TBIThrottle Body Injection discussion and questions. L03/CFI tech and other performance enhancements.
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That thing is huge, 2.25" throttle bores should feed just about anything enough air. Unfortunately your still left with the problem of feeding enough fuel to support the kind of HP that throttle body can feed. I guess you could use the N2O port to feed extra fuel into the engine insead of N20, just have to find a way to make the ecm acount for this extra fuel.
It doesn't have nitrous passages. 890 cfm is huge, although if it is flowed at 3 hg then that would be roughly 630 cfm at 1.5 hg. Still more than most would ever need, and you would have the problem of finding an adapter plate to work or boring the manifold out that large. Good find though!
Anybody remember me? LOL - Remember that I fully designed a 2.25 inch tbi unit in AutoCad Solids? Remember I never built it?
Someone go figure out how high you have to raise the injectors to get the fuel cone to hit right on the blades on that thing.---edit--- ok here's a pic for you... how many pod spacers do you have?
Also - the injector pods injector centers would no longer be correct. (unless the tolerence between the bores is too thin = it will probably crack if torqued down wrong.)
Also - you have to restrict air into the manifold with an adapter plate that doesnt make much sense. Anything bigger than the GM 2" is overkill (unless you have a 454 - above), if you need that much more air and fuel, step over to the 4 bbl holley. - or smarter yet, go to port injected, (not tpi) yank your pod and use your original tbi unit for air control..
O, and everybody better pick one up for weight savings too... it's been lightened by machining out the bottom it says!!!!
Gimmick. Probably a reason there isnt a picture. Even if it is in Summit... it's probably to see if there's a market and how many people call them for one....
Last edited by snflupigus; 02-19-2005 at 01:02 PM.
lol, oh, and hey nic, whats up? maybe the 890cfm at that price isnt too bad considering the 670cfm holley one is over $300 without the injectors/pod, but im pretty sure that Snuf is right. Why would holley sell a TBI unit under the NOS name for a lower price?? gimmick... if they were going to build a hi-performance part to be used by serious modifiers, they would use the holley name, not the Fast and the Furious NOS name...
I saw a pic of it. Not really an easy mod, it's a 4 barrel. Click on the sub link for throttle bodies on his link above. 4 barrels have been discussed on here before I believe. It would take alot of computer tuning and guessing to get a stock computer to run 4 injectors.
But it's a sweet looking throttle body, maybe a good one to pair up with a custom DFI system.
NOS-20100NOS $286.69
Estimated Ship Date: 3/10/05
OverviewBrand: Nitrous Oxide Systems (NOS)
Product Line: NOS Nitrous Oxide Throttle Bodies
Throttle Body Style: Throttle body injection, TBI
Airflow Rate (cfm): 890 cfm Venturi Quantity: 2
Venturi Diameter (mm): 57.15 mm
TPS Sensor Included: No
IAC Motor Included: No
Gaskets Included: Yes
Hardware Included: Yes
Injectors Included: Yes
Throttle Body Material: Billet aluminum
Throttle Body Finish: Natural
Quantity: Sold individually.
Great-flowing throttle bodies for nitrous applications.
Throttle Body, 2-Barrel, 890 cfm, 2.250 in. Bores, Universal, Each
Take the guesswork out of increased engine airflow with these highly effective throttle bodies from NOS. Made for a variety of fuel-injected applications, they're CNC-machined from billet aluminum and feature specially contoured air passages for optimum flow. Underneath, each body is pocket-milled for lightening and they'll accept any small-style TPS sensors
when i said step over to 4 bbl - i was saying so under the thought that if you have an engine that needs that much - you can afford the complete holley dfi system - Nobody so far has built a working gm 4bbl setup. And seriously, why would you? If you're making that much power... there are smarter ways to spend your time and money.
Originally posted by snflupigus ...if you have an engine that needs that much - you can afford the complete holley dfi system -
Sorry to drag this off-topic, but that statement is not necessarily true. Anyone (with enough money) can spend money to do things "the right way". Some of us like to (or can only afford to) push the limits of what can be done on a budget.
