. bolt them in and connect the fuel lines. Then, wrestle with the runners to get them to mate with the intake and start all of the bolts but don't tighten them. Stick the plenum on there and start the bolts. Once they're all started, tighten them up! Make sure to remember the MAT sensor. I forgot that once and had to rip it all apart again

 

I'm using Accel runners. I tried to get them on with the fuel rails tightened, but no way..
Also had the leave the fuel rails loose to tighten a lower runner bolt on each side.

Eventually had to fabricate a custom wrench to tighten the right front fuel rail bolt after the plenum was installed and the bolts tightened-up.

Some allen bolts and a long t-handle allen wrench would have made life much easier.

 

I just got a set of LT1 injectors from a fellow thirdgen.org member. I want to install these on my stock L98 car, the question is, will I need to get any computer work or get a different MAF sensor? Someone once said that when going with larger lb/hour injectors you have to change out the MAF sensor to make up for more fuel being pumped? I think its all bull that just confused me, will I be alright with my stock MAF sensor? My computer is upgraded to 89 TPI code by the way.

 

You will probably need to change your single fire and double fire constants in the S/W.
If you leave it as is, it will most likely run rich in open loop (which includes WOT). Might be OK during cruise, but BLMs will be low. All depends on how close to perfect it was before installing the LT1 injs.

A wide band O2 is what you really need to verify open loop operation.


The MAF should be OK assuming you haven't made any serious air flow mods.

 

The L98 I have is all stock, minus the upgrade to 89 code that disables the cold start injector. Can you give me some more details please on how to start this? I will obviously need a programmer to start tuning the computer, I can get info on that on the threads here.

Can a wide band o2 sensor be picked up at a local auto store?

 

There are a few different ways to go abt programming the s/w.

To do it the way I did,
Basically, you will need:

1. To have a copy of the bin file you are using. (free download, or get file from your current chip)

2. Use an bin editor to change the fuel inj constants in the bin file. (free download)

3. Use a chip burner to copy the newly modified bin file to the chip. (This will cost $100-200)

4. Install the chip. (I installed a ZIF socket to make chip swaps a lot easier).

The stickies in DIY PROM will help a lot!! That's where I learned ~95% of the stuff I needed to do.

The wide band O2 meters can be purchased on the net. Never seen one in an auto parts store. There are plans to build one available on the net. That's what I did.

You will also need a way to monitor what the ECM is doing. That was a free download also, but had to build (~$40 in parts) a MAX232 high speed serial adapter so my laptop could download ECM data faster. It downloads pretty slow without the high speed adapter.
I think it's like 160 baud without the adapter and around 9000 baud with the adapter.

Don't quote me on the baud rates, but you get the idea. It's been a couple of years since I tinkered with the s/w. There's been a lot of new products that came out in the last 2 years. Spend a few evenings reading the DIY Prom board, especially the stickies.

Good Luck!!

 

Ahh thank you for the help. Will I need to get an adjustable fuel pressure regulator as well to handle the increased fuel flow?

 

I have 24 lb LT1 injectors on my 305 tpi.
I used the stock fuel rail and new O-rings and hav had no problems.

At idle, it really is rich.
But the idle quality is fine and so is the driveabliity.
The only thing I lost is miles per gallon.

Some day I will figure out prom burning and see if that will help.

 

the LS1's are shorter but i dont think ther LT1's are.. i changed my LS1's because they caused leaks

 

I just got a gasket kit for the intake, runners, throttle body for the soon to be injector swap. The problem, the kit comes with only 4 o-rings for the LT1 injectors. When looking at the injectors they have an o-ring on the feed side as well as the spray side......do I need to replace both sets of o-rings and thus get another set?