Tom400CFI

I can answer that...
I think the volume of that plenum (huge) does actually even out those fuel "pulses" you are talking about, so the net affect is a relatively decent mixture to the cylinders. Better than an electronically controlled carb at least.

CFI-EFI is right; this thread is awash in misinformation. The problem is people who post about CFI....who NEVER HAD IT! Readers of these threads need to sift through CFI OWNERS and CFI wild-assed-speculators. As an x-owner, it's easy for me to spot which is which, but of OPs it's probably much tougher.

JLeatherman

Ok, I have a new question. There is an Offy for sale with a top plate and TBs. I am thinking about getting it, but I have a question about it's compatibility with my heads. Remember that for now I am going to be using well ported 624 heads with 2.02/1.60s in it, 3 angle staniless valves, screw-in studs, and all the goodies. The cam is pretty aggressive with around 230/236 duration. Will the Offy actually be too big for this combination, or will I be able to run it with some tuning? I would think I can run the Offy with these heads and cam with the tuning choked down a bit, and then really open it up when I can afford to upgrade my heads later on. Any thoughts? Also, I know the Offy requires a smaller wiper motor, does it also require the smaller distributor, or is that just the SY1? Also, will it use my stock air cleaner?

bogus

that pic was one I vadered off the web some time ago, the caption was put there by someone else. I simply post the image as a representation of the old Golden Ram 413s. You are correct, the Golden Ram intake was gone by the time the 383 engine came around. They did use a cross 4bbl intake on the Hemi, tho. I just saved the image... I will edit the caption out.

I found this image on ebay: http://cgi.ebay.com/ebaymotors/New-M...rdZ1QQtcZphoto

The intake is aluminum? I woulda sworn it was iron... my bad.

I have read so much on 454 TBs fitting/not fitting, the last mental score was that they did...

I have no idea how the flying toilet became a carb... that is total and unmitigated crap on my part.

The DZ302 was carb'd... yes, it was a crossfire. What I was alluding to was the actual electronics of the TB system... not the design of the xfire. If I was commenting on xfire in general, that should have been clear by the fact I did post the picture.

In this case, air flow and fuel flow are mutually inclusive.

bogus

This page has some great DZ 302 pics:

http://www.chevconnection.com/cross%20ram.htm



The CFI intake:

JETSET

I have a 305 HP ECM for a 92 RS Camaro crossfire motor with standard 6 sp tranny if anyone needs it. It is kind of rare now.

RRT vette

Hmmm

elkabong

To your point. The Offy will do will in my opinion and the stock air cleaner will work as well. I am not sure about wiper motor or the smaller distributor. Go back to the Crossfire Forum for those answers if you have not done so already. If I did not need emissions I would seriously consider a Offy or SY1 instead of the XRam.

JLeatherman

mmhmm. Madcow on the Xfire forum said with the heads only being able to flow like 230-240, the 304cfm of the Offy will make the car run like crap. Also, I'm tearing off the rest of my emissions stuff, why not take the EGR off too .

bogus

Ok, now you have done it... emissions... this is a sign of trouble... a red flag, so to speak.

Here goes nothing:

Modern emissions controls have more benefit than you realize. Sure, they control emissions, but they do so by allowing the engine to run nearly perfectly. No unnecessary richness, only necessary lean. In otherwords - EFFECIENTLY.

EGR controls NOx by keeping the combustion temps down. This is done by introducing a touch of exhaust gas. The other result? less detonation.

Modern, high-flow bullet style cats will cost you zippo in performance, but will do wonders for the various nasty exhaust smells. Personally, I have grown to hate that overly noxious emissions stench of a poorly tuned car. It's simply a waste of resources and blatent damage to our ground level air quality.

Don't leap off this cliff just because of some ignorant belief in self determination... emission controls are not the enemy... they really are our friend. And personally, I would like our air to stay breathable... especially when it only costs a couple hundred dollars and < 10 hp.

