Hey every1, my buddy has a 91 RS Camaro with the LO3 305, i was just wondering, to switch from a TBI to TPI, i would need a new intake manifold, fuel rails, plenum and runners, is that right, i might have left some things out, not sure

 

Just a few other things...fuel pump, injectors, ECM, wiring harness or modify the TBI one, MEMCAL...

 

go into the TPI board and do a search there for info. Its been covered alot.

 

Its not even worth it to go through all that work for maybe 10 hp if that. Just stick with tbi and mod it.

 

yeah, definetely mod the engine before even thinking about switching injection systems. There are much more gains, at much more cost effectiveness to be found in modding the engine first. Then, If you really want to switch to TPI, go for it. Just keep in mind a stock TPI does not flow well past 4,500rpm, and it is costly to mod. You can make TBI breath much easier and cheaper. But if the money is there, mod the TPI and go for it.

 

10 horsepower? My dad gained 17 HP and 70 TQ at the rear wheels after swapping his 200,000 mile 305 TBI over to a TPI intake setup.

Stock TPI dies after 4500 RPMs? I have news for you. With the stock peanut cam, stock swirl port heads and stock intake airflow, TBI wont pull over 4000-4500 RPMs either.

Yes the TPI swap is VERY MUCH worth it. There is a tech article on this website on how to swap, however it isnt very good.

 

what else did you do to the car during the swap? And was that a stock tbi system?

 

dar, I think ya got me George:nono:
Did you forget read when I said I made my TBI breath to 5,500 with 1.6 rockers, intake manifold, msd blaster coil, open element, headers on back, and if you want, you can include underdrive pullies. Seems like a lot of modding, but I can tell you I picked up hella more than 17 hp, and probably ended up with about the same torque gains. And the cost of these mods combined is still less than what a TPI swap would have cost me.
Now if you want the L03, even with TPI on it, to breath past 4,500rpm, you are going to have to do mods similar to mine. So why not do them first while netting more gain? Then build up the tpi, ie runners, throttle body, intake, etc.-just be prepared to spend money.
Look into ALL of your options to make more power before just swapping injection systems. There are a lot out there, and you will be more satisfied with your gains if you utilize them before you swap your fuel injection.

 

I dont know what all you people are talking about, if you switch from a TBI to TPI, you should get a major gain in performance. The TBI 305 has 170 hp, the TPI 305 has up to 230. If you do it right you'll get a big improvement. I'm not just talking a basic swap, i mean the whole damn engine. Plus a TPI setup is a hundred times better than a TBI setup. Much better performance and response.

 

Mine revs to 5k easy with tpi before it seemed to slow down at 4k. i would recomend a good catback first before you do the tpi. The tpi will give you more power over the tbi threwout the powerband, and tons of low and mid range torque.

here is the dyno from my swap
http://bitchincamaro.no-ip.com/dyno.html

Also the throttle cable will need to be swaped along with the kickdown if u got an auto. If u can get the airbox from the car get that also. You can use the tbi distributer you just might have to repin the harness u get

Im going to get it dynoed agian when i get my headers i got a 3 inch catback on it now and also have a 3inch cat and cut-out waiting for the headers.

 

You gained 9 hp and about 38 tq by switching to tpi, but you also added underdrive pulleys, air foil, aluminum driveshaft, and slp cold air intake. You probably would have gained more hp by doing those mods on the tbi. 9 hp with all those mods plus tpi isnt very much man, and the hp falls off on the tpi before you hit 4,000 rpm, where as the tbi keeps gaining power past 4,000 rpm. TPI is a good setup and makes lots of torque, but it seems to me that tbi actually makes more hp and breathes up top better just by looking at your dyno graph.

 

Yup well there u go. Im going to put a 350 under it soon and didnt want to try and start a new motor on with a new fuel system so if i had problems i would just wash the startup loob right off.