Crossfire: deserving of it's bad rep?

[VIN_#_00521__Z-51_C4]

I have an '84 with 130,000 miles on her, consistently running 11-12 l/100 km (or 19-21 mpg to you metrically challenged) on highway and around 15-16 mpg in the city. Just last weekend I ran 14.803 @ 144.26 km/h (89.66 mph).
No problems with CrossFire!

i have a L83 1984 158,888 on the clock( 10,000 in 2 yrs ) 20 in the city and 28 on the Hwy the TBI are already dialed in perfectly and i don't want to touch them and make them mad....I drove it home from new mexico ((959 Miles to omaha, Ne and stayed at 28 mpg all the way)).......only niche i ran across was the previous owner raced it( it was aligned for auto-cross,and the tires in the front were rounded to show it) new ball-joints were needed and had a cooling fan issue and the stat was stuck so it was getting too hot and would DIE on the spot that's cleared up now

 

[vettesplus]

i have an 84 4+3 with only 46k on the clock. i have only put 3000 miles on her in the last 14 years. she is a in perfect condition, mechanically and visually.....

 

[gonfishn1960]

I have to disagree, alot of the early crossfire's were big huge headaches. The manifold that was used for that set up was used earlier on Trans Ams with 2 4bl carbs on top and they fed a single plane open manifold. They thought it would be a great idea to use this set up because it was lower so they could lower the hood line on the early cars by two inches. Because of this they had huge problems with injectors sticking which would cause an air-fuel mixture of about 28:1 which is far to lean to burn. On the flip side those injectors would also dump to much fuel and flood cylindars. This was the same system Caddilac used for there 4,6,8 motor and we all know how that turned out. The later motors Caddy figured it out for them but the early ones were JUNK

 

[MoeJr]

Caddy's 4-6-8 motor problems weren't FI related it was the computers that shut the cylinders down that was the problem. Having worked on a number of CFI Vettes they all ran good once the TB's were reset. Any system will have problems no matter what the design. CFI is no worse than any other FI system when properly set.

 

[xfirez51]

TBI was SOOOOOOOOOO unreliable that GM kept putting it on trucks well into the 90's.

There's much more to the issue of the Xfire performance than just the manifold design. Unless you've worked on it and modded it, you have
just a piece of the puzzle.

 

[gonfishn1960]

I want to clear something up all you guys are talking about 85 and on vettes and I said the early models 82 the test mules from 83 and early 84 model year. I would like to quote you something and then I will tell you who wrote it "The first small step in recovering from 1981 was the use of two throttle body injectors for 1982. These were mounted on a plate and fed a single plane open manifold. The manifold was inspired by a Trans Am racing manifold that had been used with two 4bbl carbs. on the 302cid engine a decade earlier. We quickly and naively committed to the single plain manifold and compact injectors because we saw that it gave us an opportunity to lower the hood line 2 inches. We soon realized what a real bad idea it was to use this system because of inherent problems but it was to late to back out. So the engine guys had to make do. Our first problem was injectors sticking. Cadillac had the same problem and they came up with a short term fix before the 1982 model year. But not before the 1981 Cadillacs with there cylinder cut offs that had the exact same injectors ran into more problems,which shut down hundreds and hudreds of customers. There innovative fuel saving cylindar shut off called 8-6-4 became known as 8-6-4-0 for what was really a injector problem.If each injector had fueled half of the engine a stuck injector would only shut down that half of the engine and you would have been able to limp home. But because both injectors fueled a common manifold, so the result was to double the air-fuel ratio to 28:1 a mixture far to lean to burn so the cars quit. NOW WHAT WAS IT YOU WERE SAYING.....by the way these notes are from Dave McLellan....get your facts straight Please they were JUNK in the early cars

 

[MoeJr]

The fix was out before the 82 model year which would have made it a non issue for the CFI cars.

 

[gonfishn1960]

Not quite, Moe Jr. you are almost there."Our other problems was with the single -plane manifold itself.Carburetor manifolds for V-8 engines had evolved as tall and complex distribution pipes in an attempt to minimize the air fuel ratio variations that occured between cylindars. Why were they so naive as to think that they could flatten a manifold without penalty. The flat Trans Am manifold gave such poor cylindar distrubution that they had to compensate with extra fuel which lead to what I said earlier. They even lied to the press and said the increase in power to 200nhp was because of this new manifold when infact it was soley due to the new low back pressure underfloor monolith catalytic convertor. More of the power increase was also do to the new 4sp auto transmission in 1982. But the fuel problems and injector problems continued till early 84.......anything else?

 

[nelson84]

I have one of the early 84 vettes and never had a problem with it and in fact it is faster now than when it was new, with the help of these forums it is a full second faster in the 1/4 mile now and will be faster once I get my renegade intake manifold from 'Dynamic crossfire solutions", they specialize in modding crossfire cars. I will be in the 13's this summer.

