NJ SPEEDER

the injectors you have now shoudl be enough to support a 300hp crate motor. it will all boil down to tuning in the end either way. in the tech articles there is soem stuff about getting started in chip burning. soem of the info is a little dated at this pooint, but they are still a good source of understanding to get you started on teh way to at least getting a proper data log to get a good chip burned.
ask your friends who have laptops, i am sure one of them will think teh idea is cool enough to help you try it out.

later
tim

iroczrockz

I don't think I know anyone with a laptop but my wife and I have discussed the idea of getting one at some point. My problem is that I am never satisfied with just running good. I have a disease of some sort I guess. I always want to run faster and faster.

Like most people too though I am on a budget when it comes to the car and I don't get to spend money all the time on the thing. This is the time of year I get to spend some big bucks on the car (tax time).

I read somewhere that you can get all you need to burn a chip for around $150 so it may be in my future sometime.

RBob

iTrader: (1)

Will need 20psi fuel pressure to do that w/the 61's.

RBob.

iroczrockz

HHHmmm. I am only running 12psi. right now. You think by simply increasing fuel pressure will help this situation? If so I guess another pump would be in order!

RBob

iTrader: (1)

Bigger injectors at lower pressure works better. Either way a new pump is in order. The stock TBI pump is rated at 20psi max and won't flow enough for 300 hp at 12psi.

RBob.

P.S. For a laptop any old thing will do. I use both a 20Mhz 386SX and a 33MHz 486 unit.

Dominic Sorresso

RBob,

With 66# Vette injectors, I was able to pull 320hp at 10.5PSI. However, they were flat out at that point which is why I went to the BB injectors.

jims87camaro

it's amazing how this subject keeps rearing its ugly head from time to time. the problem is, the answer to the question has degraded over time. there will always be someone new to come along thinking he can reinvent the wheel.

carburetors were used on cars for the longest time. then people started to think outside the box, and electronic fuel injection was produced. and a system called throttle body injection came along. there was even a system call cross fire injection for a while. then along came tuned port injection, and the automotive world had a new way to produce repeatable horsepower and torque.

i had never owned a tbi system before my blazer. i have not messed with it at all. my '87 camaro has a carb with electric choke. i am learning about it. my '88 formula firebird had tpi, and i never had to mess with it - it ran good from the day i bought it until i got rid of it (why, oh why?). now that the speed bug has bitten me, i am entering a world where you can reinvent the wheel or try someone's proven system - or find yourself somewhere in the middle. whenever someone wins a race or a series of races at the track, the first thing someone asks them is "what're you running?" i think there is a reason for that.

while i cannot definitively state which of carb vs. tbi vs. tpi is better, i would only pose a question: if tbi was so good, then why have the car manufacturers and racing (doesn't matter what type, you pick it) moved away from tbi in favor of a carb or tpi?

it would just seem to me that if tbi was still a good system then it would still be in use on new cars, and racing would've embraced it with a big old hug. you answered the question yourself with availability of parts.

RBob

iTrader: (1)

I'd be afraid to check your AFR.

66# * 2 injectors = 132 # of fuel per hour.

132 / .5 # of fuel per hour per Hp = 264 HP.

Either the injectors flowed more or you were running lean.

RBob.

RBob

iTrader: (1)

When it comes to racing it has to do with the rules. Does NASCAR allow FI? Nope. Pro stock? Nope. Top fuelers? Yep, and the run fuel injection.

As for TBI vs port injection, there is only one advantage to port: no wet flow problems. With that one advantage it becomes easier to package the induction system.

Believe it or not there are a ton of vehicles out there that run and have run a TBI system. Why? Because it works.

RBob.

