When you change over from a crossfire inj. to a tuned port ya gotta change the wiring harness correct? Does anyone make a aftermarket wiring harness for this swap? I guess you must use a ECM from a tuned port car also? THANKS FOR THE HELP GUYS Pipe

 

Yes and yes. You can get the wiring and the ECM from the same source as the hardware. There are subtle differences from year to year and a matching set will make life a lot easier. The second piece of advice, is, DON'T. It is a fair amount of work, not cheap to do, will erode any intrinsic value the original car had, and you won't gain a thing, performance wise. If you have money you don't know what to do with, expect nothing from your time and labor, and enjoy busted knuckles and greasy fingernails, proceed as planned.

RACE ON!!!

 

How about if you change the crossfire to a carbed car? Will it even run right? which wires will need to be deleted? And what lights will be turned on in the driver info center or dash with this swap? Is it worthwhile? costly? THANKS AGAIN Pipe

 

Why the desire to eliminate the Crossfire, out of curiosity?
TBI injection is actually pretty reliable.

 

TBI, is more user frendly than carbs, IMHO.

 

Its not worth changing the CFI to TPI, the only gain is about 25hp at best. I've looked into prior to making mods on my car and the cost to do it with a used TPI will run about $900 or so and for what? A lousy 25hp, don't think so. It will be a lousy investment for you.
There is nothing wrong with a CFI if its tuned correctly and its pretty simple to work on as well. If you want to make mods then spend your money more wisely such as
1) port your intake- $0 and your labor
2)headers- cheap set $140.00, better set set $500
3) at least if you go with the x-ram and some rr's that gonna cost $600, and that investment is at least wiser than the TPI.
I installed rr's,headers,x-ram and I'm lovin the car.
And stay away from a carb I think and I don't have "facts" just opinion, I feet the TB's from the CFI are better and more reliable.

 

Maybe not in and of itself, but for future mods (ie SR, miniram, HSR, etc) it would be a good jumping off point. Get the TPI in and running correctly, then you are ready for some bigger mods.

 

I see your point.. however keep in mind that if other mod's (ie SR, miniram, etc) may not fit under the hood on the 84, the 84 has built in ductwork to deliver air to the CFI. I'm not totally sure but I believe the 84 has less room than the 85's and up, so would these mods fit? There is still and lot of things that can be done to modify the 84, at least in my eyes.

 

I agree that your suggestions are worthwhile performance alternatives (where the stock TPI is not) to the CFI, but why waste the time and money converting to TPI, only to replace it?

The CFI is a good reliable system that can be vastly improved by a DYIER.

The TPI is little, if any, improvement over the CFI. The conversion is expensive, time consuming, and offers little or no gain.

A carb conversion CAN offer a performance advantage over the CFI, but it is a step backward in technology.

Aftermarket EFI systems offer the biggest bang for the buck, if a modified Crossfire doesn't have enough BANG for your tastes. Besides the TPI alternatives Morley mentioned Holley, Edelbrock, and others, offer stand alone EFI systems.

RACE ON!!!

 

Take a look at the underside of your 1984 hood. The ductwork is off to the sides where it mates up with the air cleaner. There couldn't be more clearance above the center of the engine, without a raised profile hood.

RACE ON!!!

 

yep your right, I was thinking it went all the way across for some reason.

 

been thinking about this for a while--an ''old-fashioned'' dual quad manifold with throttlebodies instead of carbs

 

step back wards bla bla. if your going to change it from stock and are not worried about whats the car worth ( which i hate to tell you no matter what you do to it) seems the 84 thru at least `90-`91 arnt worth much 6 7k tops i wouldnt worry about that point. if your changing to the tpi to escape some problems you were having with the cfi forget that too. they will still be there plus possible others as well. since you mentioned carbed i upgraded my `90 to a carb and i didnt go with the one that has as many electrical parts as a tpi. i went with a classic holley double pumper, eldelbrock intake and 2 wire hei distributor. simple simple, simple. i dont have 25 sensors shoved up my *** telling me why the car wont run, now i have a holley telling me it will run every time i hit the gas pedal. purs like a kitty and will romp and stomp with any efi. dont get me wrong the efi works like its suppose to while stock or later model obd2 program where you can adjust for any mods. my `90 is obd1. got tired of the ecm and related hardware throwing fits every time i added a part. the carb is really working out for me. somthing to consider. i wouldnt do the cfi to tpi. that would be like letting the fox guard the hen house.

 

Things you will lose going to a carb...

