Orr I get what your saying but I don't think anyone's claiming they CAN'T make power over 5500RPM. Of course they can make power at higher RPM but a properly spec'd head for the application will make more power everywhere in the power band.

 

I don't consider the "big" afr's awesome, if you need that much flow just get some real heads, or a blower to overcome the weakness.

Anyway back to the OP's questions.. for you to run that lil 383 to 6800 you will need the 2" (50mm) tbi. The injectors to avoid are the 5235231 rochester units, better to use #17084304.
My fuel requirements are greater than yours are likely to be & I'm making it happen, however either one of us would benefit from some improvement on the OE injector's operation.

Reconsider the manifold to use, I suggest Edelbrocks 2901 for a strong tbi build http://www.summitracing.com/parts/EDL-2901/ .Requires an adapter to mount the tbi.

I think as important as any other aspect of your build is considering how you will run it. I hear guys claim that they have their OE ECM/PCM working "as well as" RBob's EBL Flash...without ever having used one.

Well don't listen to anybody dinking with some hack...Rob's system & software will outperform any "hacked" unit period, and it's easy to use.

http://www.dynamicefi.com/

If you wanna do some hacking do it to your tranz controller, there is no reason to compromise your sanity or engine operation.

Just like the head discussion that preceded this post you will find those that stubbornly argue more in defense of allegiance than fact.

 

I'm starting to like this guy.....

 

Ok, i am working with Rob´s EBL since 2 years. Not a newbie with promming... My car isn´t stock in the moment. LT1-cam, 081-heads, headers, edelbrock 3704, headers, 3" exhaust system, highflow-cat, ported TBI-unit, ultimate TBI-Mods, Zeitronix WBO2, ACD 241 fuelpump @18 PSI fuelpressure regulator with stock injectors.... Runs nice...
But now, i want to go with the stroker.... :-)

The Edelbrock 2901 is a singleplane intake manifold !! I don´t think, it´s streetable ?! In addition, i want to go with egr ! With enabled EGR, i can set +5° spark advance in cause of the colder combustion chamber like in the stock prom !

 

Sorry, I now see 700r4 your EBL has it covered yea!

You are the first person I've heard express a desire to keep an EGR employed for timing purposes. From my perspective I see cylinder filling as the first step, then you light the mixture at the right time, to achieve max pressure at the right time.

I would not be so fond of a stock timing curve myself.

To employ an egr to "deaden" the cylinder charge simply to use more timing lead, just don't jive w/me.

Egr's are good for emissions & mileage, not much good for the hotrod.

Single plane manifolds used w/EFI do not suffer the "soft bottom end" of the carb & single plane combo, so the 2901 is the ideal intake manifold.

To explain, efi is spraying well atomized fuel under pressure into the engine, instead of relying on accelerator pumps that atomize fuel poorly & vacuum to have to physically pull the fuel from the carb.

 

I can tell you this is true. I dont feel any low end soggy feelings with my 9 to 1 compression 401 using a big stall and 2.73 gears... off boost it drives around reallllly peppy I was actually surprised

 

I have had an EBL hanging around since it was in BETA! It is a great piece of equipment, but I like the 8192 baud PCM just as much when combined with an electronic transmission.

I can tell you first hand the 2912 (2901 with a Vortec port/bolt pattern) is PERFECTLY STREETABLE even in a heavy *** G-van used for towing up to 5,000 lbs. I ran 14.20s @ 99 mph on a 2.18s 60' in said 5,600 lbs G20 van with a TBI setup on a 2912, ported vortecs, 214/218 @ .050" cam, 9.5:1 compression, Doug Thorley Tri-Ys, 2 1/2" duals through cutous, 2,800 stalled 4L60E, 3.08 gears and a late model 93-95 PCM.

For those listening an ultimate TBI moded small block TBI unit flows around 540 cfm DRY @ 1.5 in/hg. A big block/smallblock marine TBI is around 660 cfm DRY @ 1.5 in/hg. Flowing it wet will decrease the flow substantially. Allowing for a completely open IAC port will increase flow approximately 15-25 CFM depending on other variables.

