Switching Crossfire to TPI
Thread Starter
Intermediate
Joined: Nov 2005
Posts: 25
Likes: 0
From: Bowling Green Kentucky
Switching Crossfire to TPI
Hey all...
I own a 1984 Crossfire Corvette and the crossfire units are just so erratic after a year of tinkering with them I have purchased a Tuned Port Injection intake/runners/injectors/wiring/computer from a 1985 Corvette. Has anyone ever done this conversion and if so how difficult was it? Any insight on this would be wonderful.
thanks,
Brian S. Young
Bowling Green Assembly Plant
I own a 1984 Crossfire Corvette and the crossfire units are just so erratic after a year of tinkering with them I have purchased a Tuned Port Injection intake/runners/injectors/wiring/computer from a 1985 Corvette. Has anyone ever done this conversion and if so how difficult was it? Any insight on this would be wonderful.
thanks,
Brian S. Young
Bowling Green Assembly Plant
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
it won't be a problem with all the stuff you got.
it should be rather straight forward. The hard part is going to be updating the harness and making it all work... you will need schematics and such... and since you work at the plant, that should not be much of a problem.
it should be rather straight forward. The hard part is going to be updating the harness and making it all work... you will need schematics and such... and since you work at the plant, that should not be much of a problem.
Thread Starter
Intermediate
Joined: Nov 2005
Posts: 25
Likes: 0
From: Bowling Green Kentucky
height shouldnt be a problem at all. One issue that I just considered was cold air intake. Since the 84 gets its air from inside the hood then I will assume some sort of cold air box will need to be fabricated (which shouldnt be a problem). The ideas are really churning the wheels for me, anymore would be greatly appreciated.
thanks again,
Brian
thanks again,
Brian
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
It is a fair amount of work, and a fair amount of money, for a very meager return. Most Crossfire owners find them smooth running and anything BUT erratic. It would seem that someone from the birth place, ought to be able to make one of the most plentiful Corvettes ever produced, run like it is supposed to.
RACE ON!!!
RACE ON!!!
Burning Brakes
Joined: Sep 2004
Posts: 869
Likes: 1
From: Bradford Pa
Originally Posted by CFI-EFI
It is a fair amount of work, and a fair amount of money, for a very meager return. Most Crossfire owners find them smooth running and anything BUT erratic. It would seem that someone from the birth place, ought to be able to make one of the most plentiful Corvettes ever produced, run like it is supposed to.
RACE ON!!!
RACE ON!!!
i agree...
in fact, my brother wants to go from TBI to TPI on his firebird while dropping a 350 in...for all out performance considering what he wants to do, i'd be tempted to go carb on his powerplant. most others instead of going to TPI would see more benefit going to carb or straight aftermarket fuel injection...
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Burning Brakes
Joined: Oct 2004
Posts: 1,019
Likes: 1
From: Weymouth Dorset
I did it on my 84 and it was well worth it, I used a 90 SD setup though.......http://forums.corvetteforum.com/show...1344779&page=2
.
.
Melting Slicks
Joined: Jan 2005
Posts: 2,658
Likes: 4
From: Clifton Park NY
http://www.itsjojo.com/- this is a link to someone that had done it a while ago. When I was thinking about doing it to mine I did email him and he reponded. Seems like a real good guy. I ended up not doing it and went another route.
Thread Starter
Intermediate
Joined: Nov 2005
Posts: 25
Likes: 0
From: Bowling Green Kentucky
Originally Posted by CFI-EFI
It would seem that someone from the birth place, ought to be able to make one of the most plentiful Corvettes ever produced, run like it is supposed to.
RACE ON!!!
RACE ON!!!
I greatly appreciate the feedback and all the great links. You guys are being a ton of help and thanks for all the personal PM's. I have already purchased the TPI so this project is going to take place within the next month or two and this forum has been great help. Please keep em coming.
Brian Y.
Burning Brakes
Joined: Feb 2006
Posts: 1,098
Likes: 1
From: Webster Texas
crossfire
The crossfire was actually a stop-gap till the TPI came online. Before it's final production form it outperformed the TPI, which was still being developed. Appx 255hp or so net. That couldn't happen so the production intake on the crossfire is severely restricted. You can go head to head with TPI cars by opening the ports to match the head and modding the swirl plates, along with 1.6-1 RR's. There is a manifold for sale at the crossfire forums that is already modded and a stock one that you can do yourself. As for reliability the crossfire is simply lower tech than the TPI, all new designs have had their probs in their day. The crossfire is actually a pretty neat and reliable design. Mine is a daily driver, runs on premium, has 114k now or so, burns 1 qt of Mobil 1 between 5k oil changes. In stock form it's quicker than the original C&D and R&T tests. I have a manifold I'll be porting shortly. Whatever you choose to do, best of luck but don't let the undeserved notion that it's unreliable keep you from having a crossfire car.