NJ SPEEDER

realistically teh answer for teh performance and production world not using TBI much is multi part.
first of all, many racing series require a carb, there is no way around it in many of the top levels of racing.
secondly, TBI is great for street/strip type performance, low cost parts, and ease of tuning. the big but in that one is that if you are in topo dollar racing and have access to fully sequential tuning equipment and millions of dollars of researchyou will see that port injection is the path to ultimate power.
third, modern productiopn methods have dramatically lowered teh cost to produce port injection parts, and with modern variable valve trains i have read that it takes less time to tune for emissions compliance with port injection

when it all boils down to it there is no one answer for everyone. i tuned carbs for years and even remeber when gm started advertising irocs with tpi. *** did that injection system get slammed (total poop injection was said a lot at the track). i used to swear taht no EFI coudl beat teh holley's i worked on, until i messed with a fuel injected car. one turn of a fuel pressure regulator instead of changing jets and watchign a few key strokes instead of recurving a distributor and i saw teh benefits of fuel injection.
i liek tpi, looks cool and makes very good power. but damn are those parts expensive. carbs are nice, but with mechanical systems you generally have little feed back for tuning unless you go otu and buy seperate data logging equipment or stand aroudn doing plug cuts and listenign to exhaust for break up. all this adds up to teh reason i chose tbi, it is a great combination of efi controls and carb style component selection.

later
tim

NJ SPEEDER

top fuel only allows mechanical injection. carbs dissappeared long long ago from that catagory.

later
tim

iroczrockz

[QUOTE][i]Originally posted by RBob

132 / .5 # of fuel per hour per Hp = 264 HP.

If I remember right .5 is the middle of the road and the average. If you divide 132 by .4 the outcome is 330 HP. If you divide it by .6 then the outcome is 220 HP. Can't remember where I seen that though. I think it is on this site though.

Dominic Sorresso

RBob,

I was running lean at top end. In a previous post, I said the AFR would go from 12.5 up towards 14:1 at 4-5000rpm when I measured it using a WB O2 on a chassis dyno. Again, my reason for going to larger injectors.
Haven't had the chance yet to check how the 80#'rs are doing but the dyno says about 343hp@4800rpm and 430lbft@3850rpm. I am hoping to do some dyno tuning this spring.

RBob

iTrader: (1)

Thank you for the response. Going from 320hp to 343hp is a decent increase in power. (I missed your other previous post someplace along the line).

My concern with the 320hp w/66's post was that someone would read it and think that they could/should do the same.

Sometimes I wonder about the lbs/# ratings of the TBI injectors. Even 80's shouldn't be enough for 343 hp. I am running what are supposed to be 90's (drk red/drk blue) and I have more then enough fuel. Sometime this winter I am going to actually measure the flow.

RBob.

iroczrockz

Originally posted by Dominic Red/Dark Red 80#
Blue/Black 90#

Hey, are we talking about different injectors here or are the colors wrong here?

Dominic Sorresso

RBob,

No. I agree with you. Based on my figures my BSFC was something like .35. The dyno runs confirmed for me what Grumpy had said all along. Everyone thinks the Xfire manifold can't be made to flow enough air. In fact, it can and the real issue is getting enough fuel. Unlike the dual TB's, the Xfire necessitates
having to revamp the fuel lines and pressure regulator scheme on the motor. I would suggest that even equalizing the injector size and pressure in a stock Xfire has, at the very least, the benefit of equalizing the power from each cylinder and cylinder bank, as well as producing more power. The motor is much quieter. You don't realize how much thrashing the unequal power pulses creates until it isn't there anymore.
One other point. You say you have 90#'rs with dark red and dark blue. I think those are the 80#. The 90's are blue and black. See previous post or:

454 2bbl Truck (89) | 124 | 57021 | 27625 | 17111784, 17111865 | TJ11 Red/Dark Red 80#
454 2bbl Truck (92) | 129 | 57229 | (none) | 17091045, 17091046, 17112557, 17112567 | TJ27 Blue/Black 90#

RBob

iTrader: (1)

Well now it gets even more interesting. Here is the info on the injectors I am using:

ACD# 217-334
GM# 17111784

# laser etched on top of injector:

5235231

Color code on top of injector:

DARK-RED/DARK-BLUE

Then of course the alleged application & flow number:

Big block pickup 90 lb/hr

I think I'll flow test them this week. As now I have no idea what they really are. It is strange that the service # matches the RED/DARK-RED posted above but not the color code.

