Performance enhancements for 82's

[Glensgages]

As MoeJr has stated, swapping 3.73s for your OEM 2.87s is maybe the single-most thing that you can do to your '82 that will provide the most drastic performance gain, but at a cost of fuel-mileage.

I went from running 15.70s @ 86 MPH, getting 23+ MPH highway with 2.87s, to running 15-flats @ almost 91 MPH with my 3.73s, but my mileage has suffered a bit, down-to 17-18 MPG highway.

For the very small amount of driving the '82 sees, I'll stick with the 3.73s, as it is more 'Corvette-like' now.
In-fact, on that 17-18 MPG trip, almost half of that (over 200 miles) was 2-lane, back roads, and around-town/lunch-hour city driving, too.

 

[lnirenberg]

What kind of RPMs at 75 mph with this setup?

 

[Glensgages]

What kind of RPMs at 75 mph with this setup?

Presently, I run BFG TA Radials 255/60R15 (approx 27" tall), and in 4th/AOD, with the converter locked-up, my speedo/tach is VERY close to 3:1 (75 MPH = 25 {hundred} RPM) across the board.
With the 2.87s, it was approx 4:1 (75 MPH was just under 20 {hundred} RPM).

The one advantage the OEM CFI set-up offers, in my opinion, is very good fuel-mileage, 'specially when using the cruise-control at highway speeds.

This Sunday (weather-permitting), I'm going to a big Corvette Show, approx 250 miles round trip, most of it Turnpike/Interstate.
3 years ago, with the 2.87s, I got 23.0 MPH going to this very same Show;
I'm curious to see my mileage-figures with 3.73s...

 

[Ryan]

Inirenberg,

My hood almost stayed stock exept that I have to cut a square piece out of the hood, because I needed like half inch of carb. clearance. And the piece I cut of I used to make a small scoop and it looks great.

Ryan

 

[lnirenberg]

Any pics?

 

[Ryan]

Yes,

I'll try that tomorrow if you can tell me how to get them from my documents to CAC.
I'm not good with sending pictures. Maybe you want me to send them to your private Email. That's easier for me to do.

Ryan

 

[Glensgages]

I don't know how to post pix either, Ryan, but I'd like to see your pictures, too.

 

[Hib Halverson]

The 82CE had a 200hp 350 in it and is probably the second most anemic-performing Corvette ever built, followed only by the 1980 California cars with the 305.

If you want to go to 350hp but keep the engine compartment sock appearing, you'd better have God doing the tuning.

The biggest challenge to performance enhancement is 1) the entire induction system is a POS and 2) the engine controls are extremely crude. To get 350hp from a stock-appearing L83 is going to require a signifcant influx of money and some very sharp engineering and a willingness to accept less than 350.

You are better shooting for 240hp then changing the axle ratio from 2.87 to 3.73 then significantly upgrading the transmission.

 

[lnirenberg]

I checked and God is booked until the summer of '08 so I will have to stand by my earlier statement--
I was just re-reading eveyone's comments and I realized when I said "keep it stock looking" I misspoke. What I meant to say was keep it stock looking with the hood closed. What goes on under the hood is not restricted in any way by a need to keep it stock looking.

Part of the plan is to change the rear to something both more stout and more aggresive. Assuming I can reach the magic 350/350/350 (displacement/hp/ftlbs) I will probably use something slightly south of 3.73s so that I can highway cruise comfortably ie below 2500 rpms in top gear converter locked up. The trick with this kind of middle ground setup is to get the torque as far down the power curve as possible.

 

[MoeJr]

lnirenberg, I assume you wanna go faster than your Audi and it can be done but you do not need 350 HP to do it. If you did what I outlined in one of my posts you should walk that Audi all day long. 2500 rpm at 75 is not bad and I think 3.73's are the best choice for you from a cruising and performance standpoint. Also i forgot 1 thing about the 82 and 84 Cross Fire cars. You will need to install an aftermarket 3-4 upshift sleeve in the transmission if you want the car to shift into OD at WOT or stay in OD with your foot to the floor. I am a bit of a purist and I still say you can beat the Audi and keep the Cross fire setup. People who talk negative about them have never driven one that was set up right.

 

[lnirenberg]

Wow, wow, wow. I don’t mean to start a battle between the rodder set and the purists, but I must rave. An architectural analogy—maybe 15 years ago a house was bought in Connecticut by a famous at the time TV talk show host. His intent was to knock the house down and incorporate it into his not substantial land holdings. But lo and behold the house had the distinction of being the 1st house in the country built out of all concrete. Architects and other preservationists (a group I count myself in—but of course no whacko I!) got up in arms and tried to stop the demolition. My in laws were friends of the prior owner so, unlike the vast majority of the yellers, I had been in this so called architectural landmark. It was an utter POS, the house was cold and damp and green slim formed on the walls. My point is not all things original are worth preserving.

Secondly, I love vettes as much as the next guy but please let’s remember who builds these things. The company has always been run as a profit making venture, not a sin, and from the early 70’s until recently the company by a bunch of bean counters who thought the way to sell cars was to have a big marketing department. Again until very recently their idea of the way to introduce a new car was to put it out half finished and fix it over time. The problem was by the time the product was worth owning nobody wanted to buy it anymore. Besides killing off some decent cars they managed to kill a whole division with this approach. The amazing thing is how good the vette remained as the die hards wrestled with the bean counters. And guess what, maybe the bean counters were right because look at the sales figures for 1978-1981, staggering huh. An 82 CE will never be a pristine 65 fuelie I don’t care how much time passes because with all its attributes the car is flawed as a sports car by being underpowered and a bit porky. My job is to take the car the die hards did manage to produce and fix it they way they would have if free of the corporate yoke.