1. The ability to pass emissions if you live in an inspection area.
2. Fuel mileage.
3. Driveability in various elevations, temperatures, etc.
4. Longevity of the engine (efi systems burn cleaner, last longer)
5. Crisp throttle response.


Your best bet to improve performance is to modify your crossfire. Easier still, sell your crossfire and buy the car you really want.

 

valid points. 1. there are ways to get around that depending on your resources. 2. buy a honda. 3. seems most people drive their vettes on sundays to the drive inn and back no really big elevation swing. 4. longevity? a person looking to modifi a sbc isnt worried about an extra 3k miles. 5. crisp throttle response? same with carb......at least mine. i done the holy " super ram " setup befor i upgraded to the carb same or better performance with out all the hassle. this is the good thing about this or any other forum you get the pro`s and con`s.

 

Go for it, and change to tpi. I am in the process of changing my crossfire to a tpi superram.

You won't just get 25 hp. TPI puts the fuel in directly to the head, so you get about a full second knocked off your 1/4 mile with stock tpi. If you go directly to a superram and good heads(vortec or better) with headers and decent exhaust you will be in the low 12's in the 1/4 mile, now that is about a 3 second gain.

The 84 is a great car as is but try not to meet a L98 or a LT-1 or LS1 at a stoplight, they will eat you for breakfast.

84 vettes have the best handling, and add a superram with all that torque, suddenly you are the big dog of the C4 family.

Don't forget you have to change:
fuel pump,fuel lines,computer,harness,buy tpi setup.

Your 84 vette is already speed density, so go with the later speed density TPI setup, your sensers are the same, and the bonus is that it will fit under your stock hood because you don't need a mass air flow sensor, just put a cone air filter on your 58mm throttle body. The superram is smaller than the stock air cleaner box on the 84, and your ducted work will put cool air to the top of your engine.

WORDS TO LIVE BY:

A VETTE LOOKS FAST SO MAKE IT FAST.

 

WORDS TO LIVE BY:

A VETTE LOOKS FAST SO MAKE IT FAST.[/QUOTE] how true. my dad told me the car looks fast standing still and iv tried many dollars later to make it so. i wish i had the money to buy 400+ hp off the show room floor.

 

i too have made the switch from cross fire to carb. but with a completely new motor.... and it has made mine come alive and run as a vette should run.... FAST....

 

Do some research. I've spoken to many people that HAVE done this and have gotten limited gains by installing the TPI, about 25 hp at most. To simplify this even more 84- stock 205 hp, 85- stock 230 hp. Don't get me wrong it will feel snappier with the TPI but overall your not gaining much

L98- I'll run with that any day, even an LT-1

And that will make the investment over $1000 now, you can spend less to get better gains

A royal PITA to get the air intake together.


I'm searching for a site that I read about 6 months ago about a guy that did this convesion. He had a real nice page with a lot of info. I then spoke to him directly and he did tell me that he would never do it again. Once I find it I will post it

 

The TPI conversion was NOT that bad, from all the research and trial and error I did, this was the plan I came up with:

TPI setup (preferrably no cold-start injector provisions)
1989 year engine harness w/out the cold start injector
(the MAF sensor is a plus IMHO)
braided fuel lines to go from the chassis to the intake (~4 feet)
TPI style waterneck, hose, etc
85+ style Fuel pump
and a K&N cone filter that I stuck onto the MAF sensor, and then connected to the throttle body with ducting that I made - it all fits under the stock hood inbetween the radiator shroud and the Intake. However, a typical cone filter stuck solely on the throttle body will NOT fit - there has to be some ductwork to allow the filter to hang down a little.

Contrary to popular belief: the 84 hood is more tapered in the front over the radiator than later years, so the air filter assemblies used in TPI cars will NOT fit. There are ways to get around this as I previously mentioned, but there is no signifigant clearance issue with a TPI and the hood.

Things I would do differently:
Skip the stock TPI and step up to a SuperRam intake (arguably the best intake for your automatic vette). I would also consider avoiding the OEM wiring harness and ECM, and going for a stand-alone controlled from Holly, Accel, etc since without a custom harness it equates to the same deal: engine management ONLY (and you lose certain functions on the digital dash like MPG readouts, etc).

Previous posts were right - you can get a lot of power out of the CFI crossfire system, but it's more outdated and there are fewer mods/resources available to work with (Yahoo search: crossfire injection forum). I knew where I was going and plan on eventually doing forced induction - much easier and more "bolt on" with a TPI style intake system. There are plenty of little things that I've done in tandem with this conversion, but the highlights I've tried to list here. Feel free to PM me questions.