Trust me, I understand your experience. There's not much support out there for the '84s. I had some connections that allowed me the info I needed regarding the PROM contents and algorithms. The code is pretty basic by today's standards, but I managed to make a bunch of cal changes so that the engine runs well, whether driving around town or on the track. Regardless, my plans are still to upgrade to a more capable ECM in the near future when I finish my '69 project.

 

I'll take a look at the 749 ECM. My problem has been that some ECMs are not easily rescaleable to use 2 or 3 Bar MAPs. If this ECM is, then that should make life a little easier for me to calibrate. I appreciate the suggestion.
The engine runs great. It pulls like a big block as soon as the boost comes on. Lotsa fun! It's not technically a Crossfire anymore (I'm not a big fan of the fuel mixture distribution in that manifold.) I'm using a 2bbl TBI off of a 454, with the fuel pressure modified by boost pressure. So far I've limited the wastegate to seven pounds while I've been dialing in the fuel and spark curves. My hobby is road course stuff, so I have to be a bit more condervative so that the engine will survive 20 - 30 minute sessions. I've played around with the fuel pressure a few times, but the max fuel pressure I've run is about 16 pounds as I'm unclear what the limit is for the injectors before they tend to lock open.

 

First things first: I have no experience with Crossfire.

I recently spent an intimate year with a 92 Z28 with TPI as a project car. After spending a lot of time on TGO and tearing the motor appart, putting together, modding, running, etc I ultimately sold the car a few months back and no longer have any desire to work on a TPI car.

Anyway, the RS Camaro's of the day had the truck's TBI system. A quick swap of vortec heads, vortec TBI intake and small cam were making huge improvements to those cars with a powerband that would actually stretch past 4500 rpm. Getting the same powerband/improvements in the TPI cars required a lot more $$$, mostly spent on induction changes. For a car that does not cost all that much in the first place, modding is a huge expense for TPI owners. To all of those who say "sell the CFI for and get a TPI" I would like to counter "Try to work out the CFI and avoid the TPI" BUT that is my opinion.

But it brings up a question: Edelbrock makes a 'dual quad' intake that has a very low profile. I believe it may even be lower than the 'Torker II" intake. Could the TB's be adapted to that intake manifold for improved flow/higher powerband? I am not sure exactly how tight the hood clearance issue is. I do know that I have found with my love for Gen III engines also comes the realization that i love high RPM power and don't care all that much about low end torque (as long as the car has some decent displacement, 5.3 L and better)

 

You probably will want to check out www.code59.org, those guys are maintaining a really good bin for the '749/'730. I'm running $60 code which is heavily modified version of $58 by Bruce Plecan (RIP).
I've been running it off and on since '04, first in my singleplane vortech fbody and now on the miniram powerdyne vette.


I've heard the same thing back in the day on TGO, lots of atomization issues. I suppose if you want to spend a ton of time and a little money on the stock intake, and 14s are your goal it's fine. Most of the fbody guys start out with a 14 second stock car and want to run 11s though.

The locking is a concern I mentioned earlier. Someone posted "this other guy did it, so your missinformed". I guess if we go by that logic everything should work cuz some guy did it once. But I like to figure out the theoretical limits to these things before I try something. If you're running 16psi of fuel pressure and 7psi of boost that tells me your running about 9psi. Generally with boost you want to see about a 1:1 pressure increase. Looks to me like you're losing a little fuel delivery under boost. I imagine you're using PE fuel under boost?

Take a look at the 2/3 bar $59 code in the '749 ECM. The '749 can drive 4 low z injectors which should be fine for your TBI app, and it supports both quasi and async fueling so I think you should have no probs getting it to work. has electric wastegate control, and a full VE map. The $60 code I'm running has a 20-100kpa fuel map, and a BPW adder for 100-190kpa, but I'm only running 6-8psi so its fine for me on a 2-bar. $59 would work better for you.

-- Joe

 

Start with porting your intake manifold. It is the single greatest performance improvement you can make to your engine, and any further up grades will require the porting in order to be fully effective. Cost = free. Is that reasonable enough?



You aren't paying attention. I believe he said earlier that he had a Crossfire Trans Am.



My swirls plate are modified. Others have removed their's.

The draw back to porting the intake manifold is the time you spend doing it. There are no performance, driveability, or economy, compromises. Can you feel the difference in a half second (.7 seconds in my case) or greater improvement to your car? I would hope no one is that numb.



A valid opinion. Both the CFI and the TPI are similarly rpm challenged. To swap from one to the other is a waste of time and money; an exercise in futility. It is hard to spend much money to upgrade the CFI because of the lack of parts availability. The expensive TPI upgrades, for the most part, involve a drastic change in manifolds.



Understandable, but then you are playing in the wrong sandbox, hanging around here.

RACE ON!!!

 

-completely.

I rmoved my swirl plstes completely and noticed no detriment to driveability or fuel economy. To help imporve the transition from TB bore to plenum area, I flaired the outlet of the TB and lid bore, like an upside down velocity stack. See pics...