Dominic, sounds like you did some nice work on the xfire. I tried to talk my brother into putting one on his car. But he just wouldn't do it. If I ever run into one in the yard it'll be put to use.

RBob.

jims87camaro

if you stand in the middle of the road long enough, you'll get run over, because you've got twice the chance of getting hit.

just out of curiosity, how much money have you spent on tbi parts over the years? enough to buy a tpi setup? ok, enough sniping.

it just doesn't add up for me. your equation works for you, but i really wouldn't recommend it for someone looking to get 400 hp. people are lazy (i should know) and they really want a quick, easy solution that isn't going to bang their pocketbook. most also run what came on their car, just because it did. those are the worst, in my opinion, because they really haven't tried any other system - they just know their system is better.

it sounds like you've been around different systems, so i cannot lump you into that category. while your setup works for you, it won't work for me. i want to go faster than a stock tbi system will allow, even with modifications. i do know that with my carb, i can easily make 400hp+ with about $1k more in parts, and that is the goal. i am leaving the door wide open, though, because i know 400hp is not going to be enough. and i know the setup i decided to go with will do exactly that - grow with me as i learn.

NJ SPEEDER

on tbi specific parts i have spent very little in reality. my intake was more expensive because i wanted a direct bolt on, so i went with teh edelbrock performer tbi, about $75 more than the equivalant carb intake. the heads are jsut off teh shelf aluminum heads, you could put them on your car jsut as easily as i pu thtem on mine, so that is nto a "tbi part". and my throttle body when i went 14.20 was an ultimate modded stocker, that was abotu $5 worht of dremel sanding drums, and my fuel pressure regulator was a diy afpr. so basically i spent enough on tbi specific parts to get a tpi air foil.
my car had exhaust and chassis work, none of which is tbi/tpi/carb specific.

you may not want to lump me into a catagory, but you are still makign assumption about how i work on cars. please refrain. thanks

tim

jims87camaro

why? i thought opposing viewpoints was actually a healthy thing, and might help someone achieve their goals.

i think you are a little too defensive. i don't think i made assumptions about how you work on cars, i made an assumption about your choice of tbi. it's not one that i would choose. that doesn't make you a lesser person. i didn't say or even imply it.

i do think the choice of tbi for 400hp+ would be the wrong move, and i will say that until i am proven wrong. sure, you want to go fast - how much do you want to spend, to coin a phrase (reminded by a friend from another board).

i am not here to bash anyone. i would only wish that you would allow another point of view to be heard. i didn't call anyone names, i didn't threaten anyone, i haven't used profanity and i think i am abiding by the rules in the user agreement that i agreed to about posting on this board when i joined. if the rules have changed, please let me know.

Prime

TBI- great system, for basic driving. Have one on our vert, for now. Then it will be going on the shelf next to the modded tbi unit off of my Camaro. The vert will be getting TPI so as to maintain the drivability of F.I.. The Camaro on the other hand got a carb. Why a carb on the Camaro? Because I wanted to go fast and determined that the TBI was the limiting factor. I gave it a shot though but once serious power was made it became as effective as pulling a sled full of lead. Now before anyone jumps on to me for not giving TBI a chance, just let me say that I did give it a chance, for the first 4 to 5 years I owned the car. Back before it was known to mod TBI. But as I said before I hit the wall, especially with the current engine combo in my car, a combo made to rev and make serious power. If one is looking to make around 350 to 375 HP and no more then a modded TBI will serve them well, but once the 400 mark is reached then carb or TPI is the way to go. The upside to carb is it will work better with the other car mods that are being limited by the TBI.

NJ SPEEDER

i want to ask a question all teh the people who think the tbi is teh limiting factor. what part of the tbi is limited? any carb style intake/ heads/ cam that will work with tpi or a carb will work with tbi. air is plenty available with tb's going up to 900cfm and up to 4 90pph injectors all controlable by a mildly modified stock ecm.
i keep hearing teh same old " i want proof" stuff. with the hundreds of time slips that have been posted here and a magazine article that put a stealth ram with 1000cfm tb vs a 670 cfm tbi it was shown that on the same motor the tbi that was short by 230 cfm made almost exactly teh same power. they even said in teh article that it wodl have been nice to see a larger tbi unit to see if it woudl make even more power than a stealth ram.

would someone please show me this great limiting factor that i keep hearing about.

tim

AJ_92RS

First I have to clarify..... that comparison WAS NOT the 670 TBI. It was the Stealth Ram against the Commander 950 with the 700 cfm TBI.

