OK - I'm now in the market for a new C4. I've currently got a 6-speed 1989 L98. 100% stock. (It's for sale, btw.)
I don't buy Vettes for the creature comforts - leather, CD player, automatic climate control, etc. I buy them because they are Vettes and I like power and I love Vettes. So this has me thinking that I want to move up to an LT4 or LT5. Given my self imposed price constraints LT5 would likely have to be limited to '90 or '91. The LT4 is a '96 only option.

Now, I got to thinking today about the LT1. Am I eliminating too many cars by not including this motor? Is the LT1 motor significantly more powerful than the L98 to justify moving to one? If I was to consider LT1 cars I'd be looking for the newest one I could find, naturally.

This is NOT a slam on LT1 cars at all, btw. I've never been in one, so I'm just asking. But if the seat of the pants feel of moving from 245 hp to 300 hp isn't all that great I don't know if I would want to spend $X more money for fancy new leather seats and a CD player.

So, help me compare/contrast the L98 vs LT1.

Thanks!

 

The LT1 is stronger then the L98 over the RPM band, they love to rev. But if you want power then you need to get a LT4 or LT5.

I'd have a hard time justifying the difference between the two motors in what you are going to pay to upgrade. A newer car will be a better car, but the LT1 shouldn't be the first thing on your list of reasons to change.

 

I'm sure there's some differing opinion on this, so here's mine:

The "best' years for each engine are:

1990-1991 L98 250 horse 350lbs torque
1993-1996 LT1 300 horse 340lbs torque
The torque between a stock L98 and LT1 is VERY close. All things being equal (transmission, reaction time etc.), "stoplight to stoplight" is going to be very close. No comparison in top-end though. At the 1/8th mile mark the LT1 car should start walking away from the L98 car.

Like I said, just my opinion though.

 

You may want to try search on this topics as it comes up quite often or try test driving one. In everyday driving, a Lt1 may not feel any quicker than a L98 except for on the highway.

 

Actually get a LT1 then do a LT4 upgrade to it. Basically the same motor. Save some cash too. It won't be legit but you'll have the same power.

 

stick with your L98

2 good bolt ons and your faster anyway..

if your buying a car and dont already have an l98 i can understand. but being an lt1 owner and racing L98 vettes, there is no reason to swap in a healthy L98 for an LT1 unless your rich, and in that case i'd like to introduce you to the Z06 :)

Lt1 also has the damn optispark

and unless you can change it yourself, $800-1000 labor charges aren't rare

 

After seeing your sig. and reading some of your posts, I have a couple
questions for you from a fellow 85' owner. First, how did you like your
3.07's compared to the 2.59's? If you were going to upgrade the gears,
would you go with the 3.07's or maybe the 3.45's? How do you like the true
duals on your car and what kind of mufflers are you using? I've thinking
about going true dual myself. Thanks!

 

That's exactly how I'm feeling about it right now.

 

why not mod your vette to be faster than a ls-1? :confused:

 

The LT1 is very easy to mod. Sure it has the opti, but don't let that bother you. It also breaths at over 4500 rpms. The single best part about the LT1 is it's flat power band. In bone stock form it makes 300 pounds of torque from 1800 clean across 4000 where it then starts to fall of SLOWLY.

Add a cam and some headers in there and your torque curve starts to change. It still makes 300 at 1800 and still begins to fall around the same spot, but all across the mid range it is greatly increased.

I made 336 hp and 345 pounds of torque out of my LT1 with a cam and long tubes, stock cylinder heads. It's a 12 second car that still manages good gas mileage.

So to answer your question. The LT5 is nice, but an early LT5 can be topped by an LT1 for fairly cheap, it won't quite have the finess, but it will be faster. The LT4 is simply a 30 hp improved LT1. It's got different heads and intake, very slightly different cam & roller rockers from the factory.

If you put roller rockers and decent springs on your LT1 you're already almost tied to the LT4. Add some intake and head work, throw in a cam, and LT4's will be running to hide.

All that being said, grab an LT4 or LT5 for the rarity of it, but the LT1 certainly isn't a slouch. If pure power is your quest you can get an LT1 cheaper than you can get either of the others and make it go just as fast.

 

It soulds like you're ready for a "new" Corvette" so you need to drive a few candidates.

But if you just want to run with the stock LT1s or even the stock LS1s, a few mods to your L98 will get the job done. Vic'89 runs high 12s/low 13s and I run low 13s/mid 13s with stock cam and heads and nearly stock TPI.

I believe your '89 was the easiest to modify of the L98s as it's the last of the MAF years and has no cold start injector.

If interested, I'll send you a list of mods with results that can get you a very streetable mid-12s Vette.

