Prototype Engines

[USAFPILOT]

Didn't GM build some 450HP LT5's that were gong to be installed on the 96 and up ZR-1s before the canceled the LT5? Did any ever find their way out of GM to a private parties hands?

[Kevin]

grahm at lpe had several next gen lt5's, not sure where they went

[tccrab]

I'd heard that a few of these engines exist but I've never seen a picture of one.

TomC

[USAFPILOT]

Originally Posted by tccrab

I'd heard that a few of these engines exist but I've never seen a picture of one.

TomC

me either...they probably look the same, but I'd like to see.

[A1990]

There were going to be differences, one injector/cylinder, variable cam timing to name a couple. Looks different too. This picture is from the 2008 Gathering.

[tomtom72]

At the 20th anni gathering over at JVD's BBQ I listened to Mr. Mclellan explain that they had a redesigned LT5 that was done to fit inside a C5. The motor was a clean sheet of paper because the C4 LT5 would not fit in a C5 as it was too tall and the C5 hood would hit our motors.

This next part I'm almost 100% positive of....Mr McLellan said that in 90/91 they had a C5 chassis, less the rear transmission as it wasn't ready yet, under cobbled together C4 body panels with a clam shell lowered to simulate the underhood clearance of the new C5. It was a test car to do testing on the C5 chassis & suspension, and it had one of these new LT5's in it and they were driving it around BG to test it! I swear I heard Mr. McLellan say that....I nearly fell off of my chair as he went on to list some of the improvements to the motor and that Lotus did this new motor specifically for the C5 program. It was rejected ofcourse due to costs?

It had the specific bore spacing that Lotus had wanted to use to suit the 4 valve head, it was to be a MAF system, one injector per cylinder, VVT, it met emissions for OBDII, it had no gas guzzler tax including the ZO6 version of the motor, and they even had a version to use in the C5 ZR-1. I think I remember that the ZO6 version was to have 600 hp, and the ZR-1 version was to be close to 700 hp w/ a gas guzzler tax ( I'm not 100% sure on that as I think I was crying by then! ) and that the regular corvette base LT5 was 450 hp! Oh, forgot this part, Mr. McLellan said that all these motors were N/A.....I think that's why I was crying or writhing in pain by then. Can you imagine what the reception would have been like for the C5 with 450 hp as the standard motor?!? I mean the car was a hit with the new chassis.

I know one thing....when I was looking to buy back into the corvette hobby back in 04 the only C5 that held my interest was the ZO6....the "standard" vette not so much. I chose my car to spend my cash on, my 90. If the C5 had used the new LT5 I would have taken a loan to buy a new ZO6 rather than buy a C4 ZR-1....I know you can have me turn in my power key, but the C5 chassis is ( IMHO ) just that little bit better than the C4 chassis.


Tom

[USAFPILOT]

I'd like to think that Lotus probably owns the rights to the design of that LT5, but maybe GM is waiting for the patent to expire or something. I hope they go back to the DOHC with the next gen vette. Didn't they shelve plans to build a new DOHC family of engines right when the economy tanked and they took all the money from the fed to stay in business? I bet we see that ramp back up again soon.

[tomtom72]

My thoughts on Lotus having patent rights would be that they were owned by GM at the time the LT5 was developed. I got the impression from Mr. McLellan's talk that as soon as Mercury Marine was making production motors Lotus started making the next gen LT5 "prototype" motor for testing....which would mean that it belonged to GM.

The thing that always amazes me about the LT5 is how quickly the motor went from an idea to a motor legal for use in a production car. Them guys were burning some serious midnite oil! Heck the LSx development started around the same time conceptually. I'm sure Mr. McLellan mentioned at the BBQ that by 90 or 91 it wasn't available to use in C5 test cars yet because I remember him saying that there were two chassis test cars. The LT5 one, and the other had an L98 in it. They used an L98 because the motor dimensions were almost the same as what was going to be the LSx.

I will add this as it is just my impression from listening to Mr. McLellan's talk at the BBQ. He wanted the next gen LT5 before the LSx was even out of prototyping so he could have it for the C5. I mean his crew designed the C5. I got to say that this is just my speculation. He never said this at the BBQ, but if you were there and were watching him while listening to him...well I got the impression that the new LT5 & the C5 was the direction he wanted corvette to go in for the future. JMHO.

Just as a fwiw. His book, "Corvette from the Inside", is worth reading along side the HOTB....it kind of gives a more complete picture of not just our cars, but the engineering philosophy that makes the corvette.


Tom

[bdw18_123]

Cool picture, A1990! I've never seen a picture of a gen II LT5. Wasn't even sure if any of those motors existed. Got anymore pics of it?

[USAFPILOT]

I just wonder if that Gen II LT5 would actually be GM'snew line of DOHC engines that were cancelled a while back. Were they bringing it back or were they just doing something different with the Northstar V8?