After considering for a long time about the performance of my crossfire injection system I have decided to change it over to TPI.
The crossfire is great and it's been 100% reliable but there's just not a lot to do that will easily increase performance.
But I DO hate to take apart a perfectly running Corvette.

Anyway, I've bought a complete engine from a 87 Vette (engine,transmission, wiring harness, computer, radiator, air cleaner,maf,radiator shroud, etc.)

I need some sage advice and encouragement on completing this job.

Anyone out there made this swap?
Any caveats?
Will my 84 hood close with the TPI system?
Will my "pinball" dash work off the 87 computer?
Would it be better to change to speed density now?
What isn't going to "fit"?
Help, please!!!!

Please help me out on this, forum members, this is the "real deal", all the talking about it is over.

Best regards,
Jim

 

I'm afraid I don't have a lot of answers. The hood MAY clear the plenum, but I think you'll have problems up front. You might see if the hood is available from the engine donor car. Otherwise, I think you could peel the ducting from under your hood. Personally, I would just get it run right, before I worried about a MAF-MAP conversion. Depending on how wild you plan to go, a MAF will adapt to a wild cam better than a speed density system. You may need a bigger MAF, though. I hate to see another Crossfire owner bite the dust, but I realize that it is a step forward, for you. Good luck! Keep us informed.

PS. I could use a "spare" intake to practice on, when you're through with yours.

 

Thanks for the reply.

I have the computer(s) to go either way, MAF or speed density.

I'm also getting all the sheet metal in front of the radiator to keep down the problem of getting the air input mounted.
( I won't run the "underhood" K&N filter that a lot of folks do)

I like the crossfire and there seems to be a lot more interest in them on the forum now but the TPI looks to be the way for me to go.
I've also been a staunch supporter of the 84' CFI Vette. Mine has been 100% reliable for the last three years.
And the stiff suspension handles like a DREAM!!!

If I decide to part with the original CFI pieces I'll certainly keep you in mind.
My plan is to pull the engine/transmission as a unit and bolt back in the 87 TPI and transmission.
Then I'll start sorting out the wiring changes that will be required.
The harness is still attached to the engine and I've got BOTH 84 and 87 wiring diagrams.

I'd REALLY LIKE to hear from someone who has walked these steps previously to fill in anything I may not be thinking of.

Anybody else??? All advice welcome, good, bad or indifferent.

 

the hood will not clear the maf ducting, you have to run a SD system. Your going to be kicking your self in the butt after all that work for an extra 30hp. If you must do it, upgrade to a larger plenum and runners.

What I would do, for sure, if it was me. I'd take the heads from the 87 engine, port them, and install them on the 84 block. The 84 has a better bottom end, forged pistons. Then i'd port the crossfire manifold and sell the 87 short block, and all the wiring and with that money i'd buy a new cam and exhaust for the xfire, and you'd be pushing a good 280-290 hp, for way way less work and alot less money.

Oh i'd also keep the 87 tranny and throw in a transgo kit.

 

ill have a x-ram for sale on the forum in 2 weeks. im going with a 383 stroker & a holly 750 carb. :yesnod: even with the x-ram,tru dual exhaust,1.6 roller rockers,k&n,computer chip & 160 thermo,underdrive pullys & performance ignition..etc..she still was under powered for me. good luck with your transplant. :cheers:

 

that xram would make an awesome addition to the l98 heads..i'd get it

 

Thanks guys! Keep that advice coming. The CFI is still in the car.

I know how to build the SBC and how to make them run but the CFI just isn't giving me a lot of options.

I could increase the CR (Change Pistons) and put on a couple of AFR 190 heads or even the Holley heads I have sitting on the bench but the breathing limit will STILL be defined by those two putrid TBIs.

With the TPI, the base can be changed, runners changed and Throttle body all can be changed to increase breathing.

TPI offers the oportunity to take advantage of those 1.6 rockers on the intakes or maybe that 219 cam.

yoslambo1 it looks like you've tried most of the readily available CFI mods and are looking for more.

As to the 30+ HP , hopefully this is a start and will give me an engine that will respond to the other dollars I'll throw at it whereas the gains NOW are relatively limited by the CFI.
Again, I'm NOT knocking the CrossFire because I've found it to be so "user friendly" and faithful as my favorite Yorky.

I just want something that can be "nipped" and "tucked" and "tweaked" that will respond in the positive HP direction.

BTW, I would NEVER consider a carb although that's where most of my experience has been built, building carbuereted circle track engines.

I'm not interested in "straight line racing" (again, not knocking those that are) it's just I'm wanting about one/half more than what the CFI is rated for now (205 at the flywheel).

So, I'm really looking for 325HP to 350HP NET at the flywheel and I won't worry about the parasitic drivetrain losses as there's nothing I can do about them anyway.
Let's don't forget these engines were measured and specified in NET HP(with the engine accessories installed) so add about 10 to 15% to the 205.
Those old 300HP 327s, etc. were GROSS output engines.
But I'm getting off the subject.