 

No that's not waht I said. Here's what I said, cut 'n pasted for you to make it real easy...
...so let's watch out for putting words in people's mouths, shall we?
The same injectors are run in boats at 30 PSI and greater. No one on this thread is ANYWHER NEAR that. So again, it's a "red herring" concern.

 

But you've never had one, done plug reads or anything like that, have you?

BTW, Who's goal was "14's"? Not mine.

 

CFI-CFI is right. I had an '83 Trans Am. that came stock w/a 305 CFI. That car didn't ahve any serp pullies or belts. I found a '60's Chevy truck and the bone yard that had a muich smaller diameter crank pully, so I snatched it, for 3 dollars. Way, WAY cheaper than and "underdrive pully kit" for $200+, and just as effective. No fish here.

 

The 700 I spent included the HAM board, EBL Flash Board and software, and original 7747 and a 100 dollar laptop and Tuner Pro.

Swirl Plates: I removed mine with no ill effects. IMO they still block the induction path so they had to go. I live in Houston so cold weather"puddlin" at start up in the cold wasn't a true concern. I had the car in DC in February-20F and had no problems then either.

 

Thats cool! You're supporting Bob so from me.

To the OP:

Looks like the pro-flo XT is gonna be around $600 with fuel rails. Add another $150-200 for injectors, about $50 for a used ECM,
$50 for an LS1 TB (used), maybe another $80 for an AFPR and $108 for a pump. An afternoon to repin the harness. So figure about $1100
for a total intake + management system upgrade. ('730 ECM, used map sensor, etc).

Swap the heads with some sportsman-II heads, $850 and a decent cam ($150) and for a grand total of about $2,100 I think we have a good low 12 second combo that should trap around 110mph.

Or you can keep the crossfire, do some porting, and go 14s.


-- Joe

 

Porting the crossfire alone will net 14's. Add 1.6-1 rockers and a converter you've got 13's. Ad exhaust ,ecm friendly cam, and heads-deep 13's. Gears-maybe 12's.

 

I have to laugh... the first question I have for you is do you own stock in the pro-flo XT?
I'm not going to say this combo won't work however you have failed to mention what is involved for tuning. If the OP has no expierence with tuning or doesn't want to do it ,it will be overwhelming for them. To start learning about chip burners,the software is another ball game. Ask me how I know this?
You seem to be totally against the crossfire and thats ok. Its even ok that you have not a lot of knowlege of it. But...your entitled to your opinion. Your out to prove that the crossfire is useless which is not true at all. With a few minor mod's which have been stated the OP will get exactly what he is looking for. Time and time again on this thread as well as many others these mods come up. They are proven mods and the best bang for the buck. The mod above is not a proven mod unless you can show us differently? Its a time consuming mod and tuning will take a while to complete. And in all honesty when your recommend mod is finished they will have a lot more invested than $2100
I will also refresh your memory that the OP is not looking to race is car only to make it worthy of its skin.
Again a few minor mods without ecm changing/tuning it will be there.

 

Corection: Or he can port the CFI and go 13's like I did, and others have. You'r learning curve is painfully slow, here, Joe. Basically, your formula MINUS the intake, fuel rails, injectors, TB, and the fuel pump and all hardware that you forgot to mention ($1100+) will still get him to his goal. What was his goal again? Hmmmm let's see....The answer is YES, Joe.
Joe, you might want to read the above quote from the OP again.

 

Though it may need to get posted 5 more times before Joe figures this out.

Hey Joe, you need an LS2. Anything less than an LS2 is complete and total garbage. Just horrible antiquated crap. Ancient fuel piddling/cast iron technology. Sell that Tin-Lizzy of yours and step into the 21st century! Your just wasting your time and money with that old Gen I & II junk! :Major sarcasm:

 

No. It's a new intake I have not got my hands on yet. I've tuned and played with TBI, various stages of TPI, an HSR, a few singleplane EFI intakes I made, holleys aftermarket singleplane EFI, and the miniram.

So by modding his crossfire, with the limitted 8bit non-programmable ECM, it is just going to tune itself for optimum AFR?

Sure, "How do you know this?"

My "opinion" is it's Junk, and for every application I've had that holds true. It also works 100% fine in stock form. We're talking about investing time and money, and I think investing into crossfire is foolish. The examples presented here by the crossfire experts have been results that are comperable to stock TPI, which in my opinion is also laughable at best.

Now if thats all someone wants, But the OP wanted opinions. I gave mine. He can go with one of the other guys opinions, or form his own.

I don't agree. I think it might be comperable to a TPI C4. I think an LT1 will spank it all day. It still might be well within the scope of the OP wants, so again, if he wants to go that route thats perfectly fine.

The combo I posted was actually done with a converted stock LT1 intake, with a minor port match to a 1205 port, 34 degrees of advance, and 9.5:1 compression. The PRO-FLO XT is similar. It can be had with a vortec or a 1205 port out of the box. Has a short runner design, but not quite as short as the miniram making it a perfect choice for a short duration street cam. It uses a monoblade LS1 throttle body, which I had very successful results using on a few homemade intakes I made back in 2004. Infact, the newer style 'fast' IAC worked wonders.


