Jump to content
HybridZ

TPI Swapping question


Recommended Posts

if you get all sensors,the wireing harness,ecu,and the manifold and all other parts the swap to any standard 23 deg sbc engine is fairly simple. ;)but be aware the standard TPI intake while great for torque and mileage in the idle to 4500 rpm range the air flow falls of a cliff as far as flow and hp potential go above that rpm level.

Link to comment
Share on other sites

Guest Anonymous

Yes-you will have to take a die grinder and reshape the center 4 intake bolt holes on the tpi manifold to fit the early head. The mounting angle is different between post 1986 heads and earlier ones. The factory wire harness is difficult to work with and I would recommend you consider a painless harness if you can afford it, along with a new prom that does not have the VATS anti theft codes. These two items will set you back about 400 bucks. Be prepared for the loss of top end power you will have with the tpi versus a four barrel carb set up. They pull great at low rpms but there is nothing above 4500 rpm. I put my tpi setup on my 1970 chevy half ton truck with the original 350 where it performs very well in this heavier vehicle.

 

The conversion is a lot of work especially if you have to convert to a high pressure efi fuel pump-the in-line pumps are fussy (they dont like to pump from a tank that is below 1/4 full) and cost about 100-200 bucks. The in-tank fuel pump set up is the way to go if you can afford the conversion.

 

You will also need to upgrade the injectors if you are going from a 305 to a 350ci engine.

 

Good luck-

Link to comment
Share on other sites

Well I guess no is as good a time as any to as some more questions. First im getting the whole running engine possibly with trans for about 300 bucks. About the intake does it fit or not looks like I already have 2 different opinions. also this is a 350 tpi and not a 305 I was just wondering if it would be better to put it on a different engine and forget the one Its on. My hopes are to get a very reliable 280-300 hp to the wheels and get fair gas mileage and highway driveability. As this will be an everyday driver I was hoping to have the fuel injection. Are there any aftermarket intakes that would give a little more top end power. How about a cam or other upgrades. Thanks alot guys

Link to comment
Share on other sites

its very possible to get around 300hp with a tpi, just cant go too radical with it and expect a 5k redline. there are a lot of upgrades for the intake for everything from throttle bodys, bored lower intakes, bigger runners, etc. etc. i have a tpi firebird and i love the tpi, they do run like trucks though, no top end. im still contemplating tpi, but relate it like this, tpi is like an electric two barrell carb in terms of flow and power band. on a mild setup i think it still kicks butt. any other oem setup is lt1 or ls1, much more expensive but more top end potential out of them, but way more expensive and exclusive only to those motors.

Link to comment
Share on other sites

nitrous wont give you a higher redline, it will make you hit that lower redline faster though. with the tpi youre torque peak comes on a lot faster than a four barrell setup on a mild motor, thats what they make, torque, not hp, im sure if you modded tb, ported all the plenums, airfoil, siamesed runners you would get maybe 6k, im not sure about that though. im going to tpi probably, and then upgrade to the holley stealthram later on once everything is wired up and running for a while.

Link to comment
Share on other sites

Originally posted by TonyM:

[QB]Yes-you will have to take a die grinder and reshape the center 4 intake bolt holes on the tpi manifold to fit the early head. The mounting angle is different between post 1986 heads and earlier ones. (TRUE on TBI but not TPI)

 

TPI intakes did not come factory installed on the newer heads with the 4 center bolts set at the new angle like the vortec heads have,all TPI intakes fit the older head port and bolt pattern just fine. TBI intakes did come that way though.

 

. The factory wire harness is difficult to work with and I would recommend you consider a painless harness if you can afford it, along with a new prom that does not have the VATS anti theft codes. These two items will set you back about 400 bucks. Be prepared for the loss of top end power you will have with the tpi versus a four barrel carb set up.The conversion is a lot of work especially if you have to convert to a high pressure efi fuel pump-the in-line pumps are fussy (they dont like to pump from a tank that is below 1/4 full) and cost about 100-200 bucks. The in-tank fuel pump set up is the way to go if you can afford the conversion (very good advise but the factory wiring can be made to work)

 

You will also need to upgrade the injectors if you are going from a 305 to a 350ci engine.

THE ECU will alter the fuel/air map/injector pulse width enough to run ok with the stock 305 injectors if you stay under 350hp

Link to comment
Share on other sites

If you are unfamiliar with EFI, as I was, using the factory harness will give you a very good education. Take it one component at a time and it's not that difficult. You will learn a lot about how it works and have some chance at trobleshooting down the road. Make sure you get everything including the fan and fuel pump relays and the VATS box.

Link to comment
Share on other sites

just polished the tpi intake on my firebird, in the car the old fashioned way. im slowly deleting all the emissions equipment as we speak and learning what is what, its still a pig though, but fun. its the posi man, posi. posi. i plan to use the stock harness if i can, really clean up the intake and possible powder coat it gunmetal or good old hugger orange, and drive it out to work out the bugs, then possibly swap the manifold out for one of those stealthrams, maybe.

Link to comment
Share on other sites

Guest Anonymous

Grumpyvette-In response to your comment about the 4 center bolt holes, I was just relating what i had to do to get a good alignment when installing a 1992 Corvette TPI on 1986 heads. The bolt hole alignment angle was different in my particular case, but 10 minutes with a die grinder was all I needed to fix that. I imagine that most TPI manifolds bolt right up to earlier heads without this modification.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...