neat

OK, long story short, here we go. I am seriously considering trading my TA in the sig for a 1991 L98 power'd corvette. The dealer has agreed to give me the C4 and $3500 in exchange for my TA. Don't get me wrong, the vette runs pretty good, but I kinda doubt it will produce the same track times as my 99 TA. My question is this: If I put that $3500 right back into the motor, will I be able to show a healthly LS1 my tailights? I need to know what's up by Monday, so doing a bunch of research myself really isn't an option.

I know this is thirdgen.org, but it seems like all the vette guys wanna talk about is how great "America's sports car" is. Personally, I would like to talk about winning the race, not how great my car is.

thanks!

Jasper89ROC

First question, why oh why are u trading an ls1 for an l98?? With that out of the way, Id change the intake first, the only problem is clearance on the vettes with the stealth ram, the miniram would fit but i think it is over priced and over rated, plus u will loose much more torque then the stealth ram. Than get like a 10" 2500 stall, headers, gear(depending on whats already in there) i know alot of vettes came with something like a 2.59? or 3.08? Id change that to a 3.42 or 3.73.
-Mark

neat

LS1 v.s. L98, have you ever priced anything for an LS1? Stock for stock they are nearly unbeatable, but strat modding and soon the L98 will be trouncing that L$1. A set of headers can cost $1500 for my TA. A good set of heads is 3k, unrealistic in my book.

BTW, the vette is a six speed car.

3.1EyeCandy

iTrader: (3)

Well...let's think about this.

Aftermarket Intake (I'll assume you'll run a LT1 intake) : $520

A heavy port job on those vette heads: ???

A healthy cam (LT4 hotcam): ???

that's what...about 1000 bucks? maybe 1500?

That should get you moving.


OR



If it was me (and I love torque)....I'd get some hi-flo runners, heavy porty the heads and plenum, and put on a Supercharger. That'll also get you moving....but will cost more because of the supercharger.

Sorry I'm unsure on the prices, poor college kids don't have time to think about buying car parts.

Jasper89ROC

I can see the headers being expensive, but where do u get 3k for the heads, port your stock ones, it is about 1200 for a stage 3 from my place. Even without touching the heads, get a gear, ls6, lid, exhaust, sticky tire and u will be running low 12's and you havent even touched the engine yet. Your gonna have to do neatly everything to that l98 to get there, then when u get the $$$ get heads and a cam for that ls1 and ur pushin 410+rwhp. I have an l98 so dont think im hatin on them but ls1 is g od:hail:

RedFirebird

I love vettes but I wouldn't do that deal. An L98 corvette goes for what, 10000 on the very high end. Thats a joke. From the sound of your post, you don't really know what you want and what you're getting into with that car. If you're not into the fact that the corvette is America's sports car and just care about going fast, the car you have now is perfect. Now of course if you could get a better deal and get say, that car plus maybe $6000, then do it. $3500 into that vette will probably get you to where you are right now minus a bunch of your time and an 11 year old car with possibly(?) other problems needing to be fixed. Anyone can sit here and come with some budget 12 second build-up on paper but its a lot more $$$ in practice, especially with tpi and emissions and considering this is an 11 year old vette that probably needs work in other areas. If you really want to have some fun, sell your car and put that money into a turbo buick.......

92superram

I'd stick with the ls1. If it was a lt1 vette, I'd say go for it. If you bought the vette, put the 3500 in it, you could possible hit some 12's, but its still a c4 vette. C4's are the poorest excuse for a vette I have ever seen. They have no character. With the ls1, you have a very beautiful, well designed and sculped car. It is also by far more technologically advanced, gets better gas mileage, and has a better chassis for racing. I would say its a no brainer. get the basic cheap mods, slap a n20 kit on it, and happily run 11's all day in a perfectly streatable, yet wild car.

neat

MTI stage 2's, $2795 plus exchange.

Hehe, you might hit that low 12 once before the rear end lets go. A good rear is going to be about $2500. Ok the now the rear is solid so I head back to the track. After another low 12 second run I return to the parts counter for a new clutch. Kiss another grand good bye.Ok, some background on why I am doing this. I live narly 6,000 ft. above sea level. My Ls1 turns high 13's up here. To cope with the massive elevation, I want to go with a turbo motor. A turbo LS1 COSTS. Period. the cost becoms astronmical if I want to build the bottom end to take more than 5 or 6 lbs. of boost. An L98 turbo car would absolutely crush a NA LS1 up here.

The turbo is a ways off, I am trying to determine if a NA $3500 enhanced L98 could run well enough for me to have some fun until I can afford the turbo.

