So far all of the 928 swap kits and parts I have found are for the LT1 due to the 610 lb weight of the factory engine compared to a LS1. I am twisting arms as best I can, but I don't really want to be a test case either. How does the LT1 compare to the LS1, both in a reasonable performance setup (my target is 350+ rwhp)? I don't really know chevy at all, and some of the LT1 cars kind of spooked me with throttle body injection which I don't recall being worth beans.

Thanks for any opinions or links, I tried lt1tech.com and its kinda dead. Also this is for a Calif car, gotta pass el smogo.

 

The only real advantage an LT1 has is the price. Other then that the LS1 has MANY advantages over the LT1.

 

The modern LT1 engine was never throttle body injected (TBI). It was port injected it's entire run from 92-97.

 

Told ya I didn't know much about LT vs LS.

My problem is all the 928 swap parts are LT1 right now.

Also what I am hearing from CARB is that OBDII swaps need to be paired with the transmission.

 

I take it you already know about http://www.renegadehybrids.com/indexx.html#

928 LT-1 conversion is there, but they also support SBC swaps, so you might find they do LS1 as well. I don't know the diff'ce between the 924, 928 and 944, to be honest.

There are a lot of design flaws in the LT1, problems with optispark, water leaks from various places, I found a website that explained all this somewhere, but can't seem to find it right now ...

 

350 wheel hp will be near impossible in an LT1 without changing internal components. I have seen full bolt on LT1s with an aftermarket cam make in the 310-325 hp range. But you would either have to go stroker >383 or a set of aftermarket heads to reach 350 whp. Unless of course you want to go with nitrous or a supercharger. With an LS1, you can achieve 350 whp with a full set of bolt-ons. Either engine is a good choice, but the ls1 weighs less and has about 50 more hp right off the bat. Both motors respond well to modifications, but the lt1 will always be behind due to the inferior head design and as stated the cam driven water pump that is prone to leaking right onto the cam driven distributor that is pricy and time consuming to replace. When everything is working on the LT1 though, its a good engine. LT1s can be had for $1,000 while an LS1 typically starts at $2,500.

 

While I agree that the LS1 is a FAR superior engine, I'm sure 350 hp from a LT1 is very possible with only bolt ons. With only a mail order tune my 68 Camaro LT1 swap pulled down 334 rwhp on the dyno.... HOT cam, LT4 intake, headers and MSD box were the only bolt ons... No additonal tuning was done and I'm sure I could pick up quite a bit more with a live tune. It's possible if I had a T-56 instead of an automatic, or did my run at sea level rather than ~3000 ft. I would've hit the number as is....
The LT1 is a solid engine and I haven't had any Optispark problems (but I live in a very dry climate).
Saying all that, as long as you are willing to fabricate a few things, there is no reason you can't drop a LSx into your "wundercar" if a LT1 will fit.....

 

An LT4 intake doesn't fit on an LT1. They have different angles on the head. You must have an LT4 engine. That also makes your 334 hp sound more realistic as LT4 engines typically see 330-345 hp at the wheels.

 

LT4 intakes will fit LT1 heads. however I neglected to mention that I do have LT4 heads.... Bottom end is all LT1 however.

 

LT1s are much cheaper. also you can do forged strokers for cheaper. heads are also cheaper.

LS1s are initialy more expensive and more expensive to modify, but are a better motor

if you are wanting a reliable daily driver go with a bolt on or cam only LS1, if you are wanting something cheaper, go bolt on LT1, if you want to extensivly modify an LT1 it will be cheaper than extensivly modifying an LS1

 

An LT1 bottom end is no different than an LT4 bottom end. You practically have an LT4. You can't advertise a bolt on lt1 making 350 whp and leave out the fact that you have an extremely expensive top end that is worth 3 times what your motor is worth. The only LT1 bottom end that is different than the LT4 is the bottom end out of the f body or b body which is a 2 bolt main, but that doesn't affect power and splayed caps on a 2 bolt main is more desirable anyway. Just wanted to clear that up, since this guy with the Porsche knows very little about GM powertrains.

 

A heads, cam, stroker LT1 will be very cheap compared to a heads, cam stroker, LS1. But with the LS1, you are looking at over 75 hp advantage with this combo. A 383 LT1 properly setup is looking at 420-440 whp. An Ls1 stroker is looking at 500+ whp.

 

Firefox2 won't let me login on camaross.com forum LT1, so I read but can't post, bought this book,

How to Rebuild Small-Block Chevy Lt-1/Lt-4 Engines: Step-By-Step Rebuild to Factory Specifications, Covers 1992-1997 Gm Cars and Trucks
Mike Mavrigian Paperback. HP Books 2002-10-01. ISBN: 1557883939

Should be here maybe by the weekend.

928 motor is OHC, so the heads with valves and cams make it tall and wide, PLENTY of room, and it weighs 610 lbs. With a LS1 I have to find 100 lbs that can be removed from the rear, thats a BIG issue with a perfect 50/50 balance 928, plus no kit yet.

