383-406 tpi motors whos running them

[Greenmachine-1970]

Been tossing around the idea of a tpi fully ported w/high flow runners on top of my 400sbc i want to build since i have everything to do it.Gonna go into my 70 c10 4x4. Wondering if any one had some real world experiance with a combo like the one im thinking about. Love to see any ones set ups or input. Thanks.

[Captainfab]

Several years ago we tried a TPI on my son's '85 IROC with a 406. After several months of trying, we gave up and put a carb on it. We never could get it running right, even with a high dollar ($575) chip from the 'experts'.

I'm not saying it can't be done, just that we didn't have good luck at all. I think you would have better luck with either a 0411 PCM or one of the many aftermarket ECU's available these days. Also, you need to be careful in your cam selection. Go with a EFI compatable cam, that will make the tuning easier.

[Greenmachine-1970]

Originally Posted by Captainfab

Several years ago we tried a TPI on my son's '85 IROC with a 406. After several months of trying, we gave up and put a carb on it. We never could get it running right, even with a high dollar ($575) chip from the 'experts'.

I'm not saying it can't be done, just that we didn't have good luck at all. I think you would have better luck with either a 0411 PCM or one of the many aftermarket ECU's available these days. Also, you need to be careful in your cam selection. Go with a EFI compatable cam, that will make the tuning easier.

I have a ez efi self tuneing ez efi retrofit system for tpi right now wich is by no means plug n play like they say. I think with a little tweaking i could get it to work i think. But i know that ive read many times that tune port engines arent the easiest to tune. What exactally was the problems with your set up?

[Orange Crate]

Greenmachine- that system is a huge advantage over the other posted experience. It can be a struggle to try to use the stock EFI computer and harness in an earlier truck, but it sounds like you have one that learns as it goes. Most EFI today use an O2 sensor to close the loop on feed back to the computer, so you will most likely need to weld an O2 bung into your down tube from the exhaust manifold (or header collector if you have those). I'm finishing up on the fuel system for my TPI 406, so adding a high pressure pump and return line has taken some time. You don't always have to add a return line all the way back to the tank, you can use an Airtex fuel pump part number E8312 which has a return port right at the pump inlet, so you are routing the excess fuel right back into the pump. This makes your plumbing a little easier. Of course you'll also need to add an in line fuel filter. Bend up hard lines for fuel delivery or rout some high pressure flex lines with decent fittings (hose clamps will not be safe enough for reliable service, except maybe on your return line, but you really shouldn't use them there either, we are talking about high pressure fuel here!) Well good luck with your project and TAKE PIX and POST them!

[Greenmachine-1970]

Originally Posted by Orange Crate

Greenmachine- that system is a huge advantage over the other posted experience. It can be a struggle to try to use the stock EFI computer and harness in an earlier truck, but it sounds like you have one that learns as it goes. Most EFI today use an O2 sensor to close the loop on feed back to the computer, so you will most likely need to weld an O2 bung into your down tube from the exhaust manifold (or header collector if you have those). I'm finishing up on the fuel system for my TPI 406, so adding a high pressure pump and return line has taken some time. You don't always have to add a return line all the way back to the tank, you can use an Airtex fuel pump part number E8312 which has a return port right at the pump inlet, so you are routing the excess fuel right back into the pump. This makes your plumbing a little easier. Of course you'll also need to add an in line fuel filter. Bend up hard lines for fuel delivery or rout some high pressure flex lines with decent fittings (hose clamps will not be safe enough for reliable service, except maybe on your return line, but you really shouldn't use them there either, we are talking about high pressure fuel here!) Well good luck with your project and TAKE PIX and POST them!

Orange crate i already have all the fuel system in place from a previous attempt with the efi system. After talking to tech and other people i think i can sort out the problems. The directions F.A.S.T. Gives you are for their throttle body set up. I made a couple huge mistakes setting it up. From talking to other people they seemed to have done the same thing having the same problems i had. That being said i will do a step by step build thread on the system as i reinstall the system seein as ez efi never made a specific set of instuctions for their kit fot the tpi. As a return line i used a existing line i belive it went to the charcoal canister im not 100% sure but it was right by the factory fuel line on the frame and went back to the tank and all hard line and efi rated hose and fittings. The 400 is still a ways out right now so when i get time its going back on my 350. I was just curious how people liked a big inch tpi in a bigger vehicle like ours mine being a 4x4 with 33" tires. I know the third gen guys dont favor them much cuz they dont rev to the moon. Thats why i was looking for a little feed back here. Good luck with your build im looking forward to hearing your results when you get it up and running.

[Captainfab]

The source of the problem that we had was the chip in the OEM ECM. That is why I suggested a different route for the ECU. If you already have the FAST controller, you should be heading in the right direction. The TPI's were meant for low to mid range power. This is what you need in a truck, particularily a 4x4. Of course you will need to upgrade the injectors to match the HP output of your 406. A better throttle body would be a nice upgrade as well.

[Orange Crate]

Greenmachine- Here is an article to keep the motivation high and to kick the nay sayers in the shins....Ha! There a some Debbie Downers on this board and they'll keep making suggestions about how bad TPI is but, a stock TPI on a 383 is capable of 500ftlbs of torque and 400hp, but some people might classify that as low power....the FAST system is a great start.

http://xtremecarzone.com.au/index.php?showtopic=386

[Greenmachine-1970]

Orange crate- i have read that article before and i belive super chevy had one called "L98 stealth mode" with similar results as the high flowing runner builds. Id be estatic with a any one of those builds numbers. I never planned to build a 406 but i happened upon a few blocks one free virgin block from my dad and another virgin one i picked up for 200bucks i just couldnt pass up. I got the tpi long before i got the blocks to put on my 350 for a few reasons 1st the carb was cutting out on steep inclines,2nd the driveability,3rd the reliability. Then i got the 400 blocks and its just been evolveing from there. I came here hoping i wasnt the only one inspired by those articles and some one would have some real world feed back on a similar combo. Thanks for all the replies so far guys!

[Greenmachine-1970]

Captinfap- i didnt know the factory computer was that bad im glad you told me incase the ez efi still gives me problems which it shouldnt knowing what i know now but if it dose for some reason i deffinantly wont go that way. I have 30# venom injectors and a throttle body is defiantly on the list as well as a aftermarket base and runners which im planning on haveing ported as well as the plenum. I dont think to much aiflow is a issue for me here lol. Ill probbably need all i can get. Thanks for the reply.

[siggyfreud]

Nothing wrong with a factory ecm with the right tune. Just a lot of bad tuners out there. You're really going to want a wide band to dial it in. The advantage of some aftermarket computers is they can use the wideband directly, which the stock computers won't.

[siggyfreud]

Depending on your power goals those 30 lb injectors might be a tad small. 400 HP could put you close to max duty cycle.