I know I won't be getting a big increase simply with the swap.
But a SR isn't out of the question. Neither is a head change to something more reasonable like the AFRs.

What about the Scoggins-Dicky base with the large tube runners and the fast burn heads?

Those are the kind of options I want to have.
As good as it is (AND IT IS GREAT), the CFI is taking all my really desirable options away.

RE: The Hood. I just had the whole car painted. Hope I don't have to change the hood. I think I can replace the sheet metal on top/in front of the radiator and hang the stock 87 filter assembly out there like GM did.
Any ideas/suggestions?

Thanks guys, I REALLY appreciate all your input. This is what makes THIS forum GREAT!!!

 

The crossfire engine is just a small block chevy, do what you want, just adress the intake manifold (port or xram) and bore the tbis, then build the engine with a 650cfm limit in mind,which is enough for a engine that winds to 5500rpm. You can do the math, even with a perfect volumetric efficiency rating, 650cfm is enough to power a 5500rpm motor.

You can port it yourself, took me 12 hours cost 25 bucks. Buy the used xram, or a new one. And have dan plett on the forum bore your tbi's for a little over 100 dollars. And you've pretty much solved your induction problem.

On the crossfire forum, dominic sorresso has done up his engine. He has trick flow heads, a ported stock manifold, 2" tbi's comp cam, some tuning and and exhaust. He's putting out around 330hp and 425+ ft-lbs. His goal is to be on par with lt4's so far he's doing a good job, now he's added 1.6 rr's and larger injectors. He's said theres a noticible improvment, but hasnt been back to the dyno yet.

If your goal is 325-350hp and a hell of alot of torque, just keep in mind, it can be done, cheaper easier, and you'll love the look of those lt1 guys when your lowly crossfire stomps them.

 

I'm not being critical, here, but to play devils advacate. If you plan to make head and intake changes, what is the point of changing engines?

 

Thanks for the replys, guys.
They are greatly appreciated.

I'm not trying to justify anything with these thoughts. They are just some of the things I've been thinking.
Here are some rambling thoughts on this project.

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Re: Why change engine?

My engine has 129,000+ miles on it.
Ditto on the 700R4.
Probably not a good idea to pull the intake and heads and just bolt on the better heads.

Those old rings would have to try and reseat with the newly torqued heads on there and that's asking a lot.

I'd have to at least plan on replacing the rings.
Might as well replace the rod and main bearings while I'm at it.
I'd probably measure the skirt clearance and find it to be way to large on an this old engine.
Will need new pistons, might as well bore it 30 over to clear up the block.
Will need a torque plate hone . .matching pistons to bores to get all the skirt clearances syncronized.
New rings . . .should go with the gapless ones, I've always liked them anyway.
I've always hated filing rings to set the end gap, too.

New rod bearings.
Get the rods reconditioned
New Pistons/Pins Floating Pins?
New main bearings
New Cam Bearings
New freeze plugs
New Timing Chain/Gear set

I think you get the idea.

These things ALWAYS snowball and end up costing 3 to 4 times your original guestimate.

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Re: Changing intake,TBIs, etc.

Let me make a guess at this one.

Here's what I'll need:

Xram Intake
2 Updated throttle bodies
Updated heads to take advantage of the newly found airflow.
Intake gasket set.

Sounds about like $1500.00 or thereabouts to me.
I can swap out the WHOLE engine for money in this price range.

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Re: ECM Programming

There's unfortunately very little information on the 84 ECM.
85 on up to 96 there is a lot of info.
But for the 84, practically nothing.
I want to get a Diacom or Autotap and see what my engine controller is doing.
Right now I've got no knock counts, TCC lockup speed, no nothing.
I'm just not "feeling the love" from getting to see all these things.
Heck, it's difficult to impossible to find ANYTHING for the 84.

I have computers for the 84, 85, 87 and 91 model years.
To have the same ECM on the 84 as the 91 would be good from the consistency point.

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Re: Modify the CFI engine.
There is a plethora of parts/information to make the L-98 run any which way you want.
Want to keep the torque down in the low RPM range? No Problem.
Want to raise it up and wind it out a little more? No problem.

With the TPI there is the Larger Baseplate, Large tube runners, larger throttle body, larger valves etc, etc. to make it run better.

The guys modifying the CrossFire are pioneers doing R&D to try and overcome the inherent design of the CFI system.
And this is 16-17 years after the thing came out.
Some very few are having a little success.
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Re: Carburetor
I'd NEVER consider a carburetor.
Even though I can change power valve, jets and set the float level on a Holley 750 double pumper with a blindfold on.
Thats old technology.

Although I have the Holley dominator intake and aluminum heads brand new, I
will not give up the fuel/air delivery accuracy of a computer controlled engine.

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Re: Install TPI on the present engine

I've given a LOT of thought to this idea.
But to make it happen I'll need all the accessory brackets, etc from a 85 on up to 87 engine. There's a lot of stuff in the way on the front of the Crossfire that will have to be moved/relocated.
The computer and wiring harness will have to be replaced.
It will be MORE work than exchanging a COMPLETE later model engine into the car.
This brings me to the point I'm at today.

