Ditching the factory TBI

[bake315]

Hi everyone.

I have decided to ditch the TBI on my ‘87 R30.  I am looking at a couple of aftermarket options, including FiTech’s Go Street EFI 400HP System.  I already have a couple of questions in with them about things like whether my existing in-tank fuel pump system will provide enough pressure, and so forth.  What I am needing help with on y’all’s end is, what else am I going to need to account for?

Appreciate the help as always.  Hope everyone has made it through this past year safe and sound.

Bake315

[VileZambonie]

Why are you ditching the factory system?

[bake315]

Why are you ditching the factory system?

Hi Vile,

To be honest, I really didn’t want to.  My original plan had been to upgrade the heads, and keep the original TBI, though upgrading the intake (as much as you can, given the very limited choices there).  What I hadn’t counted on was the subtle difference between the stock heads and literally every other type out there.  Also, given that nobody makes an intake that works with this system and can use standard type heads, that left me with the sole option of attempting to modify an intake to fit the heads.

A considerable time back I had bought the new intake as I was planning out this whole deal (the Edelbrock one, the only other one is a Holley).  What I could have had no way of knowing all this time was that during the machining process for the EGR valve, they had cut too far into the top of the intake, and had penetrated into one of the passages beneath it.  I mean, who knew?  In fact, it was just through holding it up to a bright light that I was able to see where they had cut through it.  So now I have this brand-new-out-of-the-box intake that was damaged from the factory and could not be returned because the time permitted for returns/exchanged had come and gone.  So, not only am I having to try and modify the intake, I am having to repair it as well.

Anyhow, I have been trying to modify it using air and carbon steel cutting bits, and it has not gone well.  Besides taking an eternity, it looks like a complete butcher job, to the point where I have my doubts as to whether or not it will even work.  My truck has been idle and without an engine for over a year now, and I just want to be done with it.  Maybe it means throwing good money after bad, but frankly I consider that my penance for not realizing that GM screwed me (and I’m sure a host of other folks) when they made that little change).  So, I’m trying to get this engine off the stand, out of my garage, in my truck, and my truck back on the road, and before I spend another nickel of my hard-earned cash, I am trying to learn what sort of traps and pitfalls await me by ditching this TBI system and going with an aftermarket one.

Again, it was never my intent to change, but circumstances are now requiring me to, if I ever want to drive my truck again.

Now you know the whole sad, sordid tale of my past ineptitudes. lol. So, what am I going to have to do in order to make what I am trying to do, work?

[VileZambonie]

What is done to your engine? What intake are you trying to modify? Do you have to have EGR? TBI Adapters work great for opening up the choices on intake manifolds.

[bake315]

It was a pretty mild rebuild - block bored .030, flat top pistons

These heads:
https://www.summitracing.com/parts/sum-152123

This intake:
https://www.summitracing.com/parts/edl-3704

This cam:
https://www.summitracing.com/parts/sum-1102

All of this really was chosen in an effort to stay within the capabilities of the truck’s computer, while still giving some increased performance benefits.  Everything was supposed to more or less swap over from the old setup, but got stopped cold due to the intake foul up.

Since my truck is emissions exempt, and I live in a county that doesn’t check for it, I don’t need EGR, but wanted to leave it in the event it affected tuning being on there.  Of course, I then discovered my new heads don’t have an accommodation for it anyway,  so figured on leaving it off. Even still, there was still the issue of the machining error (hole).  All that’s a rather mangled piece of aluminum now, heading for the scrapyard.

You know, for some reason it never occurred to me that there was such an animal as an adapter for this (and in a world where everyone seems to make an adapter for nearly everything).  So let me ask you, then:  Based on what I have laid out here, which intake would you go with, and which adapter?

You’re saving my bacon (and my sanity)!  Can’t know how much I appreciate it!

[VileZambonie]

A dual plane intake that will fit your heads will work. I've never been impressed with the TBI manifolds so I've always used adapter plates for TBI's. A custom chip will improve performance allowing you to delete things you don't need as well. I'm a little confused on what was wrong with the intake you bought though? The EGR passage should loop the exhaust passage to the intake port. Sounds like it was correct, why did you start grinding it up? Don't go down a rabbit hole because of one blunder (pun intended).

[bake315]

In this case, the TBI intake I bought from Edelbrock was evidently designed to work with the stock ‘87 heads; the four center bolt holes were meant for bolts that are designed to go in more vertically.  They would not even come close to the existing holes on these new heads, which are canted the same way as the rest.  In addition to wallowing out the holes on the intake, both above and below, I have had to try digging out enough from the topside so that those four bolts would at least have a shot at seating flush against the manifold, so much so that I can’t see it sealing all that well (and it looks like garbage).  In my research on this with others who have been in this predicament, many have opted to just leaving those four holes vacant, which I found to be a little bit ridiculous.  The EGR passage had nowhere to go in the new heads, as they make no allowances for it.  This left the machining error from the factory, which the wiring in my brain made it difficult for me to contemplate repairing straight out of the box.  Between spending the coin on it, only to heavily modify and repair it in addition, well, let’s just say it was resulting in some short-circuiting up top. 

So I have been looking at the intakes...  Since we are dealing with a TBI and an adapter, it really wouldn’t matter whether the intake was a spread or a straight bore, correct?  Also, I noted that some of the adapters available are steel, and others are aluminum.  My gut is telling me aluminum would be better, but we know how far my gut has gotten me to this point...

Can you tell me a little more about the custom chips?  Thanks!

[VileZambonie]

Well, new intake sounds like your best bet if you are keeping those heads. I've used both aluminum and steel, I even made my last adapter, so whatever works. Google TBI Chips

PS one of these is great https://www.summitracing.com/parts/anm-01800001320?seid=srese1&gclid=CjwKCAjwx6WDBhBQEiwA_dP8reR6VHHkKbBrYRlJwhW6njaGY7i_Mn6-A6SFpz-lP3Dp2igPM5LkNhoCFvIQAvD_BwE

[bake315]

Sounds good.  Thanks again!