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Fuel Injection on my 75?

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Old Mar 4, 2012 | 11:18 PM
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Default Fuel Injection on my 75?

I know this will open a whole can of worms but I've just got to know.

How hard is it to put TBI or direct fuel injection on my 1975 350?

I've seen kits for the TBI for $1800.00.
I don't understand why the cost is so high with wrecking yards full of used parts.

The direct injection shouldn't be that hard and there are plenty of C-4's around for parts.

I'm not happy with the 2 Carbs. I've tried and the money for another Carb. may be better spent on injection.

It's just an idea that I've been kicking around for awhile, but I believe it's a good one.

Ralph
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Old Mar 5, 2012 | 08:05 AM
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Stock TBI or TPI is fine for stock power levels and both will generally bolt right up with minor fuel system and wiring challenges. If you don't mind a little DIY and can take your time I think a TBI system would be best. The computer and harness are simple for the late '80's early '90's truck and SUV TBI are easy to find and use and the computer can be reprogrammed for your application. The TPI stuff in the cars was more difficult to adapt. Besides you can put an open element air cleaner on the throttle body and get a close to stock look. Just keep in mind there are sensors and bungs and fuel pressure and things that have to be addressed or deleted.
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Old Mar 5, 2012 | 08:18 AM
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The up front cost of fuel injection are a little steep but well worth it. Once you go with fuel injection you will never look at a carb again. I know I won't want one on my car. I did this a few years ago with a Mass Flo system. Not cheap but my motor was heavily modded. It ran perfect all the time every time. I have since sold this and am swapping in an LS3 motor definitly keeping fuel injection. So yes it can be done but don't expect it to be a bargain but for the driveability factor it is a big difference.
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Old Mar 5, 2012 | 09:59 AM
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I am converting my 73 to F/I.

The cheapest way to do this while not losing power is get a 454 TBI unit and have it bored and rebuilt. Get a manifold that will fit with the TBI/Adapter under your hood. And get a Megasquirt to control the F/I system. You will also need the GM sensors but they are cheap for the GM TBI system.

All that can be done for less than $900 and uses GM sensors so if anything goes wrong just go to Advance/AZ and pick up a new one.
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Old Mar 5, 2012 | 10:09 AM
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Originally Posted by Marlin
I am converting my 73 to F/I.

The cheapest way to do this while not losing power is get a 454 TBI unit and have it bored and rebuilt. Get a manifold that will fit with the TBI/Adapter under your hood. And get a Megasquirt to control the F/I system. You will also need the GM sensors but they are cheap for the GM TBI system.

All that can be done for less than $900 and uses GM sensors so if anything goes wrong just go to Advance/AZ and pick up a new one.
From what I've read Megasquirt is like an electronics lab experiment. Is that the FI system you'll be using? If it works good I'd be willing to try and assemble one, but all I've read about it is "Yup, got it running, but now it's time to tune"
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Old Mar 5, 2012 | 10:15 AM
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^

You can buy it and put together yourself or buy prebuilt.

I am going to run a Micorsquirt. Its prebuilt and works with the idle valve I have. It would not work well for the GM TBI units due to the different Idle valve. The Megasquirt 2 works best, IMO, for the GM TBI.

Check out the MegaSquirt forums. Its worked so well some people in Britain copied the unit and used the MS software in it. They have been put out of business for their fraud but MS still is rokcing. They are up to version 3 now.

I’m very picky with what I use, but from reading; MS has been proven and has been out for over a decade with great success.

http://en.wikipedia.org/wiki/MegaSquirt
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Old Mar 5, 2012 | 11:46 AM
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If you have lots of 'extra' money, buy a new kit. If you don't, go the "used" TBI or TPI route.
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Old Mar 5, 2012 | 12:40 PM
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TPI is a great option-- plenty of complete systems with sensors available for cheap. The addition of an electric fuel pump doesn't require you to be a certified mechanic, and you'll have to add one for whatever FI injection option you choose. And I agree with Gordonm-- once you go FI, you won't want a carb in your garage. If I was keeping my boat I was even going to convert it to TBI.
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Old Mar 5, 2012 | 01:12 PM
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I found a complete setup for $120.00.
Computer, wires, TBI and manifold off a non vortec engine.
Not sure if the fuel pump is included.

So weld in an 02 fitting, and plumb in the pump, o2 sending unit and connect the dots?

Is it that easy?

Ralph

I have ZZ4 heads, Lunati 60102 cam, headers, dual exhaust and a performer manifold.
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Old Mar 5, 2012 | 01:19 PM
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Originally Posted by Ralphbf
I found a complete setup for $120.00.
Computer, wires, TBI and manifold off a non vortec engine.
Not sure if the fuel pump is included.

So weld in an 02 fitting, and plumb in the pump, o2 sending unit and connect the dots?

Is it that easy?

