Multi-Port EFI discussion...

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Green79Scottsdale

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One of the things I would like to do to my truck someday is install fuel injection. I have done some research on the subject but still feel under-educated on things. Maybe you guys can offer your point of views and experiences on the matter.

I know I want the system I end up going with to be a multi-port type system. The throttle body systems just seem to much like a carburetor to be worth going to. There is better technology out there, so no throttle body type systems. The other thing that I hear a lot about is using factory systems for the parts availability. Being able to get a part at almost any parts store in the country is a plus. Since this would be going on a "traditional" small block that means I would be looking at the TPI, LT-1, or Vortec induction systems.

TPI : I know the reputation for being good on torque and running out of steam at a certain rpm. Seems like it would be good for a truck. I had a TPI Corvette and can attest to the claims. Also I understand you can go to a different computer to utilize sequential injector firing instead of bank firing, and ODB2 tuning.

LT-1 : Reverse flow cooling and Opti-Spark are the biggest thing with these. I am more concerned with the cooling part of it. Don't know the operating range or if it would be good for trucks.

Vortec : Don't know much about this. Claims say it is just as good as TPI for torque. Have heard about the "spider assembly", I believe that has to with the injectors? Don't know about tuning or anything else either. Also I assume it requires using Vortec heads.

I am considering aftermarket systems also. "Self-learning" systems intrigue me due to the fact I don't really need to know tuning. They are expensive, but I would still go with them if they are "better" than factory systems.

Howell : Uses all GM components. Parts availability on par with stock systems? Sounds good to me. Probably my first choice for aftermarket kit.

FAST, Holley, Edelbrock, Accel : They all offer some sort of system, some several different versions. Company specific computer and electronics, at least as far as I know.

Chevrolet PP Ram Jet : I don't hear much about this. Probably because you do not get a controller with it, you must source your own. When you get a crate motor with this system, it is only tuned to that specific motor. Also requires Vortec heads I believe. Not really interested at this point, but could be convinced otherwise.

What have you guys done? Which route would you take? What are your views on anything? This is all up for discussion.

I will not be doing something like this until I rebuild my engine. I do not see that happening anytime soon, unless I find another 400 block I could rebuild in the meantime. I was thinking about building something along the lines of the GM 383HT motor. 9:1 compression, similar cam (if not that cam, but that would mean a roller cam retrofit) and heads along the same lines. Discussion of engine details should be done in a different thread as I am only interested in the induction system in this thread.
 

89Suburban

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8T6K5

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Im far from experienced here either and like you, the more I read, the more I get cornfused.

I have a TPI 350 now that will be needing a rebuild soon.

Yes, the TPI, designed for a 305, isnt suited for a high rev'ing application. Depending on mod's will die around 4500rpm's.....perfect for a K5 DD-weekend trail rig imho.

Im looking for a 400 block (standard bore if possible - a 406 would'nt hurt), Vortec heads, aftermarket manifold and just swap everything over. Seems to be a very cost effective swap..in my particular case.

I see decent TPI set-up's, complete w/ECM-harness on CL locally for as little as $200. Just add block-heads-machine work and new manifold :)
 

Green79Scottsdale

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I have been running that same combo through my head too 8T6K5. I agree it would be a great set-up for your K5, and really any fullsize truck. We probably spend what, 5% (if that) of our time driving near that 4500rpm mark. And it's not like the motor just losses ALL power at that point, it really more just starts to decline slowly. I already have the 400 part of the equation, I just need the induction part of it. I have been watching TPI set-up's also and see them around $300-$350 complete. I just wasn't sure how the TPI compared to the Vortec and/or after market set-ups.

I have the luxury of starting with a clean slate and thought I might post some of my research conclusions here and have some guys give their thoughts and correct any thinking of mine that is wrong or skewed.
 

oneluckypops

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TPI= Nice reliability, Hard to find at times.

LT1= Is a hell of a set up, I'm sure it could do really well in a truck, IF you delete the Optispark.

Vortec= Is a reliable setup and proven in the trucks, Yes they have issues with the spider (injector), but they do have the conversion for them.
Or you could go all out and do the Marine manifold conversion, it is a true Multiport injection setup.


But if your gonna go with a factory setup and your not gonna do anything untill you rebuild the motor, Why not just do a 6.0L swap
 

MrMarty51

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I see decent TPI set-up's, complete w/ECM-harness on CL locally for as little as $200. Just add block-heads-machine work and new manifold :)
I would be interested in one of these systems if You could post up an add for them,even if they are priced a bit higher.
Thanks
 

Green79Scottsdale

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But if your gonna go with a factory setup and your not gonna do anything untill you rebuild the motor, Why not just do a 6.0L swap

You make a very good point. I can not dispute that. I guess I am more or less feeling out my options. I go back and forth between keeping it carb'd, to injecting the factory small block, to doing a 6.0L swap.
 

Green79Scottsdale

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Why not just do a 6.0L swap

I have thought about this. I guess I would counter with, why do a 6.0 swap? Everyone and their grandma is doing this swap. I am just going to stick with the "traditional" small block. I can take the couple thousand dollars it would take to do the 6.0 swap and put on a brand new EFI system on my motor. The best would be to be able to do an EFI system on a budget simply to have the manners EFI provides. And honestly, for the amount of miles I actually put on my truck (right now less than 1000 a year), even doing an EFI system is probably not worth it. Doing an LS swap is not going to happen with this truck. Now on my Monte it's a different story...
 

oneluckypops

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I have thought about this. I guess I would counter with, why do a 6.0 swap? Everyone and their grandma is doing this swap. I am just going to stick with the "traditional" small block. I can take the couple thousand dollars it would take to do the 6.0 swap and put on a brand new EFI system on my motor. The best would be to be able to do an EFI system on a budget simply to have the manners EFI provides. And honestly, for the amount of miles I actually put on my truck (right now less than 1000 a year), even doing an EFI system is probably not worth it. Doing an LS swap is not going to happen with this truck. Now on my Monte it's a different story...

First let me say it is ulimatley your decision to make, It doesnt make a difference to me either which way. BUT IMHO I beleive the newer OEM fuel injection would be a better choice for interchange, reliability, and honestly efficency. Even the oiling system is much more improved over the traditional sytle motors. WHICH IMO is another reson why GM motors today will run for so many miles with proper oil changes.

But again the decision is totally yours... I am just stating what I would do.
 

supercharged

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Just finished read your thread.
It just so happens that the combo you mention, a 383 stroker like the hp33.
I have one here from ATK awaiting the Holley Avenger MPFI system next week I hope.
Suposed to be good for 1000cfm and this motor will never need more than that.
Besides the crazy price, seemed like our best option for an after market system.
This is going in a 85 GMC shortbox .
I dont know of anyone around here that has this setup .
Now just need to decide on headers and mufflers.
Well and a whole pile of other items.
 

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