Hey, I noticed in your signature you have a 350 TPI RS...a lot of people talk the talk, but since you actually did the 350 TPI swap, I really wanted to ask you about it...I assume you started with an LO3...anyway, how much was your total cost? What are you thoughts on it? Was it hard? Would you recommend it? I've got an 89 RS with a tired 140k LO3...and I'm looking toward something else...gas mileage is a big deal for me, because I have a HUGE commute...1200 miles Thanks for any advice you could give. By the way, admins, sorry to put this under the Tech board, but I really want to get this guy's input, and I didn't see a non-tech board. Sorry to have it here!

 

Hey Baron. Actually, my signature is a little bit premature. I'm dropping the 350 in this spring hopefully. However, I can give you an idea of what you'll be facing costwise. I gave $500 for the TPI setup(air duct assembly and dual fans included), $200 for the engine harness and ecm,$75 for TPI fuel tank w/pump, and $700 for a running L98(got the exhaust manifolds, y-pipe, and 3 inch cat with it). Even though the motor was in running condition, I decided to rebuild it and freshen everything up, so I'll probably be into the motor at least another $800-$1000. The easiest way to keep the cost down on this swap is to buy a wrecked TPI car with a complete powertrain in it. I went the second best route and bought all the parts from a guy who was parting one out. In addition to all the parts I listed above, you'll want to make sure and get all the cables for the TPI(accelerator, TV if you have an auto, and cruise control). As far as how hard the swap will be, I don't think it's going to be that bad. One of the hairiest things is changing out all the wiring, but I'm going to change all that over while the motor is out, so there shouldn't be a whole lot in the way. The other thing that's a bit of a PITA is changing out the fuel tank of course. Just be real thorough about getting everything you need from the donor car. The best way to do this is to have your RS and the donor car side by side so you can compare everything. I made sure to get an 89 ecm/prom because of the VATS security system. I also noticed 87 and older wiring is slightly different(relays are different), so you'll want to shoot for 88-89 for your engine harness. My TPI unit came off an 88, so I had to block off the cold start injector(89 doesn't use it), but it was pretty simple to do. I made my own blockoff plate for the hole, and plugged the fitting in the back of the fuel rail by tapping the inside of it and screwing a stainless steel setscrew with teflon sealant into it. This is all easily reversible if you ever had the need for the ninth injector. As far as gas mileage goes, you can expect to lose a little mpg going to the TPI. Our TBI setups get incredible mileage for a V8. If you keep your TPI setup close to stock, you'll probably lose around 6-8 mpg. I took this into consideration, but I figure the slight mpg loss will be worth it for the increase in power, plus the TPI setup looks so good on an engine! Of course I don't have a 1200 mile commute either! If your biggest concern is optimum gas mileage, you're better off with the TBI. I've gotten close to 350 miles to a tank on the freeway with my L03. I even switched from 2.73 to 3.42 rearend gears, and the mileage was still awesome. If you decide to go ahead and do the swap, feel free to email me or post another ATTN for me on the board, and I'll be glad to assist with any questions you might have.


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89RS w/350 TPI; 69RS/SS w/450 HP 350/Muncie 4-Speed "Too weird to live, too rare to die."

 

Pat,

Thanks a bunch for the reply...I really appreciate all the detail you went into! I think from the sound of things I'm better off sticking with the ol' TBI for several reasons:

1. I'm so poor, when I go to KFC I have to lick other people's fingers.
2. I hardly was able to change tie rods and idler arm without running to my buddy for help.
3. I hate emptying my wallet to the A-rabs at the gas pump: the MPG really makes a difference!

I'm definitely going for full exhaust, STB, KYB shocks, waterproof the car , etc...but hey, thanks so much for the tips anyhow...and more power to you of you do it!! Keep me posted. Thanks again!

 

One other thing I'll never talk down the TBI systems about is their extreme reliability. My 305 TBI motor has 156,000 on it, and it still runs perfect. I think I'll keep that setup in mothballs after I put the 350 TPI in, just in case! The only major repair I've ever had to do to my TBI was replace the injector o-rings once.



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89RS w/350 TPI; 69RS/SS w/450 HP 350/Muncie 4-Speed "Too weird to live, too rare to die."