ok guys, i have been looking through the archives and have come upon some interesting things..

there is no black and white choice of the Holley TB VS. the 454 TB. from what i read, it all depends on injectors, injector pods, and fuel pressure.

well, i had a couple hours between classes and i really wasnt interested in doing my calc III homework, so i decided i would try to see if there is a cut and dry BEST setup as far as the throttle body goes.

BUT, there wasnt anything concrete. there was a lot of discussion, somE disagreements, and a lot of general information, but like i said, nothing concrete.

i have noticed that the Holley unit is more popular as far as use. is that only because it is easeier to get a hold of and cheaper in the long run? (ater getting injectors, etc. for the 454)

the general consensus as far as the 454 TB goes is to use the base of of the 454 and use the injector pod off of a stock L03 throttle body at a higher fuel pressure. or even better, a 350 injector pod (or just 350 injectors), again, at a higher fuel pressure.

so whats the deal?

with money as no object, just concerning power, efficeincy, and general driveability, what is the best scombo between base, injector pod, injectors, and FP?

it looks like it may be the 454 TB with the correct injector pod/injector combo may be the way to go (from looking at the posts anyways), but why is the holley TB so widely used if this is indeed the case?

anyone have any comments, ideas, or whatever, post em. i am hoping that we can all learn a lot from this...

------------------
1991 Camaro RS
GMPP 350 HO crate engine - 2" TB, MSD ignition, SLP exhaust, everything is new
700R4 - 2,400 stall converter, vette servo, shift kit
My car's webpage - z28boy.cz28.com
President - Central New York F-Body Association
Email - z28boy@twcny.rr.com
AIM - "Z28 Boy"



[This message has been edited by Z28 Boy (edited November 30, 2001).]

 

the bores on the 454 are supposedly a little bit smaller. I'm in Calc3 too. you should drop me an IM

edit: smaller not bigger
------------------
-Tas
'89 Formula WS-6

305, TBI, 700R4, P.A.W. 14x3 open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips, Hooker 1-5/8" 50 state legal headers, Dynomax 3" I pipe (PN 44063 and 43248)
Super GRK_Taz World
F-Body Dual Exaust
EFI & Intake Options

[This message has been edited by Tas (edited November 30, 2001).]

 

I believe they are essentially identical castings except for minor pod diffs. I believe that Holley paid GM for the casting rights and actually makes some of GM's castings, now, but not sure...

The Holley injectors are notorious for long-term problems, especially if you use high-pressure with them and/or high duty cycles (too small of an injector for the cause). The GM injectors take pressure VERY well and I have not of heard of any failing prematurely and from anything other than normal age/wear.

 

it was rumored that holley TBIs were refurbished 454s, thus the 454 would have a slightly smaller bore, if it were true. Anyone ever measure them both?

------------------
-Tas
'89 Formula WS-6

305, TBI, 700R4, P.A.W. 14x3 open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips, Hooker 1-5/8" 50 state legal headers, Dynomax 3" I pipe (PN 44063 and 43248)
Super GRK_Taz World
F-Body Dual Exaust
EFI & Intake Options

 

i dont think they are refurbished. at least mine wasnt. they are totally different castings. the GM one is good quality and has a lot of "holes" where there isnt any material, and the holley is a lot different.

so, as far as mine goes, there is no way it is refurbished.

as far as the size of the bores goes...just by looking at the TB in relation to my adaptor or even a gasket, they are pretty damn close. there may be a very slight difference in size, but i dont think that it is noticeable.

-brian

------------------
1991 Camaro RS
GMPP 350 HO crate engine - Holley TB, MSD ignition, SLP exhaust, everything is new
700R4 - 2,400 stall converter, vette servo, shift kit
My car's webpage - z28boy.cz28.com
President - Central New York F-Body Association
Email - z28boy@twcny.rr.com
AIM - "Z28 Boy"

 

I heard Holley used Dodge injectors in thier unit. I don't want to disease up my Chevy with Dodge parts (sorry Tas!)