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The Crossfire Engine/Tranny will be removed intact and sealed to rest until another plan comes along that includes it.

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The newer aluminum head TPI engine will respond a lot better to a little increase in CR or a little plenum porting.
I'll get the AutoXray or Diacom and get my computer involved in fine tuning the engine.
I'll get the EPROM burner and eraser and change some of the engine parameters then probably put the original MemCal & Chip back into it.
(I already have the blank 256K chips)
That'll be a lot of fun.

The present 84 computer just not lend itself well to reprogramming.
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What do you think guys?

Oh BTW, the 91 is my backup transportation in case my old beater 86 Honda Prelude decides to take a couple of days off.
I really don't want to have it torn down more than a few hours.

The 84 is purely a toy and can spend long periods of time in the operating room.

EFI-CFI?
Nick?
Yoslambo?

Thanks for the input and best regards,

Jim

 

w@w thats alot of typing :eek: ....if your tranny hasnt been rebuilt yet you better have $ aside for a rebuild....ive been through 2 700r-4's already. i think you should check out http://www.allchevyengines.com they offer fuel injected stuff 2. if you want to convert to tuned port there are plenty of dead camaros in the boneyard. i recently bought a smashed iroc for $200.00! :D yeah i know i robbed it. i got $550.oo for the engine $100 for computer with harness, $300 for the tranny....etc....... im sure you can find what you are looking for. i still say good old carburation is best......i hate stupid check engine lights :cuss i cant wait to be back to the basic's! no more :bs ! good luck whatever you choose! :cheers:

 

heres what i can add

Whats the mileage on the 87 engine, if it low, i would port the heads and install the longblock inplace of the 84 block, ditto on the tranny, you'll get the factory roller cam, and aluminum heads, plus the 1 piece rear seal.

if you use the 87 long block your looking at
400 for the xram
100-150(not exactly sure) for boring the tbis'
misc for gaskets

There's unfortunately very little information on the 84 ECM.
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Not a problem, you use a 7747 ecm from a pickup, the most hacked ecm out there, i bought mine for 40 bucks. Oy make a adapter with simple instructions on the crossfire forum for 20 bucks, and you dint need to hack your factory harness. The new ecm is 100 times faster, and fully programmable. Then you use winaldl.webhop.net Custom design software for tuning, by a forum member. Its free, costs 3 bucks to make the cable and works awesome. If maps out blms ints and spark knocks just like tuner cat maps them. So you you have a knock at 2000rpm 50KP, you just goto that cell in tuner cat and remove some spark. Also tuner cat is free for the 7747, you have to pay 65 for other ecm definitions.

true enough

not true..we have basicly figured out all the necessary steps. simple mod's will net you 275-280hp, a full planned well thought out engine, should net you in the 330-340hp range, i do believe the xram will flow better than a ported manifold, which will allow you to move the torque curve up and build some more power. One member lives near me, he has a zz4 engine, with an xram, with stock tbis and a stock ecm. He has no problem beating lt1 vettes.

AcK! Never, even the mos primitave tbi system, is light years ahead of a carb. Can you adjust your choke 1000 times a minute? the only benefit a carb has is top end power. I can modify my spark curve at any point without affecting the rest of the curve, you cant do that on a carbed system, same with the fuel curve.

lots of work, little gain, yes it does set you up with a better base for future mods, yes dry flow is superior, but if power equal to an lt4 is enough for you, its easy use the crossfire. Personal i'd use an 91 setup, less wires, it'll fit under the hood.

The crossfire will respond equally as well. they like compression.

winaldl is free and light years beyond both of those.

use the 7747 and all your programming problems will be solved.

Thats what i can comment on. Dont get me wrong, if you have a smoking 406 waiting to go and a super ram, i'd be the first to rip that crossfire out and burn it on my lawn. I just hate to see a perfectly good car butchered, we the owners goals can be met without killing it. I also hate the myth a crossfire cant be made to run, i've seen and experience what they can do, im convinced.

Using every method availible to us, a crossfire could be made to put out about 500-550hp on n20, thats enough power for plenty of people. We have another member who super charged his, was making about 340hp on a relativley stock engine, he's no rebuiling the entire thing with afr heads and other goodies. It should be quite the beast.

Also keep in mind, its the first c4, and the only c4 with that engine, it will be worth money someday. Not alot are left. Every mod i've listed is easily reversible.

 

here this might be a better option for you, if you do go ahead and decide on the tpi setup.
http://www.lt1intake.com

they modify and lt1 intake for use on a normal sbc, you get the miniram for a 1/4 the cost

 

Atta boy, Nick!!! Give him Hell!!

Jim,
I wasn't trying to be critical. Like I said, I was just playing "devil's advocate". You seem to have thought this through very carefully. I have a plan, not everyone agrees with. Just do it your way! Good luck and keep us posted.