Hello again , looking to dump my cross fire de-jection system ...

a few questio's
I have a very old but perfect "Single plane aluminum intake ( Wiend-X-celerator ) . Open plenum style

so .. What is the difference between the Single and dual plane intake manifolds ?

and one more please ,

Have a Holley dual feedspread bore carb on the shelf . .. however ... jre-jetting is the only way to tune

My machinist buddy says to go ... Quadrojet

He claims there are numerous metering needles and other little ad on goodies available to fine tune this Rochester / Carter / Quadro

The cross fire set up is Great on bottom end and goes down hill at a rapid pace after 3500 R's .. so bye bye X- Fire

Advise is Good
Lawrence and his first vette at 62
So Cal style

 

First, w/regard to "dumping your CFI"...you MAY be able to meet your goals w/the CFI and retain all the functionality and driveablity that your car should have. I went low 13's with my CFI and porting it as much as you possibly can, is the key to that. What are your goals? If interested, I can elaborate.

Single plane and dual plane intakes:

A single plane intake is designed for higher RPM use, when used with a carb!. Reason is velocity through the carburetor. The single plane has one common chamber (called the plenum) that all 8 cylinder draw their air/fuel mix from. At low RPM with a carb, (assuming a vacuum secondary carb), one cylinder at a time draws air from 2 barrels, and when the secondaries open, 4 barrels. This improves high RPM/high airflow breathing.

In a dual plane, the intake is split in 1/2, according to the firing order. In a SBC, one side feeds cylinders 8,3,5,2 and the other side feeds 1,4,6,7. The two sides each draw from only 1/2 of the carburetor, so at lower RPM's, any given cylinder will only be drawing through one barrel. This increases the velocity through the carb at low speeds, improving the draw, and air fuel mix.

The need for velocity through the "carb" in an EFI engine doesn't exist. You don't need good velocity through what is in the carb's place; the throttle body. Because fuel is injected based on measured or calc'ed air flow, velocity is not needed and therefore, a "dual plane intake" is also not needed on an EFI engine. Your stock, CFI intake is a single plane intake; all 8 cylinders draw from one common chamber which is fed by the two TB's.

 

The xfire to carb comes up so often we need a how to stickey.
Any way, well said Tom! a duel plane has a big advantage below 2500 if you are using any meaningfull valve timing. It should have a noticeable advantage below about 4000. A single plane will pull stronger over 4000.

btw that Holley spread bore is about as easy to tune as anything else out there.

 

I would use a dual plane intake and the Q-jet, with the tuning they are hard to beat. Good gas mileage and power with good drivability. (Your machinist is correct)

 

Do you have to pass smog ? I guess not or you would not be asking this. You know after the carb you will be thinking, cam, heads, headers. Just sayin'.

 

If you have the divider plate that came with it use it.
A performer EPS weiand airstrike or non air gap would work good.
Youll enjoy the DP a lot more on the street.
Unless you got a lot of gear, head big cam stick with the dual plane long as you can

 

An old friend of mine hit 12.9's on a stock '84 Vette with nitrous and drag radials. So the crossfire is not so bad. Plus don't the '84's come with a factory ram air or something? Thats cool.

 

Getting the car smogged will be difficult every 2 years in California.

 

DUH! cant believe I missed that.
Yeah he will fail with any carbed intake period.
Get that crossfire working.

 

Tom said it all. You can always put it back om when smog time comes up.

 

I missed it too. your stuck with the xfire unless you want to move to the US.

 

Oh yeah , Im down here in smoggo land ... San-Bern , So Cal ... how ever We can prevail and lastly ... Arizona ... a hop skip if needed

please explain why the carb setup will never pass smog "please" ... be specific ... remember that you are dealing with the old and wicked ..
looking forward to tons more of Senior Moments

 

I likey , please give me all you can on the 12 ET's with the X-fire set up ...

Im a machinist with a bag of cartridge rolls .. and familiar with the intake porting dealy ...it's amazing how small the intake ports are ...
when it meets the head ports is almost 3/8ths inch smaller .. easy enough to carve open ... however 2 things come to mind .. cartride rolling the aluminum is a chore but surley can get done ...

The plenums on the inside are long and look way to long ... can they be shortened and or drilled full of holes to increase " intake Volume " ,,, not talking bout velocity here

and lastly .... the throttle body's which can be opened up to a max of 2.2 inches is still less than a four barrel .. please address this if you can

bottom line .. the cross fire looks very tricky and awsome visually ... but but but
A single Quadro jet and spread bore looks mighty tasty ..
Advise is good
Lawrence So Cal Style

 

I likey you ... why not

 

What 's gone wrong here ... please reread my post and let me know exactly what is confusing you ?

 

Perfect .... gottcha

 

Carb won't pass smog in CA because it isn't OEM, and won't pass visual. It doesn't look stock. Not even close.

Porting; The end of the runner, where it meets the head is only 1/2 the problem. The rest of the problem is the rest of the runner(s) length. You need to port the whole runner, floor, walls and ceiling until it's paper thin. Don't be afraid to breach it; you can fix with good epoxy and it will work and last.

Porting II; Don't waste your time "porting" with cartridge rolls. Use an aluminum die grinding bit like these:

^They are WAY faster, and work way better.

Porting III; Don't shorten the runners. They are a good 'mid length runner' (like the HSR intake) that makes a great combination of low, mid and top end power...once ported out to a proper cross sectional area. Shortening them will hurt low-mid power; it will behave more like a miniram. You can get "drill bit extensions" and get the reach you need to go all the way through each runner, to do that proper porting job. A WELL ported CFI intake will make power past 5500 RPM on a stock 350. A huge improvement over stock.

Throttle Body; 2.2" is not less than a 4 bbl, because you don't have a venturi restricting flow in the EFI throttle body, like you do in each of the 4 bbls of the carb. Stock CFI TB's flow ~500 CFM (IIRC). 2.09" is about all you can bore, w/o sleeving. That is 53mm (x2) and should flow more than you'll ever need. You can sleeve the things and go bigger, BUT, on stock or stockish 350, you'll gain nothing with bored TB's. I've seen an upper 13's CFI car gain squat, with bored TB's.

Since you still haven't stated a performance goal or a budget, it's hard to give the best advice, but the above should be a good conversation starter.

 

Performance Goal .. to the absolute limit for street drive ability ..
trips to the beach , and weekend warrior autocross and strip ..than drive to doctors Monday

Budget = SSI fixed income at 63 (a so to limited budget ) but add in free time and good hands
my machine shop closed to public now .. recovering from liver transplant and oldness

I will get those bits .. I have some wax so far.. mostly in ears .. Hah !

 

If you want to get real crafty with the xfire their is a really nice ol offy cross ram in the C4 parts classifieds

 

just got off the tele with Indy .. Wow .. that's incredible ... I spoke with the gentleman .. a very nice guy ..
just to much for my budget ..
Fuel consumption must be astronomical also ... Hmm ?
thanks for that one ...