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View Full Version : TPI INJECTION SHOULD should i have any concerns?


jnyblazer
02-27-2013, 09:55 PM
it has a bored out gm thottle body,and 42.2lb brand new injectors some porting done, the guy who has this is a tuner and program it up to get it running for stock 350 till i can get up to him to get it all perfectly tuned, he is asking 450 for what you see, computer is easy find, and he will make a custom wiring harness for me with all the extra stuff cut out and simplified+plus labled , has anyone done this convertion before and how did you find it[cheers]

epic3
02-27-2013, 10:14 PM
thats a good deal

jnyblazer
02-27-2013, 10:20 PM
thats a good deal


we if it will work on my block i would be happy, just want to but the intake assemble and throw it on the shelf, and start collecting the parts to go fuel injection#yeah

jnyblazer
02-27-2013, 10:20 PM
buy***

Kingblazer84
02-27-2013, 10:51 PM
Here's some info

TPI is cool, but its a pain to convert to, Stuff you will have to decide- what year intake manifold your are planning to use, stock tpi manifolds will not bolt up to vortec heads, and 87 and up differ from the rest due to the angle of the intake bolts, then you have the cold start injector, plus you have to decide if you are going to run a MAF or Speed Density system. The main problem I found with TPI is that a stock plenum is saturated with air at 4500 rpm, remember GM never designed this system with 350 ci in mind. Large Cams will work with Speed Density systems, but remember tpi is for torque not horsepower so pic a cam with 5500rpm max in mind with no more than 230 degrees duration. The cam I had in mine was a edlebrock, it had 244 degrees duration at .050, i have ported heads and plenum, bored out Throttle body (stock bore size is 48mm, mine is 53.5 mm maximum sized before you go through the casting-- but when I bored mine out I paid close attention and cut the butterflies with less clearance than stock, if i could go back I would not do this, and I tig welded the upper vacuum port, it helped a little but not really worth all the trouble) plus free flowing exhaust.. Arizona Speed and Marine, Street and Performance, PCM's for less all of these places can hook you up with the computer. My advice is that if you are ever planning to build a TPI engine that makes more than 350 hp go with the Holley Stealth Ram.. It flows way better than the stock unit.. When you start on your fuel system, dont waste your time with the 155lph pump, get a Walbro 255lph, get the largest diameter fuel line you can run and get a good Fuel pressure Regulator, my 87 TPI ran about 44 psi, my 91 TPI ran north of 49psi.. TPI engines typically run better with 55-60 psi fuel pressure. If I were doing this on a budget, I would pic a Speed density setup, use the small cap remote coil distributor and for a healthy 350, better just put a set of 30 lbs/hr injectors in it (you can find those in olds quad 4 engines, 36lb hour are in the GTP s/c 3.8's and if your really goin for the gold I've found 42 lb/hr inj in mazda Rotary) just remember that larger injectors are not always needed, and when you switch up to them you need to have the computer tuned to run them, it WILL run without being tuned but it will be unpredictable, and run rich. Oh and when it comes time for exhaust, be sure to hunt down a set of Lt-1 exhaust manifolds, theyre cast tubular headers that bolt right up and allow you a bit more power over stock tpi exhaust manifolds plus easy installation and a b*** to put the O2 sensor in..If you want a better cheaper way, another route is to snag a TPI intake off an Lt-1 and have the back machined to allow a distributor to drop in, you will have to drill out the intake bolts h***s(center) and i cant remember but there are a few more mods(cooling) that must be done to run on a GEN I sbc.. The advantage to this is that its short runners allow 6500rpm plus power, its identical to the TPIS's mini-ram (which is like over 800 bucks).. Man, ive been rambling on here for a bit, sorry, Im not trying to be D*** Britannica about TPI.. If you need more info or have questions holler at me or Will Burton..

Kingblazer84
02-27-2013, 10:55 PM
http://www.hotrodlane.cc/NewTPI%20links%20page/TPI%20links%20page.html#tpitech

jnyblazer
02-27-2013, 11:04 PM
wow thanks bro, what i have is a newer two bolt main block i believe he said this manifold was off 95 truck 383 the guy is a tuner, so that part is covered,i bought the world industries 2.02 steel heads, and its fully rollered flat top pistons, and a mild rv cam, i would like to go for this, i think it would be a interesting build, and yes i would need some help for sure, do you think it will fit my block?

85chevy
02-27-2013, 11:04 PM
Save ur money and buy a newer EFI system a lot of compelete kits and easier to program

jnyblazer
02-27-2013, 11:16 PM
Save ur money and buy a newer EFI system a lot of compelete kits and easier to program


just trying to work with the block i have and if i can pull it off for cheap it would be nice

m j
02-28-2013, 06:41 AM
the block has nothing to do with the swap.
the intake bolts to the heads. so you need to know what heads you have in regards to intake bolt pattern
chevy changed the pattern to be more like fords :)

4skin
03-01-2013, 02:23 AM
and how much is he charging you for this harness and then figure out your fuel pump lines o2 sensor computer and getting the computer programed
and you have a old injection system that is limited by design
and then look at a fast eziefi or something similar
now compare prices between a used old patched together system that will only work on that motor
and a system that is all new is easily programed by you not paying some one to do it and if you change heads or go big block you plop it on your intake and spend ten minutes tuning it
and personal experience with fast is they stand behind there stuff
yes the initial cost at once hurts but you really need to look at cost of a piece here a piece there and figure if you spend 8 hrs chasing down a fitting or the right computer what is your time worth
or you open the box up start puting it together and under 8 hrs its running
just a opinon