1991Z07

Hey everyone!

Been a lurker here for a few months...and time I introduced myself.

I'm working on a new track car (for me) to go along with my daily driver...







I bought a '92 ZR1 rolling chassis last year...and had originally planned to drop a 427 Gen 1 into it until my machinist died and all my parts mysteriously were not there when I went to claim them.

SO, now I have to start over from scratch...and since there isn't really any good reason to do it with a Gen 1 motor, I started to research dropping an LSx into it.

Plans are:

• LS7 with 12.5:1 C/R running e85 or better
• Heads/cam/intake...shooting for about 650 RWHP...maybe a bit more later
• T56 with faceplated 2-5 gears
• Gen 1 Viper DANA 44 rear end
• C6 Z06 or Z07 calipers & rotors
• Full cage

With the ZR1 body I can cram 335's under the rear end so I have at least SOME good tire patches to maintain traction. This will be predominately a track/open road race car...street manners are not an issue.

I've already started acquiring some parts...

• Lexan rear hatch
• Carbon fiber top
• Carbon fiber clamshell hood

With the parts already acquired plus the LS7, it appears I'll have already shaved a good 300+ pounds from the car in LT1 trim and 450+ pounds in LT5 trim...all up high so the C/G will drop significantly.

This will be a slow process for me...I am just about to embark on building a new house for a friend. They start the foundation next week.

First I have a frame shop appointment to get the passenger frame rail pulled...it rode a guardrail at the drag strip after a blowout. Bent in ~1.5" and up ~ 1". Passenger door still operates easily...but needs to be addressed first before I start on anything else.



The cage I plan to model after the Greenwood G572 project...











I love that you can ACTUALLY see back between the "seats" with this design...basically putting a roll hoop above each seat.

Also, with the floor supports this way I can eliminate the "C" beam connecting the trans to the differential...and strengthen the entire drivetrain.

I hope to have it done by next year (2014) in time for track season...but I may be dreaming with everything I have on my plate.

Gonna be a fun project...can't wait to get started and will certainly keep everyone apprised of the progress as I plug away at various portions.

There is a wealth of knowledge here...you guys rock!

merim123

iTrader: (11)

kick *** project! I've always thought it would be cool to take a first generation zr-1 and do a new zr-1 powertrain to it. But like your approach better on keeping the weight low and ls7. looks to be an awesome setup.

TopNotchLSX

WOW!! This is a great project! I have been wanting to see an LS7 C4 for a while now and you are doing it right!. Good luck and I'm subscribed.

SKULL

iTrader: (7)

omg! what happen to this c4zr1?????

85MikeTPI

iTrader: (9)

"First I have a frame shop appointment to get the passenger frame rail pulled...it rode a guardrail at the drag strip after a blowout. Bent in ~1.5" and up ~ 1". Passenger door still operates easily...but needs to be addressed first before I start on anything else. "

Project GatTagO

iTrader: (7)

Words...words...words...

1991Z07

I think I explained it pretty well...

The car had a right rear blowout at the drag strip, took a hard right and went up on top of the guard rail. The (2x) previous owner decided to part the car out...took the drivetrain out and sold the body to the person I ultimately bought it from.

I wanted a ZR1...because the bodywork allows me to put 335's under the back end without any problem and still be inside the fenders. The ultimate track car...when given a diet of an LSx motor and some selective carbon fiber body parts.

I bought it complete as far as the body was concerned...I have bumpers, gill panels and a new passenger door to get it back to a condition to have it painted.

After a cage is installed and I have some beefing up in the right places done...of course.

cam

iTrader: (9)

Thats a kick *** platform to start with for such a swap. A bit of a shame to do in a real ZR1 but awesome nonetheless

Cobra4B

iTrader: (9)

That cage won't pass tech with NASA or SCCA if you ever want to do more than HPDEs and Timetrials. Best to do a legal cage for future resale even if you only intend to do HPDE with it. Also, best to research the current issues ongoing with the LS7 cylinder heads before dumping a bunch of money into one. The Corvetteforum C6Z06 section is a wealth of knowledge on this subject.

Beautiful garage... good luck with the project.

EDIT - FWIW here's a few shots of the cage in my C5Z06... I can see out the rear just fine.

1991Z07

I figured the cage would need some tweaking to stand up to some of the requirements of some sanctioning bodies...and those pictures are not showing the cage completed either.