 

Ok, i understand. But where are the connectors for the heater and the brake booster on this 2901 intake manifold ? It´s also important....

 

The edl-2901 looks like its going to take up a lot of space under the firebird hood.
Could the Weiand 7547-1 http://www.summitracing.com/parts/WND-7547-1/?rtype=10 be perfectly streetable on a emission legal 350-383 ci?

Heather hose could be rerouted to one of the front two tapped holes on the intake manifold.
The brake booster line could probably be tapped in the runner or plenum similar as on the stock intake.

Also how much will the quantity of HC ppm be increased by the missin EGR?
I just realize this is really easy to find out, do the emission test disable EGR and repeat the emission test.

Apperently the cam can also help pas emissions without EGR.
From here http://www.grandsportregistry.com/lt1vslt4.htm "The LT4's more aggressive camshaft profile compliments all the valvetrain upgrades. The cam has more lift, duration and valve overlap. Exhaust valve lift is .479" (12.17mm) (net is less .006" inch (0.15mm) lash), @ .050 (1.27mm) Lift, up from .459" (11.66mm) for the LT1, and the intake is .476" (12.09mm) (net is less .004 (0.10mm) inch lash), up from the LT1's .447" (11.35mm). Duration is also increased slightly on both exhaust and intake... 203 deg. Intake and 210 deg. Exhaust with 115 deg. lobe separation and 1 degree of retard. By increasing overlap significantly, it eliminated the need for an external exhaust gas recirculation (EGR) device."

If the need for EGR can be overcome to pass emission tests, the head and intake choice gets much larger.

 

Ok. I must say, the edelbrock and the weiand intakes look very nice. On the weiand, i can use the one hole on the siamesed runner from cylinder 6 and 8 for the brake booster.
The water tube for the heater, i can connect in front of the intake, nearly the the thermostat, right hand. Other side the CTS.

But i don´t understand ?! Why should be a single plane better for my 383 than a dual plane intake ??

Ok, now, i want to go without EGR. :-)

 

I've been wondering the same about the Weiand & this Edelbrock

http://www.summitracing.com/parts/EDL-5001/

Obviously not optimum like a 2901 but better than dual plane?

My problem is that the runners are getting quite short, dropping toward 5th order harmonics, maybe. Even if length is not an issue, the port entry is very low.

Neither one was ever known to work all that great w/carbs,
has made me shy in FI application.

 

Ok, in the dyno2003, the singleplane-intake will gain 30 horsepower...mmmhhhh....

But I don´t know. How do you think about the dyno2003-application ??


If you say, i should go with singleplane, then, i´ll go with it. 4-barrel or 2-barrel ??? To date, i thought dualplanes are better than singleplane for "streetapplications".....


I am very interested to see a finished, streetable 383 TBI camaro or transam. I want to know which parts are fitted, its setup exactly... :-)

 

If the single plane is worrysome to you might want to look at the Holley Projection TBI unit. Highrise dual plane. I believe it flows considerably better than what you have now(Edel TBI). I run it with GM 7.4L TBI. Good to 6000 rpms. Can the 2901 be shaved to for hood clearance or use a 2.00 carb bonnet like this...[IMG][/IMG]

Does not the 2901 require machining to clear the throttle blades of a 2.00 TBI?
Holley did not. It appears it cannot be shaved much and needs a adapter plate.

I have at the house measurements of the Weiand low profile with plate (.50 inch) and GM 7.4L TBI height. for overall. 2.00 carb bonnet clears the injectors by .25 inch. needs 2- .50 inch alum spacers under bonnet(Jegs).

 

Single planes got a bad reputation from the garbage Torquer series IMO.

A 383 will make more low end power then you ever need even with a single plane.

 

Thats just not true who told you you cant use a tight LSA with them or any good head? They flat out scream.
most do use a wider lsa with a FI setup as they tune a bit easier

If the guy has a mild 383 that doesnt rev high and a tall gear a good 180 head will do him fine. 195 is more popular and will give him growing room but...
Not every motor was built to rev high or needs it depends on tastes
Building HP is a lot more expensive than building torque

 

I'll stand by my position. Some heads like tight LSAs and some don't. Just is what it is....a small port head is going to hit the wall and choke off with a narrow LSA. Just physics.

