crossfire

[aja37]

Looking for some feedback on the crossfire system. Just Purchased an 84 that was equiped with the crossfire system, but the previous owner had an eldebroack manifold and weber carburator installed because of problems with the crossfire system. After getting the car home I've been unable to keep it running without pouring gas directly into the carburator. I know I need to investigate the situation further, fuel pump etc., but haven't had the time. My Question is simply this: should I continue to find out what the existing problem is or purchase what's needed to put it back to the original crossfire system? Is the crossfire system a throttle body system?
PS.... This was purchased for my grandson's 16th birthday this coming March
I own a 1970 350/350 that I've been driving and restoring for the last 15yrs and he had become an enthusiast of these fine machines .

 

[grumpyvette]

ID FIX THE CURRENT INTAKE AND CARB!
IT FAR SIMPLIER AND WILL WORK BETTER

HERES SOME INFO FROM A DIFFERANT THREAD

the stock 1984 engine had about 205hp

HERES THE MAIN PROBLEM....THE EXTREMELY RESTRICTIVE CFI INTAKE ITSELF

The new L98 engine increased horsepower from 205 to 230 plus a gain in fuel enconomy due in part to new Bosch fuel injection with tuned runners. bye 1991 the L98 was up to 245hp!
theres very little advantage to swapping to a TPI intake, because you need to swap not only the computer and wireing and buy and install a TPI intake, but new throttle body and the TPI is still only a 40hp upgrade at best and still very restrictive. everyone I know thats useing a TPI engine wants better airflow, your stock cross fire intake is totally out of airflow by about 4000rpm, the TPI only raises the rpm level to about 4700rpm where it also hits a flow wall resticting the engine, your far better off swapping a few parts on your 1984 like in the post listed below

http://www.crossfire.homeip.net:81/...CF?+Possible?&Forum_Title=Alternate+Induction

look at it this way, youve got a known good corvette that lacks power, drop about $2000 in the listed heads,cam,intake and your about 115 plus hp ahead, (thats a minimum of 320hp)(youll really be much higher its just that that hp level,is a almost total no brainer) a totally differant engine, if your into even more hp, install a 383 kit with 10.5:1 cpr pistons. either way youll leave stock TPI cars seeing fast dissappearing tail lights. getting 350-370hp is not that hard!!! (especially on a 383 cid displacement ,AFR 190cc cylinderhead ,custom SY1,CRANE CAM EQUIPED 10.5:1 cpr engine with headers)

look at combo #15,#16,#17 http://www.ryanscarpage.50megs.com/combos2.html
custom lid on SY1

SY1 with custom lid

SY1 runners
SY-1 with custom lid
CRANE 114132 cam
AFR 195cc heads
an EASY 80-100HP BOOST over the stock intake
if your willing to put up with a slightly rougher idle in exchange for an additional 10-15hp (110-115 total over the stock engine use a CRANE #114142 cam) if you want even more power add a 383 high compression engine kit
look at combo #15,#16,#17
http://www.ryanscarpage.50megs.com/combos2.html

sure the milder cam I said runs well with the modified cross fire SY1 will cost some hp but youll see the diffeance, and remember the SY1 is made to produce more power than almost any single carb intake!

this approach allows you to stay with all the orignal wireing, cpu,throttle bodies, air cleaners,ETC.
yeah youll need to have a custom lid made but they are available or you can make it yourself, or have a local machine shop build a custom lid. yes youll need to find and purchase a used SY1 as EDELBROCK no longer sells them. (EBAY has them almost daily in the $250-$350 range. the stock CFI intake has a very hard time EVEN WHEN EXTENSIVELY PORTED REACHING 350HP, an UNTOUCHED SY1 can EASILLY flow in the 475hp range!

heres the same info useing the OFFENHAUSER BASE,(KEEP IN MIND THE EDELBROCK SY1 avoids all the problems with the wipper motor clearances

http://jobyteknik.homeip.net/corvette/2002-11_offy_installation/

unless your rich or hopelessly masochistic get a SY1

the sy1 flows close to 270cfm out of the box, a cfi flows 170-190cfm (DEPENDS ON WHICH PORT (STOCK) and theres not enought room to port without cutting/welding (EXPENSIVE AND TIME CONSUMEING AND EASILY SCREWED UP)

these are the STOCK CFI INTAKE RUNNERS,THEY WILL NOT SUPPORT A LARGE INCREASI IN HP WITHOUT MASSIVE CUTTING AND REWELDING WORK,WHICH COSTS FAR MORE AND WORK FAR LESS EFFECTIVELY THAN AN SY1 SWAP WITH A CUSTOM LID

this is the port work necessary to get them to flow even as pittifly as a TPI

 

[aja37]

Thanks for all the input grumpy. Very much appreciated. Will keep you posted when I decide what to do.

 

[MoeJr]

I'll pipe in my 2 cents. I have an 84 Vette with original Cross Fire. If you have it set up properly like I did it is a fine system. Grumpy is right the intake is restrictive but it is torquey as heck and alot of fun below 5k rpm.

Seeings that someone already hacked the car and put in a Carb I would just get a nice quadrajet carb for it and be done with it. They get great gas mileage and make good power. You can buy new Q-Jets from summit for around 500 bucks or get a junkyard one and have it rebuilt by someone who know how to rebuild and set up a QJet.

 

[wishuwerehere82]

I'll bet you do have a fuel pump problem. It should be fairly easy to find out if this is true.
Since the pump is in the tank, it make a buzzing sound when you turn on the key then stops after a second or two when the line is pressurized. If it keeps running, there's no pressure building in the line. Or if it doesn't make a sound, it's bad.
Listen for the buzz.

