I was sitting here pondering "why did GM make the L03 TBI". Most V6's of that era put out roughly the same power as the L03 and got better gas milleage so I was wondering if anyone has an answer to this so I can sleep better at night. I am not knocking this motor...just curious thats all.

BTW my TransAm aparently is sporting the L03.

 

Torque!!!

Steve

 

Torque is it, while the LO3 made only 30 more hp than the 3.1 v6 it makes something like 70 more lb/ft of torque

 

because the majority of BUYERS didnt care how much power it had, as long as it was a V8.

 

Also that was GM's fuel injection set-up to go on any vehicle. There are only a handlfull of types of FI and that was the cheapest, most reliable way of giving customers FI vehicles. You can see the development over the years. TBI went to multi port and that is where it has pretty much stayed. Every GM V6 today is some sort of multiport. Even the 4 bangers are. They are now getting into direct cylinder injection where fuel is introduced directly into the cylinder head and completely bypasses the manifold.

 

well.... that was later...


first they had the low output carbed models.... like the L03, the V6 was darn close in power, and there was another, better V8 you could get...

but people wanted a V8 and they bought it even with the power loss compared to the other V8...

GM only added TBI later on because of emissions reasons... they couldnt do waht they wanted with the computer controled carb, so the swapped to the cheapest EFI they had.

 

Yea I didn't mention that and assumed people knew that about the carbs. But GM used the TBI as its leap into the FI/emmisions market. What better way to do it than on the lowest V8 optioned camaro. If you wanted better you could get better (TPI) but it was a good base option none the less for its time and the LO3 was sorta a guiea pig with benifits (emmisons and fuel economy). They learned a lot from that injection set-up over the years and sold a boat load of reliable cars/trucks using it. Notice how the FI systems cars have today are incredibly reliable. We can thank our TBI forefathers for that

 

not to go agienst what you just said, but TBI was WELL into use before then...

think 82-83 crossfire cars..... or the late 70s early 80s single barrel TBI 4cyl cars....

the reason they didnt have EFI until 87 was cost.. carbs were cheaper... once they HAD to switch to meet ever tightening requirements, they did.

 

Yea I geuss I forgot about cross fire. But that was an exclusive system at the time. You are right though. If it weren't for the ealry 80's single TBI cars the carb would have hung around a little longer. What I should have said was, because of the early 80's TBI systems they were able to make TBI cheap enough to put it on practically every car in the late 80's and early 90's. TBI development peaked and replaced the carb (because of matched costs) when the LO3 rolled around, so hence why it got it. When the requirments changed then they started working on multi port systems and slowly strayed away from TBI.

 

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Thanks for answering my question.

 

There's a lot of reasons. The main factor being it's cheap and they could still market it as a v8, like said before. It has 2 injectors unlike the tpi's 8. The computer is more simple, it's more reliable. I believe tbi was a good option for the truck guys, especially for reliability and simplicity. There's a lot less parts to work with and generally they don't have as many problems as the more complicated tpi setup, so it's one less thing to worry about when pulling a load or offroading. They simply carried it over to the f body too. All in all, it's not a bad setup really. As you learn more you find out there's a lot more thing's hampering the L03's performance than the tbi system. I for one actually prefer it over other forms of fuel injection for those very reasons. I'm not exactly rich and the simplicity and cheapness enable me to spend my money elsewhere where it's really needed.

 

I agree completely and I lot of people overlook this. You can make your 305TBI extremely fun to drive just by getting rid of some of the crap GM attached to it. Well said 25thRSS

 

when you get down to it, TBIs are exactly like quadrajet carbs.


the initally get a really bad rap because the engine under them is a low output POS...
plus people like to blame them, because they can SEE them.. its right on top...




but like the quadrajet, the TBI can be made to perform respectivly, IF YOU KNOW HOW TO DO IT.
most people dont... theres thoes that get it to work ok... and then theres the elite few that get it to do amazing things that others have a hell of a time trying to copy.

most give up and go for the far easier to learn because its better documented TPI or carb route.


but anyhoo... no sence in kicking this very dead, decaying horse... i just wish i could drag it to the glue factory once and for all and be done with it.