I still take the position 180 is too small, I'd like to see 200s. The CSA will choke the port and you'll wind up with a dump truck.

RPM=HP and HP=Speed.

Torque is for tow trucks.

 

The original torquer was so limited in power-band & badly misnamed that it was discontinued, the torquer II that is sold now has longer, smaller runners.

Still...

 

It's like that huge guy they call "Tiny".

They have a Vic Jr that is just shorter then the Performer RPM. That's what I would use my self so it will fit under the stock hood. It will fit in a Camaro I don't know about the TA though.

 

They cost the same to build you just spend your money on the right heads, it's that easy.

So what's this growing room you get with 195's? Turbo, nitrous? Sounds like magazine spank to me.

It may scream but it will scream louder with the right heads.

 

Would also be good to know which intake manifold matches or can be matched to the TBI TB the best.
The good detailed pics have been removed from this tread, but it still shows the bad match up. https://www.thirdgen.org/forums/tbi/...ne-intake.html

The weiand 7525 appers was popular (looks similar to the weiand x elerator) http://forums.corvetteforum.com/1568042705-post1.html

Now how important is the CSA of the intake manifold? should it be the same as the heads?

 

Now, i am not sure. I read every day about intake manifolds. Now, i want to go with dualplane.... because:

A singleplane seems to be nice for engines with carbs to get higher rpms. The engine soaks air and the aircolumn soaks the fuel from the carb. With carb, just 2 questions.

1. If you want to go with higher torque in lower rpms, go with dualplane, because of the higher velocity of the air column in the smaller runners.

- Lower mileage
- better gas response

2. If you want to go with more horsepower and higher rpms, go with singleplane. The disadvantage is, you´ll get a leak of power in lower rpm because of the lower velocity of the air column in the big runners. The engine needs rpms to get higher velocity in the runners.

- More Power at higher rpms
- (I think, the man from the gas station will be your best friend.. :-) )


Ok, but for TBI-guys, there are other questions, too.

I´ve one injector for cylinder 1,3,5 and 7. The second one is for the cylinders 2,4,6 and 8. With a singleplane on TBI, there is no assignment. It could be, one cylinder runs too rich, the other too lean. An absolute mess.. :-)
The engine soaks just the air. The injectors sprays the fuel to the cylinder. The engine doesn´t soaks the fuel... That´s "the problem" with EFI. I can´t compare with carbs.....

How do aou think about this theory ???

 

The theory is good BUT a bigger displacement will draw more velocity in a given area. So a runner that will not have enough velocity feeding 350ci can have good velocity with larger 383ci and 400ci.

I know Fast355 did a single plane 305 TBI with EBL that absolutely ripped. If I'm not mistaken it was the same 2 barrel Edel intake that was linked earlier.

If you need EGR though all this is pointless.

DD2003 is a decent tool IMO if you use it right. Don't look at it as "this is how much power I'm making" and use it more for seeing RPM peaks, changes in power bands, ect. But you put one wrong piece of data in and it will spit out lies.

Thomas from what I read the CSA of the intake manifold runner is important but in TBI/Carb application it rarely gets under the volume of the pushrod pinch. I'm sure at some point it should be considered and surely worth looking into. You would consider this more if you were running TPI where it's a real problem.

 

Your theory is a little unclear...Don't be comparing carb behavior to EFI.

If you want a divided plenum, notch the tbi adapter & install a divider plate.

 

I can tell you as low as 1,200 RPM the 2bbl single plane did not have a noticeable torque loss over the dual plane. The single plane also returned slightly better fuel economy.

As far as a 4bbl single plane with plenum divider, that is to improve the CARB BOOSTER SIGNAL. NOT NEEDED WITH TBI.

 

What´s the difference between a dualplane-intake and a singleplane-intake with divider ??

 

Ok. Now, i understand. A single-plane-intake WITH divider-plate will never works properly on a TBI. Normaly, the RH injector sprays to the cylinders 3,5,2,8. The LH injector sprays to the cylinders 1,7,4,6. But with a divider-plate on a single-plane, the RH injector is attached to the cylinders 2,4,6,8 and the LH injector is attached to the cylinders 1,3,5,7.