JLeatherman

Ok, I'm gonna have to disagree on the emissions front. I've been fighting this one for a while now.

EGR does reduce NOx with some exhaust gas, and yes, you may ping a little less. However, what is NOx a product of? Combustion temps. A perfectly tuned engine produces lots of NOx. I personally intend to keep exhaust in the exhaust manifold where it belongs, and tune my engine optimally without it. Also, on the Xfire car, EGR screws up the manifold flow, which could certainly adversely affect performance. I will not limit my choice of manifolds for the sake of an EGR valve.

High flow cats truly aren't any more restrictive than high flow mufflers, and probably don't hurt performance. However, what smell are you talking about because the smell I hate most is the sulphurous, rotten egg smell of a cold car with a catalytic converter. My truck (1966 chevy) doesn't have any emissions stuff, it is well tuned, and I love the smell of its exhaust at any temperature. My car won't be poorly tuned and will not be pumping unburned hydrocarbons into the air.


A couple hundred dollars? That would barely buy me the cats. Headers with AIR fittings are twice as expensive as non-emissions ones, and the only aftermarket manifold with EGR is the Xram. Not to mention, the government uses half this emissions stuff just to make more money. I just finished fighting my way through emissions 3 weeks ago right before the car came off the road. Emissions controls clutter my engine compartment, add complexity to an already unecessarily complex system, add weight, and are not going back on my car with the new motor. As a victim of the left-coasts' borderline obsessive emissions control laws I would have thought you would have grown to hate emissions controls more than most.

Anyway, I'm sure there are lots of different views on emissions here, and that is not what I'm trying to do with this thread. My car is getting street-rod tags, without emissions restrictions, before the next emissions test is due.

CFI-EFI

Regardless of who wrote the caption, it is YOUR error if you post erroneous, and wrong, information. It is bad enough if you don't know, but you can't even plagiarize correctly.



Of course, your "bad". It is becoming more and more common. You often shoot you moth off with no idea of what you are talking about. Another prime example follows.



So rather than remain quiet on a subject, of which you are unsure, you choose to lead the unknowing into YOUR abyss of ignorance and irresponsibility.

Today, you speak of TBs. Your original gibberish said, "I am pretty sure the 454 TBI injectors will fit the CFI intake.". The injectors don't install into the manifold. They install into the TBs. It is the TBs that DON'T fit the Crossfire manifold. Your totally incorrect, improper, statement caused a somewhat lengthy correction.



Crap, like most of the post. It wasn't one of your usual "misspeaks", either. You used the Flying Toilet as an example of how large carbs are only suitable for racing.



It would have been easy to say that the first time around, if that is REALLY what you meant. You SAID, "Let me try this one on for you: The basic architecture of the Xfire is now 20+ years old.". The "basic architecture" of the Crossfire is feeding one bank of cylinders with air from above the opposite bank, where they CROSS. If you meant throttle body injection, or electronic fuel injection, you should have said so.



That is pure hog wash. Air flow and fuel flow are mutually inclusive? MY fuel runs through a fuel line and is moved by a fuel pump. You can't include the air in there. In back to back sentences, you said, "It has much better fuel delivery potential, it just needs a better intake.

I hope this starts to help solve your problem here... Remember - it's all about the air flow!!!". Which is it? As usual, it seems as though YOU have no clue, but that doesn't restrain you from posting garbage.

RACE ON!!!

Tom400CFI

My opinion is that the Offy would work "fine" if you can sort out the wiper motor. But it is also my opinion that w/that cam, and those heads, your manifold will not be a good match for the rest of your combo. It won't make the engine "run like crap" like "MADCOW" from the CFI forum said -I don't know who he is; he wasn't even on that forum when I used to be on there a lot. The bigger Offy intake MAY cause you to loose some low end torque w/those heads, but that's the worst case. It will RUN, fine if the tunning is decent.