Building an L98 for boost could be done for thousands less than an LS1. Don't get me wrong, I love the performance of my LS1, but vendors are just too proud of LS1 stuff.

dacuma

IMO your asking for a headache, You want to trade your 4 year old car for a 11year old vette. Now hears the prob, it will be cheaper to mod the vette, but man do you know how many probs your going to run into? Your going to have all kinds of things breaking on you! Not only cause of abuse, but cause of age. I got a 13year old Iroc, I love it to death, but man stuff is just old and breaks out on it. Half of that 3500 might go to repairs. But your going to find out the hard way, Well anyway what I would do if I were you, is go ahead a get a Super Charger. That will give you alittle something your looking for.

'87FAKE-IROC-Z

I agree that you should get more $ with your trade in unless the Vette is in GOOD shape.
With that out of the way, I'd start like this with your $3500.
AFR 190 heads-$1650
Find a used SuperRam setup-$700-900
LPE 219/219 cam-$350
A decent set of headers- really don't know-$500?
Custom chip or DIYS-$250-350
Cat-back-?
Don't know how much this comes to in real life, just going on what I paid for some of my stuff, but this combo gets those Vettes into the high 11s @ 112-116 pretty frequently with good traction.
This is assuming you do all the work to save $.
Good luck whichever way you go.

ZZsmpch

iTrader: (1)

Did you check to see what the difference between insuring a four seat car is compared to a two seater? Of course he'll do the deal, he wins and you lose. You should be able to sell your LS1 and buy TWO L98 Vettes. You're really going to get hosed if you do the deal. If I were you, and going backwards, I wouldn't go any further than an LT1 Vette. Of course I did a lot of drugs when I was a teenager, so take that into consideration too :lala: :lala: :lala:

2QUIK6

I was just about to mention the cost of insuring a Vette, might want to check on that. If your goal is to get a turbo charged motor to compensate for the elevation then why not get a proven car with the turbo already on it. Way less headaches and lots of easy and cheap mods to make them go even faster, and insurance isn't that bad, and they are far more dependable than building up a turbocharged/supercharged L98 to run similar times. 11's are easy in a TTA with less than $2k in mods. If your looking for drag strip performance, keep in mind that the factory TPI runs out of breath at 4k rpms. I've got a torque monster loving truck with a L98 TPI thats perfect for daily driving with lots of power down low where you want it on the street, but for the strip, I'll go with either turbo car in my sig...

u r sofa king we tah did

personally id do it, take the 3500 and stroke the motor. your getting a fresh rotating assembly and more cubic inches to boot. vettes with tpi are no slouches, thats for sure. with the super ram and LPE 219 combo they run mid-low 12s on a stock shortblock.

u r sofa king we tah did

that has to be one of the stuipidest remarks ive ever read on this board. my tpi vette gets 31mpg on highway with stock prom and stock car, xplain that. any good c4 will hook better than a fbody and in a auto-x the vette has a huge advantage with suspension and wieght

Jasper89ROC

That probably(I would hope) includes a fully built valvetrain, i was talking about just getting them ported/milled


I have seen those 10 bolts pull 1.5/1.6 60' all day long, they arent that weak

i dont think strapping a turbo to a car will change the elevation will it? Yes it will add a significant amount of power, but your still racing at 6000 feet, a turbo isnt gonna change that.

Hodge

If you were going to an LT1 I'd say go for it but the L98 just requires too much work to get to the LS1's standards.

IMO

Hodge

neat

Actually, a tubo cars feels the hurt considerably less at high elevation. NA cars will gain almost a full second by dropping to sea level from where I am at. Turbo cars are only picking up about 2 to 3 tenths.

As far as looking for an LT1 vette, no way. I have too many friends with LT1's to fall for that old trick. Too many optispark issues, too many issues period. The TPI L98 is just a small block chevy with a TPI unit on it. LT1's are mega crap in my book. I might be wrong, but please don't try to conviice me that an LT1 is the way to go, too many personal horror stories.

Irregardless, the vette went to auction yesterday. I'll see if it comes back later in the week.

2QUIK6

As far as the turbo compensating for the elevation issue. Its not really compensating, but with a turbo, you can always adjust the boost to a higher psi at higher elevations to compensate for the loss of natural air pressure, simply adjust for max boost without detonation. Now, take that same car, and bring it down to a lower elevation with the turbo at the same adjustment, it will make more boost at the same setting, but will detonate, thus at the lower elevation you would need to turn down the boost psi.
The setting is the same, just different boost levels are produced as an end result because the incoming air pressure is different and the differing elevations....make any sense

neat

Ok, here is the skinny on turbo's and elevation.

