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Piece together TBI set up or go carb?

nvrenuf said:
Are there any upgrades for the throttle body itself that I should consider? Bigger injectors? Adjustable regulator? Etc...
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Certainly an adjustable regulator will make it easier to tune. Not sure on injectors, but they do offer higher capacity versions if needed. You can also do the throttle body spacer and some other stuff that is supposed to boost power. I've heard headers are actually the biggest bang for the buck. If you did go with TBI, its nice that you can start out stock and throw as much money as you want at it to get more power.

One thing that might add to the cost/value consideration with a carb is the cam selection. Better check into that.
 
While this isn't a crazy motor, it's far from stock. I'm running a .566 lift roller cam and both Howell & Eagle Mark say its no problem.

Does tbi ever exceed 15 psi of pressure? I'm currently using a 15 lbs gauge and it would be nice to keep it.
 
nvrenuf said:
Does tbi ever exceed 15 psi of pressure? I'm currently using a 15 lbs gauge and it would be nice to keep it.
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Yes it can. Mine is set to and runs well at about 16psi and I only have a 350 with the only significant modification being corvette exhaust manifolds. I've read people needing up to 18psi if you have a motor that can really breathe.

Edit: You might be able to use bigger injectors and lower fuel pressure, that's a total wild guess though.
 
The pumps seem to be the limiting factor. Just went through this on my Dad's 454, it was incapable of providing enough fuel to be "safe" under load. I adjusted the stock FPR about 8 times, as it requires partial disassembly/reassembly of the TB each time, until I ended up with the spring at a hair less than coil bind. Could never get the pumps to put out more than 14PSI. Got it up 2PSI, which was enough, but would have liked a few more.

From what I've read, the TPI pumps from Camaro's are recommended, that way you don't ever have to worry about the pump becoming the limiting factor.
 
I run a Walbro 255 replacement for a TPI Camaro and love it... 13.8 rock steady all the time..
 
Is the tpi pump internal or external? If internal does it mount on the same bracket as the tbi pump?

What model camaro would use tpi? --- never mind, I see ryoken's part number. Thanks!
 
internal... exact replacement for TBI pumps.... they run about $125...
 
Avery4jc said:
If you play the what if game you'll never go anywhere. As with anything prepare as best you can but in the end you can't carry a spare truck. :D
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I could not have said this any better. I have met too many people who think this way, and they end up being the people who never get anything done on their truck and usually end up selling it and playing fantacy football their whole life and not ever really living life :haha:
 
I replaced a pump on my old '88 IROC Camaro, TPI engine, the pump motor unit looked identical to the one in my Burb. TPI ones run a bit more pressure, I don't remember right off, but I know it's not 15psi.

Looks like and it does sound familiar, that the TPI setup runs at about 50psi. Might be a bit more than needed, obviously, make sure you have a good return line.. :-P
 
Kay86K5 said:
I could not have said this any better. I have met too many people who think this way, and they end up being the people who never get anything done on their truck and usually end up selling it and playing fantacy football their whole life and not ever really living life :haha:
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That hurts. To be fair, the whole overland thing is geared toward being resistant to failures and simple/adaptable. I assume you carry tools and commonly broken parts if you go far from home? There's a compromise I think, and having a spare computer in your box doesn't seem unreasonable. As far as this thread goes, I'm just saying that I'd bias toward a factory stock setup.
 
4xcrazy said:
I replaced a pump on my old '88 IROC Camaro, TPI engine, the pump motor unit looked identical to the one in my Burb. TPI ones run a bit more pressure, I don't remember right off, but I know it's not 15psi.

Looks like and it does sound familiar, that the TPI setup runs at about 50psi. Might be a bit more than needed, obviously, make sure you have a good return line.. :-P
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all MPI systems generally run 40 to 45 psi.. the walbro runs about 45...
 
