pologreen1

So, lots of talk lately and opinions on these cars. I am asking here to get more thoughts than in just the zr1 section. I have been serious 2 times about buying one but they are not show cars for me. I have looked at higher mileage cars.

I could see having one that was nice to keep for a collector, BUT... If I got one I would actually like the motor to be 440+ cubes. I know it has been done n the past, but what needs to change? What can be done to them, what has to be done to them to do this.

A zr1 is powerful and cool for the time compared to a c4, but I would want something more fun than 375-405hp.

AgentEran

I believe you need a 4.125 crank.. and the cylinders need to be re-sleeved for 4.00" diameter.

Not gonna be cheap at all.

Check these links out..

https://www.corvetteforum.com/forums...5-upgrade.html

http://www.lingenfelter.com/engine-p...hp-415-cid-lt5

JrRifleCoach

First the Zr1 is a C4.
Second if your looking at something in the 400hp range, a C5 Z06 is much better car.

I know, I have one. And I've driven a stock ZR and one thats been modified. The Z06 is technically advanced with better traction/handling control, suspension design and brakes. Better fuel economy and ergonomics. Spare engine parts, both OEM and performance can be found anywhere at reasonable prices.

Try to find a head gasket for a LT5 for less than $300 a pair. (LSx < 150)
Or timing chains for less than $400 a set. (LSx < 160)
Waterpumps for less than $200 used. (LSxWaterpumps for less than $200 used.)

Point is that repairs will be required.

MHO YMMV

pologreen1

That is what I was thinking. It would be cool to have something different and be 600+hp but seems like not the smartest thing to do with a zr1.

Can a c4 zr1 support 1000hp boosted?

JrRifleCoach

Not really since the drive train is still a C4
400-450hp max reliable

FASTAZU

http://www.zr1specialist.com/HAT%20W...20upgrades.htm


Love my 500hp LT5 with stock drive train other than 3.73 gears never had any issues.

JrRifleCoach

However the question was 1000 HP.



To emphasize my point on cost. Thanks for bring it up WeGone. Haibeck charges $19,000 for a 150 hp upgrade.
My buddy just received his back and it is a thrill to hammer on. The sound @ 8K is tremendous!

A LSx can produce the same if not more for less than half that price.
Plus the C5 drive train will take even more HP.






.

Paul Workman

Cubic inch to cubic inch, the DOHC tips its hat to nobody, all else (e.g., FI, etc.) being equal.

But, if good manners and Corvette heritage aren't important to you, then a tricked LSx of some flavor might be considered. (AND, its a good thing parts are cheap...you're gonna need 'em...lots of 'em: just not sure that is a virtue(?)).

However, for a touch of reality, the fastest cars in the last two WANNAGOFAST 1/2 mile shootouts in Monee, IL were V6 FI cars (but also DOHC, I might add....) Just sayin...

Just porting and headers and free-flowing exhaust on a 350 LT5 can yield over 500 hp at the crank (over 430 at measured at the wheels) without giving anything away! Until you drop the hammer, many suspect nothing until it's too late! Many a peevish, unsuspecting ricer as well as one or more LS1, 2, 3, and 6 drivers got a chance to appreciate the fact my mild-mannered LT5 is NO slouch, in spite of its age! It's "power under the curve" that makes the difference (and "gets um"). It's "peak" power that salesmen and "car rag" writers go all agog about.

MavsAK

headers free flowing exhaust, some mild port work, and a cam on an LS6 will yield the same or more..and in a much lighter package and still have good driving manners. The LS family, isn't the Gen 1 and 2 family where you end up with a car that can't drive for **** to make power, it's a whole nother world and level, much like the LT5.


The LT5 is a great engine, but there's reasons GM put it aside rather than revisit DOHC for the special corvettes. It's heavy, and worse has a very high center of gravity.
Power per cube isn't what matters, Power Per Pound Is, and that's where DOHC comes up short in anything but an inline four.

bb62

There are reasons that GM dropped the LT5, but none of the reasons you suggested.

The weight reduction was an ancillary benefit and not a decision factor. Neither was center of gravity (which at most would be a few millimeters). Power per pound was not a factor either.

What WERE factors in the decision were the package space of the engine (to fit under the hoodline of the projected C5) and the fact that the LT5 was NIH. The rationale GM used to continue with the OHV technology was the power delivered per package size (not cubes, and not weight).

trilkb

The price of a flywheel makes me want to throw up....I like the idea of the rest of the car though! I like the (subtle) body/wheel differences too! I do agree that I would probably own a c5z06 befor a c4 zr1, if not just a C6 with a manual trans.

Paul Workman

Well, Mavs, w/ all due respect that isn't so

I'll show you mine, and you show me yours...

This is my 500+ hp (432 at the wheels) LT5 idling. Important to note, this motor is running on STOCK CAMS and STOCK throttle body. It also has LT headers, X pipe and 3" dual exhausts.


And, now the numbers to back it up...



And, for comparison, an LS6 claimed to have 500 hp...


That's one of the virtues of the 4-valve DOHC architecture: it breathes so damn well it doesn't have to have low-end robbing lift and overlap to make the power. No... The LSx can't come close to the same power the DOHC LT5 can make without FI or running like a "box of rocks" and giving up street manners/drivability. To have both, there's no replacement for displacement. (But, The LSx doesn't have the corner on displacement either...)

http://aesracing.net/product_info_lt5.htm

Don't get me wrong, my friend. I'm NOT kicking sand in the LSx eyes. It is a marvel of engineering in its own right. Both architectures have their plus and minus columns. Could we agree on that? pologreen1 asked for info on the ZR-1. Well, the ZR-1, aside from the wider body and some interior upgrades and the LT5 IS a C4. But, off the bat the OP gets a flood of LSx and C5 irrelevance. (Sorta like getting distracted by being up to yer butt in alligators when all you wanted was to drain the swamp!)