At sea level, the atmospheric pressure is 14.7 psi. Basically there is 14.7 psi trying to get into and around everything. At a higher elevation this number drops. Less air, make sense?

A turbo compresses the air available to it. At sea level, with 14.7 psi to work with, the turbo will have to spin (to make the math easy I will use unrealistic numbers) 1000 times a minute to create 1 lb. of boost. When the ambient air pressure drops below 14.7 the turbo will still create 1 lb of boost, however it will do it at a higher RPM. (1500 RPMS instead of 1000) Turbo's are regulated by the amount of boost supplied, not the number of revolutions the turbine makes.

So, a turbo charged car will only lose the the little time it takes to spin the turbo up to 1500 RPMS v.s. 1000 at sea level. The boost DOES NOT change from sea level to elevation. A car that can handle 10 lbs of boost at sea level, can not take any more boost at a higher altitude.

Infact, vacuum drops as elevation rises. So a turbo has less vacuum to overcome in order to make boost at a higher elevation than at sea level. It does not equal out evenly though, the less dense air does not directly correspond to the loss of vacuum. That is why the turbo cars see the slight loss with increasing elevation.

Another way to look at it is the pipe between the turbo outlet and the motor is a self contained atmoshpere. That tube knows nothing about the outside world. Three lbs. of boost inside that tube is three lbs. of boost. Be it sea level, or 5000 above.

And that my friends, is the skinny.

Thought's, comments, criticism's??? Am I totally wrong? Lemme know what's up.

2QUIK6

Well not exactly, there are many things involved, intake air pressure, wastegate spring tension, turbine impeller size, exhaust port size, wastegate port size, etc.
The same concept is true say not only for elevation, but for air temperature. Say 90 degree intake air vs. 45 degree intake air, or changes in humidity will affect the turbo. Now, maybe if your running 6-8# you may not notice much difference in these changes, but I can tell you, my GN is setup to run 17-18# of boost in the summer, when the air is cooler in the winter, without changing the wastegate spring tension, it will produce around 2# more because the turbine is controlled by exhuast gases, if your motor is turning say 3k rpms, then it will have 'x' amount of exhaust gas to power the turbo, if the intake pressure is higher (lower alt) those same revolutions of the turbine are going to produce that 17-18 #s faster, and if it is too fast for the wastegate, or the wastegate port to expell to keep the boost down at the 18# spring setting, then the boost will climb.
*
Now factor in an electronic boost solenoid, and it will affect the vacuum going to the wastegate accuator and affect spoolup and max #s, and with it the boost pressure can be better controlled. I use a beeder valve type setup on mine but would love to have a Boost Commander setup.

neat

So with a wastegate that works properly the boost should not change. Just because a lower altitude causes the turbo to spoool faster, peak boost shouldn't change. Just like a cooler day, or a more humid day.

As long as the exhaust pulse contains enough enery to spin the impeller, at a certain RPM you will achieve max boost, the wastegate will open, and boost should not climb. unless the wastegate can not keep up.

BuckeyeROC

Dude, I've only read a few of the posts, but do not sell your 99 TA for a 91 Vette and $3500, that is a horrible deal. Save up some money and put some heads and a cam in that LS1 and a few bolt ons and run 11's NA in a daily drivable car.

If you are looking for lower insurance payments and/or car payments or even something a little cheaper to mod, at least get your money's worth out of that 99 TA and buy something you want. But trade it for a 91 Vette and $3500, no way would I do it!

neat

Ok, read all the posts before you reply next time.

The vette went to the auction on Monday, it was supposed to return today if it was not sold. I have not been to the dealer to see if the vette is back or not.

11's in a heads and cam LS1 would be impossible where I live. the plan is eventually to go with a turbo motor. A turbo LS1 is a finacial impossibility at this stage in my life. However, a turbo L98 is not.

Right now I am wondering if a $3500 enhanced TPI motor would hang with a relatively stock LS1. I just want to be able to have some fun until I can afford the turbo motor.

Thanks for the input though.

Ed Maher

3500, a little luck and an L98 corvette could hang with a stock LS1. Couldn't be wasting any money in the effort. Probably something like longtubes and a real exhaust, port the stock heads up, a healthy cam, used/low buck intake parts and a nice torque converter.
That kind of set-up would eat stockish LS1s at sea level, why not at altitude too.

As for the LT1 comments. I agree with the guy who said too many headaches. Reverse cooling is not that cool, and creates problems in itself. And thats not mentioning the CONSTANT opti-crap failures and everything else. It's just a SBC with decent AL heads on it stock and trouble.