Mastiff said:
That hurts. To be fair, the whole overland thing is geared toward being resistant to failures and simple/adaptable. I assume you carry tools and commonly broken parts if you go far from home? There's a compromise I think, and having a spare computer in your box doesn't seem unreasonable. As far as this thread goes, I'm just saying that I'd bias toward a factory stock setup.
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Didn't mean to affend. And didn't make my comment to single you out and say that you are like that, I was just saying to majority of the people I have seen with that type of attitude tend to do that. And I have to say, everyone knows that ujoints/axle shafts ect... go when out wheeling. That is why they are a common thing to carry. We carry tools/extra parts that have historically gone bad when out. I have to say that I have never met someone who carries an extra computer for fear that it will go on them. Not saying that the possibility isn't there, but like Avery4jc said, you can't carry an extra truck with you. If something odd goes like that, than just do what you need to do to get it home and fix it then. That's all we were saying

End hijack
 
nvrenuf said:
I've got a decently built, carb'd 454 that, like everybody, I'd like to convert to fuel injection but, like everybody, I haven't had the money for a kit.

I have a ('90) 454 throttle body and computer and a little research suggests that I may be able to complete this with a $325 Howell harness and $150 custom chip (+ sensors).

That said, is tbi worth it? With so many fancy kits on the market most folks frown at tbi but surely it's better than a carb, right? Some local folks have suggested that tbi is too restrictive and say I'd better just as well off with a nice SMI or Jet q-jet. Could this be right? Doesn't seem possible to me.

Motor specs;
454
Unmodified 781 heads (2.06, 1.72 valves)
Edelbrock Performer intake
~9.4 comp
Hyd roller cam (.566, 215 @ .050, 110 cl)
Shorty headers, single 3" exhaust
MSD distributor, 6al box and coil

I'm inclined to get the harness and chip without ignition and use my MSD parts however it was also suggested using the tbi ESC would be a superior option. Really?

I'm tbi illiterate and appreciate any advice you guys have on this. I have more questions but lets get thru this post first. :D
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Get the harness if you have the money, if you have more time and enjoy projects then build a stand alone harness from a TBI truck. But forget the chip with harness, here's an example.
http://coloradok5.com/forums/showthread.php?t=309306

TPI pump can be internal or external. With your cam you will be fine with the BB TB and injectors but will probably need 15-16 PSI to feed enough fuel at WOT high RPM. So yes to adjustable regulator.

Don't take out some of the best features of a TBI system like the distributor and ESC with knock sensor!

As far as reliability? You've got to be kidding me if you have any doubt these factory TBI systems are not reliable... people have issues and half are man made, the other half is usually simple fix from old parts or more and more cheap parts. When you buy parts like sensors who cars if it has a lifetime warrenty? I don't want to replace parts for a lifetime!

So you hear of issues? What about the other millions that just wore out and went to JY without ever having one single failure from the TBI EFI system?

My 1990 Suburban has 150k miles and every single part of the TBI EFI is factory installed! Even the fuel pump!

Take a factory stock TBI truck and unplug all the senors and pull the chip out of the ECM! Guess what happens? It still runs, although not that great but still runs in Limp Home Mode!
 
eagle mark said:
Don't take out some of the best features of a TBI system like the distributor and ESC with knock sensor!
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I thought I read somewhere that 454's didn't use a knock sensor? I could be mistaken. :dunno:
 
I don't run a knock sensor on my TBI swap and it runs smooth as silk...
 
nvrenuf said:
I thought I read somewhere that 454's didn't use a knock sensor? I could be mistaken. :dunno:
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Some did and some didn't. What I've seen is that from about '87 to '89, the knock sensor and ESC wiring was deleted. The '90 or '91 and up harnesses I've worked with have all had knock sensors. They also used different harnesses and ECMs to run the 4L80E transmission thru '92.
 
eagle mark said:
As far as reliability? You've got to be kidding me if you have any doubt these factory TBI systems are not reliable... people have issues and half are man made, the other half is usually simple fix from old parts or more and more cheap parts. When you buy parts like sensors who cars if it has a lifetime warrenty? I don't want to replace parts for a lifetime!

So you hear of issues? What about the other millions that just wore out and went to JY without ever having one single failure from the TBI EFI system?

My 1990 Suburban has 150k miles and every single part of the TBI EFI is factory installed! Even the fuel pump!

Take a factory stock TBI truck and unplug all the senors and pull the chip out of the ECM! Guess what happens? It still runs, although not that great but still runs in Limp Home Mode!
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Amen brother!!
 
+1 for fuel injection!

Although I went with TPI and not TBI, fuel injection is one of the best things I have done to my Blazer. I pieced my setup together, but got all new sensor initially. It has been mostly trouble free since I put it all together.
 
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