Z06 FAN

Just wondering why people have went from TPI to carb? Were you having TPI problems, if so what were they? I am having some problems with a 87 Iroc I purchased and am on the fence about going carb. Most of the problems are probably not TPI related. I will be removing the engine soon to rebuild or replace and need to either go the carb route or keep the TPI.

redneckjoe

i guess its preferance? i just like the reliability of a carbed car. parts are generally a little cheaper too. tpi will get better milage. fuel injected cars usually require computer tuning after heavy mods. emissions might be another consideration or keeping the car original? the main reason i went to carb was, my car had a stock 305 in it & i had a mild built, carbed 350 sitting around. not a fan of breaking down on the side of the road cause the in tank electric fuelpump died or some electrical glitch, or bad 25+ year old wiring. JMO, im old school. lol

travis401

iTrader: (1)

the answer to that question would depend on what issues youre having. if its something simple to fix, then going carb doesnt make sense. it also depends on your budget. going carb isnt cheap unless you score some nice deals.

youll need a new intake manifold, the carb itself, new distributor, have to wire all that in yourself and then theres the carb tuning, because left face it, you cant just throw a carb on there and expect it to run 100% right. and if you have an auto trans, then you have to either rig a TCC lockup, or buy a kit to do it for you.

then theres the legality issues. going from tpi to carb is illegal, regardless of emissions testing in your state (im assuming youre in the us here). it a federal crime to remove any factory installed emssions equipment, which you would do swapping on the carb.

Kevin Vandevenne

iTrader: (3)

I converted a 91 GTA over to a carb setup and in the end I regretted doing it. When I started the swap, I was more focused on building a strip/street car. By the time I had the swap all done, my priorities changed, and I really just wanted a car to cruise in. The carb setup proved to be more of a head ache than the TPI setup had ever been. I really don't have anything against carbs, and wouldn't have a problem with a carbed powered car if i either started with a carbed car to begin with, or was building a car from scratch/rolling chasis. I'd don't think I would ever convert an FI car over to carb again though.

soarestransam

carb is alot easier to work on in my point of view less headache from all the sensors an engine light going on dont need to pay attention to all the wiring an bologna the tpi has dont have to deal with emission poop but one thing good about the tpi is gas mileage when i had tpi i use to get 200 miles on a full tank crusing now with the carb im getting around 102 to a full tank

Aaron_SK

iTrader: (1)

This is such a fantastic post that I cannot stop laughing. I thank you, Sir.

leejo2005

200 cruising miles is pretty poor. 100 doubly so.

On average I get 315 on my TPI 305 with aftermarket cam, heads and 3.7 gears through a T5. I don't consider it to be all that impressive. It's only 20mpg or so.

Johnny Blaze

iTrader: (15)

Me too. Went drag racing, put a big block in it. Now I want a good street car again, and can't sell this one. KJeeping it carb'd now, but I wish I still had the stelth ram set up.

Z06 FAN

Thanks for the responses, I have been on the fence since I bought my 87 iroc a couple weeks ago. I'm just going thru everything now trying to get my Factory TPI running the way it should.

InfernalVortex

iTrader: (4)

The only reason I switched from TBI to carb (It would have been the same with TPI, though) was because I was upgrading to my 350. I make more power with the carb than I could with TPI. I think TBI could match the carb performance if all the planets aligned properly and I got all the correct parts, good intake, etc, and a good tune on the TBI. But thats a bit of a stretch.

But the only reason I'd switch would be for a high powered engine swap. I cant stand the idea of paying $3-$6k for a nice 350 and having some factory fuel injection system keeping me from getting the power I already paid for. Carbs will remedy that, but you'll pay more for gas.

When I first put the carb on the car I couldnt ever get it to run quite right. After learning to tweak on it bit by bit over the last couple of years I've got it running pretty damn good. When it's warm it runs and drives just as well as a fuel injected car. And when something goes wrong and it doesnt crank, it's pretty damn easy to figure out why.