But I don't plan to do anything but track days, open road racing and autocrosses with it. If body panels for a ZR1 were more readily available...it might be different, but considering that nobody makes them and to get one involves finding a wrecked donor...or stretching a standard C4's rear to make it wider means I'm not in any hurry to be on track with a slew of other cars rubbing paint.

I've seen that 10 billion post on the Forum on guide wear...and the heads will be dealt with before the engine goes into the car. Of particular interest (to me) is that Katech runs stock parts on their builds and have never had a failure yet...so that tells me that it is more HOW it is done, not the quality of the stock parts that are in it.

Katech only changes the valves to non-OEM when bronze guides are used, based on the incompatibility of the stock valve stem coatings with bronze guides. That is the only reason...

Even though I "could" probably just drop a donor motor in without any work done...the LS7 I get will be freshened before it is installed. I've seen just about every LS7 post on the Corvette Forum over the past 8 or 9 years and have noted the things needed to make them solid track motors...I have a laundry list of "to do's" that will be done internally to make it survive, and my track cars always get a teardown for periodic maintenance. Until I see no need for an annual check...the heads will be pulled and measured over the winter every year, and oil analysis will be done every few months to determine if any bearing wear is noted.

Only a few minor items are needed to make LS7's survive hard track use...primarily in the dry-sump system. Katech upgrades to the ARE stage 2 system for their Track Attack motors...

I've had quite a few people ask why I want an LS7 vs. doing a stroked/bored LS2/LS3 and the answer is that the LS7 is designed to race, same as the LT4 was. They engineered internal air passages and oil returns in those motors as a direct result of things learned while racing them...things specific to them that are NOT found in an LS2/LS3 and the LT1. IF I were just going to "occasionally" take it to the track and most of its life were going to be on the roads, an LS2/LS3 would certainly be cheaper and would work OK...for a while.

Thanks...it took me almost a year to get it done like I wanted. Here are some shots from when I had just finished painting the floor...before it got cluttered up with "stuff"...









All the men who come over love it...the wives hate it. I've heard so many times "Wow!" come out of his mouth followed shortly by "Don't even THINK about it!" from hers...

Makes me wish I could hear their conversation on the way home...

Cobra4B

iTrader: (9)

Sounds like you're planning on doing a ton of HPDE weekends etc. Even so, best to check out the cage rules for the sanctioning bodies of the open road race groups you're considering and then NASA/SCCA. If you build the cage wrong even the open road race groups might limit you to a lower speed class. I've never done one of those, but I've heard they're getting more serious about tech/safety as they've grown in popularity. Also, IMO, you are more at risk of needing that cage doing the open road race stuff as the surface is not an ideal race track and there aren't usually safety barriers other than rocks and trees!

Also... I said it before... but resale is huge. If you ever get done with the toy and want to sell it having the cage legal opens up your market considerably. I'd rather buy a stock car and start from scratch then buy one with a random cage that doesn't pass tech no matter how good the fab work.

Not to get into a lengthy debate on LS motors, but the main issue with the LS2/3/7 is the oil returns. They repositioned them (vs. the LS1/6) to make room for the larger intake runners in the heads. The LS7 isn't immune to any of this... which is why GM put a dry-sump on the car and why they ditched the Z-51 option in the lesser cars and created the Grand Sport with the dry-sump LS3.

It sounds like you've done your homework and are aware of the potential issues. I just didn't want to see you spend thousands on a LS7 crate motor and have issues when you finally get the car on track. In my circle we see way more issues in the LS2/3/7 crowd than we have in the LS1/6 crowd.

Is that all Lista cabinets/drawers? Beautiful. I work out of a regular 20x20 2-car garage, but I hear many of the same comments when people in my neighborhood walk buy. People are always shocked to see a garage that gets used!




I'll end the threadjacking... with a garage like that you may want to check out Garage Journal if you aren't already familiar with it. It's a forum dedicated 100% to tools, garages, and shops etc.

http://www.garagejournal.com/forum/s...d.php?t=181290

1991Z07

One of our club members is the head tech guy for the Big Bend Open Road Race organization...he's an engineer and is HIGHLY ****-retentive. He's designing the cage in his engineering CAD system and stress analyzing the layout until it exceeds their requirements...the cage will meet their Unlimited Class specs, so it will basically be a NASCAR-spec cage. Like I said...things will need to be tweaked but I understand your point. I wouldn't dream of shortchanging the safety of myself or a passenger...the cage will meet and/or exceed the safety requirements of most racing organizations.

