bhepp

I recently just joined and recently got a corvette, The one thing I was wondering about is the cross fire injection. Does anyone know of any problems to watch for in the future or is it a good set up. I heard its not the best and wanted to know what you guys think. Thanks

0Paul Ruggeri

Its not that there's any special problem, they just don't make much power. There are things you can do to up the HP, but as the farmer from Vermont once said, "If I was planin' on goin' fast, I won't start from here".

Have Fun, Paul

bhepp

So will it be possible to do the normal bolt on's and still get good performance,

Or would it be smarter to switch it out.

JLeatherman

That depends on just how much HP you want. Unless you're going to do some significant internal engine mods (stroker, really big cam, etc) the crossfire will be fine. CFI-EFI will be on here shortly I'm sure, and his car runs reasonably fast given the pretty simple mods to it. As with the TPI cars (85-91) breathing is the power-limiting factor here and the crossfire doesn't breathe terribly well. However, a mild cam selection, basic intake manifold porting, and a free-flowing exhaust will yield a corvette that is quite streetable and still passes emissions and other inspections. If you want to go really fast, though, you should look elsewhere unless you've got a lot of engine/FI experience. On the crossfire forum, which I will link at the bottom of the page, there are a couple guys running pretty serious 383 strokers under heavily modified crossfire intakes. If you search around you'll find the X-ram, a modified version of the crossfire. Don't put it on a stock motor, though, it's really mainly for modified motors. If you're looking to go really fast, though, you probably ought to start with a different car. If you're looking for a fun, inexpensive vette the '84 is fine. With some simple mods it will run as fast as an average TPI car. There are numerous maintenance issues you need to check out as well (balancing the throttle bodies, sensors, fuel pressure, etc). Check out the crossfire forum and make a similar intro post and you'll find plenty of help.

http://crossfire.home-ip.net

I have an 84, and it was fun with the crossfire. Never really gave me any trouble (aside from the usual maintenance problems). However, when I went to a 383 I decided that since I don't like tuning FI systems I'd go carb. That pretty much gets you ostracized from both parties (TPI and CFI).

elkabong

Here is a good link to the Crossfire Forum - http://www.crossfire.homeip.net/.

There is a ton of information there. As far as what to do it depends on you. If you are willing to learn then your imagination and pocket book are the limiting factors. If not then you would be better off selling your 84 and going with a 85+ Vette. You will have more opportunity for bolt-ons and after market parts. But as an example I have a 383 in mine with a XRam. I do my own tuning and I am still in the process. My 84 runs high 12s and my goal is 12 flat. Granted I am a glutton for punishment and every time another Vette owner (non 84) says "You are wasting your time with the ceasefire......" I get more motivated.

At the end of the day it is only air, gas and spark!

jhammons01

Wow, Harsh words for one of the most reliable C4s.

I am not sure if you want to run sub 10s.........

If you want to look out for things on your car. You need to focus your eyes on the 'other' components. And by that you'll need to start looking at the rear wheel bearings, half shafts, and U-joints. All together there are 4 U-joints, replace them all if you can't find where the PO already did.

The Master cylinder will go, wait for a Hot day and you may experience blow by. The MC is a 1 hour job if you don't count the time pulling the plastic cups off your old MC and getting them onto the new MC. It is an easy Job.

The rear wheel bearings are probably out of spec by now. Search for a thread on the subject by JrRifleCoach. If you have a shutter that you can't pinpoint it most likely is a wheel bearing or.......

The suspension durometors have all deteriorated. All the bushings need to be replaced, there is a kit for ~$90 that has everything you need. Just understand that it leads to a lot of labor. For instance, GM sells a the rear Dogbones for ~$45 each and it takes minutes to pull one off and replace as it is held on by two nuts......but the bushings are fractions of the cost. You have to press the old ones out and replace. The real is not near as hard as the front setup.

Do you have an Auto or 4+3 tranny? That is a whole different post.

Your Dash will start blinking....that is a grounding issue. Could be the solder has gotten old and cracked on the PCB or the connectors have corroded. Worse case is the dash is really dim and the Turn signals and bright light (blue) indicator are real bright.

Your Headlights will stop flipping up or down. Don't fret this one. There are plastic gears inside that strip out over 22 years. putting new gears in there will take about an hour each side. Basically pulling out the motor and cracking it open to expose the gears is all it takes. pull out the old ones and put in the new ones........put it all back together, Done.

Make sure you check your Spark Plug wire looms (the plastic doodads that hold your wires in place). If they are old and brittle it won't be long until your wires fall and contact each other or exhaust components creating a "CrossFire" that is not by design. Buy new Looms and the really thick Plug wires and replace all that right now.

The Valve covers are leaking about 1/8 of a quart of oil for every tank of gas. If you have an oil leak check there first.

The radiator is being choked for airflow by all the trash that is in between it and the condenser. Your engine will run a little hot due to this. There is a shroud covering both and is held in place by the coolant hoses. When you flush and change the hoses, make sure you pull the shroud off and clean out in between them. Do this before any drastic changes to address the heat issues.......like a lower Temp Thermostat.

I'm sure I'll think of other things but that is enough to spend the first year of ownership of an '84.

CFI-EFI

Not the best, in what way? What IS the best? There is nothing more "to watch for in the future" than with any other car. The time to study up on a purchase is BEFORE you make it.

Swapping out the Crossfire IS an alternative, but that was best considered before the commitment was made to a Crossfire. Going to a carb is a step backward in technology. A carb CAN (but not always) provide an increase in performance. A swap to a TPI is a total waste of time and money. For all the effort and expense, there will be little to no increase in performance. That leaves a good after market EFI system as the way to go. Don't be too quick to give up in the Crossfire. On the other side of the coin from elkabong, I have an all stock, 165,000 mile engine with nothing more than a home ported intake manifold, that runs high 13s. I have less than $1500.00 invested in all my up grades.

