Inliners International Forums General Discussion Hi Performance Carb to TBI advice/answers /HELP

I've been considering converting my son's 250 from carb, Holley 390, to TBI. Also, anticipate addition of low boost turbo setup after getting the TBI operational.
Our goals are to increase mileage, cold weather operability and performance.
1st, what can we expect in terms of mileage gains and cold weather operability with a TBI setup?
2nd, what are our options for donor throttle bodies, fuel pump, etc? 2.8, 4.3, 5.0, 5.7 and what years/chassis?
3rd, what distributor do I have to run for it to be ecu controlled (is there one available?)

The Megasquirt II appears to be our best option, but are there any other options that comparable for performance and/or better pricing? And whatever system we choose it will have to be compatible with the turbo. I've been on the DIYAutotune site and the install of the MS2 with the relay board appears to be relatively staright forward, but is somewhat pricey.

As always, looking for all suggestions and input. Thanks in advance. Jim

I would go with port injection and a dry intake. You have to come up with a way to install the injectors right at the intake/cylinder-head gasket surface but in the long run I think you will have a much better running engine. There is lots of megasquirt info out there, keep reading. On this site there is a thread where the guy machines and installs injector bungs on a 4bbl intake.

There is a lot on this site about TBI conversions. Here are links to a demo efidiy and I did at Bonneville in '08. I was working on a TBI/Turbo 292 that never got finished. It was a fun project that was sidelined by mandatory projects. (life) I built a Megasquirt and got an old laptop to run it. I did more work on the laptop than I did on the truck. MS had to be done in Windows and I use a MAC. I have pics of the MS build also. It was very intimidating at first but not really hard, just lots of little pieces.

The link I used was "Help needed to change 4 piles into 1" ( a bad choice for the topic) If you click on my name and then on my posts it shows up on the 12th page of my posts. There is a lot of BS there but a lot of good stuff too. Also check the posts of others who posted on that thread like efidiy, dice man, and others whose posts indicate they were working on TBI projects. This is a strange way to search a site but our search engine here sucks. When efidiy put the TBI on my '53 pickup with a GMC 270 it was running in less than an hour. We had a vacuum leak, a fuel leak, lots of wind and it was getting dark so we quit before we got a good tune. I put the carb back on by borrowed flashlight. I will finish this when other projects get out of the way. I'll stick with TBI because it is so easy and plenty good enough for the street. Mechanically it is like adapting a carb. You need an electric fuel pump and a return line, and a few wires. Hope this helps. Beater
292

TBI/TURBO

Megasquirt

TBI conversion donor

TBIConversion Pix

Beater.. that was a while back when we did the KOA conversion....

For folks that missed it, we did a parking lot conversion to TBI literally in the KOA campground. this was also the first time Tom and myself met too..

If all goes well I'll be at Bville in Aug for speed week. time to finish the TBI project.. This time though you know what its about so all the BS items that went wrong can be addressed before you leave home. Put everything together as it will be installed then drive down on the carb.

It you have everything ready except the TBI installed. Drive done - swap the TBI on and it'll be running in 30 min's. I have 250 tune up from TX saved so its a minor tweak.

That sounds good to me. I could have the '53 ready for "Round 2" by August. The original plan for my MS was the 292 in the '68 flatbed but The '53 is pretty well set up still. I can easily set it up for a more permanent conversion. That 250 tune will be close to the needs of my 270.