I think the Holley unit is more widely used because the 454 TB, in my area, is like trying to find Atlantis. Most of the dirty yokels at the junkyard can't even tell me what throttle body injection is, so explaining to them what I need off the 454 engine is usually difficult.

For my combo, I don't think I need 2" bores anyway. So I opted to take a 350 TB and bore it out to 48mm, like I had posted.

------------------
'92 Astro, GM crate 350, Holley Pro-Jection Intake, MSD 6AL, 3.42's, 2.5" exhaust, Flowmaster 40 2 chamber, B&M 2nd stage shift kit, 255 60 R15 tires on AR-727's, Polished & Bored TBI, Custom EPROM in progress

 

MOPAR

 

LOL

 

holley designed the unit for gm, gm screwed them and contracted rochester to build them for em.

2" bores are 2" bores people.

Only difference with the holley and the 454 is well, the age of the aluminium. , they are a different casting but are essentially the same, only difference is that one was made for mass production ease of installation and the other isnt. The pods are different, obviously, there is enough info on the boards for me not to go into that.

so, for the throttle body castings without the pod, there is no worth while differences except cosmetic. (besides iat/iac - and even those are cosmetic. aka, just look different )

[This message has been edited by snflupigus (edited November 30, 2001).]

 

I thought that the Holley unit had the IAC swept further forward. If you've seen the picture I took of my intake, you know that the EGR valve and IAC hit each other big time. That's why I had to omit the EGR for now. Because of that, I was assuming the the Holley TB had the IAC in a slighty different position.

 

so, here is what i am currently running as of today when i wrote this...

-holley base
-GM injector pod
-GM 40 lb injectors
-AFPR

i plan on bumping up the fuel pressure to compensate for the small injectors.

from what i have heard and form the research that i have done, the holley base/GM injector pod seems to be the hot ticket. anyone agree? disagree?

ideally, i should probably have the 55 lb injectors correct? i think that once i get them i will be all set.

what do you guys think?

-brian



[This message has been edited by Z28 Boy (edited December 02, 2001).]

 

 

Ya, that seems to be the agreement around here. holley tb, gm pod.

you should get 65#ers.. in my opinion.

 

Help us out. We need to find a good cheap source for injectors. I'm looking for 350 injectors if anybody has any extra.
How about some BB injectors, crossfire injectors for the 350 vettes work too.

 

If you look in the BIG Holley/Weiand catalog, there are some GM TBI-style injectors for use on the Holley single injector conversion TBI units. I assume they are GM-made injectors for sale by Holley? I don't have the catalog at work but they are like 90-95pph injectors for use on the Jeep single bbl TBI conversion system, I think??? Wonder what they cost at Jeg's/Summit?

 

AMMMEEENN my brotha!!!!!

no but really...we need a good source for some cheaper injectors. i NEED a set of either the 55 or 65 pounders. but i dont want tp pay a premium for them.

i was thinking 55 pounders for one reason: high fuel pressure. i figured i would be better to get an injector that was possibly a little bit too small for my application, but run it at a higher fuel pressure because the quality of the "cone" or whatever the hell is it is better at higher FP. what do you guys think?

55 lb/hr @ high FP with better fuel distribution/atomization?

65 lb/hr @ lower FP?

-brian

[This message has been edited by Z28 Boy (edited December 04, 2001).]