 

[gonfishn1960]

Everyone that is defensive about these injectors has a 84 or 85 vette and I think you guys think I am dumping on your rides, quite the opposet I just happen to know a little about these cars and as was said in a earlier post new technology has it's drawbacks. GM was under the gun big time on emmisions and gas mileage by the goverment so the ran with what they had. That is why in a small way they are in the mess they are, but also if I may point out, if the manifold and crossfire system is so good why are you going with Dynamic and why did GM out source to BOSCH for the injection systems from 85 on

 

[MoeJr]

Everyone that is defensive about these injectors has a 84 or 85 vette and I think you guys think I am dumping on your rides, quite the opposet I just happen to know a little about these cars and as was said in a earlier post new technology has it's drawbacks. GM was under the gun big time on emmisions and gas mileage by the goverment so the ran with what they had. That is why in a small way they are in the mess they are, but also if I may point out, if the manifold and crossfire system is so good why are you going with Dynamic and why did GM out source to BOSCH for the injection systems from 85 on

I never had one come through our shop with injector problems but I agree the manifold design is poor. I got to admit I replaced more port style injectors than TBI.

If the injectors were an issue than they deserve the bad rap not the whole system. CFI isn't the best but it is not so bad we should be treating it like the plague. It can run very well with properly working parts.

 

[nelson84]

I never said the intake on the crossfire is good, I have been looking for a replacement for my 84 vette for years and now somebody has actually made one that works on a 350 not that x-ram. I have an x-ram too. I just stated that the crossfire works great as in reliability not performance. I went out and bought an 85 vette because I was sick of trying to make my 84 crossfire perform under 14 seconds.

 

[gonfishn1960]

I have not owned a vette with that system and I am from Mass, some of you may have heard of Corvette Mikes theres one in Plymouth Mass, another in the Midwest and another in Cali each owned by different guys. Mike in Plymouth is an extremely knowledgable guy when it comes to Vettes and I value his opinion alot and he thinks that it was a great design for its time...I just don't see that one. The thing was rushed to market, it was piece meal at best at first and that system is destroying the resale of those cars. Guys you can buy a low mileage 84,85,or 86 for no money and except for the quirky dash and the Z51 handling package that makes the car ride like a tank, it is a far better car than a C3 but those things are killing resale. I dont know if you guys know this but those early C4's never made it off the proving grounds for real road testing because of the threat of spy photos. So when the press drove them for a short time in Cali and Yoesemity Park the thought the car was set up for them to fly. But that was a new spring rate PKG RPOZ51 that was killing the ride so they told dealers to not order that RPO and customers were pissed until they learned that was why the car rode so shitty. My point is that this is the same thing as the injection system. It was rushed with little or no R&D

 

[gonfishn1960]

crossfire injection problems killing resale on great cars

I have not owned a vette with that system and I am from Mass, some of you may have heard of Corvette Mikes theres one in Plymouth Mass, another in the Midwest and another in Cali each owned by different guys. Mike in Plymouth is an extremely knowledgable guy when it comes to Vettes and I value his opinion alot and he thinks that it was a great design for its time...I just don't see that one. The thing was rushed to market, it was piece meal at best at first and that system is destroying the resale of those cars. Guys you can buy a low mileage 84,85,or 86 for no money and except for the quirky dash and the Z51 handling package that makes the car ride like a tank, it is a far better car than a C3 but those things are killing resale. I dont know if you guys know this but those early C4's never made it off the proving grounds for real road testing because of the threat of spy photos. So when the press drove them for a short time in Cali and Yoesemity Park the thought the car was set up for them to fly. But that was a new spring rate PKG RPOZ51 that was killing the ride so they told dealers to not order that RPO and customers were pissed until they learned that was why the car rode so shitty. My point is that this is the same thing as the injection system. It was rushed with little or no R&D

 

[nelson84]

That is crazy talk, the z51 suspension is a sought after option, a real vette owner would want Z51. If it was so terrible, how did it pull over 1 G on the skid pad. You are basing you opionon on some tool that sells cars for a living? Did he also say that the L88 was a poor design because it would over heat in traffic that is why they didn't order very many?otfl In the future do not take advice from a car salesman:Lotfl

If you don't like early C4's because they are inexpensive, you better check what name brand of jeans you are wearing and hussle to the store right away and buy an $800 pair because they are so much better than the $125 pair because the sales girl said so because she knows alot about jeans:L:Lotflotflotflotfl

 

[xrcrx]

I have to disagree, alot of the early crossfire's were big huge headaches. The manifold that was used for that set up was used earlier on Trans Ams with 2 4bl carbs on top and they fed a single plane open manifold. They thought it would be a great idea to use this set up because it was lower so they could lower the hood line on the early cars by two inches. Because of this they had huge problems with injectors sticking which would cause an air-fuel mixture of about 28:1 which is far to lean to burn. On the flip side those injectors would also dump to much fuel and flood cylindars. This was the same system Caddilac used for there 4,6,8 motor and we all know how that turned out. The later motors Caddy figured it out for them but the early ones were JUNK

