I have a 83 Trans Am it was black & gold and tan interior, when i got it the motor had been swapped the engine code says LU5, i would like to know what this option was? it does have an overdrive shift plate... 10-bolt rear 3.23 gears,,,, Was the LU5 option rare?

 

cross fire injection. fairly rare. don't know all the numbers

 

is it possible to find a harness for this year?? i have the ECM already,

i do know where to find a 350 crossfire from a 84 corvette, how much effort would it be to put the 350 crossfire in my t/a? would i use the harness and ECM from the vette?

 

should be an 82 vette. shouldn't be a big deal to do that conversion. the L98 was more powerful though.

 

I would like to do the swap but do away with the tbi/harness/ecm and put two carbs sitting about the same place to use the vette air cleaner assembly (looks better than the t/a cleaners)(my opinion), i will be upgrading the motor as well,,, not sure if anyones done this before, but i would like to be the first (not likely)

im not so crazy about computer controled cars myself, just given it a thought, i had the car for a few years know and never new what motor it was suposed to have..

 

so you want to put carbs on a L83 manifold?

 

i would use the base of the crossfire intake and custom make the top piece from 3/8ths aluminum for the carbs to rest on,

 

sounds cool. so you gonna find some old 1bbl carbs? keep me posted on your progress.

 

sorry i forgot to mention im gonna try 2- 4 barrel holleys (450 vac. sec carbs), ill go with a high lift cam, ported heads, 2.02 valves, roller rockers, little more compression,msd ignition, headers, possibly, maybe, a T5 or T56,
when i get started ill start posting pics and progress....?????????

 

If you want to get crazy, you'd be further ahead to get a 302 or 327 and an offenhauser crossram intake and two four barrels. The biggest problem with CFI is the crap intake.

When you get down to it, most people hated CFI because they're dog slow. The horsepower rating is higher then the carbs, but the carbed cars are faster. The L69 ran circles around them. I drove my 83 coupe with the 140hp 305 4bbl for a couple years, and test drove a 83 Z28 with the LU5. It was like someone dipped my car in jello. Unless you care more about how cool it looks sitting, then how it actually drives, CFI is a complete waste of time.

 

so basicly performance wise im wasting my time with the crossfire intake?

 

Absolutely. The engineers started with the 69 Z28 crossram intake, and to get enough velocity to make it work at all they made the ports tiny. Even the original Crossram didn't work well at low speeds. From a performance standpoint a 600CFM carb on a cheap aluminum intake would run better.

 

the renegade on the other hand...

http://www.crossfireinjection.net/DCS%20News.html

 

I've ported (port matched) and cleaned up the intake on my LU5. I have L69 manifolds/y-pipe to replace the stock setup as they were/are shared with the LG4 as was the rest of the exhaust. The next inline is to have the TBIs rebushed and possibly ported. I've upgrade the ignition while still looking somewhat stock.

The LU5 is basically good as it has almost as hot a cam as the L69 with the same heads. The L69/T-5 had the advantage of being manual shift and 3.73 gears - the deepest available for the LU5/700R4 was 3.23. At the time the lack of knowledge,poor design and maintance hurt the LU5. This is similar conditions faced by the early ,'57 Rochester, fuel injection.

If you can keep her stock ,running and be happy with the results would be great IMHO as there are so few original CFI cars left.

 

lots of potential to raise the HP well over stock with the
CFI-as stated the stock intake manifold is most of the
problem,in 1995,i modified/ported the manifold on the
'84 vette "L-83"350 in my camaro,added a 1/4" lid
spacer,did a mild port job on the heads;-resulted in a
dramatic increase in power over stock vette
has been totally reliable for 15yrs so far
engine came with the vette injectors,so only had to
install '82 vette chip to run(for '83 LU5 an'84 chip is
needed as the ECMs are different between '82 and'83)
CFI runs great and just rocks if done right

 

You're not going to be taking down LS1's with a CFI, but it's rare, technically interesting, looks cool - and there's a certain satisfaction in getting it to purr like a kitten.

Hey coolram, after you ported your intake, what was the "seat of the pants" difference in the way it drove?

 

I own an 82 z28 camaro indy 500 edition and am looking to keep the crossfire setup. I've heard of people swapping out the intake manifold with a sy1 or offy cross ram and making a custom top lid to fit the two throttle bodies. Does anyone know how difficult it is to make the custom top lid for this to work?

 

Chazman with just the ported intake she feels somewhat "mushy" off idle but pulls better through the gears than before. I know the TBIs need to be rebushed at the least. And she will breath better once I have the L69 manifolds/y-pipe/cat and cat-back on. Mine still has the original cross-over dual mufflers so i know that doesn't help breathing. I don't care for headers in the cramped space of an F-Body for street use plus the L69 manifolds only give it away if someone knows the part/casting numbers.

