I have a 91' RS (305 TBI) that I'm building with my son as his first car and I have an opportunity to pickup a complete crossfire setup w/computer. Since this is the first Camaro I've built I still have a lot to learn. How much better/nicer is the crossfire compared to the standard TBI ? Is there any real advantage to this swap ? It'll need an engine sometime in the future and I'd like to build a nice 327 for it and thought the crossfire might be a nice way to top it off but really don't know much about them. If I use it on the existing 305 is it just a plug-n-play deal where I can install the intake, throttle bodies and just swap computers or what ? Any info or insights will be greatly appreciated.

 

ive heard crossfire is no good, go tpi

 

Ok, but just *why* is the crossfire supposed to suck ? Quite frankly I have no real interest in swapping to TPI because it's a lot more expensive as well as being considerably more complicated. I'll admit that the TPI manifold looks pretty sexy when the hood is popped but they're a dime-a-dozen, everyone & his brother has one. I think the dual throttle bodies of a crossfire would look pretty sweet as well as being uncommon. From what I've been able to look up & read so far a well tuned crossfire setup can generate just about as much power as a TPI. I like the relative simplicity of a throttle body EFI compared to a multiport, also, a stock crossfire setup needs to come pretty cheap because it essentially has to be used as a core for upgrades/rebuilding. I'd like to hear from guys running one or someone who has swapped one in, or one of you history/technology guys with more experience & info than me (which is almost everyone) . Truth be told I'm a Blue Oval guy at heart, but God has a funny sense of humor and has blessed me with a firstborn who's almost ready to drive and simply loves everything with the word Camaro stamped on it. So what can I do other than read everything I can, ask for help from guys like y'all, and learn how to build a Chevy (and thank the Lord every night that he didn't want some sort of freaking Honda with red neon lights underneath and a 4ft carbon fiber wing on the back) ?

What I hear so far is that the throttle bodies have to be bored out to at least 2" and also need the shafts rebushed due to age & wear and a lot of the other problems are solved with a new/faster computer because the OEM box really wasn't up to the task in the first place. I haven't been able to find any photos of an installed crossfire but I *have* seen the original 68'/69' Z28 crossram dual-quad carb setup that the crossfire was based on at a car show and I though it looked pretty nice. I'm just looking for more info and trying to figure out if it's worth chasing this one down & negotiating with the owner to get it at a reasonable price and I was hoping some of the members here had some experience with them so I could get some feedback and help making a decision. As I mentioned I think it would be a good way to top off a nice 327 for this car. I like the idea of something different (a 327 instead of just a run of the mill 305 or 350) and the crossfire doesn't seem to have been a very common option (I think it was only on the 82' & 84' Vettes & 82' & 83' Camaros or something like that). I like the dual quad look & the offset crossfire is visually appealing (to me anyways ) I don't know how much of a hassle it is to sync the throttle bodies or if there are any other quirks with the system that make it a real dog.

 

i swapped my z28 over to crossfire back in '94,then
modified it for a big increase in power over the 205 hp
rating of the '84 vette L83 engine i put in my z28.
Most of the problem is the intake runners,in stock form
are small cross section,and the inlets of each runner
have a sharp,as cast edge(modified/ported my intake,
made a huge difference) the stock throttle bodies will
flow enough air for about 300-320 h/p before they need
enlarged(syncronizing is very easy if you have the right
tools) The stock ecm is not real fast but will do the job
fine,later ecms can be adapted if wanted.The stock
fuel pump is another C/F weakness-upgrades are easy
Some of the reasons i put a C/F in mine are i wanted
to keep my car early'80s"period correct",liked the
unique,exotic look of the C/F,wanted to experiment,
Also,after the mods runs real strong,smooth and is
extremely reliable there is way more modification
info avalible now than in 1994
Myself i would not put a C/F on a third newer than
1984,for a '90s thirdgen i would be temped to swap
in an LT1 or LT4 as that is period correct for those and
strong running stock.
The stock TBI can also be modified for more power
don't have time now,but i will give more details on
my c/f mods later

 

if you want to adapt a crossfire to a TBI Lo3 camaro,
you could probably adapt the original TBI harness and
ECM to operate the CFI(using a custom chip if needed)
with a properly modified manifold(or a DCS"renegade"
aftermarket CFI manifold) that would be a unique
high performance induction setup
Modifing my original C/F manifold was a bit of an
ordeal-had to do lots of welding and die-grinding to
rework my original C/F manifold into a high performance
item,also added a 1/4"lidspacer,did mild port job on
the heads.