Ralph

I have ZZ4 heads, Lunati 60102 cam, headers, dual exhaust and a performer manifold.
That was a small block setup though right? If so it will run but limit your power.
The bore is small on those TBI units as they were meant for a low reving truck. You need to get a Big block TBI and even then it still needs to be bored if you want to make good power above 4000rpm.
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Old Mar 5, 2012 | 02:59 PM
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Thanks for the heads up on that.

What about the fuel pump? Is there a simple answer?

What RPM is the stock unit good to?

Will I need the Big Block computer to run the TBI?

How and how far does the TBI get bored?
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Old Mar 5, 2012 | 03:29 PM
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They still sell the Holley Pro-Jection system in TBI and it is $900-1000 IIRC.
I've been running that on my 81 for 8-9 yrs.
The car would sit for 50 weeks unstarted, then fire right up when i visited every summer for 2 weeks.......................
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Old Mar 5, 2012 | 04:42 PM
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Originally Posted by Ralphbf
Thanks for the heads up on that.

What about the fuel pump? Is there a simple answer?

What RPM is the stock unit good to?

Will I need the Big Block computer to run the TBI?

How and how far does the TBI get bored?

Look at ebay under "454 tbi bored"

If you have a salvage yard near you might be able to get one cheap and have a shop bore it and replace the butterfly plates.

As for the computer a factory one would be a problem IMO as they were meant for trucks not performance cars. The big block TBI should work on the small block computer as Holley sold BB tbi units as "upgrades" for the 305/350 cars/trucks that used them.

I would get a megasquirt 2 myself as it allows more control over the F/I system and also can use computer controlled spark.
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Old Mar 5, 2012 | 05:13 PM
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Originally Posted by Marlin
Look at ebay under "454 tbi bored"

If you have a salvage yard near you might be able to get one cheap and have a shop bore it and replace the butterfly plates.

As for the computer a factory one would be a problem IMO as they were meant for trucks not performance cars. The big block TBI should work on the small block computer as Holley sold BB tbi units as "upgrades" for the 305/350 cars/trucks that used them.

I would get a megasquirt 2 myself as it allows more control over the F/I system and also can use computer controlled spark.
http://www.diyautotune.com/tech_arti...part1-nova.htm
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Old Mar 30, 2012 | 09:36 AM
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Originally Posted by SH-60B
From what I've read Megasquirt is like an electronics lab experiment. Is that the FI system you'll be using? If it works good I'd be willing to try and assemble one, but all I've read about it is "Yup, got it running, but now it's time to tune"
Hehe... It used to be.. It started as a DIY setup, but they have done a lot of growing up. DIY Autotune has fully built ones along with a line of PNP units that plug right into the stock wiring harness of many cars.
The feature set of the MegaSquirt 3 can take on just about any high end standalone controller.
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Old Mar 30, 2012 | 01:47 PM
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Default Sticking with a carb

Fuel injection is great no doubt,but since I went with this carb all my tuning problems have gone away and I couldn't be happier.Getting 20 mpg on the highway.Well spent 239.00 for sure.Good luck with your project..
[IMG][/IMG]
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Old Mar 30, 2012 | 02:04 PM
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Originally Posted by SH-60B
From what I've read Megasquirt is like an electronics lab experiment. Is that the FI system you'll be using? If it works good I'd be willing to try and assemble one, but all I've read about it is "Yup, got it running, but now it's time to tune"
This is the big issue, getting that serial D 9pin to .com with a modern lap top, so you can send files to the seller/supplier for advice in tuning....

without that, you got almost no chance to tune the damn thing,

maybe 6 years ago by now, I tried and crYed over it for about a month, finally gave up....sold it off,

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Old Mar 30, 2012 | 02:17 PM
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Originally Posted by mrvette
This is the big issue, getting that serial D 9pin to .com with a modern lap top, so you can send files to the seller/supplier for advice in tuning....

without that, you got almost no chance to tune the damn thing,

maybe 6 years ago by now, I tried and crYed over it for about a month, finally gave up....sold it off,

You know they have USB adapters, that has not been a real issue for a while unless you tried to use one that has not been tested.

http://www.diyautotune.com/catalog/u...tune-p-67.html

Megasquirt has come a long way from the MS1 days.
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Old Mar 30, 2012 | 02:27 PM
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MS3's have on board USB or a DB9, it is your choice. MS2 or MS1 is only DB9.

As you say, few laptops have a native serial port any more. It would be silly to put one on as you can buy a usb to serial converter for $15-$20 and that allows you to keep the usb cable shorter and use a real serial cable for most of the length.
As cars have such a high level Electro Magnetic noise, real RS232 serial is far more reliable than usb. You need very well shielded USB cables to work well in a car, especially a race car with high output coild and low impedance injectors.

That is why so many after market controllers are still using good old fashion RS232 with a DB9. FAST, DFI, BIGSTUFF3, etc..
But more and more are doing either the on board USB like MS3 has or CAN as MegaSquirt 2 and MegaSquirt 3 also offer.
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