TBIThrottle Body Injection discussion and questions. L03/CFI tech and other performance enhancements.
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hey guys,
i am sure at least on of you guys has it written down someplace. i was wonderring if anyoen ahd ever flowed a stock TB, as cast, no ultimate mods??? how about with ultimate mods???? i am working on my next great evil plan to take tbi where no one has taken it before and i can't find the @#%&*# numbers i need. lol
thanks
tim
__________________ 91 Camaro RS-LO3,Auto
New Motor Started
3rd Annual East Coast F-Body Nationals - August 16th @ Englishtown
Originally posted by NJ SPEEDER hey guys,
i am sure at least on of you guys has it written down someplace. i was wonderring if anyoen ahd ever flowed a stock TB, as cast, no ultimate mods??? how about with ultimate mods???? i am working on my next great evil plan to take tbi where no one has taken it before and i can't find the @#%&*# numbers i need. lol
Originally posted by steve8586iroc What do you have up your sleeve NJ. You know we all can keep a secret.
Steve
hehehehehehehehehehehehehe..........you'll see
i will say two things, it ain't what you are all thinking and it will be TBI
other info to follow once the build up starts.
later
tim
__________________ 91 Camaro RS-LO3,Auto
New Motor Started
3rd Annual East Coast F-Body Nationals - August 16th @ Englishtown
hehehehehehehehehehehehehe..........you'll see
i will say two things, it ain't what you are all thinking and it will be TBI
other info to follow once the build up starts.
later
tim
Dude... you're killing us!!!! About some more hints... Either that or up the #$%^ up and get the project started so that you can give us some details!!! :rockon:
another hint.....hmmmmm.....ok , it is gonna make my car go really really fast i am gonna rebuild the whole car, every nut and bolt is coming off at the end of the season for a complete resto.
it is an all out, no holds barred, TBI build up
:lala:
later
tim
__________________ 91 Camaro RS-LO3,Auto
New Motor Started
3rd Annual East Coast F-Body Nationals - August 16th @ Englishtown
I seriously doubt that it'll flow 520cfm with the injector towers in place. Holley rates their 1.68" throttle body at 400cfm. Another bad thing about this flow rate debate is that these throttle bodies are flow tested at a 3" pressure drop. If you think about it that way, the Holley 670cfm throttle body doesn't even flow as much (in actuality) as a 650cfm double pumper.
All the #'s I've heard are pretty accurate. I have heard 525 just open bore bench flow. I hope that it will flow at least 500 with the injector pod in place though. This is only what I have heard. Hey incidently has anyone tried turbo city's modified TBI? I wonder if it would be a waste of money to get one of those instead of the holley or a 454 TBI?
__________________ FORMER CARS:
'88 GTA - 5.7 TPI, Hooker headers, UD pulleys, Accel coil, 3" exaust/no cat, Dynomax, 3.27 posi, K&N, no MAF screens, Gutted air box, TPI air foil, 10* timing advance, ran a 14.6 @ 94mph...
'92 RS Heritage pkg - 305 TBI, Automatic, Lots of bolt-on performance and handling mods; 3.23 limited slip w/rear disc ran a 15.3 @ 90mph...
So if 1 TBI isn't enough, go with 2, geeze, what's the big deal?
If the holley 670 doesn't flow as much as a 650 double pumper then tell my car that. Considering a 600 or even a 625cfm carb is usually plenty for 400hp, what's the problem?
BTW, I think I know what NJ is doing and it isn't with a 305, more cubes is my only hint and the intake is pretty weird, definatly a first.
__________________ , Jon [color=red]
Still have the RedSled, new toy 2007 Yamaha FZ6
"Success - it 's what you do with what you've got."~Woody Hayes
600cfm is plenty for 400hp. remeber, the formula's for determining how much air flow you really need have little to do with your hp goal. they have more to do with how many cubes you have and how many rpm you intend to spin. you are only looking to match the cfm number to the air supply needs of the engien to take so many breaths so quickly.
the most common formula i have found is:
(CID*Max. RPM)/3456= CFM Required
example:
(350*6000)/3456= 607cfm
you can certainly make 400hp with a small block below 6000rpm. the thing to remeber is that this is an approx of the min. needed, so yes, more cfm may benfit the motor.
if you really wanna see what you can do with small carb/cfm motors i woudl suggest going to a local short track, a lot of those classes have carb restrictions that sound rediculous, like a 400cfm 2 barrel class i read about, but they still make a lot of power(the 400cfm guys were making in the 340's at the crank!)