I can change between single-plane and dual-plane but never go with a divided single-plane. That´s my theory.

Ok, but i understand with the cubicinches. The same intake will have much more velocity on a 383cui engine than on a 305cui or 350cui engine.

 

If you swapped connections on the injectors that would re-sync the injectors with their original cylinder bank, allowing you to devide the plenum and maintain injector sync, if you so desired.

 

Look the guy has a stroker hes driving on the STREET with a TBI and a 5500 max. He needs torque, thats what squirts you across the intersection and gets you going. If hes trying to optimize his combo for HIS driving then help him get there the first time.

Otherwise its like saying hey stick a 260@ 050 cam and a 235cc head in it so you can grow into it later. See the point?

Good 180 head will suit him just fine, most driving is done at part throttle and well below 5500 anyway. Sheesh....

Some good info on this thread and a lot of misinformation.

 

The 383 will have PLENTY of torque.

If it were mine, I would put some Vortecs on it, with the 2912 intake, 454 TBI unit, a little roller cam in the 214/218 @ .050 range, L98 based exhaust, Dynamic EFI EBL and look at buying tires every other week and paying the speeding tickets as they came along.

I plugged the numbers into DD2003, for a 9.5:1 compression 383 using L98 shorty headers, dual cats, low restriction exhaust, 660 cfm 454 TBI unit, running ported vortecs with 245 CFM @ .500 intake flow/180 @ .500 exhaust flow, my custom grind Reed roller cam, 214/218 @ .050, 274/288 @ .004, .510/.538" lift, 114* LSA, 108* ICL and here are the results.

423 HP @ 5,000 and 466 TQ @ 4,000 with more than 385 ft/lbs @ 2,000. It is making over 300 TQ @ 1,500 rpm. At 6,000 rpm it is still making 350 ft/lbs and 400 HP. Set this sucker up with a 700r4, 2,400 rpm converter, 3.23 gears and the car will FLY.

If you want more power, open up the exhaust. Install 1 3/4" primary long tube headers, Tri-Y if possible and run a dual 2.5" into 3.5" single exhaust.

Here are the numbers I got. 400 ft/lbs from 2,000 rpm, over 325 TQ from 1,500. 450 HP @ 5,500 and 480 TQ @ 4,000.

 

Nah, you can go divided dual plane with TBI. All you need to do is force the injectors to run totally in ASYNCH in the program. Don't worry about doing it this way. The V6 calibrations all ran totally in Asynch. It also helps that the injectors have much more useable pulsewidth in asynch. More pulsewidth = more fuel.

Asynch fires both injectors at the same time once every 12.5 msec. That is 8 firings per second. In comparison at 6,000 rpm a normal TBI setup has 5 msec between injector firings, not counting opening and closing times. So at 6,000 rpm the injectors might be able to fire 4.25 msec worth of fuel. In Asynch you might be able to run 12 msec per two firings. So that is 8.5msec vs 12 msec and the corresponding increase in fuel delivery.

 

lol... bad idea.

The correct solution is to run the fuel pressure necessary to supply fuel requirements in sync mode.

Much to-do about nothing, as the 2901 needs no divider, however I would swap drivers...
Just for fun.

 

No its not a bad idea to run in asynch. I ran my Van with 8 indepenent EGT sensors in my doug throley header ports and a datalogging setup just because at one point. Pulling a 5,000 lbs trailer up a 8% grade for miles at a time with the single plane on it the EGTs in Asynch had less variance than they did on the same trip with a dual plane and I was making more power.

Synch mode did me no good at 6,500, just too many injector firings to properly supply the fuel. I was falling over at 5,500 with what should have been plenty of duty cycle left in Synch. Switched to Asynch and gained 1,000 rpm of pull.

 

Ok guys, now, i bought AFR 195 cylinder heads (# 1040) with 65ccm chambers and angled plugs. I think, it´s ok. It should work properly with my 383cui. The velocity and flow should be correct.