But what have you got to lose by porting the stock intake? It won't cost you anything, and you could do a cool back-to-back of the ported CFI intake vs the Offy.

Again, if you were doing heads now, I'd say go w/the Offy, hands down. But with those heads, I think it'll be a wash, results wise.

CFI-EFI

The other problem is that by the time you machine the heads and buy and install the 2.02/1.60 valves and port the cast IRON, you will have spent more time and effort than what it would cost for some good heads.

Also, back on the subject of the emissions hardware, most of what you say about the EGR is true, however, you are ignoring one important point. The power robbed by lowered combustion temps (heat IS horse power) is not a factor at WOT, when you are looking for max power. The EGR valve is never open at idle or at WOT. It would be a shame to have to dial your base timing back to 2° BTDC, and lose all the economy and power associated with such a move, in order to be able to cruise down the highway without the engine detonating is self to death in the process.

RACE ON!!!

bogus

you know something, I appologize and all you do is bury me in it deeper.

I am done trying to communicate with you, ok? I try to be nice, I try to be accepting, and you keep treating me like a first grader. I made some mistakes based on poor info (which I admitted to) and you STILL won't leave it or accept it. There is a part of you that just revels in making me look stupid... I don't understand it... I don't get it... just make your comments and leave it at that. I don't need commentary, ok? I feel I have to walk on eggshells around you, and I don't like it. It's as if every little phrase, word or statement is graded and analysed for error... if the word choice is just a little off, that's enough for a flame.

Oh, as far as air flow and fuel flow being mutually inclusive - it's because they share the same space inside the manifold. If you were not such an absolutist you might have figured out what I meant... but instead, you had to rub my nose in it.

That's it... I am done...

69427

I still disagree that there is a decent fuel distribution in the manifold, despite whatever the plenum size is. I dug out McLellan's book (Corvette from the Inside), and on page 80 he himself comments on the poor fuel distribution.

69427

It wasn't oil, and it wasn't an old engine at the time. As I mentioned in a previous post, even Dave Mclellan agreed that the "manifold gave such poor cylinder distribution that we had to compensate with extra fuel".

CAPTAIN COMMANDO

The fuel distribution on my 84' looks bad at 144,xxx miles when I check the plugs every 3 months. But it runs 14.4's and its almost stock. It passes california smog just fine for its age and mileage.

144k on a stock long block engine with a ported stock intake and it passes california smog. It must burn properly for it to pass even with its poor distribution. The plugs always read different but it passes fine

I'd say keep the stock piece,work with it and port it,if you don't like it,put a carb on it. I haven't heard anyone from the crossfire forum that a Offy/SY1 has given positive results. Only stock intakes and X-rams seem to work with tuning or not.

Dominic Sorresso

69427,

The question is WHY was the fuel distribution poor. Some of us are using another manifold with an adapter on top. Some of us have decided to optimize the Xfire. CFI has ported the heck out of his with good results. I decided to address Xfire "problems" including:
1. Different size injectors
2. A shallow plenum
3. Mismatched intake/head ports
4. Poor a/f mixture path
5. Lousy casting
6. Slow ECM
Bruce Plecan first modded a Xfire in the mid 90's. He ran a 13.4 using street tires, an auto, and 3.23 gears.
Putting all this together, you'd wonder what engineer (i.e. Dave McLellan) would design a manifold like this, especially engineers that are supposed to be building one of the best sports cars on the planet.
The Xfire was obviously a compromise. But the fundamental design is not the as bad as its execution.
BTW, who hasn't seen a SBC where #8 didn't run richer than the other cylinders?

LS6 Motor

This was interesting thread, it ended up right where I thought it would. This should have been locked two pages ago!

Mr Mojo

It's only one page for me

You know what I like best about being a moderator?

I can post a pic and lock the thread and leave the rest of you guessing.

Anybody know what manifolds the attached pics are?