 

[aja37]

When I first purchased my 70 it had a Holly 750 double pumper, and I couldn't pass up a gas station. I found a Rochester Quadrajet on the floor of a friends shop and another friend ended up rebuilding it for me. That was a good move for me then and it sounds like a good move for the 84 right now. Thanks for your input Moe. This is why I joined this site. I've found it very helpful. Lots of knowledgeable people.

 

[aja37]

I haven't been able to work on the car because I've been working a lot of overtime, but my first thought is the pump, although what you've described on the noise is what's happening. The buzzing stops after a few seconds. I plan on disconnecting the line from the carb. and seeing if it pumps 1st chance I get. Will keep you posted on the results and thanks for your input too. Like I said before this is a GREAT site.

 

[Grizzly]

I would only make one suggestion, that you find out what you can and can not do under the inspection laws of the state it will be registered in. The things discussed here, while they may solve one problem, may result in a car that can't be licensed in NY. I know you couldn't do it here in PA on a 1984 model year car.

Good Luck....................Griz

 

[MoeJr]

Good Point Grizzly. I didn't even think of that.

 

[aja37]

Good point you brought up Grizzly. I have a couple of mechanics that I work with who should be able to answer whether it will be able to pass inspection. I did purchase it in NJ, but never gave it a thought about safty or emmission inspection here in NY. Again thanks to all who are bringing different thought to mind. I forget about this site for once in a while, but am very happy when ever I have questions about one thing or another because every time I ask a question I get GREAT info and feed back from all the terific members at this website.

 

[wishuwerehere82]

In NY they do not test for emmissions on a vehicle older than 1996. They do not hook up the ECM port to the computer for inspection, nor do they sniff the tailpipe for smog. Just a basic under car inspection for Cats and suspension, brakes. There should be no reason to open the hood for a NYS inspection.
But the code does specify that OEM systems should be retained. I doubt most inspectors would know the difference if they saw it.

 

[bossvette]

one thing to remember is the pressure of the fuel pump a carb is down around 5-7 lbs; a TBI requires 12-15; and EFI is 35+ the 84 pump will be running too much pressure for a carb unless you use a regulator. I don't know if you would need a return line but it may be a good idea.

 

[MoeJr]

Just to give you a little more tothink about check out this link.

http://www.swko.com/~lionsden/crossfire.htm

On my 84 the engine needs to be shifting at 4600-4700 for best performance. Just as an FYI

 

[CAJUN C4]

Might Cosider an X-Ram. My 84' has a 355 CI ZZ4, Roller cam & 1:6 roller rockers,750 CFM custom bored TBI's,No problem beating stock LT1's

www.x-ram.com

 

[aja37]

Cajun, Checked out that web site and liked what I seen and read. First things first, I was able to check out the car this past weekend and discovered that it's not pumping any gas to the carb, so I will probably have to replace the fuel pump. Any tips for replacing it would be really appreciated. Always looking for shortcuts that work. Thanks for X-ram website.

 

[CAJUN C4]

Cajun, Checked out that web site and liked what I seen and read. First things first, I was able to check out the car this past weekend and discovered that it's not pumping any gas to the carb, so I will probably have to replace the fuel pump. Any tips for replacing it would be really appreciated. Always looking for shortcuts that work. Thanks for X-ram website.

It's not terribly hard to change take the Lid off then the attaching screws for the pump assy' it then pulls out after you disconnect the 2 lines..pretty straight forward your shop manual will have details & pictures.If not,let me know and I'll E-mail you some.

Dennis

 

[bosshogg]

Cajun is right on that the pump is not that hard to replace, but you might want to check for a clogged filter or a pinched line somewhere first...welcome to the world of the "MONEY PIT". Hope you get it fixed soon.
I hate it when WORK interferes with our play time.
Happy Holidays to all !!!

 

[aja37]

Boss, I've had my "MONEY PIT" for a while... :cool I'll be passing this one to my poor grandson. Just HOPE he saves a little for College, :eyerole ...
PS..did do some homework and found out how to get to the pump, "that's what I'm talking about",

 

[minifridge1138]

Carb Crossfire Replacement

I own a 1982 corvette. The previous owner replaced the crossfire with an edelbrock intake and a holley 4 barrel carb. I had to replace the edelbrock manifold with a Holley, and i'm getting 15 mpg average (hopefully that will improve when i spend a weekend to tune the carb, but it is too cold right now). My car still has a lot of the stock wiring harnesses hanging in the engine compartment. My next big project is to replace the wiring. Anyway, what does this have to do with your car? Well my car had an electric fuel pump in the tank, but for some reason this would not work with the carburetor (perhaps the elec. fuel pump was controlled by the computer that is not there anymore or the elec. pump could not provide enough fuel to feed the holley double pumper), so the owner installed a mechanical fuel pump. However, he was lazy, so instead of replacing the pump in the tank, he simply hooked the mechanical fuel pump to what had been the TBI fuel return to the tank. So my car is pumping fuel from the return line. The return line is not mounted at the bottom of the tank, so I can not get the last 6 gallons of fuel out of the tank. I'm empty when the needle is at 3/4.

Given the cost and effort it would take to get the crossfire back, I would stick with the carb. I'm getting almost the same mileage as CF driver's report, and I've heard the CF can be great when properly tuned, but that the carb is simpler to work with. Your best bet for the fuel problem is to install a mechanical fuel pump and remove the pump in the tank.

Good Luck, I'm sure someone will be very happy in March.

 

[KANE]

Cajun, Checked out that web site and liked what I seen and read. First things first, I was able to check out the car this past weekend and discovered that it's not pumping any gas to the carb, so I will probably have to replace the fuel pump...

All the more reason to go with a TPI swap. I'd do that and be done with it.

FYI- I picked up a set of SLP runners for $200 on ebay and complete manifold and fuel rails for $100. You can build it with a lot of good parts for little cash with ebay.