RACE ON!!!

0Paul Ruggeri

I know CFI-EFI is a true believer, but the idea that TPI offers no performance increase over throttle bodies is nonsense. An 85 Corvette has 25 more HP than an 84. I don't remember the torque #s, but they're even better. A stock 85 is at least 1 sec. quicker than a stock 84. TPI makes more power, gets better milage and idles better, that's why Chevy went to it! Would it be worth swapping to? Probably not. If smog checks aren't a worry, a good carb and intake is much easier and cost effective.
Check out CFI-EFI's other post to see how "stock" his CAR is.

Paul

CFI-EFI

I'll tell him, and everyone else how stock my car is. It's no secret. I have a 2600 RPM stall Vigilant converter, true dual exhaust with an X pipe, and I race on BFG drag radials. Did I forget anything? I didn't leave anything out intentionally. I DON'T have, headers, gears, a cam, ported heads, roller rockers, or any other engine add ons. I have home ported my intake manifold and that was the biggest single change I've made to the car. It has 165,000 miles on it and it has never had a head off.

Stock TPIs are not a lot better than the Crossfire. It is great sport for the masses to pooh pooh the lowly Crossfire, but the TPI guys would be in the same boat, or worse, if it weren't for the shear numbers of TPI production. The salvation of the TPI is big mouth intake manifolds, over sized runners, and special plenums. For $1000.00 to $1500.00 the TPI manifold can be up graded significantly, and the car turned into a performer. There is no such option for the low production Crossfire (thank goodness). The TPI is difficult to make a lot better, at home. The after market allows you to start over... at great expense. With the Crossfire, one is virtually forced to "do it yourself", for little expense, but significant gains. A home rodded Crossfire will run circles around a similarly rodded (for similar cost) TPI.

To convert a Crossfire to a TPI for an increase in performance would be a huge waste of time and money. To convert a Crossfire to a TPI just so it can receive typical TPI up grades would be too. Now converting it directly to a Mini Ram or a Super Ram, or whatever is a different story.

RACE ON!!!

0Paul Ruggeri

You have to have a real sense of humor to write stuff like that! There are completely stock TPIs that are faster than your car. Don't take it personnallly, I'm impressed with what you've done with your 84, but get real. Chevy didn't change to TPI because crossfire, ceasefire, misfire injection was a better set up.
I'll tell what though, if you haven't openned up the intake ports on your car, it can be done without removing the heads (I've done it), try that and some 1:6 rollers and I bet you pick up 2 tenths.

Racin' with ya, Paul

Buccaneer

This post is starting to get pretty funny.

CFI-EFI

There is nothing funny there. No faster stock TPIs that I have see reported, and especially not the early, lower compression engines. And certainly not at my drag strip.



I wonder what it is about my writing that has people coming back and telling me I've said things that I didn't. I NEVER said the Crossfire was a better set up than TPI. In other threads I have said TPI is definitely, technically, much superior to CFI TBI. But in the case of the early C4s, technical superiority doesn't add up to much of a performance advantage.



Are you talking about the head ports? I can't imagine. Tell me more.

RACE ON!!!

0Paul Ruggeri

When I get home I'll look up some old magazine test of 84 and 85s to get some numbers for you. I think you'll see the performance difference was substantial.
As far as porting the heads, this is an old trick I learned when I first started working on Corvettes about 20 years ago. After you remove the manifold you see the top of the intake ports tapers in. Sort of like a triangle. This clearly restricts airflow. What you can do is tape off the lifter valley with duct tape. Push wads of cotton or toilet paper into the intake ports. This is critical, it has to be enough to prevent bits of metal falling down the port. Now you just scribe the gasket hole around the port and with a die grinder open up the port! Go in about a half an inch to smooth it out. After you've done all 8, use a shop vac to vacuum up the bits of metal as you slowly pull each wad out. At the Vette shop where I worked back in the 80s we used to do this all the time to Crossfire and iron head TPIs. I don't have any dyno #s for you, but I know it helped, especially if you had other mods.

Have Fun, Paul

0Paul Ruggeri

OK, here are the magazine numbers. March 83, Road and Track; 84 Vette auto,3.31-1 gears=15.5@88.0mph. Dec. 84, Car and Driver; 85 Vette auto,3.07-1 gears=14.1@95.0mph. Is this a significant performance increase? Could an equally prepped 84 run circles around an 85? Only in someone's dreams. There will always be certain cars that run above their pay grade, but the average 84 is no match for the average 85, case closed.

Paul

bhepp

Well, I bought this car as a fun thing to have before the 09 Camaro's come out. So im not to worried about the crossfire being troublesome. I had just heard they weren't as strong as the 85's and up. I know I want a good set of heads put on it but other than that, thats all I really have my head on doing. Dont have to many more ideas other than a paint job (most likely black). I have to say though the response on this post were amazing, I thank you all alot for the info.

jhammons01

well, don't get drawn into the discussion of how much your Crossfire sux.

basically it is a nice powerful Chevy V8 that runs pretty good in stock form.

I'd like reiterate my list as these are the things you are going to need to address if you are driving the car that much.

vettin_it

hey bhepp, Are you from the phoenix area? i thought Ive seen the car in your picture floating around on craigslist.

bhepp

I am in phx

And what kind of things are you talkin about jhammons01?

vettin_it

well congrats on getting your vette! you should check out the pavillions car show some saturday. lots of nice vettes there.

Oh and the 84 may not be as fast as other vettes but..it still kicks ricers ***!

jhammons01

that big **** post up at the top.....the one that took me 30 minutes to type out.....