I have found a 91 convertable vette with a 6 speed. Am I going to be upset that I didn't get a 92+ with the LT1 engine? The car has some mods to the engine, like exhaust and intake.
I want to make sure I don't make a bad decision. I know there is about 50 HP diff.. That seems like a lot!

 

What are you going to use it for? If it's a cruiser that you'll be doing occasional red light scooting between 0 and 50 MPH, the L98 is the LT1's equal. The low RPM L98 torque make it a great daily driver and stoplight car. However, if you intend to blast around at high speeds, it will feel more like a wheezing truck motor. The L98 internals (cam, heads etc) limit the motor to about 4500 RPM. The LT1 pulls hard to it's 5800 RPM red line. If you're looking at a convertible, something tells me you're looking for a boulevard cruiser, not an Autobahn car or Road Racer.


[Modified by Rick93Z07, 5:59 PM 5/27/2002]

 

Depending on what exahust and intkae is on the L98, it very may well be VERY VERY close to the LT1 in horsepower, and it already is higher in torque. An L98 can be made to outrun an LT1 very cheaply.

 

just add 4inch tailpipes and "type R" stickers and you there.... :D

 

Scorp,

You might want to qualify that. The L98 can be made to outrun an LT1 on the "bottom end" very cheaply. In it's element (stoplight drag), gears are an effective equalizer. However, the L98 can not play above 80 MPH without substantial and expensive internal mods.

 

It's been my observation that there is no comparrison between the L98 and the LT1 espicially in a 6 spd car. LT1 is hands down the winner, on bottom end and Top end. If speed is your factor, you will be slightly dissapointed with the 91' vs 92'.

 

Says who?

 

 

I said that Scorp, in case you didn't notice who you were quoting:

It is based upon many track miles and dyno tests. "Substantial mods" are necessary to raise the useable powerband peak into the 5500+ RPM range. This is what's necessary to produce LT1 HP. The L98 heads and cam do not flow like an LT1, so they can not produce power like an LT1. Big bolt-on primaries and intakes will reduce torque. The powerband is limited by the heart of the motor (heads and cam). Perhaps you don't think heads and cam are substantial mods, I dunno.


[Modified by Rick93Z07, 11:56 AM 5/28/2002]

 

What are you talking about? :confused:

HP is a product of RPM and Torque. Who cares where in fact the HP is made as long as the car is geared correctly to use it. Just because an L98 doesn't spin to 5800 does not mean it cannot make as much HP as an LT1, and outrun an LT1.

 

At least with a '91 you won't have an optispark to deal with.


'92 LT1

 

Scorp,

Torque does not do work. Rear wheel horsepower accurately represents propulsion, independent of RPM. A motor producing 300 lb-ft at 2000 RPM is producing only half the power of a motor producing 300 lb-ft at 4000 RPM. The RPM itself is not the problem. It's a fact that an engine's power output is proportional to RPM, unless limited by airflow. You can not produce LT1 HP figures 1300 RPM lower in the truck-like L98 power range unless you have a stroker or power adders (blower, Nitrous etc). There is no magic elixor.

You must be kidding. Steeper gearing? Do you think a steeper gear that requires you to upshift into 5th earlier is the answer for high speed acceleration? Hardly. The LT1 and L98 both have a 6 speed. Once you're over 60 MPH, the ideal rear axle gear is based upon the particular course and the transmission gear ratios. The ZF ratios are fixed, so who cares if you're in 3rd or 4th? The engine prefers 2nd, 3rd and 4th as opposed to 3rd, 4th and 5th due to ratio spacing. A rear axle ratio can be optimized for a particular track or "event"....but outside that limited format, any ratio will exhibit it's weaknesses. For example, I would like to use 3rd and 4th at Watkins Glen instead of having to upshift into 5th for the back straight. My car needs a 12% lower gear (numerically) to improve lap times there. At other tracks it would surely be different.