I wouldn't switch from factory EFI to a carb on a stock engine. And I wouldnt switch back to any factory Gen I/II EFI system if you paid me to do it because I'm not going to leave my high RPM power on the table. When I switch to a Gen III motor in several years, I'll try to convert it back over to EFI then, since the GenIII efi systems are so much better.

I would, however, consider those LS1 PCM conversions for Gen I blocks and running a carb intake with the fuel rails and $500 overpriced throttle bodies, but that's more expensive than a Gen III engine swap.

lightningZ

I switched my 91 Z28 over to carb this past winter and removed the smog pump, to clean up the engine bay but am having a hard time finding a smaller pulley for the tensioner. the stock one is just barely too big of diameter to fit over my new serpentine belt. If the belt is smaller it wont fit, if its bigger it has too much slack and rubs itself below. I need help!! Any suggestions on where to find a custom pulley. I tried ebay, napa and tsc.. no luck!

travis401

iTrader: (1)

ditching the smog pump on the serp system doesnt require any new pulleys. it requires you to route the belt a little differently and a different sized belt.
https://www.thirdgen.org/serpentine

oil pan 4

iTrader: (1)

If you go carb the only way you are going to get it close to working as well as TPI is to get a rod and jet set, tune with a wide band air fuel meter, vacuum gauge and tachometer.

travis401

iTrader: (1)

agreed, carb tuning requires some work, just throwing a carb out of the box on will get it running, but not nearly as well as it can. if you get a holley carb, theres a great sticky on carb tuning.

lightningZ

thanks for the article/photos. Are there descriptions for the 3 photos? the first looks stock except a dummy pulley in the place of the smog pump even though it doesnt seem to contact the belt? The second looks like my final goal, but is the the 968K6 belt or a different size? and the third looks cool but is lacking a power steering pump.. i want to keep ps and ac. Any help appreciated

travis401

iTrader: (1)

i found that the 98.6" belt is just a tad too long and doesnt let the tensioner pulley operate in its full range of motion. i run a 98" belt and it fits perfect.
in case you didnt know the numbers on the belt are how long it is. 986k6 stands for a 98.6" 6 ribbed belt. I kept ps and ac as well. you cant remove the ac and smog pump and still run the serp system without an ac or smog delete pulley.

lightningZ

so your 98.0" belt is run like which picture from the link, the top view im guessing? or if you could post a pic of your cars engine bay with all the accessories and im assuming you are still using your stock pulley and not having rubbing issues where tensioner comes down and where the belt runs from the water pump to the ac? lots of questions i know.. lol thank you

travis401

iTrader: (1)

ive got the engine bay taped up at the moment so i cant snap any pics of it. but yea, my 98" belt is ran exactly like the pic with the ac and p/s and i dont have any issues with rubbing.

racerquinny

iTrader: (1)

i just bought an 87' trans am. the motor prolly was tpi or tbi. it has wires and connectors everywhere. the guy who swapped it didnt do a good job of seeing which wire went where. im guessing he just wanted to get it running. i have some electrical problems..

1.my dash lights do not work, i got them to work for atleast 45 secs then they turned off again..it happened again.
2.i have no horn...no power goign to the wires.
3. i guess the guy didnt want any heat so he ripped out the blower motor box, the motor is there. the wires are cut going to it (purple wire) i bought a resistor..but i need the purple wire to power the motor.

heres my wireing...


heres the trans am i picked up for $500

travis401

iTrader: (1)

if youre asking for help on the wiring issues, id suggest starting a new thread with the symptoms in the electronics or engine swap forums.

one92rs

iTrader: (5)

unless you or someone you know is decent with carbs you are going to have a couple aheadaches with it. i went from tbi to carb and liked it at first. but got really tired of having to change the carb tuning to weather.

lightningZ

ok thanks travis youve been a big help buddy. ill post pics soon