Passing smog, quality of the driving experience, mean more than cost. Main issue is this has to pass a California referee smog check (block and head IDs checked with car on a rack), new motor has to be California legal, newer than the car, and have 100% of its smog equipment functional, which makes OBDII very hard (tranny controls). Any mods that would be legal with the motor in a chevy though are legal with the motor in the 928 as long as everything is hooked up and works, AND you have plenty of documentation.

If I can't pass smog and hit 0-60 close to 5 seconds for less than about $10k, give or take a grand, I will stay with a Porsche motor or just look for a Vette instead.

****** BIG TIP *******
If you ever want a vette, just start talking about doing an engine swap into a 20 year old Porsche and pretty soon the wife says, why don't you just buy a vette?

 

928 I start with will be between 80 and 89, older more likely than newer, and I will have some choice of which year, so if a 85 engine would be great, then I would find a 928 old enough to use it etc. I know nothing about what year what engine was in various chevys, or what smog equipment it used that I would need to drag along.

Do LT1/LT4 engines fall in that data range or newer?

When did Chevy go OBDII, is that LT1/LT4 or LSx?

It looks to me like something like a ZZ4, which has a CARB EO# should work, but I don't really know what it is either. Should have overnighted the book maybe.

 

First off, the zz4 is only carb approved for pre 1992 and that is only if you are using a TPI setup engine out of a 1992 or earlier camaro or 1991 or earlier Vette.

The LT1 came out in 1992 in the Corvette and 1993 in the Camaro. You want to stay away from these motors if you can due to the non sequential injection system and the non-programmable computer. These engines make just as much power as later LT1s, but do not have the tune-ability. They must be "chipped" to change parameters. The only smog equipment for 1992 and 1993 is the electric smog pump, single catalityc converter and the Evap system purge solenoid on the intake manifold.

In 1994, LT1s became sequintially fired and had fully programmable computers that can be modified with programs like LT1edit and Cat Tunerz. These are considered the first OBD1 engines. In addition to previous smog equipment, the LT1 now has an EGR valve on the back of the intake manifold.

In 1995 the LT1 got an improved optispark distributor that is also much cheaper to replace if need be. In 1995 the LT1 began using an OBDII style connector but were still OBD1, meaning that you can still use Cat Tunerz and LT1edit to modify the computer.

1996 was the first year for the OBDII LT1 engine. Everything on the engine remained the same except for a modified timing cover with a crank sensor in the front of it. The computer for 1996 is all new and requires much more expensive software to tune. LT1edit makes software for the OBDII computers. The OBDII cars are also very difficult to tune and most people with 96 cars convert to the OBDI computer. The OBDII computers also have downstream O2 sensors which previous LT1s never had.

No changes were made to the LT1 in 1997.

The LT4 was a 1 year run engine that can only be found in 1996 special eddition Corvettes and Gran Sport Corvettes. The LT4 is the same as an LT1 with improved flowing cylinder heads, improved camshaft, and an improved intake manifold.

The LT1s found in some early 1993 camaros had 4 bolt main caps for extra strength while the rest of the LT1 camaros from then on out only had 2 bolt main caps. All camaros had aluminum heads.

All LT1 corvettes had 4 bolt main caps. All Corvettes had aluminum heads.

All Caprices, Impalas, Roadmasters, and Fleetwoods had 2 bolt main caps with Iron heads except for the Police version of the Caprice with the B4C package that had Aluminum heads.

1997 was the last year for the iron block LT1 and the first year of the brand new all aluminum LS1.

All LS1 engines are OBDII and respond greatly to tuning. HPTuners and LT1Edit are the premier tuning programs for these engines.

LS1s are equiped with 2 catalitic converters, an electric air pump and an Evap purge solenoid. EGR valves were used from 1998-2000 in the camaro and then dropped for the 2001-2002 model year where the LS6 intake manifold was used in its spot. Corvettes did not use an EGR valve in 1997 but did use it from 1998-2000. None of the LS6 engines ever had an EGR valve and neither did the LS2 engines.

 

Another one of these threads......

 

Any links to those threads much appreciated, I did do a fair amount of searching but too many short words to be very selective.

I have no knowledge, so no bias for or against any of these motors, I don't even need to understand it, as long as I can get it to pass smog, and hook up with the 928 stuff.

I don't need to find a car with a donor ZZ4 etc., two of the local Chevy dealers apparently stock them as crate motors. I would buy the crate motor and find a donor car that it was calif legal to put the crate motor in, and get all the smog boxes from that donor car and potentially use the motor from it as the core for the crate motor if needed.

I know I still have a long ways to go, before I even "think" I have it figured out enough to start buying anything besides books.

 

what is the weight difference bet ween the LT1 and LS1??

 

The LS1 has aluminum heads and block. I believe the entire thing weighs about 400 pounds.

You might actually have to ADD 200 pounds to the rear!



That might not be a bad way to go……

 

Not to play devil's advocate, but depending on your horsepower goals, you can get an LT1 to 350-400 hp for alot cheaper than an LS1.