I don't know what i'd rather have personally if i was going to make the choice. The vette would be damn tempting if it was in the right shape. The last of the L98 vettes, nice one to have...

Bort62

I would Rather have a l98 Vette Than a 4th Gen anyday.

neat

Hehe, that was me, the topic starter. LT1's are too much of a headache. they are awesome when and if they work right, but it seems like everyone I know with one ALWAYS has something wrong with it.

The vette is a polo green, sixs peed car with black interior. It has every option there is available, and both tops. It also has just over 50k on the clock. I dunno, I guess I'll go see if it is still there tomorrow.

89transam

Sheet....Ill give you $3500 and my 89 GTA for your car, I would bet that that $3500 into my car will be a hella lot faster than a vette.

Its a 383 with TES headers and 3' catback , world product heads

18 k on the motor 12 k on the tranny , red, t tops, leather




EDIT ::Plus insurance would be lower than that vette

neat

What kinda power does the 383 make now? i just got back from an F-body dyno day at a local shop. Most of the 383 cars were pretty dissapointing. In fact, the most powerful car there was a 1993 Cobra mustang. Stock 302 with a TO4E turbo and a cam suited for the turbo. 473 RWHP and 500 RWTQ. FWIW, I put down 321 HP and 336 TQ.

89transam

On desktop dyno with 600 Cfm its

339 HP
444 TQ

at the flywheel

CrazyHawaiian

Dont do it!! Man the L98 wont be cheap to turbocharge unless you have welding skills and stuff. There are no pre-made kits. None. In fact there aren't even any pre-made turbo manifolds or turbo headers. You'll have to either make them custom, or find them off discontinued turbo kits from the 80's (Gale Banks TT kit). Then once you deal with that, you'll need a completely aftermarket FMU setup since no-one makes a piggy-back for the stock computer. Also think about all the parts you'll need to upgrade before even rebuilding the engine or installing the turbo. These engines are old. I have spent hours adding everything up and comparing the cost of what I think would be a proper L98 single turbo setup, to the cost of actually swapping a ARE built LS1 into my 3rd gen and turbocharging it with Robs kit from LS1 Motorsports. If comes out to about the same cost. The difference is piece of mind. You can enter the custom unknown zone with a turbo L98. Yes it would be completely custom and probably make more power than you can imagine ... but what if it dosnt work? It might take a month to find out why. Going the turbo LS1 route on the other hand is backed by a company with a pre-made kit and a bunch of other people also using it. If is dosnt work you're more likely to find help.

But hey if you can weld your own headers and afford to have the car down for months while you build it, you are right the L98 could be a much cheaper alternative.

My .02

Ed Maher

An LS1 is not a SBC. Kits or not, TTing an LS1 car is not for the faint of heart or a regular enthusiast, if for no other reason than $$$. Not only do you need the TT kit (big $$$) then you need a bulletproof bottom end (big $$$) and might as well get someone to tune it since it'd be a helluva risk with big $$$$ x2 into it already to just ham fistedly play with it

An L98 vette has plenty of room to play with for turbos. OK so it;lll most likely be a custom job, but at least the engine can be a low buck solution. And it's been done so much more that there is more help from others in tuning, etc.

RedIrocZ-28

Matt Harlan ( one of GM's Special project engineers ) Put 10#'s of boost on a stock bottom LS1 and made 575hp at the wheels. I personally saw him run a 10.8 @ 130 on only 6#'s. LS1's are 6 bolt main blocks fellas. L98's are 2 bolt blocks. You do the math. For the topic poster: MOVE to a lower elevation city or just buy a TT kit for the LS1. Its cheaper to keep your car than try to mod an L98 to withstand the boost a stock LS1 can handle.

Later

neat

There are no premade kits, NONE for the LS1 either. Incon got about 65 them completed before they went under. So it would be a total custom job on an LS1 too.You must be kidding. You can build a stout SBC out of summit for less than 3k pretty easy. How much is an ARE short block? not flaming, I really don't know. For starters, I am determined to have a twin kit. Beyond that Raymer's kit was supposed to be available months ago. Still nothing. I am not bashing on Rob, its just that I'd really rather not wait another year before I spend the 6 GRAND on a turbo system that doesn't do what I want it to do.The header's are the hardest part. A buddy of mine has built a bunch of headers for turbo charged 4 cylinders before, so that really isn't a problem.

neat

Name one other person who has done it and not scatter'd the motor. Harlan is an amazing individual with an incredible amount of knowledge and talent. I suppose it is possible to run that much boost on a stock LS1, but the probability is pretty slight of the motor hanging on for very long.I'm pretty sure it was a 10.97 @ a high 120 MPH, but you were there after all, I wasn't.