This TB seems like the only upgrade (at the production level) to the Holley. And at a reasonable price too...
no... it still fits... because you cant outgrow the constraints of the stock throttle body without spending considerable dollars and time upgrading the engine itself...
If you NEED an upgrade from the holley 2" because your engine is starved for air - you've already spent considerable money.
Again, simply put, you're not going to need a 2.25 inch 2bbl tbi unit unless you've already spent thousands... and you've already been tuning on your own, and you've learned & understand fully by your own tuning experience that you now NEED more air than the 2" unit can supply.
Unless you're researched enough to KNOW you need more air...
What he said. Two 90 lb/hr injectors are going to be maxed out way before the throttle body becomes a restriction. If your running crazy fuel pressure (in the 30's) you might need a slightly bigger TB, but your getting to the point money wise as well as feasiblility wise to go to another form of injection.
Originally posted by snflupigus You dont need a bigger throttle body people!!!!
since when is doing things out of necessity the american way? america is the land of excess and even though i believe you, and anyone who knows his a$$ from a hole in the ground does too, there will still be some dumb idiot who will spend the money on a TBI that will provide more air flow than he will ever need... ill stick with my stock TBI with ultimate TBI mods until i actually get to over 350-400hp... new injectors, a VAFPR and good tuning is all you need to bring out the best in TBI... that and getting rid of the top end parts that came with it... regardless, anyone who isnt listening to snuf, should... dont waste your dough, buy yourself some nice shiny stickers and a huge wing... if will do you the same bit of good as that TBI
Jon (jprevost) came out from Jersey last weekend and Bill (azvolfan) and I were able to see him in all his glory tuning Bill's car...
One thing he convinced me of is that the vafpr is not needed when tuning the ecm is understood and it actually makes things more difficult.
Another thing that he confirmed( as I've talked about this for literally years now with many members of the board) is that 2" is as much as anybody really needs with tbi. Air is not the problem on TBI.
I wish he'd post more but I know he's busy. All I can say is that I think most long awaited questions concerning tbi issues will be answered by him thoroughly soon. Jon, want to confirm that?
i havent been on TGO very long, but from what i have heard and seen, Prevost is the man when it comes to TBI... and, from the sounds of things, he knows his sh!t cuz bill had his car professionally dyno-tuned and Prevost made it better... if he says 2" is more than enough, then damn it, 2" is more than enough... 670cfm is plenty...
Originally posted by snflupigus Anybody remember me? LOL - Remember that I fully designed a 2.25 inch tbi unit in AutoCad Solids? Remember I never built it?
Thats why we don't remember you Nic, you're all talk! LOL, j/k...
Snuf hit the nail right on the head.....then continued to pound it in till it was sticking out the other side of the board. Stuffing more air into your car isn't going to do you didly squat unless the engine can acutally USE the extra air. And, just like Snuf said, unless you've already spent half your 401K on your 305, it won't do you any good. Listen to the experts here, they know what they are talking about
Bruce (90RS305)
__________________ "The INFAMOUS Bruce" Gun-Metal Grey 1990 Camaro RS L03' 305 TBI 5 speed One Of Only 2,787 Produced!! --1/4mile = 15.3 @ 87.00mph--
There isn't really any reason for me to reply. You guys are all coming to the right conclusions about TBi and it's restrictions. Fuel, yes, air, not nearly as much. Like Bruce said, what good is the extra air if you don't have the fuel to burn it? Fuel is where your power is, you need enough fuel AND air to make increases in power, not one or the other.
My proof that 2" is plenty of air is all over GM. Yes you want all the air you can get but focus on where TBI hurts... code and fuel.
Thanks guys for the plug .
There are SO many ways to get the code to work, some are easier than others and some ways will save you time now but cost you later when things start getting really close. That's where experience comes into play. I wish I had webspace, if I did I'd have a step by step tutorial on how to tune TBI code. Bruce's 7747 programming 101 is a tad out-dated but still a great base. Anybody got some free webspace they want to give me that doesn't have banners?