Canookman IMHO on a real Indy Replica she would be better left original. Though you could do just what I'm doing and still have the original look. I would suggest getting another '82-'83 intake to port. As 8t2 z-chev mentioned the '82 ECM is shared with the '82 CFI Vette. And the '83 ECM is shared with the '84 CFI Vette. They do interchange if I remember correctly. Also you could go with a later ('87-'92) TBI ECM. Your harness would have to be repinned among other things - the TBI Forum section is a good place to start.

 

coolram62,you might have low fuel pressure if your C/F
is mushy off the line-a fuel pump upgrade is a common
C/F modification,a TPI pump is often used along with a
bump in fuel pressure.
'82 and '83 ECMs,though different,('83 is smaller-2PCBs
instead of 3 in the '82)they plug in the same and work
the same-have used both in my car,no difference was
noticed in how they ran-just use the correct year chip

 

8t2 z-chev you're right as I still have the CFI pump and my fuel pressure is 13psi from the pump. I have a second set of TBIs I'm going to have rebushed and do the mods to adjust fuel pressure. This will be neccessary when I upgrade to the '85+ TPI pump you are speaking of. The CFI system really likes 15-18psi instead of the 9-12 in the service manual. Kep in mind I decreased initial port velocity with the ported manifold which contributes to being soft off the line. But there is a definite difference after that only limited now by the restrictive exhaust (again LU5 shared it with the LG4).

The '83's ECM is a bit faster ,and a little more flexible, than the '82's. Not a big difference but with the '83 you can use a EPROM for a '84 CFI Vette (they share the ECM). The bigger uograde would be the switch to a later ('87 +) TBI ECM.

We have to keep at least some factory equipped CFI cars on the road. They weren't the fastest but have potential. And it's unique as chazman noted.

 

Or EBL, there's also the later model truck PCM that fast355 used to run. check out the TBI board, there's all sorts of goodies there that can help you out(the stickies are worth the read!)

 

i want to uprade my 305ci CFI to a 350ci CFI

did you guys ever heard of the renagade manifold for the crossfire injection?

 

Hi all,
FYI, No such thing as 83 Corvett. The 84 Corvette was release in April of 83 as a mid year replacement.

 

Actually I have a LU5 crossfire engine that makes 280hp, 95 more than stock and it runs great. so it can be done

 

Tells us more about what you did.......

 

I'm interested as well.

 

What year crossfire do you have and what is the make of the car? What mods did you do ?

 

Well it has 0.30 flat tops, 458 lift cam, 350 LS1 valve springs, Shaved 0.20 off the heads, headers with 3 inch single flowmaster exhaust. I used electric fans and got rid of the smog stuff. roller tip rockers, and I use royal purple in every oriface..

 

it is a 82 camaro Z28 all factory correct numbers..

 

Now I have a question for you.. With these mods on this car the push rods now drag in the bottoms of the guides. I kept everything mostly stock to avoid machining. any ideas on what and why this happened ?? and what to do to solve this issue?? thanks for your in put!!!

 

NEVER USE PVS roller tip rockers. the rocker ***** did not seat, the pushrod pockets force the push rods to bind on the head casting. These things literaly were burning up.. Problem solved, now lets hope the cam survived...

 

got any photos of the car and mods?

 

I do have photos if some one could tell me how to post them..LOL

 

The only time I've seen a 305 get to those numbers was with L98 aluminum corvette heads, headers, cam, ported intake. I know this because I built my camaro that way back in the day.

If you've got 280hp out of an LU5 with stock unported heads, and a stock intake I'd say you've nearly upset the laws of physics... There have to be more details....

 

You seem pretty knowedgeable on computer tuning. Do you you think it's worth retuning an nearly stock LU5's ignition and fuel tables with a different chip?

I ask because on some of the Corvette forums I frequent, almost everyone gets a ~.3 secnd 1/4 mile improvement when they add a chip to their CFI. It makes me wonder if these early computers were programmed very conservatively.

 

When they "add a chip" to their car, does anyone know for sure what is different in the chip? Is it more timing? More or less fuel? I'd guess that the LU5 is very conservatively timed like the later TBI stuff. I really don't have any idea what it takes to burn chips for the older stuff like that, I've just not read up on it. If you want to play with it as a hobby I'd say go for it, obviously the vette guys get good results. Unless I miss my guess, you're not racing or abusing your early Z very often, so if you're looking for something you can really feel tuning all by itself may not satisfy you. In other words, spend the time and effort to tune the old ecm because its a fun hobby, but don't expect a world full of gains.