And, just as a point of interest, perhaps, the "FBI" (the ZR-1 gang from IL) has won the team trophy 3* of the last 4 years; awarded to the team with the fastest 3 times in a local all Corvette shootout where MOST of the competitors were LSx'es...FWIW.

*Would have been a total of 5 out of 7 years if the FBI gang had registered for trophies every year (didn't one year), and the host hadn't (one year only) changed the trophy to include bracket racing instead of fastest times. Not too bad for dem ol' LT5s, huh?

JrRifleCoach

PAUL YOUR ZR1 IS JUST FABULOUS!!
I can't believe that I would ever doubt that a LSx could come close to yours on or off the track.
What was I thinking?!?

1993C4LT1

mike100

an LT5 over 400 cubic inches is cost prohibitive and the easy (and correct) answer is to get a C6. You have to really want a C4 ZR-1. There's some nice fix-ups to make them run right, but don't do it to beat a C5 Z or to compete head to head with modern sports cars. The C4 is pretty happy with 450 hp or so... the brakes and handling just aren't up to par compared to newer gens.

The reason to get a ZR-1 is the special rareness of it at car meets and all the intangibles that a dohc engine bring like the extended torque curve that doesn't just drop suddenly. It is also over built and balanced extremely well and offers a smooth driving experience that even my C6 lacks. It just feels premium.

for performance metrics strictly, the car itself is behind the times and one needs to consider more than just the powertrain.

Paul Workman

Very well said....

MavsAK

This is Ch@0s's 390rwhp Iron LSX 5.7 It made 390 with stock 241 heads, which have plenty of room for porting, and would easily hit the 500hp marker with porting, or later model heads.



And a bonus a 500hp TA LS1

Sounds like a pretty good idle to me.

Also your LT-5 has stock cams because no one actually makes cams for it

http://www.trucktrend.com/how-to/eng...5-3l-big-bang/ And let's see an LT-5 do that on stock internals without blowing itself to pieces. (it Can't)

For it's time the LT-5 was one of the world's most advanced engines if not the most. It's a technological landmark on it's own merit. I'm not knocking it, but like the Gen 1 SBC it's time has passed. Sure I could build a forced induction monster that will keep up with a forced induction monster. But an LSX with FI will still make more power. It's just how it is. (Mine will out torque it though at a given hp, that much the Long runner intakes still do better at least.)

NA to NA, you can't build a Gen 1 or 2 engine that will make 500 hp that will idle. That's the territory for BBCs of the old architectures.
And it comes back down to power per cube meaning next to nothing vs power per pound. A 90 model C4 weighs in at 3290...an LT5 90 model weighs in over 3400. That's the weight of a big block right there in weight delta vs an L98.

It depends what the OP's goals are.
I want an LT-5, don't get me wrong. I hound ebay at least twice a month looking for an LT-5, that if nothing else I want as a centerpiece for my living room or maybe my garage. (I collect engines.) Hell, I'd be tempted to LT-5 swap my C4, if I weren't already so far into my L-98's build, or LT-5 swap my Z-28...but I have a BBC that I picked up for free, that I'm going to make a 496 stroker out of and turbo charge it, or depending on final cost, just LSX swap it.

LT-5s are badass. But parts availability, if you're planning on doing what the car was meant for does mean a lot. If it's going to be a garage queen that's one thing, but if you plan on really using the engine, as more than a loafer/DD I'd be a little nervous. It's one of the reasons I didn't pull the trigger on a 90 ZR-1 that was up for sale near me, a year ago. The money was right for the car...but if something went wrong... I'd be almost in it for as much as it cost me to buy the car in a rebuild, in the worst case scenario.

I love the looks, of the LT-5, and there's something decidedly awesome about being able to rev 5.7 liters to 8k rpms, and still be able to idle smooth afterwards. It's a great mill, I won't argue that. I just don't know about what kind of can of worms you'd get into if something breaks.

Deakins

I'm not quite sure how you are making these very broad statements about the LS platform versus the Gen 1 platform. If the gen 1 days have passed I guess we should go tell the world of outlaw sprint car guys because that's all they are using to make about 900 hp NA... The LS engine was developed for a few reasons, none of which had anything to do with it being some super magical "breakthrough" design.

If it's what you have and that leads it to being what you love go for it...I'll stick with my all aluminum SB2.2 engine. As for the LT5, it's a nice piece and I would pick one up for the right price any day. There are a good number of parts available at a reasonable cost if you bother to actually go look for them. Just my .02

MavsAK

Actually it IS a break through design. Those 900 hp NA engines? Try driving one of those on the street, and on pump gas. You can't.

A 500hp gen 1 engine is a rowdy not really streetable beast in NA form. A 500 LS or LT-5 on the other hand can still return 20s on mpg, and idle all day long at a stop light and run on 91 octane.

The LS block, and architecture is vastly stronger than an SBC, it takes AFR cnc ported heads just to get what an LS pair of heads STARTS life at.

http://www.trucktrend.com/how-to/eng...5-3l-big-bang/ This literally can't happen on a stock internal SBC. 1308 hp, and the internals stood up to the job. 160,000 mile rings even.

The LS is light years ahead of the SBC. Thinking otherwise is a complete denial of reality. The LS platform wouldn't be the go to swap for just about everything on four (and sometimes two) wheels if it weren't.

We're well off topic now of course, so that's the last I'll say on it.

Deakins

I'm not even going to continue this as it is clear that we are on completely different pages. I point out what the most demanding application is using when it come to SBC architecture (where money is no object and you can run virtually anything you want) and you bring me a magazine article..enough said. OP, I apologize for the thread getting off track bud.