I don't think their is a such thing as a mod that doesn't require tuning. The factory calibration is so bad out of the box one could gain just by spending a day on that. If these guys can't tune their car, they shouldn't mod them.

I know what you guys are getting at. He can 'do it' with what he has. I just feel (again my opinion), that sinking money into that setup is foolish. The money can be spent on parts that are better for the long haul. A year or two down the road, he may want to peform more mods and end up having to forklift the whole system. The other two guys who posted in here with very modified stuff, one had nearly $700 into just the ECM/management, and the other didn't even HAVE a crossfire setup anymore. Another guy wants a pat in the back because he got a 400 block into the 14s on short money?! You kidding me, all the guys I know with 400s are in the 10s.


-- Joe

 

But you're still agressively advocating it. (?) Over other recomondations that have been repeatedly PROVEN to MEET THE CRITERIA. (??)



No. He will have to make mechaical timing and FP changes (free, BTW) to accomodate the changes to the hard parts. The changes will be sufficient to meet the criteria and have great drivability.

What you seem to be "challenged" by is this concept: "Modding" the CFI doesn't cost money. Any appreciable amount anyway. And it meets the criteria.

Show us a bone, box stock TPI that runs low 13's please. About that, your are FOS.

You sure did! your ill informed, "never had one" opinion. Did you see mine about yoru car? I've never had an LTx car, but they are such out dated junk, why would anyone bother?? You need to get rid of that farm equipment and step into the LS world.


No stock or close to stock LT1 ever beat me. Ever. I was running toe to toe w/LS1's.


"Wonders" on what?




How pompus. I'm SO glad I don't live in your aloof, holier-than-thou shoes. Tell us what it's like...being so great!

What money? Still...slow on the uptake aren't we?

13's Joe. Low 13's. It was an 8.1 compression junkyard dog. And yes, I AM please that I got the the 13's for ~$1500...INCLUDING the whole engine! Who wouldn't be...besides "Lord Joe-tard".

 

Tom thanks you saved me a lot of time of typing

Joe, I will answer your question about tuning. About 8 months ago I decided I wanted to try it. Didn't know which way to go so I did some research and it was very overwhelming. Changing ecms,repin,ostrich,prom and so on. Now I know nothing about tuning while doing this. Finally I found the ebl/flash/ham just like xrcrx, however mine was less than $500. Anyways I went that route since it has the ve learn, thank god. Do I now understand it completely... NO I don't and I'll be the first to admit it. I still need to get back on the dyno to finish the tune.

FWIW-I would recommend to you that before bashing /trying to prove something doesn't work whether its a cfi or anything else for that matter you should first understand it. Maybe if you went to the cfi forum you can read up on it a bit before jumping into an upgrade that is only going to cost you a lot of time and aggravation down the road, for the more inexperience mechanic.

I don't go onto TPI to miniram convertion threads and give advice because I'm not that educated on them.
Your obvisously more of a tuner person and that cool and maybe if you had a cfi your answer would be to just rip it out and put in what you want, thats fine too.But you would do that to achieve your goals.
But in order to achieve a goal of 300chp on the cfi the cheapest,quickest,more cost effective way is to follow through with the mods that have already been listed. This is the goal of the OP. Not everyone wants a 12sec car.

 

Did you read the stickys on TGO? A lot of us spent a ton of time writing up all the info needed. I know the EBL is nice, and Bob put a lot of time into it. I just choose to use tunercat & datamaster as I have alot of different platforms I tune and the UI is the same.

I understand it plenty. I don't need to try it. I have a lot of very well trusted friends that played with crossfire well over 10 years ago, 15 now that I think about it. I've read their test data, posts, and very well documented trials. Why reinvent failure?

I'll agree with you on that.

But why do you think Joby ditched his crossfire, and why Dom sold his car? After a while your desires change and you want more.

-- Joe

 

For those lurking.

The snapshot is shows typical fuel and spark tables for a MAP based system, suck as crossfire.

Some folks have pointed out that tuning only requires advancing the distributor manually, and raising (or lowering) the fuel pressure.

This is very poor advice. The engine requires different amounts of fuel based on load at various RPMS, and changes to the intake/porting will change velocity and change the way the MAP responds. Almost any change you do to the engine will change how the sensors respond to the ECM.

Now for part throttle driving, a lot of this will be corrected by the 02 sensor when in closed loop, unless things are beyond the scope of correction.

When dyno tuning an engine, if you have a wideband connected as well as an egt you will find at some RPM load combinations you will need to subtract a ton of fuel, and add fuel at other points. The same goes for advance. Sometimes you'll want a lot, or a little advance at idle. Your decel and dfco conditions will probably want a lot of advance to clean up and keep the pops from happening in the exhaust, additionally you'll want to make sure the advance slope is clean and it comes in at the right time. Right after peak torque generally adding a few more degrees of advance will give it more kick safely.

GLOBALLY CHANGING FUEL PRESSURE AND INITIAL ADVANCE doesn't take any of these into consideration. This is very poor tuning skills, only performed by the most novice.

Reading plugs only goes so far. You'll never know the truly lean spots because the rich spots will cover up the plugs.

EGT's are very helpful as well.


-- Joe