Conversions & Swaps LSX Engines in Non-LSX Vehicles
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L92 into 3rd gen.

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Old 10-13-2009, 09:41 AM
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Default L92 into 3rd gen.

I'm looking into swapping a L92 into my car. I plan to get a LS1 4th gen parts car for the harness, accesories, PCM, transmission, etc. I know I'll need to get the adapters for the LS1 harness to work on the L92 (going to use the car intake, not the truck). I plan to delete the VVT, etc and cam the engine. Are there any major issues in getting the PCM to run the L92? From what I've read, the only thing is the difference in the MAF plugs and injector plugs, but I may have missed something...
Also, I'm using a cable throttle.
Old 10-13-2009, 09:41 PM
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Uhhh, no offense, but what's the point??? If you're going to get rid of the VVT, the DBW, and everything else that actually makes it an L92, then heck, you might as well just get an LQ4 or similar older engine that already has the stuff you want.

It's not even worth trying to make the ECM from the LS1 car try to run the newer engine - not only would you have to replace the water pump & front accessories, the oil pan, the intake, etc., but the L92 uses a 58x crank, while the LS1 ECM is strictly 24x.

Also - you won't be able to use the intake manifold from the LS1 car on the L92 - the intake ports are completely different. The LS1 uses the older "cathedral ports" (tall & skinny) while for the newer L92/LS3/LS9 engines, GM has gone back to rectangular ports (think of a big block Chevy engine, & you'll be fairly close).

I have an L92 in my thirdgen, but I've kept the VVT, used the E38 ECM & the correct truck harness, etc.

Like I said, I don't mean any offense, but with everything you're looking at replacing, it seems like you'd be a LOT farther ahead if you were to just start with a more suitable engine. The extra 12 cubic inches between the 6L engines and the L92 aren't going to make that big of a difference for all of the extra work you're looking at.
Old 10-15-2009, 09:15 PM
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Sorry it took me so long to reply.
I want a L92 to get the heads and long block all at once. I'm also interested in the weight savings, and 6.2s are all aluminum while most 6.0s aren't- LS2 6.0 blocks are still pretty high and don't have the superior heads of the L92.

I knew the differences in the ports and that the LS1/6 intake wouldn't work on the L92, I was refering to the LS3 intake. I was under the impression the LS1 harness would work with the L92 if you used the correct adapter harness with the injectors/MAF. I didn't know about the difference in the camshafts.

I've seen in most situtions people seem to be deleting the VVT in the L92s, but I was also aware that camshafts were available for the L92s with VVT, so I thought there would be some advantage to deleting it.

I'm still in the preliminary stages of this (was planning a plan jane LS1 swap), so I'm just digging for info into what will work and what want. I'm already ahead from your one post lol. New series of questions-
Won't the accesories from the LS1 F-bodies work with the L92? I don't see a truck oil pan working in a third gen, so I'd need at least that right? Why did you decided to keep the VVT?
Old 10-16-2009, 10:25 PM
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Originally Posted by 91_RS_LS1
Sorry it took me so long to reply.
No worries, it's taken me a while to reply as well...

Originally Posted by 91_RS_LS1
I want a L92 to get the heads and long block all at once. I'm also interested in the weight savings, and 6.2s are all aluminum while most 6.0s aren't- LS2 6.0 blocks are still pretty high and don't have the superior heads of the L92.
OK, I can definitely see wanting the weight off the front end, so that you could have a more "finely-balanced" car - that was a motivating factor for me as well. And better cylinder head flow is definitely a plus, so those are two good, valid points.

Originally Posted by 91_RS_LS1
I knew the differences in the ports and that the LS1/6 intake wouldn't work on the L92, I was refering to the LS3 intake.
Ah, OK, my bad - seems like everyone wants to try to use the cathedral-port intakes, not knowing that these are different...

Originally Posted by 91_RS_LS1
I was under the impression the LS1 harness would work with the L92 if you used the correct adapter harness with the injectors/MAF.
Actually, I don't have any knowledge about that - I just went ahead & bought a new engine harness for my L92...