 

It's funny, but I actually think this is the first post ever where I have agreed with EVERYTHING said. This is truly a great post.

 

One thing we all forgot, the SOUND of V8 POWER. Even though the stock exhaust is whisper quite.

Steve

 

OOO!! Marketing!! Yay!! My turn!! I know this one!!

A few people in this thread just about quoted the GM personell in charge of the F-Body production exactly. "They could market it as a V8." GM (Chevy especially) is known for selling vehicles to people looking for a car that is more of a status simbol than anything. Don't forget that even though you can pick up good condition third gen for under $4000 now, back in the 80s-early 90's these cars weren't the cheapest things on the road. Camaro's over the years have been targeted more towards the "Mid-Life Crisis" guys that fall in the "slightly more than breaking even" income bracket. As the IROC-Z and the Z28 were great to have, not everyone that wanted a Camaro needed all the extra stuff or saw all the extra power necessary. All they wanted was a V8 sports car to show off to the other guys in the office. Hmm...what does GM do? "Hey, we can make an LO3 for pennies on the dollar, stick it in ANY body package we want, and still sell it for a good couple $$!!"

Simply put, GM made a #&@*! load of money off of the LO3.

Bruce (90RS305)

 

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Do a search on TBI here in TGO. Your gonna get so many different threads, you should be able to hone in on just about any topic. But, if you can't find what your looking for, use the PM system or just make sure you post in the appropriate thread... *nudge*...

Bruce (90RS305)

 

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Lol, my bad... PM system

 

Josh, the stock tb is probably good to about 275hp, with larger injectors and the ult tbi mods, maybe a little more. If you wish to feed more hp then you would have to step up to a larger tb, turbo city makes a bored out tb but it's not as big as the 454 or Holley tb's. As fare as a good book for tbi, right here is the best one(TGO) I've found yet. Here on the tbi board you can find almost anything you'll need to know, either thur the search function or just asking about it. When you start to burn chips for your new engine, your questions can be answered here as well, if we can't answer the question then someone over on the diy-ecm board can. There is also a good read by Traxon on how to get started in chip burning at the top of the diy-ecm board as well. You should be able to get all you need to know here at TGO, if not I'm sure someone can send you in the right direction.

Steve

 

so is the L03 the name of the block?

I have been hearing alot of names being tossed around for GM Engines like L03 L06 L69 L98 WS6 LT1 LS1 LS6. Did GM call the 305 the L03 based on the block or is it based on the performance parts.

 

Not so much for the performance parts as for the complete engine package. L03 being the 305 tbi package, L69 is the 305HO carb pkg, LB9 is the 305 tpi pkg, L98 350tpi, L05 350 tbi and so on and so on...

Steve

 

so lets say I do that TPI swap ... does my engine become a LB9?

 

No. The LB9 is different from our engines because it came with better flowing heads, sometimes a bigger cam, better exhaust, and then the TPI system.

 

Yeah, you'd go from an LO3 to a faster....LO3....

Bruce (90RS305)

 

ok how can i change the tbi -tpi? is it expensive? i mean someone told me they would do it for $500 is that a good or bad price? kus if i can get 45 HP for 500.... umm yea u better no im gonna do it.... lol...thanx

 

Does that $500.00 include the whole tpi setup, manafold-injectors-ecm-wiring harness, and installation? If not you're looking at $700.00 to $1000.00 to get it up and running. Just depends on how much you can score a stock tpi system for.
For that much cash you could get that much or more out of your tbi system. Replace the heads, cam, intake and exhaust, do the ultimate tbi mods and a better air filter, that should get you a good running 305 with a little chip tuning. And just to let you know, if you just put a tpi setup on your engine with out any other mods you won't see the gains you hope to see. I wouldn't think you see any more than a 10 to 15hp gain and about 15 to 25lb-ft of torque if that much.

Steve

 

makes sense... ill look further into it.... thanx for the info before i blew the cash...