74 LS4-454

Also posted on the ZR-1 forum......as pointed out there are some inaccuracies with the HP & TQ info in one screen shot.....

Passing time and searching the net for some ZR-1 related items and came across this video that was part of the 93 Corvette Owners Manual pack. Scrolling through the video there is just about 3 minutes dedicated to the technical advancements from the 92 LT5 to the 93 LT5, which of course also effected the 94 & 95 LT5's.
It starts at 46:42 and ends around 49:22
Thought it may be of interest to those who haven't seen this video.



Enjoy......Tom

Dynomite

Excellent post and some very interesting but subtle 1993-1995 Engine design considerations

I have to watch the mixing of my ZR-1 Heads, Injector Housings 1993-1995 with 1990-1992 components which would compromise the improvements

mike100

6:02 minute mark ftw

74 LS4-454

Yes, very interesting to note as the engineer stated how the Heads, IH's and the Plenum were port matched for better flow, if I am understanding this correctly.
It appears to me that more porting is done and more advantageous on the 90 to 92 models then would be on the 93 to 95 models. Although I know owners with 93 to 95 models who have had or have done some porting themselves, and from what I have observed, have had good results.. I would also imagine that you would have to be much more careful in the amount of material being removed, as the later items were already done at the factory. JMO

And you probably do need to be careful about mixing and matching...

74 LS4-454

Always very enjoyable to watch JH shift through the gears....he was one of the best at that time!That clip is also in the 92 MY video.

billschroeder5842

Don't' overlook the fact that the exhaust was modified which helped quite it. The mufflers stayed the same but the resonator was changed with the inside diameter opened. The early model had a 1 5/8 and the later models had 2 5/8 which more closely matches the rest of the exhaust.

74 LS4-454

Another good point.....along with the other changes in the parts used and improved for the 93 MY. And from what I understand the Cam timing changes also contributed to the increase in HP. That 30 HP increase was a nice jump for the time from one MY to another. Although from what I have heard and have read, is that you can't tell to much of a difference between a stock 90 to 92 and a stock 93 to 95. I can't confirm one way or another, as I have only driven my 94. And not that it really matters, I am just happy to own a ZR-1, whatever year it is!!!

Rkreigh

funny story about the injector "bump" in the injector housings. GM was going to use a different injector and went with the multics but didn't revise the casting. Later 93 they took out the bump which indeed means that the earlier cars benefit a bit more from porting.

The dunns heads came about when AL Birmal couldn't fill the last orders and some of the later cars have one Dunns and one AL Birmal head as they cleared out the inventory. The Dunns heads are somewhat legendary but the truth is once you mod and port there is potential in ALL the castings and the LT5 delivers regardless of year.

Take a look at what Demps is doing with porting. He's burning some midnight oil to get the best flow out of the heads and intake and really doing some gorgeous work.

I've been out of work and lucky enough to spend some time seeing the work in progress and it's amazing. Demps is very reasonable too and it's sure nice to have him in the area.

74 LS4-454

Of course the technology and the know how has increased vastly from that time. And now people are willing as before, to push the limits into seeing what other gains can be obtained.
I for one am satisfied with the performance of my 94 Z. It runs really well and always puts a smile on my face. Also the fact that I have the 82 and the 74 BB coming back to life this year, puts a limit on the amount of $$$ available for the ZR-1. If I didn't have the other two, I would probably be more open to try out some mods on the 94.
With that being said, I did purchase a lot of replacement items from Jerrys to make sure I keep the 94 running the best way it can...
Either way, mods or no mods, still a pleasure to drive each and every time, but then again have felt this way abut every Corvette I have owned.......

ghlkal

OP, nice find.

Thanks for sharing this