 

Brian, some injectors like high fuel pressure, some don't. The Holley units are a POS and can't handle fuel pressure without dripping fuel. GM injectors like higher fuel pressure but again, they won't last as long. The advantage of running higher fuel pressure is that up to a limit the spray is a fine mist, once you past that limit the injectors will have an ugly spray. I would go with the 350 injectors and crank the fuel pressure up to about 18 for your motor just to be happy with that stock eprom. When you get a custom eprom you can make it so it isn't running so rich at idle in open loop. The problem you'll have is that it's gotta run rich in open loop or you'll starve the motor beyond 4500rpm!
If anybody knows where to get used injectors, please post

 

so whats the deal with new injectors? are they still available from GM? how much will they run? i heard that they are pretty expensive.

snuf, i know that your family owns a GM dealership and can get them cheaper than we can..but do you know what that price is considered? the reason i ask is because i am friends with the parts manager at the local Chevy dealer (because i go in all the time) and he gives me the "wholesale" price..which saves me a a pretty good amount of money. is that the same price? i think its pretty close to GM Parts Direct.

who knows...then there is turbo city that charges 140 bucks for 2 injectors. PLUS a $110 core charge!

-brian

 

gm parts.com is a dealership who gets "kickbacks" and other stuff from delco for selling in quantity.

they sell most for what my dealership gets it for. sorry.

 

well when i just got my 65 lb cop car injectors (pn 17112412) the guy that helps me out gave them to me for like 95 bucks. which is still a little above GM Parts Direct's price. they have them for about 83 bucks.

I think this is because he basically adds a few bucks to their "cost", which would basically be GMPD's price.

oh well..works for me..

-brian

 

Calling Doug Flynn..... Calling Doug Flynn....

------------------
Black 1983 Trans Am
350 Cross-Fire Injection
T5 World Class
3.42 Locker
7747 ECM
Flowtech Headers
!Cat
Factory 98 WS6 muffler (oval tip)

 

who's doug flynn????

 

I don't understand the logic behind getting the 65lbs/hr injectors for a 300+hp engine.

The stock 170hp L03 injectors are around 50lbs/hr. Now you've double your HP and you haven't picked the largest injector availible? Seems to me you'd want 100lbs/hr injectors.

Sure you can raise the fuel pressure up to get 100lbs/hr but why stray any farther from design specs than nessesary. Just works the fuel pump and injectors harder.

 

Just to print some facts.

In all 2 Bbl and 4 Bbl TBI units, Holley used to use their own TBI injectors that they made in-house. These injectors do not like to see higher pressures (18-20+ PSI). The injectors were rated at 15 psi and went out the door at 15 psi.

Since about the last 1-1/2 years all 2 and 4 bbl TBI units use GM Delphi injectors. These are a very good injector and are OEM parts used by GM in many vehicles. These injectors are preset at 12 or 21 psi depending on the application. They can be run at much, much higher pressures.

The throttle bodies Holley sells are brand new castings owned by Holley.

Hope this clears some things up.

 

actually, the stock L03 injectors are rated at 40 lb/hr.

a 65 lb/hr injector is definitely enough for a 330 horsepower engine when the fuel pressure is bumped up a little.

just because its twice the power doent really mean it need twice the fuel.

-brian

 

40 is bearly enough injector for 160hp. They are closer to 50lbs/hr

You need aprox 98lbs/hr each to make 330hp at .5 bsfc and 85% duty cycle. To get 98lbs/hr from 65lbs/hr injectors you will have to raise the FP from 10psi up to aprox 22psi. Thats double, not a little.

Yes it does. Its that simple. If you keep the bsfc and duty cycle the same you will need double.

You can double check me if you like. The math is all here.
http://www.rceng.com/technical.htm

or here
http://www.concentric.net/~Gmckissi/sdacgl/FUEL.HTM

or here
http://www.grapeaperacing.com/GrapeA...linjectors.htm

 

A 65#/hr injector is *not* enough for a 330 hp engine. Bumping the fp from 11 psi (close to stock for most TBI engines) to 18 psi will only give you the ability to make approx 28% more power than stock. So that means a 230 hp engine can get enough fuel to support around 290 hp.

A 330 hp engine needs 43% more fuel than a 230 hp engine, and 43% more fuel means double the fuel pressure; so that means you'd need to run 22 psi instead of 11 psi.

