need some insight on tpi conversion

**95tahoepos** · 05-28-2012, 09:55 AM

ok so in earlier posts i was talking about putting some vortec heads and a cam in my tahoe for a nice bump in power. BUT the "tim taylor syndrome" got to me once again when i found a tpi intake in my garage that i completely forgot about. now i dont know much about chevys but im not new to working on cars. i have built a few 400+ hp turbo hondas,so i know all about tuning and how sensors work.
so correct me if i am wrong. when slapping a tpi intake on there instead of the tbi unit i should be able to run it with a tune on the tbi ecm correct? the way i figure it is basically like adding different injectors. take a look at everything on the tbi manifold/throttle body. the only difference other than the ever so long intake runners and that extremely attractive plenum and throttle body is the injectors right?
so for honda you can swap out your factory 120cc crap injectors for some massive 1600cc injectors to make you able to spin the living **** out of your enormous turbo. so why can i do the same for the tpi setup.... only no turbo and 22lb/hr injectors?
if im wrong let me know cause ive never gotten into tuning a chevy but this seems very possible given my back ground.
always see people pushing the info that you HAVE to change the whole friggin harness. but the only reason i see you absolutely needing the old harness and ecm is due to the 700r4. well pardon my french but **** a 700r4. my 4l60 is good enough. but if push comes to shove i have the complete tpi kit intake with all sensors distributor 700r4 complete wire harness from front bumper to rear and ecm even have the 145mph guage cluster. so either way im doing this.
it only depends on how.
so lets here some ideas on tuning hardware/software. i would take the easy way out and just swap the harness but i will need to tune anyways due to the vortec heads and the big cam. btw i candyno if need be too, which will most likely happen no matter what.

**95tahoepos** · 05-28-2012, 10:06 AM

ok forgot to mention the tahoe is 95 so obd1, dont know exact ecm # but its the one it came with from factory, 4x4, 5.7, 4l60e. just need some good advise on how to tune this pig.
ps , yes i know i need higher psi pump.

**Fast305** · 05-28-2012, 10:36 AM

The cost of the lower intake manifold for Vortec heads might scare you away from this swap. Having done this swap, I can tell you I want more top-end HP out of my setup. I will most likely be swapping back to an Edelbrock Victor Jr. 2bbl vortec intake and TBI.

**95tahoepos** · 05-28-2012, 10:56 AM

yeah i know its $450. im not scared. i already got the heads, ordered the cam and the tpi is free basically so im only into this $300 and some change. another $450 plus a fuel pump and some tuning goodies...... no problem.
my main concern is how to tune it. i was looking at some injector charts and it looks like if i just put in the high pressure pump and a regulator and hook up the wide band i should be able to handle it. dont know if i will need to change timing curves tho. timing is a big part in what im used to so....
what do you think?

**Doober** · 05-28-2012, 11:21 AM

You'll need larger runners too to take advantage of top end too. TPI makes more torque than conventional intakes, and I say it's totally doable. Build a ~9.5:1 383 if you so desire and make a torque monster out of it... somewhere between 210-220 on the intake will make for a great street engine.

www.dynamicefi.com

Bob is excellent for tech support, and you can piggyback another ECM with the 4L60E, or simply bolt in a non-electronic trans and do away with the extra ECM. That way you can just run a stock TPI TV (similar to kickdown, but proper adjustment is crucial to trans life) cable. I have the EBL on a 383 with Vortecs and a mild Comp cam. Driveability is no different from a stock truck (mainly due to the cam choice I'm sure) and torque is awesome, but I think I'll be upping the cam when funds/time are available.

**95tahoepos** · 05-28-2012, 11:31 AM

hey i was actually talking to you the other day about a new cam. i ended up ordering that bare bones even tho that other guy told me it was too big.
im not gonna build up displacment right now i want keep the 350 cause im lazy and dont want to pull the engine back out. atleast for right now it stays a 350.
so you think with fuel pressure regulator high flow pump and a wideband i should be ok? or is it pretty much a piggy back or stand alone or kaboom?

**jim_in_dorris** · 05-28-2012, 10:27 PM

If you aren't afraid of tuning, do the memcal and injector driver mods to your existing ECM (soldering required), then (I assume you have a $0d ECM) make the code mods including the changes to timing for the vortec heads and grin. No piggyback needed. If you use the search feature, you will find that fast has documented everything you need to do.

**Doober** · 05-29-2012, 06:53 AM

With TPI you can change injectors instead of messing with fuel pressure, that makes things easier far as fueling goes. I have a stock Vortec pump in mine and so far it's holding up, but you may need aftermarket since you'll be using higher pressure. I would definitely get a wideband, and the EBL is capable of port injection so you won't have to burn any chips.

**Fast305** · 06-04-2012, 08:32 PM

Originally Posted by Doober

With TPI you can change injectors instead of messing with fuel pressure, that makes things easier far as fueling goes. I have a stock Vortec pump in mine and so far it's holding up, but you may need aftermarket since you'll be using higher pressure. I would definitely get a wideband, and the EBL is capable of port injection so you won't have to burn any chips.

I wouldn't worry about the stock Vortec pump much, being that it is the very same pump GM ships with the Ramjet 502 crate engine.