Quote:

LS1's are 6 bolt main blocks fellas. L98's are 2 bolt blocks. You do the math. For the topic poster: MOVE to a lower elevation city or just buy a TT kit for the LS1. Its cheaper to keep your car than try to mod an L98 to withstand the boost a stock LS1 can handle.

Later

You really think a stock LS1 with 10.3:1 compression can take more boost than a 9:1 compression L98??? 6 bolt main or no, that's a ton of compression to be adding boost too. On top of that, the L98 could be made really stout for less than cost of an LS1 turbo kit. The Incon kits were over 6k, and you are looking at 6k for any other single kit out there. Buying a TT kit for an LS1 in an impossibility. Their aren't any out there. Beyond that, if I scatter an L98, what would it cost to replace? The LS1? Do the math fella.

As far as moving goes, I am active duty military. Uncle Sam prolly wouldn't take too kind to me scurrying off to a lower elevation.

neat

FWIW, the vette never came back from the auction so its kind of a moot point right now.

ZZsmpch

iTrader: (1)

The LS1 may have 6 bolt mains, but it NEEDS to have them. It's an aluminum block and would probably put GM out of business with warrenty claims if it weren't. Now if you build one up using a 6.0 truck block, you may be on to something.

CrazyHawaiian

Ok, well if you have your mind set on it, then go for it. I'm still under the impression the newer LS1's will always have a larger turbo aftermarket scene than the L98's. But I'm not gonna say its not possible. Here's some info I found from an older post in the Power Adder section. I talked with Precision Turbo & Engine about turbocharging a L98. Here's what I found:

Good luck on your project. BTW the 360ci ARE built engine was $4600. Lates.

neat

I dunno, FI costs no matter what route you decide to go. Espescially when the kit needs to be engineer'd in your garage.

As far as the fuel components and things of that nature, I don't see why the LS1 wouldn't require those things as well. I just don't know what to do, arrrgh.

In the end I want a somewhat reliable twin turbo V8 car that will just crack the 11's at his altitude. My goal with the TA when I bought it was to run an 11.99.

Due to elevation, my car normally turns about a 13.8 or so. A buddy of mine with a TPI GTA has gone a best of 13.1 with about 3k invested in the motor. I'm just tired of taking it in the *** from aftermarket parts companies, just because I have an LS1.

mystikkal_69

iTrader: (2)

:sillylol:
they like to stick to anyone & everyone they can.

2QUIK6

You could have a variety of cars that would run 11's at any altitude with some easy mods and bolts on if you went with the turbo 6 or a car power by one and the after market parts are plentiful.

Kingtal0n

I know its moot now but I would like to say that the LS1 4th gens are by far the nicest all around vehicle for street performance <b>front the factory </b> I have ever seen.(opinion)

If you consider that the car is all around decent, no its not super fast, but it has enough power for the average person who wants a nice daily driver, not to mention the suspension is already decent, as is fuel economy and *** knows with a nice exhaust/intake and maybe a hypertech they runs 12's easy at sea level. I would model my car after the LS1 if i could afford it, for a daily driver, you cant beat the power to fuel economy ratio, not to mention they arnt exactly totally cast bottom ends, a nice set of hypereutectic pistons sits down there...

I know somone with a stock LS1 motor and a 200 Shot of NOS, Ford 9" 4.11 Rear, TH400 tranny, running Mid 10's in the 1/4 mile. <b> stock LS1 motor </b> he gets 13 MPG with that 4000 Stall and drives it everywhere.
You can see his car at:
www.sffba.com
user: MattWS6
Usually posts under <b>Broward Section</b>

So im not just blowing smoke up everyone's @$$ I seriouselly consider that when they(GM?) designed the new LS1 4th gens there was ALOT of thought put into how they would perform both as a street car and a fun car, with the reliability to back both up. (onion.. yum)

Now, if your the type of person who loves breaking down in the middle of a long drive, or doesnt mind checking plugs / valve lash every other day, or likes to find fuel/water/powersteering/rear/tranny/oil leaks in umpteenmillion places every other day, or likes shattering car parts like nothing, or doesnt mind that unidentified rattle from under the hood/floorboard, and likes constantly tuning and changing and fixing and wrenching and busting knuckles (Hey this describes me!) Then you would probably enjoy an older, cheaper, faster car.
But the tradeoff here is the same as when your choosing the right cam for your engine, do you want that low end torque or that high end horsepower... Do you want that reliable daily driver or that weekend power house... I have found you cant have both unless you sell your house and dump the $$$ into your car.(monty)
<...../rant.....>