Not meaning to be a wet blanket here, but.....

Can I just ask why everyone spends so much $, and works so hard at getting the TBI system to work?

I've done alot to mine, spent hundreds and hours above what carburation would cost just to get it to run, and it still doesn't. And I have to question this. All the fastest cars I've ever seen had carbs - granted I'm old (38), and my childhood is filled with Saturday afternoon Nova runs at the strip. All the adapters, rigged throttle cables, sensor checks and rechecks, and hours spent trying to figure out why the computer chokes - and I'm told that it's because FI is more "efficient". Efficient where? Certainly not my wallet! Granted, maybe some smog police check every little thing, for me, I don't think they'd know the difference, unless I failed the sniffer. So 9 months later, I'm thinking I'll go to carb, so that I can actually drive my car, instead of watch it rot in the driveway.

But before I jump off the bandwagon here, in an effort to make an informed decision, I'd simply like to know - what is the point?

 

You sound frustrated, Im sorry you haven't had good reasults yet. The most expensive mods I have done (headers and complete exhaust, posi and gears etc) had nothing to doe with TBI, a tuned port or carbed car would have needed them anyway. Some people do the mods and dont seem to get the same results as others. It has to be in the tuning some how. I have been lucky I guess with every mod I have made. I picked up 2 MPH in the 1/4 with just a $ 20 open element air cleaner (my first mod). I helped my neighbor kid put headers and 3" exhaust on his car. Made a custom chip for him and his otherwise bone stock RS with LO3, 700R4 and 2:73 rear end picked up 1.5 seconds 0 to 60 and 8 MPH in the 1/4 mile.

My car ran in the 14.90s at 95mph with ehaust gears and LT1 cam( with no chip tunning). I know thats not fast, but stock it traped at 82 MPH.

If its a tuning issue maybe you will get it sorted out and start enjoying some gains.

There are alot of things I like about FI over carbs and I'm even older then you (46).Sucessfully worked with carbs when I was younger but I won't go back.

 

The point of tuning TBI for me is that TBI is all I can afford. I bought my car for $1600. There is no way I could have bought a TPI car for that. And why, because it's fun. TBI is easier than TPI, that's how I look at it. It's fun to modify cars, no matter what kind it is.

 

I guess that if I could actually find anyone that would even attempt to burn some chips, for under $500, and before the sun burns out, I might would have some hope. But everywhere I turn, chip burning costs more than bolting on a carb, and when I give in and pay for it, no one actually does anything - they let me sit and wonder for months on end, and then I find out they did nothing yet. To top it off, all the "rod builders" I know of around here tell me it won't happen anyway, that you just can't mod the chip enough to make the computer like the mods, so there's no guarantee.

I understand how to make a motor run - but the task of getting someone else to make an old, obsolete computer chip think that IT knows how to make a motor run is a world I don't have the patience for.

I think the smog tester in NC won't even notice carb or TBI, as long as it passes. And any carb car ought to pass, if tuned properly. What major anything will I lose by going carb?

 

www.tbichips.com , he only charges like $100 for custom chips, just send his some data and tell him your mods.

 

Been there, done that - 2 months wasted waiting on him. He was nice enough to refund my cash, but no farther ahead in endeavor to actually drive my car.

 

Are you logging and reviewing data using WINALDL or similar?
S-D

 

TBI I hear is the easiest and cheapest FI to tune. Plus it's used in a ton of GM vehicles. The 305ci matter however is a discresionary idea that many people would rather swap a 350 for... not me! I'm poor!

 

hey camaronewbie


Give mark riley a call at turbo tune in greensboro. he is a very good tuner on all kinds of modded FI cars. (336 378-1252)

he also has a chassis dyno too

I have known mark for yrs and he is a great tuner.

 

I do TBI or fuel injection in general because not everyone can do it. I learned how motors worked with a scewdriver and a box full of jets. Now I learn even more with a laptop. I like TBI because I'm the limitation, not the ECM. It's a challenge thats why alot of us do it. I had a perfectly running 13 sec car with a carb. I slapped a tbi on it and it would barely run. Now that I have it figured out I have a 13 sec car that gets 4 mpg better fuel millage, starts up no problem, and I can scare the hell outta the importers with the laptop on the front seat. The look on their face is worth it all.