YOU keep trying to compare the 670 CFM rating of the Holley TBI replacement to the CFM of something else..... and it doesn't work that way. :nono:

The Stealth Ram is 1000 CFM, but it's a 2 bore, so it's flowed at 3"/Hg. The Commander 900 with the 700 cfm TB has 4 bores, so it's flowed at 1.5"/Hg (same way as a 4V carb). They all have to be flowed at the same rate (1.5" or 3") for it to be an "apples to apples" comparison.

The Stealth Ram would flow 707 cfm (only 7 cfm more than the Commander 950 with the 700 cfm TBI) if flow rated at 1.5", but it did produce ~10 more HP. IMO that's not worth the $1000, but that's why that magazine (Hot Rod IIRC) only used the 700 cfm TBI as a comparison. It's a 4 bore TBI unit. They couldn't use the cheaper 900 cfm version and make the Stealth Ram look bad.

The Holley 670 replacement for our cars (which is actually made for a truck) only flows 475 cfm @ 1.5"/Hg. That's equivilant to a VERY SMALL 4 barrel carb.

Please..... if you're going to compare them, at least show all the facts and convert cfm numbers using the same flow rates. That way everyone is aware of that MAJOR difference.

RBob

iTrader: (1)

Whoa, please check the sticky at the top of this board. I've posted info from the article in question. To clear up some mis-info here's the basic's on the flows from the article:

HSR: used a 58mm TB (no flow rating specified)
MPFI: a 1000 CFM 4bbl TB
TBI: a 700 CFM 4bbl

The HSR & MPFI system made nearly identical power. The graphs pretty much overlaid each other. The TBI was down ~ 10Hp at the peak (per the article).


I've also noted in some of the posts on this thread how folks claim to not want to use their STOCK TBI, then go an put and AFTERMARKET 4bbl carb on, and say how much better it is. Yikes, talk about apples and oranges. . .

RBob.

fly89gta

iTrader: (1)

bah, get a turbo and SFI, you're good to go

NJ SPEEDER

man if i coudl only afford it

Dominic Sorresso

RBob,

The 90# injectors I have show a laser cut number of
17084303-ACR and a 7251 GM#

Dominic Sorresso

Its possible that some of us have worked on carb'd motors before(No EFI in the 60's and 70's) and that we now own motors with TBI. And that some of us just get our jollies from just trying to maximize what we have. Can a carb or TPI run faster? Sure. But that isn't the point of why I have done what I have to my TB system. I wanted to see what I could squeeze out of it. I would never get into an argument about TBI being better or more powerful than carb or PFI systems. Unfortunately, when somebody asks the question about how much power a TBI can support, we always end up with someone else trashing the system and saying you can get more power from carbs or PFI. Well, DUH! That wasn't the question. Frankly, I like the idea of surprising some guy in an LS-1 when he reads CROSSFIRE INJECTION on the side of my Vette. And then I can still raise the hood and the motor looks stock. Seeing the surprised look on somebody's face makes it all worthwhile.

NJ SPEEDER

i am closing this thread. it has become apparent that the information that is trying to be put up here is getting lost on a bunch of peopel who woudl rather talk abotu other forms of induction.
i am sure all of you know who you are and can now go back to the boards you normally post on with the knowledge that you have ruined yet another thread on teh tbi board.
a lot fo us have worked with different forms of induction before and had success with all of them. if you prefer one over another that is great, go out and enjoy it. this is the tbi board, ifg you don't want to discuss tbi then you need to find another place to post.
thankyou to teh people who entered this thread with an open mind and lent useful information. i am sorry i have to do this.

later
tim