What are the differences between a 92 LT1 fuel injection system and the LT4 fuel injection system? Does it make a big difference in power and or fuel economy? What I thought I understood was the 92 has a batch system and the LT4 has a sequential system. What does that mean?

Batch system - all 4 injectors on a side fire off at the same time. Sequential they fire individually in sequence with the cylinder firing. You will find very little difference between the two systems.

Sequential Fuel injection started in 1994 on LT1. Can be found on both LT1 and LT4 after that time.

LT4 injectors are also 26.4lb

Not to be anal... but I have been corrected.

Batch is when all 8 fire. What we have in the 92-93 LT1 is bank to bank.

I disagree with the assessment there isn't any difference. The logic systems are most different. And then there is result... my 1992 LT1/MN6 will get no more than 27 mpg highway. The 1994+ with LT1/MN6 (and even the LT4), will get over 30 mpg highway without issue. Several people I know get in the 31-33 range. And the only real functional difference is the change from bank to bank to sequential. There might be more memory or even faster operations, but those will not result in 3-5 mpg increases of this nature.

I will be honest that I personally drove my 92 LT1 (with roller rockers and shortie headers) from Washinton DC to Lake Wylie, SC, (near Charlotte) on 3/4 tank of fuel and averaged 36 mpg. And that was all cruise control at 65 mph. Also had new tires and the top up. At times my instantanous read out was in the 40's. I realize that after I complete this project of LT4 top end and a hot cam that I will never see that mileage again. But the fun pedal should be better. I found a site that showed all the differences between the LT1 and the LT4. That answered most of my questions. Thanks for the replies.

The best I can show proof was 31MPG obtained on flat highway. This was with factory engine and heads before any mods. I reset and recorded the following photograph.

Now with the 383 the best I have seen was yesterday 22mpg highway. Around Town and City is about 17-18mpg.

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32 highway on my 92.

Don, I wish mine got that good around town, at about ~12. I get a little better on the highway ~25. Curious as to why...

Back when my 92 was stock (well it had a Corsa).... the best I got on a real trip (DC to Newbern NC) was 28mpg average for the entire trip. Thats running 75mph in VA and 80mph in NC on I-95 and 65mph in a 55 on state roads.

Shorter 50-60 mile rides straight on the hwy it would get 33mpg if I drove easily.

Now with the big motor mileage is not that great. About 9-11mpg around town and on the hwy I averaged 24mpg for a 25mile drive. We'll see how it does on the trip to Carlisle in a few weeks.
Will

I'll be up in Carlisle, too. I'm flying up and going with my brother-in-law who owns a new Grand Sport. Might as well go in style. We'll hit the Sat show.

I did take a picture of my dash showing the incredible mileage. I'll have to find it. People don't believe my story," how can a 300 hp V8 get into the 30 mpg range" is what I get from non-believers.

Mine only gets about 12 around town, mostly cause I am still in open loop.

Once warmed up, it jumps to 15-16.

On the highway, last March I drove out to Riverside for three days of movie festivals and such (Riverside Legends III) and averaged 21 on that run, but that's LA freeway driving... one moment your doing 80, the next 30. Go figure.

When I clocked my 27 average, that was going to FL in 2001. I did 2 different mileages, one overall, from Dover, DE, to Lake Placid, FL, where my brother lived at the time. 1065 miles. Overall, it was 25. That included a lot of rural country roads and urban cities getting from Dover to south of Washington, DC (Rt 10 from Wyoming, DE, to Md 304, to Md 301 to US 50 to Beltway to 95).

The overall was from about Woodbridge, VA (or Quantico, VA, really no difference) to Deland, FL, just west of Daytona. That was 27, cruise set at 75-80.

I didn't include that cluster of Orlando or the rural highway from I-4 to Lake Placid (US-27), too damned many old folks, tractor-trailers and traffic lights.


I suspect if I had laid off to 65 that my MPGs would have gone up a bit, maybe 30... I don't see my 92 ever hitting 36.

Don't get me wrong, I do use the fun pedal and it's like flushing a toilet into my engine and the mpg disappears. If anyone else has done the LT4 heads and intake upgrade with a hotcam, what mileage do you get? I know with this upgrade not many are worried about gas mileage. Just curious.

One other thing, I thought the LT4 injectors were 28lbs