 

Other than dealing with the electronics is the C/F a bolt-on swap ? I thought I read something about it not bolting right up to my TBI heads but I may have misread the post and haven't been able to find it a second time to clarify. Are there any changes I'd have to make to get it running ? I don't need to have this thing port-matched or anything do I ? What all is needed to sync the TB's ? If I pick this thing up I'd prefer to use it as-is for now on the 305 & then modify/upgrade/rebuild it later on to run it on the 327. If it'll work with my current ECM that would be a big plus. The seller has the original ECM to go with it, should I grab it or am I better off with the newer 91' ECM ? Will this thing ultimately run better with an aftermarket/stand-alone ECM or am I better off using what's in the car now and burning a custom chip ? Logic tells me the ECM from a 91' would be faster/better than the original 82/83 unit but just because something makes sense to me doesn't mean GM did anything of the sort

How much work was involved in opening up your ports ? ?

 

You may want to check out the crossfire guys at http://crossfire.homeip.net I have an 83 Z28 with original crossfire and those guys have helped me more than words can say.

 

i'm active over at CFIV too
crossfire manifold will not bolt up to most '87-later head
,so you will have to put earlier heads on the 305 block
port matching the manifolds to the heads was not done
by the factory,but does help.sycronizing theT/Bs will
only be needed if they are out of sync,to syncronize
them,you need two special tools to block the IAC valves
and a pair of sensitive vacume gauges,can also make
some simple "water columb"gauges out of vinyl tube.
A 7747 ECM from '87-early'90s chevy pickups is often
used as an upgrade ECM for crossfires(i beleve a
custom chip is needed)it's a faster more modernECM
that uses an erasable chip that can be re-programmed
while the original c/f chip cannot,chip must be replaced
with one that has different program.Not sure what ECM
a '91 TBI camaro uses,but it's pretty close to a 7747
and has the same plugs,original C/F ECMs will not plug
in.
Modifying my manifold involved using a tig welder to
build up the intakes to each port about 1/2"higher
than original so the intakes could be enlarged and
given a"bellmouth"or flared shape with a rounded edge
to grab more air with low resriction,the rest of each
runner was then hogged out about 1/8"all around and
the siamese ports were also smoothed.To better clear
the modifications,a 1/4"thick lidspacer was made of
aluminum to raise the lid 1/4"above the manifold.
decided the heads could benefit from some work too,
so removed and ported-intake ports matched and
smoothed just a little,lots of bowl work for both
intake and exhaust,streamlined guide bosses,reworked
and slightly raised exhaust ports,a little unshrouding
work around the exhaust valve Rest of the engine is
stock '84 vette L-83,including cam.Once back together
the difference was unreal instead of going lame
above 4200 rpm,pulled strong to 5200,easily revs to
5500 and beyond-i'd say this added at least 40hp/
30-40 FTLBs torque. Did the hop up in '95 and still
very satisfied with the performance! with big stereo,
stout SFCs,fluid coolers,air system,extra crossmembers
4whl disc,etc etc my car is heavy,about 3800 i recon
(if this engine was in my 3200#'69 it would really
rock)

 

I am one of a few that swapped out the crossfire to the 2 barrell TBI unit.

reason being the CF I dont believe would not support the mods I had done. I did try the XRam but found it was tempermental in a cold weather environment. I am pleased with the performance it has given me.

In hindsight I would should have gone port fuel injection(not TPI).

 

1) Poor port flow, need massive porting to just be average.
2) Complicated throttle linkage.
3) Occasionally caught fire.

The crossfire intake is one of those neat ideas that was very poor in execution. The standard TBI on your car paired with a single plane manifold will do everything the crossfire does but better, stronger, faster.

 

Back in 1982 and 1984 the technology was not there yet as far as emmishions vs performance. The 1984(not1982) platform was all about performance as far as the design of the vehicle as it relates to track/skidpad. I believe it had the best cornering ever of any US domestic vehicle. Not sure how it measured up to a <$50K Porsche? I recall .99 or so as measured. Unfortunately the motor was not up to task. Rumor has it that the engine and especially manifold was purposefully designed to restrict the engine HP as the TPI in 1985 was ready to go and it I recall had a bit more HP and TQ than 1984. ther are photos of the intake manifold port compared to a traditional performance carb intake. Tiny sums it up nicely.