If I swap out a ls1 intake with 24lbs injectors to a ls6 intake with 28 lbs injectors, will I need a tune or a computer adjustment? Also is there a difference, performance wise, with the newer by wire throttle body on the newer ls6 manifold than the one that was on the ls1 (99) manifold ? I know if I use the newer throttle body I will need the by-wire adapter and the coolant tubes and plugs for the manifold swap. Thanks

 

yes you would need a new tune.

 

You will have to compensate for the larger injectors

 

i disagree. yes a tune would make use of the bigger injectors but the car will run fine without a tune. how can i be so sure? i drive the snot out of my 99 with the same setup you are proposing.

 

BTW, you can use your original throttle body (the LS1 TB is the same as the LS6 TB).

 

You can drive the car without tuning it with larger injectors, but you will waste more fuel, run more rich. If you get a tune, that will will be addressed and the A/F ratio will leveled out.

 

I also ran the same setup on a 99 with a ported throttle body without a tune and it was fine, no problems. I later got a tune and it was much better but no real problems without it.

 

When I installed a LS6 IM on my '99 I too installed 28# injectors. I drove it to the tuner that way and had no issues...

 

If your engine is stock why dont you just reuse your 26# injectors, the 28# apparently will not add any power, as for the new air flow your computer will relearn/adjust to it.

 

Yep, you don't need the extra fuel unless you're doing more. Stick with the 26# now and install the 28# when you do a cam.

 

The 26# injectors will run near the max duty cycle, the 28# will run with reserve, or more room for later improvements. There is a informative post somewhere around here with the data. The computer will learn the new air flow fairly quick. In my case I saw a small improvement in fuel economy and it doesn't run rich. My Ti exhaust tips are clean on the inside with no sign of wetness like my Jeep with no cats and bigger Ford injectors. As far as a improvement in performance, it was minor. I did the swap as part of the foundation for where I'm heading in the end. Next weekend will be the LT Headers, cats, and x pipe. Later in the spring I hope to do the heads and cam. At that point I will dyno tune. I hope by then I'm done, but you never know.

 

http://forums.corvetteforum.com/sear...rchid=14695476

http://forums.corvetteforum.com/c5-t...e-450rwhp.html

 

Guys, thanks for the responses. I should have been clearer on my engine. It is a 372 stroker with cnc'd ls1 heads and forged bottom. In 99 there was'nt a better manifold than the ls1. I was going to swap to the ls6 manifold for now and get a set of headers in the future. I would love the fast intake but can't justify the cost at the moment. I want to hold off on a tune until I get the headers. By the sound of things I should be able to go with the 28 lbs injectors since the engine is modified, it also has a mild cam. According to the builder it has about 435 hp at the crank when built in 99. I never had it dynoed and I am considering to get one for a basline, and to see if I am indeed at 435 as stated by the builder, bought the car used a few years ago. After the intake and header install I know I will definatly get a tune to get the most out of it. I was getting very different opinions regarding the tune after the intake swap, most saying its a swap and thats it, I did'nt know about the injecter difference until I started researching this. Is there a way to play with the fuel management without messing up the builders original tune or is that considered part of a tune. Thanks again for all the insight. Just measuring twice before I cut it once.
Frank