You can't compare cfm of a carb to cfm of a TBI just like you can't compare the cfm flow of a TB on TPI to a carb! They're completely different intake systems that accomplish the same thing but go about doing it differently. Look at the EFI they have on that 502 motor in GM performance crate engines, it's got a stock L98 TB, the reason it can use that small of a TB is the design of the rest of the intake. It's got a huge area to draw lots of air and so it doesn't need a massive throttle body. Hence the explination for why a huge TB almost never makes you faster unless you have a small intake on a large engine.
TBI is more like a carb but it doesn't rely on the design of the actual throttle blades to atomize the fuel at WOT! If you had a 2" TBI, a large intake manifold like the victor jr and a spacer for the TB, you give the engine a very large area to draw pre-mixed air and fuel. This is why cfm ratings don't make or break an engines output, it's just tuning with spacers, intake design, cam, displacement, the WHOLE SHE BANG!
Carb cfm ratings are more important that EFI for street driven reasons. A huge carb at low rpm is going to be very inconsistant with fuel delivery, EFI doesn't have that problem. In other words, you could tune a winpy motor with EFI with dual 1000cfm TB and 16 p&h injectors...but you don't need all that. It won't hurt anything but it's a waste of money and nothing hurts more than looking faster than you really are. In the same boat, you could tune an EFI system with a huge intake and a small throttle body, it would just require a different approach to tuning and probably sacrifice a little bit of peak power vs a smooth torque curve. Something to that order.
I don't have any doubts that the holley 2" 670 unit will flow enough air for 420hp, I just need to make sure the fuel delivery and timing is tuned and that I bring it to get dynoed .
Originally posted by JPrevost
BTW, I think I know what NJ is doing and it isn't with a 305, more cubes is my only hint and the intake is pretty weird, definatly a first.
hehehehehehehehehe :lala:
this motor will be built this summer. it won't go in the car until at least mid winter. but i will be sure to vid tape the first for ya
later
tim
__________________ 91 Camaro RS-LO3,Auto
New Motor Started
3rd Annual East Coast F-Body Nationals - August 16th @ Englishtown
since everyone is soooo curious i got a deal for ya.
i am in the final stages of plannign this thing. once i figure out the final induction plans, and have everything collected, i will post the whole build up plan. i will also post up the numbers from desk top dyno that i will run for the combo. unfortunately, dd2000 does nto comensate a little extra power that it shoudl make because it is fuel injected, but it should be a good estimate.
'til then, keep wondering
:lala:
later
tim
__________________ 91 Camaro RS-LO3,Auto
New Motor Started
3rd Annual East Coast F-Body Nationals - August 16th @ Englishtown
not a big block, not using my edelbrock heads....
this is kinda fun...hehe
i ran a base line of the set up on desktop dyno tonight. now i am really looking forward to building this engine
hehe:lala:
later
tim
__________________ 91 Camaro RS-LO3,Auto
New Motor Started
3rd Annual East Coast F-Body Nationals - August 16th @ Englishtown
Naw.. I think it'll be a SBC with some kind of forced induction (either a blower or turbos). I'm guesiing it would be a roots-type blower since he give us a hint..... the software he was using does not figure in with FI (only carbs?) Thus, seeing that FI is not common on roots-type blowers (gerneral speaking), maybe that's the route his taking.
I would love to see a SBC with a 6-71 and dual TBIs!!! Now that's my future plans for my bird (already got the hood for it!!
I think if I were Tim I'd do something like a 400 small block with a
Offenhauser/Edelbrock/GM cross-ram intake and dual stock 500cfm TB units with 55# injectors and a custom eprom and a trick air cleaner setup.
Yeah, that's what I'd do if I had the money.
Either that or build a 454 small block and use the same intake.
Check out this link to the chevy cross-fire intake and how they modified it to accept a single carb. If you had a big enough engine and the tinker time you could just get 2 pairs of vette/f-body cross-fire TB units and use 4 single barrel TBIs but that's a mess with the fuel line routing so unless you've got lots of time and are good at fabrication, I wouldn't attempt it.
__________________ , Jon [color=red]
Still have the RedSled, new toy 2007 Yamaha FZ6
"Success - it 's what you do with what you've got."~Woody Hayes