 

Our goal was to get it done with NO machine work, however the best gain was opening up the intake and a new computer, some one beat me to the head porting. Yes you are correct, but there are a lot of things a guy can do in the assembly process to free up quite a few poneys.. "these are speed secerets" I'll sell you the secerets but no one has been able to afford them yet.... LOL

 

Where did you get a new computer for a crossfire?

 

This sounds like a bunch of BS to me. Your lack of details and over abundance of lip service, telling us about your "speed secrets" only lead us to doubt your claims. I've built a few engines as have many others here so we're not all that gullable. How do you know it made 280hp? Did u have it put on a dyno or is that what you THINK it makes?

 

Even with the regular mods, 280hp is not happening with these cars. Not even with extensive upgrades and NOS would it do that from what I've seen.

I love my Crossfire, but if you managed to make that much power, you have definitely done way more to the car than it will ever be worth, ruined its collector value, and completely wasted your efforts as you could have achieved 280 hp much easier with a carb setup.

I smell bs.

 

#1 I have been doing stuff like this for years and There are some things done that I WILL NOT TELL as I get paid to do these things.
#2 I have not de-valued this car in any way other than a BIG exhaust, It even has the stock wheels and brakes.
#3 I own and run one of the best dynos in the country( 224X Dynojet)
#4 I have a programed ecu from turbo city (they dont make these anymore)
#5 Our goal was 300 but with-out nos it did not happen.
#6 My altitude corrected HP is 250. If any one has any doubts (as I can tell you do) I challenge you to a horse power pull off... THANKS!!!!!

 

#1 lots of us have been doing this for years, I really don't think we need your help, and clearly you're not willing to share anyway so why are you here?
#2 no one cares if you devalued your car or not, I certainly don't. Congrats on your BIG exhuast, I have 3" duals on mine, aren't you impressed?
#3 shold I be impressed?
#4 congrats, you have an outdated ECM. I'd really be impressed if you found a way to run a decent ECM...
#5 shucks...
#6 250hp is NOT 280 like you initially claimed. There are quite a few guys around here with 250hp out of a 305 and stock heads.

 

No machine work?

Nobody can afford your speed secrets? HAHA you're killing me man, one of the best "speed secrets" is a 350 with a 4bbl, cam, exhaust, heads, etc. and last time I checked, that's not a comparatively expensive setup.

New computer? Please, there's not a ton you can do to a crossfire ecm that can wake the thing up, it's ancient technology and the entire fuel injection system is only meant to make something like 16 calculations per second, and even with an upgraded computer, there's little that the rest of your system can do to keep up with that new technology. It simply wasn't designed to operate as fast as multiport designs. So don't even try to feed us that bs cuz all your crossfire does is spit gas into a pool in the intake. It's about as caveman as you can get as far as efi goes.

From what you're telling us, it seems like you have essentially done almost nothing to your engine. And a stock crossfire makes something like 175 horses. There's no way you can free up 100 extra horsepower from a simple intake and stock head port. And I especially don't think you can get significant gains in the assembly of the engine. 210 hp? Ya, I might believe that, but anything more without significant modification is a little far fetched.

I'm not trying to be a jerk, I just don't believe you at all.

 

I am skeptical too. I KNOW that you can get 250 chp out of a CFI 350 pretty easily. Very easily. 250 whp is attainable too...but in this case something seems odd.

You're going to come on a forum, tout your "speed secrets" and then leave us all hanging?? Trust me, no one on this forum is a potential customer of yours. You'll loose no business by sharing here. You might gain a little respect, however.

 

You all asked, and I told all I was willing to as a good crew chief don't devuldge his secrets. I do not care if you do not believe me as I have no reason to lie.

 

That sounds awsome, you must really know crossfires. Put a renegade on that worked over engine and you would probably hit your goal of 300 hp. You could PM me some of your secrets if you want, no pressure.

 

That settles it!

Im sorry we ever doubted you! Praise to you and your amazing engine and impressive dyno!

Where do we sign up to give you money to make our cars as fast as yours?

 

Looks like I created quite a stir! Sorry guys if you do not believe me. I have spent 4 years working on this car, and lots of hrs in the garage. You all know that there are a ton of (small) things that you can do to free up hp. I totally did em all on paper and the math did not add up, so I tried every thing I could come up with and it was off by 50 hp. but amazing gains. so in my next post I'll run it all down for you. and thanks for your input.

 

Please do. I worked on my CFI car for 12 years. So I can't wait to hear what I missed out on!

 

We could all use some pointers on these TBI engines.