 

:lol: :lol:

That's a good one :)

 

Mind if I butt in on your offer ? - please send to jg2@aol.com

 

That's like comparing apples and oranges. It really depends on what you are trying to do. Are you looking at a motor with cheap aftermarket parts to make it run better? Or will you keep it stock and just want to have an ample amount of stock usable horsepower? The L98 is very reliable and makes mucho torque down low where most people drive there vettes. It is proven and reliable. The aftermarket parts are cheap. All these advantages make it hard to beat. However a stock LT1 or LT5 would be a nice driver. I am not too sure about which one is more reliable as a stock motor. Both have their share of minor problems.

:cheers:

 

My car came from the factory with the 3.07's, so I can't really compare to the 2.59's.
I replaced my stock exhaust with the duals and had a very noticeable gain, but unfortunately I didn't have enough sense :( to do a before and after run with my G-Tech. My stock exhaust was pretty rough to start with though. I had a pretty major crease on the right pipe from a previous owner, after removing the mufflers I could hear particles shaking around inside of them. I'm not sure how much of my gain was from the duals and how much was just from doing away with all the restrictions in the old exhaust. I didn't notice any loss in low end torque, in fact I had more.
Originally I had a pair of Hooker Aero-Chambers I was planning to put on, but after reading some posts on the volume level, I figured it would probably be unbearable with no cat to help muffle the sound. Instead I went with modified GM replacement mufflers. I believe they came from the later L98 cars, as the second outlet which is completely blocked off on ours has a hole about 1/2 or so in it. The mufflers had the stock inlets removed (very restrictive) and instead had a 2 1/2 inch mandrel bent pipe welded in its place. They also had the outlet pipes removed with dual square "early" ZR1 tips welded in their place. I don't plan on doing any major mods, and I believe the flow on them is more than sufficient for my combination (I'm sure some people will probably disagree though). The ZR1 tips are just enough to be a little different without being too flashy. The sound is louder than the stockers, but not "too" loud. I think I have a pretty compromise between sound, flow and looks. They ran less than $100 for the pair. If you're interested in them I can try to find the email adress of the company.

 

Just wondering how you like the G-Tech? Do you think it is accurate? Have you compared it to say a real dyno or the track?

 

The quality of C4s improved over the years. The 95 is supposed to have a lot of improvements over the 94 which I have. I don't know if there was that much change for 96. The 96 model is a good year if you want an LT4 or Grand Sport car. If you just want an LT1, look for a 95. It has a better opti, mass air flow, and easier (cheaper software is available) to modify ecm that does not have OBDII.

The LT1 has two advantages over the L98. The higher rpm intake that gives the engine a wider torque curve and the reverse flow heads which allow for 1.5 pts of extra compression. The L98 is better if you want to build an affordable large stroker engine.

 

wiat a sec... the L98 doesn't have that frickin optispark that seems to be a humongoid pain in the rear? well crap, if the L98 would be less of a hassle and i can get it in low 13's or 12's for pretty cheap then i'll most likely go for that. what do they run stock?

 

I'm not sure if the opticrap is really "as" bad as people say. My 96 has 70,000 on the origional, but it is the newer vented style. It is obviously not Gm's brightest idea. The forum has around 37,000 members. Only a percentage of these members are C4 drivers, and a smaller percentage are LT1 drivers. I don't know what the math works out to be, but there are only a relatively small number out of the thousands of LT1 vettes made. A small number of people have had problems with there opti, but we hear about it because they post about it, there are tons of lt1s that have not had problems but we never hear about that. My opti will eventually go, and I will fix it, and continue to love my LT1. Don't let this fear of the opticrap stop you from buying a great Lt1 car. Never driven an L98, but have heard they are great cars. Hell, I still miss my L83, and they are always looked down upon. L83 was fun right off the line, then ran out of breath quickly. Good luck.

Bart

 

I had an 89 IROC with the L98. It was the cleanest IROC I had seen in years, it was bought new by a doctor then in 94 his 35 year old son inherited it, he said he rarely drove it and it showed. I acquired it with 68,000 miles. It only had 70,000 miles when, we think, an electrical problem caused an injector to fail, which in turn caused the #7 cylinder to scorch. I say electrical because the injectors were not clogged. $2700 for a remanufactured motor and to have the injectors rebuilt. This all happened a few weeks after having the intake gasket replaced, another common L98 problem. Then the tranny started to slip. All this within a period of 6 months. I was lucky enough to find a kid to sell it to and still break even. Could have been a freak thing with my IROC, but I am not a big fan of the L98. It pulled very hard off-the-line but ran out of breath around 3500 RPM.

Because of my past problems, I'm going with an LT1 when I get my Vette. I have had some extended windsheild time behind an LT1 Z28's and Trans Am's and I really like the feel off the line, and they pull strong up to redline. If nothing else, the LT1 sounds so mean! :reddevil

Please L98 owners, don't take this a flame, I just had some really bad experiances with that engine. :cry This is just one guys opinion out of thousands of happy L98 owners. :chevy