I wouldn't dream of buying an LS7 crate...$16.5k for a motor before it needs any work done is way more than what I am willing to spend. I've already had a member here contact me about buying his 15k mile LS7 for $8,500...and I've seen them for 1/2 that other places. LG Motorsports had a 500 mile takeout from a customer car for $9,500 a few weeks ago...so deals are out there for far less than the cost of a crate motor with little concern for them being "used".

I weighed the options of building this car as a Gen 1 SBC vs. an LSx and to get the same power potential and weight, the Gen 1 SBC would cost nearly what an LS7 crate new is. I'd need 18* heads, an AL block, custom intake, etc. and by the time you tally all that together, an LS is light years ahead. I'd guess that most of the problems you see in your circle with LSx motors is they didn't do everything needed to make them live in a competition environment. Yes...they can fail. Any motor can. But it's also interesting to note that while GM used Katech there was never a retirement from a race due to engine failure. Ever...including the 24 hour endurance races. They'll do that level of prep for the mere sum of $17k plus my motor. If I win the lotto...or our company gets bought out I might go that route one day. Until then...I'll just have to trust my machinist to do everything I ask to make it live without spending that kind of cash.

Everything in the garage is Moduline...I had a quote from Lista that nearly stopped my heart. Moduline came in at 1/3 the cost. Just as nice...they mostly do these cabinets for trailers, lightweight and strong.

Thanks...I'll give it a look when I get some time.

Cobra4B

iTrader: (9)

I see the Moduline logos now. As for the cage the only thing that got me started was the dual main hoops, that specific item won't pass tech for NASA or SCCA. I thought you were considering doing that type of set up. Good luck!

esham

1991Z07

No...but I was considering the "X" bracing to look like that a bit. The requirements I've seen "suggest" that the bracing comes down to the tunnel, and so looking at the one Greenwood did I thought it might be possible to make the outer hoop continuous and then brace down to the tunnel as shown.

Just imagine this with a bar joining the two hoops together at the top, only the outer hoop is a continuous piece. I believe that would satisfy SCCA and NASA specs...it certainly works for the Open Road Race specs...almost a direct copy of the NASCAR tunnel brace.



I want to avoid the diagonal cross brace behind me as much as possible. I have it in my '91 C4 right now, and it is directly in my view out the back making it very difficult to see.

cam

iTrader: (9)

Cages are a pain.... Damned if you do, damned if you dont.

But that chassis would still perform quite freakin well. Lightweight too, low cg, stiff enough for the suspension to run true. My kind of car

Cobra4B

iTrader: (9)

In the stock car that "bulkhead" behind the seats is flimsy sheet metal. Thus, an x-brace going to the center area would be worthless. Rules generally dictate that you have to run from one top corner to the opposing lower point where the main hoop meets the chassis. In the pictures you've linked they've done extensive re-engineering of the chassis to make the area below the "bulkhead" structural.

I've really never seen people do much more than the traditional diagonal and harness bar for the main hoop. It's the rear down bars that they get creative.

If you want I can send you a 10 page doc of various C5 road race cage designs (may be close enough to the C4 chassis to be of value) that I used to work out my final design with my cage builder.

Blackpanther99

iTrader: (8)

This is an awesome build ill be checking the progress on this one for sure.

1991Z07

Yes...please send it. At least it will give me something else to give some ideas.

There is actually a beam going between the frame rails back there right above the differential snout...I used it to mount a snubber to make my D44 live longer. It is folded sheet metal...but can be replaced with something a little more substantial.

I'm going to need to make similar changes to the rear structure on mine anyway...I have nothing to secure the front ears of a Viper D44 to as is...so there will need to be some major structural work done under there to secure that. The stock D44 is terribly weak...and I have seen too many break when you have sticky tires and a manual trans. This will see SOME 1/4 mile action...but most of it will be road racing.

Even then, I've seen stock D44's go south with race tires.

The Viper version I've seen stock units at the strip with 1000+ HP (turbo) and drag radials run for years before they give up.

cam

iTrader: (9)

What have you seen fail on these rears? Ive seen control arms snap and drive shafts spin up but nothing else