Originally Posted by 91_RS_LS1
I've seen in most situtions people seem to be deleting the VVT in the L92s, but I was also aware that camshafts were available for the L92s with VVT, so I thought there would be some advantage to deleting it.
Depends on your perspective, I guess. Deleting the VVT does make the engine more simple (and I'm a BIG believer in simplicity, especially as far as it relates to reliability), but you have to weight that against what the more-complex setup provides. I mean, honestly, a 1949 flathead-style engine is more simple & (arguably) easier to work on, but pretty much everyone agrees that the benefits of the more-modern OHV setup outweigh the simplicity of the earlier design.

Quite a few people (at this point) apparently feel that the "tried & true" is a better choice for them than the slightly-more-complex VVT setup. I've looked at the potential that the VVT offers, & to me, it's just staggering. So, I'd argue that the benefits (which I expect to enjoy for tens of thousands of miles) outweigh the grief & hassles that come with a somewhat-more-complex installation (which is HOPEFULLY a rather shorter time-frame!).

Originally Posted by 91_RS_LS1
I'm still in the preliminary stages of this (was planning a plan jane LS1 swap), so I'm just digging for info into what will work and what want. I'm already ahead from your one post lol. New series of questions-
Won't the accesories from the LS1 F-bodies work with the L92? I don't see a truck oil pan working in a third gen, so I'd need at least that right? Why did you decide to keep the VVT?
Not entirely sure what you mean by "I'm already ahead from your one post", but your questions are fairly easy -

"Won't the accesories from the LS1 F-bodies work with the L92?" - Not as far as just "swapping them out". If you look at the front of a VVT-equipped engine, you'll see what looks (more or less) like a thicker timing cover with a couple of sensors on it. This is the VVT actuating assembly, (this picture shows the extra hardware fairly well, look just in front of the timing gear on the camshaft) & because of it, the water pump sticks out a bit further from the block. Thus, the crank pulley sticks out a bit more as well, etc, etc, etc. This is one of the bigger reasons why (to my knowledge) no one else has retained the VVT setup in a third-gen F-body, & also why a lot of people eliminate the VVT functionality from their engines - it just makes fitting the engine in a bit easier. I hope to find out this weekend if the radiator & fan assembly will all fit together with the VVT setup in my car.

I don't see a truck oil pan working in a third gen, so I'd need at least that right? - Exactly right. I've installed a truck pan on my L92, & while I think it'll be fine, but it's an untested combination. Because of the VVT, the normal oil pressure in my engine will be quite a bit higher than what's normal in "normal" engines - in fact, I'm going to be installing the 0-100psi oil pressure gauge that I bought in my wife's F-body, & buying a 0-150psi gauge for my car. In ancient times, uncharted areas of the sea were marked on maps with legends like "Here be monsters"... Sometimes it still feels that way in this day & age...

Why did you decide to keep the VVT? - I'm guessing that there are three reasons:

1 - People have said that you couldn't do it. Don't ask me why, but that just drove me utterly bat$#it. I guess I'm just ornery & stubborn enough that by God I will freaking FIND a way to do it, even if I have to save up for a custom two-part radiator that sits in the fenderwells in front of the wheels to work with the front accessory drive... (And it's a bit like the old joke - "WHY are you slamming your hand in the door??" "Because it feels SO much better when I stop!")

2 - I couldn't be one of the first people to drop an LS-series engine into a thirdgen, but I CAN blaze a new trail with a VVT swap. And considering the fact that the engine was available for a fairly decent price right at the time when I was looking to do my swap, well, it all just kind of fell together at the right time, I guess.

3 - The potential power & efficiency advantages that are possible with that design - here are a few quotes:

"While installing the VVT system on a single-cam OHV engine doesn't offer up any adjustability of intake/exhaust overlap timing, it should be noted that simply advancing or retarding the overall valve timing can have significant effects on an engine's powerband, as hot-rodders have known for decades. Typically speaking, advancing the cam timing offers more low-end power, while upper-end performance benefits from retarding camshaft timing."
Link
And being able to advance the camshaft's position relative to the crankshaft at low RPM AND dial it back at higher RPMs means that you can gain the benefits of both - without losing power anywhere!