Eric
84 Z51 Auto
05 Repsol Replica
00 TLR 1000
Eric
84 Z51 Auto
05 Repsol Replica
00 TLR 1000
Melting Slicks
Joined: Jan 2005
Posts: 2,658
Likes: 4
From: Clifton Park NY
I tend to agree. It seems that the CFI is a pretty reliable piece. I've never have had any problems with mine and it seems you see more threads on here about TPI problems, injectors and such. Don't get me wrong about the TPI.
I have made some nice mods to mine and love the way it runs. But I've also got the opininon that is not worth making the swap from CFI to TPI. But it also depends on what the end result your looking for is.
I have made some nice mods to mine and love the way it runs. But I've also got the opininon that is not worth making the swap from CFI to TPI. But it also depends on what the end result your looking for is.
Tech Contributor
Joined: Jun 2004
Posts: 20,910
Likes: 962
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
It's your car, so certainly make it the way you want. I wasn't thrilled about the performance of my '84 (it completely ran out of breath above 4000 RPM), so I pulled the engine several years ago for some tweaking. After discovering the restrictiveness of the manifold ports, and the lousy fuel distribution inside it (I always wondered how they managed to inject the fuel in the correct intake air sequence. I found out they DIDN'T!), I then decided to do away with the whole CFI manifold system. I adapted a two barrel BBC TBI unit to a carb manifold, and wired up the TPS and IAC harnesses to this unit. The round 14" air cleaner fits over this TBI, so it actually looks carbureted at first glance. (I also turbocharged the engine, but the performance improvement even without boost is very noticeable.) I had to modify the ECM PROM calibration to deal with this new engine combination (mostly the boost issues), but I'm sure there's lots of additional Forum support out there if you needed to do a calibration change.
Like I said, it's your car and your choice. Do what makes you happy, and mainly, have fun with it!
Like I said, it's your car and your choice. Do what makes you happy, and mainly, have fun with it!
Thread Starter
Intermediate
Joined: Nov 2005
Posts: 25
Likes: 0
From: Bowling Green Kentucky
Please do not misunderstand. I love my car. I have been driving it for about 10 months. Some of the guys have looked at it that work in the "repair hole" and have set the CFI. They have "adjusted" them for me about 3 times in the 10 months. About 2 or so months ago they were acting up again so I purchased 2 rebuilt CFI units and replaced my original ones. Once again the guys at the corvette plant set them for me and they ran wonderful... for about 2 months... They just started acting up again so I took the plunge and bought this TPI off of the 1985 Corvette. I would assume some people have great luck with the CFI but me and most of my friends here in the corvette plant (with the exception of one) have been having more intermittent problems with thier CFI vehicles than people with thier TPI. I do apologize if I offended anyone about thier CFI but me and the plant cant seem to keep mine running the way I want it to run. I am going to post an intake, 2 CFI units, and an air cleaner on the parts section if anyone is interested just PM me.
thanks again,
Brian S. Young
Bowling Green Assembly
thanks again,
Brian S. Young
Bowling Green Assembly
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
I wonder why it's so tempermental?
That is one thing I have never heard re: xfire, is it being tempermental - think tri-power if you want tempermental!
There is another forum member, Alcee1, who is has the SWEETEST 1984 I have ever seen... ported intake, Edelbrock heads, bored TBs, the works. That thing flat out RUNS. Talk to him.
I would be asking the guys in the repair hole why it falls out of tune...
Another upgrade for the xfire is a later model ECU. I think it's from the 1987 Chevy/GMC Truck.
That is one thing I have never heard re: xfire, is it being tempermental - think tri-power if you want tempermental!
There is another forum member, Alcee1, who is has the SWEETEST 1984 I have ever seen... ported intake, Edelbrock heads, bored TBs, the works. That thing flat out RUNS. Talk to him.
I would be asking the guys in the repair hole why it falls out of tune...
Another upgrade for the xfire is a later model ECU. I think it's from the 1987 Chevy/GMC Truck.
Pro
Joined: Jul 2002
Posts: 703
Likes: 0
From: Milwaukee Wi
former crossfire but still all TBI...
previous crossfire vette. 350 cid, xram, 2.0 TB's, 454 injectors, edel rpm aluminum 64 cc heads, crame 2040 cam 210/216 @.05, crane roller rockers, ceramic hedman 1 5/8 headers, dual exhaust/crossover, hooker aero chambers, 7747. Innovative WB.
CHANGES COMPLETED 10/13/2004:
7.4L TB on Holley TBI manifold(Projection), Summit AC with K & N, Aeromotive FP reg, Comp Cams 224/230 @.05 114 LSA, Innovative input of tps/rpm/map data.
09/2005 fresh paint(red of course)
previous crossfire vette. 350 cid, xram, 2.0 TB's, 454 injectors, edel rpm aluminum 64 cc heads, crame 2040 cam 210/216 @.05, crane roller rockers, ceramic hedman 1 5/8 headers, dual exhaust/crossover, hooker aero chambers, 7747. Innovative WB.
CHANGES COMPLETED 10/13/2004:
7.4L TB on Holley TBI manifold(Projection), Summit AC with K & N, Aeromotive FP reg, Comp Cams 224/230 @.05 114 LSA, Innovative input of tps/rpm/map data.
09/2005 fresh paint(red of course)