I also bought Harland Sharp Roller rocker arms, ratio 1:1.5.

To the camshaft. I´ve seen, the lobe separation is between 118° on low performance stock engines and 101° on high performance racing engines. I think, 110° will be ok for nice street performance. Ok, to create a nice bin-file will be more difficult, but it´s possible....

Now, just the intake-question.... :-(

1. Holley 2" TB with holley dual plane intake ??
2. Edelbrock 3704 bored to 2" with 454 BBC TB ??
3. 2-barrel-carb intake with adapterplate and 454 BBC TB ??
4. 4-barrel-carb intake with adapterplate and 454 BBC TB ??
5. The weiand single plane looks also very nice with adapter plate, but i don´t know with the hood clearence....

I don´t want to go in asynch mode... It should work properly in synch mode... like the stock engine, just bigger, better....

 

Good choice, the 180s were too small. DUMPTRUCK!

Good product.

..

Call Bullet/Crower. I'd like to see you stick closer to 112/114. But call the experts who really know this stuff. The tech support at either is great.

Talk about this with the cam guys. Match them up. Probably the most important decision you're going to make is matching the intake/cam.

 

I do not understand why you are afraid of Asynch. The factory did it starting in 1991 on TBI V8 engines. The 1992 only 299 ecm's operate in Asynch above 2,400 rpm and the later model TBI PCMs switch to asynch around 2,200 rpm. Its honestly a better way to meter fuel with a large open plenum intake.

 

I disabled mine(asynch) only because I was trying to produce a better idle. Issue was need for 80 lbs at 19.5 lbs fuel pressure. Honestly i am uncertain if that was done B4 I added VAFPR(11 lbs FP idle) or when I had idle at 19.5 lbs. Reapproching this concept and I may go asynch due to recent add on of N20 (75HP) to allow more fuel as now I am feeding the N20 fuel jet.

 

The only time async is better is at high rpm with an overwhelmed fuel system.
Passing along/adding/clipping pulsewidth is undesirable.

You CANNOT change the crank time available @ rpm to inject fuel, period.

Running at or near static is to be avoided.

Not my style.

Run enough pressure & injector, there will be no need for the async band-aid.

I would be happiest w/2901, 454tbi & 17112560/17084304RPD injectors.
The manifold needs to be matched with AFR ports, not by gasket.

 

With a dual plane manifold I would agree with you, with the single plane I DO NOT. Here is why. In synch the injectors fire alternating every other distributor reference pulse. However the engine can draw air through both openings in the throttle body. The A/F mixture distribution is better in asynch at higher load and rpm with a single plane.

I would love to see you crank 6,500-7,000 rpm out of a TBI setup WITHOUT using ansynch.

You have to go asynch above about 6,000 rpm regardless of how large your injectors are. There is just not enough time to inject the necessary fuel when the injector is spending 30-40% of the available time opening and closing, when it could be spending 10%. This is the same reason the later model SFI stuff goes into batch fire mode at higher rpms.

 

Ok ok...Thank you !! I´ve got the engine, i´ll get the heads, pushrods and roller rockers. I´ll buy a 454 throttlebody with 90´injectors or 85´injectors. I want to buy a dualplane-intake but i don´t know which one ??!!
I must looking for hood clearence, looking for the ignitioncoilthreads and the tb-linkage...

I´ve got one problem, i don´t understand the "flow-story"... :-(

The maximum lift of the intake lobe is 0.500". The AFR-heads flow 280 cfm @0.500" lift. I think, 280 cfm is the maximum flow of every cylinder...
Why should i use a 700 cfm intake.. Sorry, i don´t understand anything.. Please help me to understand... Thank you !!

 

88, quit talking about 80 or 90lb injectors, that's just nonsense, call the stupid injectors by their part number! Use the 74-75lb ones I posted for you.

I do not have a dual-plane manifold suggestion for you.

Fast, hell I'll agree w/you that 2 injector systems benefit from high rpm async for just that reason (4.25ms @ 6k). 4k is a good switchover point.
It is my opinion that the open/closing of the sync (dual) pulse aids atomization,...doing more to break up the fuel.

I don't think mine will be turning 7K lol.