 

its a matter of control.

that is the ONLY advantage of EFI.


if you have the knowlage, and are willing to take the inital hit to the wallet, you have more control over the fueling and spark of your motor then you can have with a mechanical setup.


for example, im taking a rather HUGE hit to the wallet in a diffrent manifold, injectors, fuel pump, laptop, harness, ect.... to run multipoint EFI on my 400SBC.. i could have gotten away with spending under $70... i mean i HAD the carb, intake, and HEI already ( i sold them now...)


but.... i wanted to run boost.. and i want absolute control over the fueling and spark of the motor...



to be totally honest, the economy diff between a WELL TUNED carb and a good TBI is almost nill.. and if you dont want(or need) the control over the motor, then you dont need to keep it.


am i saying you should swap to carb? no.. choice is entirely up to you.

since you already spent the cash, i think your best bet right now is to sit down and learn this stuff for yourself... its all very basic and simple.... its just that there are so many basic parts that overall it appears complex and bewildering... but if you concentrate and learn how it works, it becomes much easier.


EFI in itself is not more efficent. EFI is nothing more then a way to have more control over the motor... it takes a person tuning the car and setting the fuel just right and the spark where the motor wants it to make the motor efficent.


just like a carbed guy at the strip can take 4 tenths off by tuning it, it takes a EFI guy to tune his car.. the only diff is you type in the numbers in the computer instead of pulling jets from a box.

 

i came close to swapping the TBI to carb.
i dont know what the result would have been. entighten me as to the cost and the areas that need the changes done to swap to carb. are they carb, linkage, air cleaner, fuel pump? how about tach, spedo?
spark is ecu controlled. how to manage spark or change it without burning chips(assume a modded engine)? what about sensors that feedback to ECU from the TB's. like TPS? i see some issues here.
seems the conversion may not be cheap either.

 

same air cleaner.
linkage is similar, but probly needs some work depending on manifold.

need carb manifold,

keep fuel pump, use a 3 port regulator to keep a carb happy fuel pressure.

get a non computer controled HEI OR burn a chip to run the computer for spark only.


all the gauges run off seperate sensors... except the electric speed on 90+ camaros and whatever birds have elec speedos. they need the ECM to buffer the VSS signal.


its not really that hard.... if you have a 4bbl manifold (with adapter) and a open element already, all you really have to do is swap the TBI for carb, put the regulator in, and drop in a diffrent dizzy.

 

Sorry to say this, but if you won't tune the ECU yourself get a carb. There is no point in keeping the TBI setup if you don't have emissions and you are not willing to tune it. Paying 500 a pop or even 100 bucks a pop is gonna add up really quick.

 

Ive always been with fuel injection cars, and Ive never had any problems with them. One thing about fuel injection is that the computer only knows as much as you tell it and not a drop more. In some ways you have to know how to work ont eh computers terms. Kind of annoying but once you get used to it, its really neat to see what you can get out of the car, and all of it is for free, the only cost is the time to set it up. Both me and my brother had teh same motor in our cars. His had a holley and Vac advance distributer, and mine has EFI. My car could run circles around his, hands down. The efi allows for alot of very precise tuning so you can get teh most out of a setup, even a crappy low output V8 with a 2.25 in exaust like my car. Hell, Ive grown to like it so much Ive even taught myself some motorola assy. so I can increase my computers capabilities. One of the major downfalls, though, is that you have to be on the computers terms, and understand some engine theory as well, which is hard, and understandably, some people are turned off by it.

 

Your brother didn't have his car setup right. Carbs are very good for performance.

 

what you said about EFI and carbs performing the same is not exactly true. There are some setups where the differences would be small but in a setup like mine the difference is huge. I [i]have[i] tuned the carb extensively, datalog, have a wideband, etc. Does it run good? Well, its ok at the strip but driving around town I have to watch my rpms constantly and use that as a guide to know whether or not I can punch it. You cannot make vacuum signal appear when there is none and pump shot can only do so much. I allready have about the largest pump shot volume and squirter combination I can go short of custom machining the carb body. Maybe a double pumper would cure this but then I suspect my mileage would go to crap since the rate of opening doesnt change the amount of added pump shot and if you open slowly you dont need alot of pump shot. Maybe Im wrong, anyone wanna loan me a dbl pumper?