Gonfshn, I not only own an 84 but have done real research and written articles on the car and it's development. you are sorely mistaken. Calling the crossfire manifold a simple single plane is a real misnomer and the 2X4 trans am intake you are referring to was completely different. The runners in the crossfire intake are tuned to a specific length , their small diameter makes high rpms out of the question but boost intake velocity thus producing a very flat torque curve . The injectors were not a problem, though getting technicians trained on doing diagnosis on drivability issues was a problem at the dealer level at that time in automotive history. the system was also used on 82-84 Z28's and Trans Ams. Over 300,00 Crossfire powered 305 and 350 V8's were produced. The rapid transition to mpi over the cfi stoppd most hot rodding of the cfi system in its tracks. Nonetheless, there are many 13 sec and a few 12 sec cfi cars. The cfi system had nothing to do with the Caddy v468 which had problems relating lack of good computer control as the operating systems available for their idea were simply not fast/smart enough at that time. Now cylinder on demand is a fact of life on many GM and even Chryco V8's. Your statements regarding the cfi show a lack of real knowledge/reseach of this engine family and seem to be based on conversations with people who "know" Corvettes, promoting unsubstantiated rumor and downright bad info. As for the Z51 pkg, it was overpromoted by the dealers, as it was intended for the track enthusiast. The ride was not compromised in any way for the street as its sole mission was to dominate the track. It did so. The suspension was detuned for the following years and it still dominated the track, but a 84 z51 car could readily handle a later model car in anything but a straightline for quite sometime.

 

[Cadillac Tech]

Well said You are right, the Cadillac 8-6-4 system was quite different from CFI and the computers at the time weren't up to the task of engine management. Many of us technicians had never seen anything like CFI before and were clueless as to what to do to fix them. It took us a while but we got better with all fuel injection systems.

 

[gonfishn1960]

Here we go again, another miss informed corvette owner.These cars road great on California smooth roads, but driving them in Michigan was another story. The Z51 was far too stiff for the typical frost heaved damaged roads. The car felt like it was launching itself over every bump. They went back to the original lower spring rates for which the car was designed. Then they returned the shocks for the lower rate springs. the shock absorbers which are a misnomer because they actually transmit shock that control body motions and wheel hop also introduce large impulsive forces when the car would go over a sharp vertical disturbance such as a frost heave. The stiff suspension increased the dynamic force input from the rough roads and the closeclose frequency coupling between wheel hop and the first modes of the structure amplified this response, making the ride feel harsh and at times shacky. Car and Driver also complained about the harsh ride. Chevy agreed with them, but couldn't say they agreed. The result was all they could do was wait till late 85 and as GM said try to stop dealers from ordering the Z51 where it was a problem.......now I ask you does that sound like DEALER B.S.....and you should check your JEANS I think they are cutting of blood supply to your HEAD

 

[gonfishn1960]

XRCRX.....Thanks for that but I have one question..why did GM go to BOSCH for there fuel injection systems if what you are trying to sell is the truth. Also that Crossfire system lasted HOW LONG on vettes not even 2 model years. You are right GM made a mistake they should have left them on the vettes for 10 more years ARE YOU FOR REAL

 

[xrcrx]

XRCRX.....Thanks for that but I have one question..why did GM go to BOSCH for there fuel injection systems if what you are trying to sell is the truth. Also that Crossfire system lasted HOW LONG on vettes not even 2 model years. You are right GM made a mistake they should have left them on the vettes for 10 more years ARE YOU FOR REAL

Dude, never said the change to MPI was not an upgrade , I did not mention a timeline. I did however state that your description of the origins and problems w/cfi were horribly misinformed. cfi was a wet flow system that was more efficient than the previous electronic carb, mpi was the logical next step. Never was in dispute, reread your post and my reply. your presentation on the cfi was in error . You are wrong. As for the z51 pkg, what i posted was that it was designed for the track-yes, thats right, an essentially smooth surface, on bad roads it sucks. i've driven mine across the country so i have first hand knowledge. The base suspension is the one most owners should have bought but the dealers pushed the z51 option, only to get an earful about ride quality. Yep, i still have my car and driver , road and track and motor trend issues for that car. They raved about the z51 handling prowess, then a few months later slagged the ride quality in every day driving. The softer suspension still was better than any competitor, hence the Vette being undefeated till being forced out of Showroom Stock competition till everyone else could catch up. As for your acct of my bloodflow to my head ,I don't recall making any personal attacks on you and till now it wasn't personal. If you note-i said you were misinformed, not stupid , not even ignorant, which would be a proper statement. You're an asshat to even go there. If you wanna disagree in an open forum that is fine, but grow up and leave the high school BS outside.