Perhaps you are implying an L98 gearing could be optimized for a particular course or comparison format (drag racing) in order to offset some of the HP deficit. I would agree with that, but the benefit would not equate to street use or other driving venues.


[Modified by Rick93Z07, 1:39 PM 5/28/2002]

 

If you are going to be winding her out and modding your car I would say go with an LT1. The LT1 has a much better intake for future mods while the L98 intake will eventually have to be replaced if you ever plan to turn more than 4500 rpms.

Personally, if I had had the money when I bought mine I would have gone with the LT1. As it is I have spent more money on modding my L98 than I probably would have on upgrading and then modding an LT1. An Lt1 still has good torque down low, so I wouldn't count it out because of that. The L98 is a strong motor also, but it just isn't made to turn the same rpms.

 

to speak on behalf of the tuned port engine, although its not my particular fortei to make low RPM HP and torque as most of you already know, the tuned port is a very strong motor. its heads and cam and intake are setup for each other and work well for what the motor was designed to do. Raistlin and i have been on the race track a few times and i have a 94 lt1 with an LT4 cam in it and a mezierre electric waterpump, SLP claw intake and flowmaster mufflers... our cars run very similar times both in the 13.4x region and MPH is given to him...perhaps he'll pipe in here again.. he ran 103.xx MPH to my 101.3 MPH. I have a great deal of respect and love for the tuned port motor, and even with the long tube runners have seen these motors make considerable power and run low 12's setup properly. another angle to take into consideration is what modifications do you plan on doing to the car? if a heads and cam swap is somehting you may be interested in down the road, etc.. these are all things that can be added to enhance your car. L98's are cheaper partswise then the LT1 and most certainly have a broader market of parts to choose from. The opti spark is another benefit with the L98, there isn't one! plug wires are far simpler to deal with, and blocks are much more prevelant as well as better deals on rebuilds and internals.. i suppose a more in depth look at what you expect from your Corvette and what you expect to do to your Corvette would certainly weigh heavily on which you ultimately decide on. please add some information so that the responses can be more in tune and beneficial to your query.

Best Regards,
Chris
CC Performance Engineering


[Modified by lcvette, 12:13 PM 5/28/2002]

 

I think there is another question to ask here... beyond potential power gains and the like.

From what I can see, the power is available. sure, you have to spend $$ either way... mods for an LT1 are more expensive than they are for the L98, but, fewer mods will have a greater impact on the LT1, $ for $.

that said, I think the bigger issue is the Corvette Forum motto: "Buy the newest you can afford".

there is a reason for this... the 92s are that much better screwed together. They are also that much more refined. The dash was updated a bit more. the LT1 is a smooth operator!!!

thats my .02 worth...


[Modified by bogus, 5:11 PM 5/28/2002]

 

:nonod:
What is your basis for this statement?
I would have to disagree.

 

Maybe what he meant was...the mods required to produce a 300 HP LT1 cost $0?

The LT1 can produce 425HP in an OEM-looking, street emissions certified form while retaining a stock, unported LT1 intake, OEM GM LT1 ported heads, cam and bolt-ons. More Performance, Lingenfelter and other's have been selling this dyno combo for many years. The L98 heads and intake are not useful for serious performance. They must be replaced to obtain decent power. The resulting motor combo does not pass visual emissions certification. Worse yet, a 50 state legal exhaust requires a Y-pipe and single restrictive converter configuration.


[Modified by Rick93Z07, 6:57 PM 5/28/2002]

 

Go with he 91,you won't regret it! :chevy

:chevy

 

what I ment was that with a baseline that much higher, by installing a hot cam, rolling rockers, a 52mm throttle body and a K&N will return much more than doing the same things to an L98.

To get the same kinda flow rates with an L98, requires something like a super ram and heads...

 

I would say go with the 91. I love mine, and I can beat lt1's all day long, with my intake, and very inexpensive bolt ons.
And from what I have seen, the 91 looks the same as the 92 except for the engine and tailpipes