Actually, it does. In fact, you always needs a little more than twice the fuel to double the hp, because the injectors are not likely to spray as well... and double the power means four times the fuel pressure, approximately.

No multivariable calculus in the following:

hp = (inject_fuel_lb/hour)(#_injectors)(duty_cycle)/BSFC

#_injectors, duty cycle, and BSFC are close to constant for a given engine rpm, so the only variable to increase power is the injector fuel delivery. If you want double the power, you need double the fuel.

FYI, FWIW, YMMV. - Ken


[This message has been edited by kdrolt (edited December 09, 2001).]

 

I currently have a holley 670 unit with a GM injector pod on it. To install youll need to do some grinding at the rear of the holley so the fuel fittings fit. Youll also need to have or fab an injector pod spacer. The GM injector pod doesnt cover the hole where the fuel paths are in the Holley TB perfectly like the holley injector pod but i feel its not a concern cause we are talking about a milimeter gap of unfiltered air, thats with an injector pod spacer as just a copy of the injector pod gasket. I havent looked at it in a while but you could probably just make it a little bigger and it will fit fine. I dont car enough about such a small gap personally. Youll also have to drill and tap the holley casting to install the aircleaner stud. Again, its all childs play.
I ran the holley injectors for a short time which are actually copies of dodge tbi injectors.
In short, They suck. No ifs ands or buts, the injectors shoot several individual streams rather than a "cone" that the gm injectors spray, to make matters worse, even if you spaced the injector pod a ton the streams still pretty much hit the throttle blades dead center when you really want to hit the edges of the blades for a number of reasons.
They also cant handle alot of pressure and they are also way larger than stock injectors which for me just presented a problem.
I stuck with the stock 305 injectors and installed an external regulator made by NOS, it can be vacuum referenced but ive left that disconnected. I run 20 psi. At this pressure and at the height the injector pod is the cone hits the edges of the throttle blades about perfectly. I dont know why there is so much debate over this, just find whichever TB you can cheaper and run the GM pod on it. To me its as simple as that, i found my holley for 50 bux. Just keep a lookout on the net for em. I think the 454 unit has a slightly different IAC setup but hey you are modding a car not plugging in a VCR there are gonna be some things youll need to rig up so it will work right

I cant speak from experience for very high hp spectrum of tbi setups but in my case and in my experience, those fuel consumption equations for a given HP so you can size your injectors are Horse ****. In every instance ive ever seen those numbers applied to real life the motor would just drown in fuel. I personally think it just ends up with way too high of a fuel demand estimate.. or maybe the hp in the equation equals 2 hp in real life.

i think for up around 400 hp and whatnot things would get tricky because you will need a pretty damn big injector or high FP. Either way i think it will make idle and low speed crappy so the only thing i can think of to remedy this is to run a vacuum referenced afpr so that you dont have such short shots of fuel on the low end making things choppy and just tune the chip like it wasnt there, heck might make it so the pump shot is alot closer etc

hmm what else, run a centered adapter plate...
thats about it.. I want to emphasize not to go crazy on the fuel side of it. For like a year my car was probably running like a 7:1 wot afr fuel ratio because people harp on having enough fuel so much youd think everyone and every car on the street was running lean. I think the opposite is mostly true.

 

btw I run a late model vortec pickup truck fuel pump. direct drop in replacement except that the pump is rated 42 GPH at 36 psi. It doesnt even break a sweat on my setup

 

hey kdrolt..thanks for the non-multivariable calculus lesson.

for what its worth, when i was speaking of 330 HP in my post, i actually meant 300. my motor was rated at 330, and sometimes that number gets stuck in my head..but anyways..

from what i have learned the past few years, as far as TBI goes, to get twice the HP you dont necessarily need twice the injector. that is from what i have read, and some of what i have seen firsthand. granted, most of what i have learned has been right here on these boards, and we all know the integrity of the internet. not everyone is always right, and we shouldnt take anything seriously without looking into it.

it appears that you guys have indeed looked into it, and you evidently have a better understanding of the whole subject than i do. so, i apologize for my mistake...but again, i was going laregely from my experiences on this site and others. and again, as we all know, the real world is often different than a bunch of equations. there are MANY factors that go into a fuel injection setup (cam, heads, compression ratio, etc.).

so, i am not TOTALLY convinced of what you guys have to say, but only because i havent researched it enough to have a solid position one way or another.