 

[MoeJr]

No fighting here. Just don't want to chuck the Cross Fire if ya don't have to. I am in Manchester NH. We should get together and meet. I still feel we can dust that Audi with the CFI in place.

 

[lnirenberg]

I own some property in Derry and Goffstown and should get up there more. I probably need to take a trip next week so when I figure it out I'll drop you a note and we'll meet for lunch.

 

[Glensgages]

No fighting here. Just don't want to chuck the Cross Fire if ya don't have to..... I still feel we can dust that Audi with the CFI in place.

No fightin' here, either:
MoeJr and I share the same signature!


All I'm trying to say is this;
even 20 years later, even with all that the fine members of the Cross-Fire forum have accomplished, the Cross-Fire is still a fairly-limited power-making induction system.

Here's the reason that I decided to NOT proceed trying to build a high-output Cross-Fire (altho I frequent that web-site for info and knowledge):

the 'current-thinking' regarding a hi-po Cross-Fire is:
port the OEM intake, or buy one of the few aftermarket/replacement (X-RAM, SY-1, etc.) intakes offered;
get a non-OEM fuel-pump ('85-up LT1);
get a non-original ECM and 'graft' it into the existing electrical system;
're-program' the ECM (I'm admittedly NOT a computer-type kinda guy);
add a non-OEM fuel pressure regulator;
over-bore the TBs,
add different injectors,
etc., all in the hopes of getting " close-to " 350 HP.

Getting more than 350 HP from a single 4-bbl 350" SBC can be accomplished with parts bought at Wal-Mart by a competent back-yard hot-rodder.

Now, if you take both 350 HP cars (one a Cross-Fire, the other a 4-bbl) out on the road for an extended trip, and both of them suffer a mechanical problem, which one is easier to get parts for, repair, and continue down the road:
the "no-2-pieces-are-alike" Cross-Fire, or the 'generic' 4-bbl 350" SBC car?

Just my $.02 worth.....

 

[MoeJr]

Thanks Glen. I agree that the single 4bbl is easier to get that 350 hp. But I don't think it is gonna take even 300 hp to beat his VW errr Audi. Sorry couldn't help myself. However it is his car and his choice and all I can do is offer my advice.:bar

 

[wishuwerehere82]

You guys are close to making me get a crate motor and forget my problems with the L-83 Cross-fire.

Grey clouds are going to clear up, put on a happy face!

Pete.

 

[MoeJr]

Pete don't you become a defector now. I cannot believe you Sally's here. My 84 runs excellent. I cannot understand why you guys aren't getting yours to run good too. I think you both need to bring those Cross Fire cars to NH for some lovin and tuning.

 

[Evolution1980]

My less than 2¢ here...
First off, doing engine mods is always one of those things that never stops where you expect it to. You're going to beef up the engine internals, yet strangle those mods with the stock exhaust setup??? Seems kinda wasteful, so you then end up getting headers, and straight back exhaust, blah blah blah.

Here's yet another suggestion from yet another person ("me"!)
1) Remove CrossFire engine and all it's carb / injection system. Place it all in a bag with some desicant packs. Store it away until you ever decide to put it back in the car.

2) Buy ZZ4 crate engine and get yourself a Q-jet carb from an '80 vette. Drop that in your car with a 3" open element air filter (it'll clear your hood with about 3/4" to spare).

Want more?
3) Your stock 3+1 transmission is a 3.07 rear. Converting to a 700R4 trans will effectively give you 3.73 gearing for first gear, along with a kickass OD for the highway (70mph @ 1900rpms)

4) Get rid of the cast iron exhaust manifolds and throw on some headers.

Let me tell you what this will get you...
13 second 1/4 mile times (give or take a couple tenths)
155+ mph top speed
I know this all works because it's what I just parked in my garage 20 minutes ago...

(BTW...You haven't mentioned anything about emissions checks, so "we" are assuming that's a non-issue for you...)

How fast do you want to go? ...How much money do you have?

 

[Glensgages]

Want more?
3) Your stock 3+1 transmission is a 3.07 rear. Converting to a 700R4 trans will effectively give you 3.73 gearing for first gear, along with a kickass OD for the highway (70mph @ 1900rpms)

Evo:

ALL '82s came with A/OD 700R4 transmissions, and either 2.72, or 2.87 gearing from Bowling Green;
that's how i run 75 MPH at less than 2000 RPMs.

Your 13-second/ZZ4 alternative is spot-on, but I'm of the impression that lnirenberg would rather use his stock L-83 short-block.....

{EDIT} should-read "That's how I ran 75 MPH at less than 2000 RPM", with "ran" being the operative-word, "ran", as-in "when I had the 2.87s"...

 

[82ColEd]

What are you doin' out that late Andre ? On a school night too ? Tse Tse.. Youth..

Not getting fightin here either, i know the 82CE isnt a runner by any stretch, but i am more with Evo1980 (Andre): Drop in another engine if you so desire (and keep the old one), rather then fighting with the x-fire..

Also: Throw some pictures our way so we can drool over a nice car..
Stefan