"Although Godbold returned to this subject, it quickly became obvious that he had other ideas aching to burst out of his mind. Ideas that can be summed up in the initials VVT-that's variable valve timing to you and me. "The L92 truck motor is incredibly impressive, making 400 SAE corrected horsepower stock and 430 hp with headers," he began. "With one of our cams and the phaser limiter kit, we made 500 hp, and it did not lose power anywhere."

and

"The whole thing is better. You can move the cam around in the motor. Say you do a NASCAR cam with a 110 LSA. You can run it at 102, 106, 110, and 114 centerlines and get an idea of how it responds. It may fill in a gap, 104, 108...look at torque curve...102 best torque, 114 best high-end power. Good teams look at the specific track, look at where the engine spends time. This is something that would have taken us a lot of time and four guys on the dyno, and analyzing data in the past. Then, after you do it, you have to compromise. With the cam phaser, you can advance or retard the cam centerline to the position it runs best at each rpm. That's cool, really cool. You can get a 60-plus horsepower gain, with no loss anywhere. You can have control of the cam timing by tweaking a curve in your ECU, just like typical electronic ignition timing. It's like going from points to coil-on-plug."
Link
In all honesty, I don't see the peak power numbers being especially different between VVT-equipped and non-VVT-equipped engines that are otherwise identical - but I FULLY expect that the "power under the curve" or "average" power will be significantly different, as will the average BFSC numbers for the two engines. And since "power under the curve" is where it's accessible in everyday driving, maybe you can start to see the appeal a little bit...

EDIT: I found another link with a 4-minute video that explains it a bit...

I hope this helps to explain (just a little bit) where I'm coming from in my first response in this thread.


(I wonder... Does Pepto-Bismol make anything to treat verbal diarrhea???)

Last edited by V8Rumble; 10-16-2009 at 10:38 PM.
Old 10-17-2009, 11:18 PM
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Thanks for taking the time to reply and answer all my questions so thouroughly. I will follow your build to see how things go with the VVT installation. I've known the theory and benefits to VVT for a while (some friends are Honda guys and love the VTEC lol) but never considered the implications in a V8. If your build is successful (without major complications lol) I'll be likely to follow your example. It'll still be another year or so before I can get started, so I hope the extra time will allow me to make things as easy on myself as I can lol.

Originally Posted by V8Rumble
Not entirely sure what you mean by "I'm already ahead from your one post", but your questions are fairly easy -

I meant that I'm ahead of what I knew before from the 1st post you made (I have more knowledge now than before you posted). I just noticed a mistake I made in my post though. Heads and long block... kinda redundant lol.

I have found out that the L92 will run in a 4th gen car with the LS1 harness/PCM. There is a member on Z28.com that has installed a L92 in his SS. He deleted the VVT but is considering reinstalling it. Here's a quote from his post:

Originally Posted by 01badz28
The VVT stuff was unproven when I started buying parts, so I just went with a custom cam. I've still got the VVT parts boxed up if I change my mind, but it would be a PITA to rewire the thing. Yes, I'm using the stock LS1 ecm and harness. I'm using the Lingenfelter trigger box, cam sensor convertor, and the usual LS2/3 to LS1 conversion harnesses you need. It runs extremely well.
I'm thinking that if I don't get the truck harness (since I'm planning on buying a complete, wrecked, 4th gen as I mentioned before) I could use the 4th gen harness/PCM, but use the adaptations he mentions in order for it to work. That's if I don't use VVT, in which case I'll buy a truck harness with the engine and if the adaptations he mentioned aren't more expensive than just buying the truck harness/PCM to begin with and selling the LS1 setup on TGO.

And trust me, diarrhea is preferable to no info



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