hey i need some info. do any of yall tpi guys know how hard it is to turn your car to tuned port instead of tbi. and do you know about how much this is going to cost me. if i get the plenum and base, etc. i would buy it used. is there any one that has a manual on how to make the swap? thanks.

 

Not really sure but I think you would need a new harness, ECM, chip and a few new sensors and injectors.
PAINLESS WIRING has two different harnessess one for MAF systems (1986-89) $286.95 and one for Speed Density systems (1990-UP) for $276.96 at Summit.Oh if you go for a MAF system you will need a MAF sensor $400 new don't know the junk yard price. I think the Speed Density sensor is much cheaper, don't know for sure.
The ECM (Electronic Control Module) you can get at a junk yard between $50 - $120. Just make sure you get the right year you need so you match it to the harness year.
The chip well it depends if you have any mods, cam and heads, if not sometimes when you get a ECM from the junk yard it has a chip in it, don't know if it is good.
Or get a custom one if you have mods $350 min! Or if no mods just order a performance from ADS or JET, don't really recommend this. Or go to the PROM board and learn how to program one. Either way it is a little expensive.
Injectors around $250 if you go with 24# injectors. Then you need a adjustable fuel pressure regulator (AFPR) ~$50 and a guage to set it ~$60. Oh only use 24# injectors on a 350 or larger! If you have a 305 then get 19# injectors and I don't have a price for them.
Sensors any where from $5 to $20 and how many depends on the system you choose MAF or Speed Density.

Can anyone back me up on this?

Good Luck!

 

I remember hearing about someone awhile back (when we had a nontech board) about someone who was working on a kit that would let you keep all your stock tbi wiring. Just splice in the 4 injector leads to the tbi injector wiring (tpi is batch fire anyway so i twon't matter).

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87 IROC-Z, 5.7, auto, 3.27, leather, !cat, Holley fpr, K&N'S, SLP 1-3/4" Jet-Hot coated headers, SLP .218/.224 .495/.502 cam, Comp 1.5 roller tip rockers, $uperPITAram, Edelbrock lower intake, Holley 52mm tb, Dynomax\Flowmaster catback. Coming Soon(?)- Fasttrack/Accell DFI

1989 Pontiac 20th Anniversary Turbo Trans Am - 160,000 miles, K&N filter

 

There is a tech article here on how to convert your car from TBI to TPI. Check it out.

My dad is converting his 92 RS to TPI and re-using the stock wire harness, by repinning it. But he's not making a kit.

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1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

DO NOT USE Painless Wiring unless you are going to cut a hole in the firewall behind the motor. I used the Speed Density harness, and I ran it through the factory passthrough behind the passanger side fender, and my wiring harness was now 3 feet to short. I had to cut it in half and solder in 3 feet of all the wires (about 20) not fun at all.

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ASE Master Tech + L1
Savannah, GA

'87 Trans Am
S/D TPI retrofit including functional PassKey,
22# injectors,
Ported Plenum,
TB Coolant Bypass,
SSM SFC,
Boxed LCAs,
8mm Accel wires,
Flowmaster Exhaust,
16" GTA rims,
Corvette Servo,
KYB Shocks

'97 Bonneville SSE

 

Email josephandres@aol.com
He's selling a TPI setup for $75 located in Jersey.

I also know a guy who has injectors for $75. They are 22lbs.



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'92 Formula
305 TPI 5speed
1LE package
Mods: SLP headers,SLP catback,SLP air foil,ported plenum,Crane AFPR (42psi),MSD6AL,homemade cold air,K&Ns,3:73s,JET fan switch, Macewen white face gauges...ZZ9 cam (i still have to install it )

 

try thirdgenparts in fl for a harness ...i got mine for $100 ...and again dont buy the painless wiring as its a pain
the tbi to tpi tech article is to speed density tpi not maf

 

yes there is a way of just splicing in to the tbi wires and run one for each side I have done this before. just run the left wire to the left bank and the right wire to the right bank. be sure to run each side parallel. not through each inj. or the increased load will hurt the ecm. use the vacum port on the back of the plenum for you map. it will really come down to just putting sensors in the new spot. I can't remember if I had to cut the wire for air temp to use the solid sensore or if the plug fit it well any ways it is not really that hard just think it through.