You are completely right about the control though, with a carb you are at the mercy of just 4 jets and the factory tailored fuel curve that is set by varying the sizes of the airbleeds and fuel passages, emulsion tubes, etc. Can you make adjustments? yes.. but its much harder to make consistent adjustments than it is with efi, carbs have a little bit of voodoo to them. For example, my carb starts to go rich at 5700 + rpm. changing Jets just changes across the board. So whats a guy to do other than just live with it or take chances drilling air bleeds. I also for the life of me cannot get it to be rich enough from 3500-5000 rpm. The primary jets are allready so big that part throttle is on the rich side and i had to make my own custom rods with an extreme step down to the power step which is like needle thin. Can I fix it? maybe... it will probably take a whole lot of trial and error though. With FI i just crack open the laptop and add more fuel to the cells involved, super straight forward

I have run TBI on this engine with essentially the same setup. IT wasnt tuned right for WOT but part throttle response was excellent. I never had to worry about what rpm I was at and all i had to do was turn the key and boom the car was on (granted my current carb had no choke)

If i could only get the injectors to fire during crank now I would be ecstatic and this is where carbs are at the advantage. I have been chasing this problem for weeks trying to get EFI running again and I cannot find a reason why its not. With a carb if there is a problem its going to be right there in the carb and everything is completely straight forward in its function. You dont have to worry about stuff from left field like intermittent shorts, radio interference, static electricity, solar flares, the coriolis effect etc messing you up

You can also just bolt a carb on and do nothing and chances are its going to run allright. With TBI if you just bolted it on to a hot 350 and did nothing it would run like total crap

 

No, your definatly right about the pump shot. Too much at low rpms and loads can drown the motor in gas and it stumbles. Having the MAP and TPS AE is very useful.

 

Well, I appreciate all the input. I understand the arguements, and I'm still trying to keep TBI. It's hard when you can't do the chips yourself. Everyone says chips are easy - but I spent the last month reading, and questioning, and looking, and I don't see how I could do it myself.

I downloaded the TunerPro software. I figured out enough mechanical stuff to do the mods myself - that's mechanics - it's something I can see, feel, smell, and hit with a big hammer. With chips, way more learning than I realistically have the time or patience for - and there's nothing to hit with the big hammer! So I'll leave all that to someone else.

Same guy still has my car, still insists he's gonna get a chip for me that works, still insists it's not gonna cost me over $200, and still insists that it won't take him much longer, so I'll let him have at it for a few more weeks. Maybe for kicks - if all that happens, someday I'll spend the time and effort to learn it, and more finely tune it myself.

I think it's great that the rest of you have the time, the money, the patience to do this programming & tuning. For me - I haven't drove my car in 9 months now, and it IS supposed to be my daily driver - I've completely worn out my 1984 Bronco II awaiting chip burns, and now I'm borrowing someone's car - I just want to be done with the Camaro project, and move on to the Bronco project - a 302/C4 combo (NO CPU!!!) with 6" lift and nasty big meats to bang around in the woods and on the beach.

That project will never happen either - regardless of my determination, nothing ever gets finished in my life. But we all have to have our false hopes to hold on to!

Thanks again for the input!

 

One thing is that you really wont truly start learning untill you actually get a few chips done. Then you can see how it all works. Thats when the learning really starts. Another thing about tuning is that you can collect all the data you need while you jsut drive the car. Get a cheap POS laptop from ebay or a computer show, hook it up, and toss it in the corner while you drive to work, or go do some shopping, or what have you. When you finally get some time, look at the data and any notes that you might have scribbled down in windows note pad and then make the changes to the bin and go drive some more. If you get stuck, just ask some questions. Someone here is bound to know the answer.

 

Couldn't have said it any better myself.
Tuning yourself with the equipment I use would cost under $220. Pocket programmer and Craig Moate's flash prom adaptor (replaced eproms with flashprom). TunerPro to tune, winaldl to log, bingo bango you've got everything you need to change anything in the calibration.
Carbs are great, I just wish the ccc's were Holley .
A carb is great for somebody that hasn't got the time to tune EFI or doesn't drive the car daily. For most of us, driving these cars is a daily deal and the price of gas isn't going to come down.... so pucker up and save with highway mode being already evoked in your EFI .

 

You know....I could ask the same question about TPI. It's extremely expensive, and is limited just like TBI in many ways. The real question is...why do we mod these cars period?

Why, I'll tell you why...CUZ WE LOVE THEM!

 

Another option would be to get a holley 950 commander and harness. Use that to control your TBI. That way you can tune it on the fly and have tech support from holley.