BUT, i have seen on NUMEROUS sites on the net and some sources in print that the L03 injectors are rated at ~40 lb/hr. no offense, but i don't believe that they are rated that high until i see a LOT more proof of it. end of story.

so what injectors are you guys recommending to me to reaching 300-330 HP? it looks like you are saying to go with an 80 pound injector? at which FPs should these run at?

i want to learn all i can about this subject..so leave any insights you may have.

-brian


[This message has been edited by Z28 Boy (edited December 09, 2001).]

 

oh..and what does YMMV mean???

 

Would you expand on these things you noted?

I would argue that based on your 93.66mph in the quarter you have roughly 250hp at the crank.

250hp according to the phony equations requires 73.5lbs/hr per injector.

We will assume that the stock L03 injectors flow 50lbs/hr each @ 10psi. This is reasonable because the equations say you need 53lbs/hr each to make 170hp @ .5 bsfc and %80 duty cycle.

When you raise the pressure on the stock L03 injectors to 20psi they now flow 70.3lbs/hr each. Not exact, but its close enough IMHO to use as injector sizing guideline.

Later,
Brent


[This message has been edited by Brent (edited December 09, 2001).]

 

brent...can you explain some of the stuff in the equations? well actually i think the only thing that i am weary on is the BSFC.

if you could give me a clue as to what that is it would be great..thanks.

-brian

 

BSFC = Brake Specific Fuel Consumption

It is the measured fuel flow in pounds per hour divided by the horsepower.

They measure the hp with a dyno and they measure the fuel flow into the carb or injection during the dyno pull.

http://www.westechperformance.com/pa.../fuelflow.html

[This message has been edited by Brent (edited December 09, 2001).]

 

so wouldn it vary according to the power of teh car? because some of the links you posted before assumed it to be .5. is that a fair assumption on all fuel TBI cars?

im sorry if these questions are dumb, but i dont know that much about this stuff. i usually try to get bettr "informed" prior to aksing questions.

-brian

 

It is perfectly fair to use .5 bsfc as a guideline for sizing injectors on a naturally aspirated engine. Especially when you are talking about wet flow manifold applications where distribution may not be optimal.

 

ok cool..thanks for the info.

-brian

 

It is very important to use the proper BSFC and real HP numbers when calculating injectors sizes. BSFC numbers can range from .38 for an efficient race engine to over .6 for a forced induction engine.

A difference of .05 on the BSFC will have a big effect on the calculated injector size, plus most people think they have more power than they really do.

The math always works out, you just need the correct inputs.

I would agree that .5 would be a good safe number for a naturally aspirated TBI engine.

 

Brent, Im almost 100% certain that the 305 injectors are only 40 or 45 lbs, the 350 standard injectors are 55 and the cop car injectors are 65.

I dont know if you took into account duty cycle but it seems like you didnt,in which case, I have to say im NO WHERE NEAR 100% duty cycle, not evenclose.. I ran those equations for injector sizing for even more modest hp numbers than you guessed and started off a base tune on that and it was so rediculously rich i thought the car was just leaning out completely it ran so bad( i didnt know how to read plugs at the time) I had to back off a substantial amount on the fuel to get it even near decent

I cant be more specific because I havent messed with the car really for like 6 months, and am not even on my computer to look at thebins i went through. But i know this, I went like a year driving around with a car that was rediculously rich because of all the bs numbers