I have a TBI engine I'm in the middle of tuning. I don't drive the vehicle very often and I'm tired of tuning. I've heard from countless engine builders and mechanics that the TBI's are junk and I should stop wasting my time, money, and gas, and switch to a carb.

I have a larger TBI with larger injectors for my 350, but they all say this isn't enough. The dyno software I have says TBI and carbs produce similar power, but before I get crazy and start cutting up a perfectly good wire harness and selling parts of my engine for pennies on the dollar, I want to know who has done the swap, and if you're happy with the results.

Obviously the TBI in it's original state leaves much to be desired, but I've done things to mine (larger, more fuel, tuning, etc.) so I'm wondering if anyone has swapped from a "modified" TBI to a carb and if they liked the results.

 

i had a tbi 305. i did all there was to do to the tbi. but i never had it tuned. kept running rich as hell. so i did the swap. been driving on it for some time now and would never go back.

 

I am about 90% done and would never go back (well really cant I deleted 90% of the wireing harness)

 

I switched to a carb 3 years ago, when I put in my 350. I had a 1990 TBI car that I did everything to, I ported/polished 416 heads, 1 size larger intake valves, LT1 cam, headers, better intake, gutted cat, VaFPR, 1.6:1 Roller tip rockers, dual snorkel - I did it all. But, in the end I couldn't get anyone to program a chip to make it all work, and I don't have the skills to do it. So, I ended up with a very rich running car that just barely ran - I could feel the potential there, but could never access it - the ECM held me back.

So, when I got the 1992 (and they lifted the emissions requirements in my state), I knew carb was for me - carb ran out of the box with very little tuning, and for me, it's great, because I can take a dist. wrench and a pocket knife and tune my car in 5 minutes if/when needed (and it's never needed unless I change something). It's old school, but it works - and it makes me happy because I can do it without relying on anyone else, or a bunch of programming I don't understand.

 

I do program the ECM, and it's not hard to figure out WOT tuning. You tune the fuel for the most performance, then you tune the spark, then fuel again and that's about all you have. Everything below WOT (where you actually drive 99% of the time) is a little more tricky. Then you throw in curve ***** like bigger injectors, or a VAFPR and things start to get a lot more complicated.

Camaronewbie and one92RS, you guys never had a tune done, so you left a lot on the table. It's no different than doing all the mods and leaving an untuned 2-barrel on there. It's not going to be all it can be.

Rick1805, is it driveable at 90% done? Why wouldn't you go back?

I read a post last night on here from Fast305 that said he would never go back to a carb from TBI. He's heavily involved in the tuning forum and seems to know his $hit, but he is also a WAY better tuner than I am.

I'm still not sure what to do.

All of the people (outside of the forums) that told me to ditch the TBI are older guys, (though they are engine builders and mechanics). I'm not ragging on the old guys, but sometimes people just don't know what they don't know and since they are from the carb era, it still makes me wonder if their suggestions aren't biased. Having said that, race cars are mostly carbureted, so chalk another one up for carbs.

I'm getting anxious because my "toy" is sitting in the garage because I can't tune it well enough to pass emissions. A "carb guy" told me he could get it to pass if I swapped to a carb. He has a 454 with a roller cam, ported heads, headers and no cats...and he passes emissions with flying colors. I've seen him do it.

 

Oh yeah - I agree - it was rough at best. I did get a chip tuned - several in fact. I tried the TBIchips.com guy, and after 3 months of never hearing from him, I gave up. Then a local guy tried his hand at it, and got her at least running again, but it was way rich, and although you could just 'feel' the potential, he couldn't get it tuned out into the open - but at least it was driveable again.

And I'm the first to admit that I myself did not have the time, patience, etc. to try my hand at it. I used to do computer programming and used to love it - but I guess at heart I'm old school, and love turning the wrenches (even in the rain) over spending hours in front of the computer number crunching.

Kudos to the guys that do it - it's just not for me. You gotta enjoy what you're doing - that's the most important part - it's your ride, love it your way. And thus my pick of carb over EFI.

 

Like Nike says..Just Do It!!!

you wont be disspointed

 

i have done a lot of tuning on ls1's with hp tuners. sold it all when i got rid of my 2002 silvy with a 5.3 running 12.79@108 with a 175 shot and 32* timing on and off the gas. im sure there was going to be a lot more with tuning. i wasnt going to repair the egr and emissions. plus the new engine i am going to drop in will go past what a tbi could do. and i didnt want to go with another fuel injectio system. im building a 355 vortec engine that is going to go in. and it is going to be carbed as well. so as with the problems i did not want to fix plus the fact the new engine will be carbed which is a lot cheaper than doing an aftermarket fuel injection system it was win win for me. now---if the ls1 bug hits me---i will do fuel injection then but that is a whole different animal.

 

TBIchips was a joke. Not that Brian doesn't know what he's doing, but after doing some tuning myself, there's no way you could tune a modified engine in any type of acceptable time frame.

Well, maybe I should "just do it". The worst that happens is I'm out of some money. I don't think I'll have any less HP/TQ with a carb. I don't really care that I can get in and go with EFI. I don't care about MPG for this application.

Guess I should start shopping.