Question on Fuel Injection

[Redskinsjbs]

Hi all,

I am thinking a little ways down the road here, so just bear with me.

I eventually would like to convert my GT to a fuel injection engine. For now, the reasons for doing so would be because of the better gas mileage and the added benefit of being both more reliable and stable.

So here is the question. Is it possible for me to put in a new fuel injection engine into my 73 GT with minimal (As close to zero) alterations to the engine bay.

I would like to keep the body as close to original as I can just in case I feel like converting the car into a show car in the future.

[bgdowski]

Well by "new" do you mean an engine in current production cars, or do you mean a fresh 1.9L-2.4L Opel engine that shares the same block as the one you have? I actually talked to OGTS recently about this, and they gave me the lowdown... There are 2.2L-2.4L DOHC EFI motors out there made by opel, that will basically bolt into the car with a 5speed trans, along with wiring and all that good stuff that comes along with the magical EFI system, but they are VERY rare and limited production (which means $$$$$). There are also 1.9-2.4L Jetronic FI systems that you can throw onto a spare motor, and call that your "new" engine! I do not know of any other motor that will bolt into the GT without major modification.

[Redskinsjbs]

I guess that I really want to do away with the carb, so any new or like new engine that bolts in will do

[CDN OpelNut]

You can bolt in a fuel injection system from a 1975 Opel that came with it. Minor mods to the fuel system but no engine bay modifications. There are lots of cars on this site with that. No modern engine will go in without some cutting.

[Redskinsjbs]

Ok, so most likely a dumb question, but canI convert my original 1.9L block to fuel injection?

[jordan]

Originally Posted by Redskinsjbs Ok, so most likely a dumb question, but canI convert my original 1.9L block to fuel injection?

Absolutely, you will need the complete factory bosch system from a '75 US manta (easiest to obtain) [ecu, manifold/linkage/injecors/throttle body, mass airflow meter, fuel pump, efi mechanical advance distributor, and wiring harness ] Then all associated plumbing from the tank to the fuel rail, and then a return line back to the tank needs to be put together. You would also have to make some modification to throttle linkage so a cable can be used.

[Redskinsjbs]

Wow! Thats Great! So what price would I be looking at? $2000? I am really just trying to size up the workload / payment and therefore resulting workload needed to convert my car.

[GTJIM]

There is quite a lot of info spread around this site and other Opel sites on the WWW.

Like:

About Opel fuel injection systems

Fuel Injection

Lots more for you to find!

[LeftLaneGuy]

Originally Posted by Redskinsjbs Wow! Thats Great! So what price would I be looking at? $2000? I am really just trying to size up the workload / payment and therefore resulting workload needed to convert my car.

It's actually fairly easy, and straighforward... There are a few little 'tricks' for the swap into a GT, but they're nothing too tough. I won't say I was the *first* person to swap '75 injection into a GT, but I was surely *one of the first few* who did.. Mine was done in '90... It was a complete swap from a wrecked '75 Ascona... To anyone from the OMC back then, you may remember the car; Metallic burgundy with gold BBS rims @ the first Queen Mary meet.. It got ALOT of attention that weekend.

You will be best served by buying an EFI car and swapping everything. Piecing it together will be a chore. Unless you find someone who has a complete set-up.

But, honestly, there are so many products in the market now, that it's almost foolish to do unless you want to say it's an "Opel EFI system".

[wrench459]

Originally Posted by LeftLaneGuy But, honestly, there are so many products in the market now, that it's almost foolish to do unless you want to say it's an "Opel EFI system".

Well said... I can't thing of anything to add or subtract from that statement.

[davegt27]

the only mods I remember where cutting the hood latch off the passenger side of the hood

and cutting a hole in the fire wall to pass the FI wire harness through

oh I had to add clamps under the car for the fuel line

75 FI would be the cheapest

but you could do quad TB's on some Opel sidedraft manifolds

also I first saw the mod on a video Gil had sent me, I think the vid was on there first trip to Germany in 1987 so it was a pretty common swap in Germany

David

[Redskinsjbs]

I was reading up on the Opel EFI systems and they seem to have some mpg problems. From what I have read, the airflow reader can be a tad touchy, and so at idle it can dump excess fuel...or something along the lines of that.

So I originally was thinking about Fuel injection because it was both more reliable and more fuel efficient than a carb system.

So here is the altered question.

Is it worth it to put fuel injection in my GT if you weigh in amount of time and money saved from the lowered amount of maitnance?

[RallyBob]

Originally Posted by Redskinsjbs I was reading up on the Opel EFI systems and they seem to have some mpg problems. From what I have read, the airflow reader can be a tad touchy, and so at idle it can dump excess fuel...or something along the lines of that. So I originally was thinking about Fuel injection because it was both more reliable and more fuel efficient than a carb system. So here is the altered question. Is it worth it to put fuel injection in my GT if you weigh in amount of time and money saved from the lowered amount of maitnance?

The stock 1.9 L-Jetronic is definitely not know for being easy to live with. Sure, some people have had great luck with it, but by far more systems have been removed from 1975 Opels than have been re-installed.

Mileage is not a strong point, primarily due to the crude nature of the ECU, and the extra-large injectors. The injectors flow enough fuel to feed 160 hp, but the engine only makes 80 hp in stock form! It doesn't mean that the car runs that rich, but it does mean that the orifice at the injector is larger than is optimal, therefore atomization is not so good.

Later Opels, even the newer 2.4's with 126 hp, used injectors that were rated for only 10-15 hp above stock. Meaning the spray pattern is far better for atomization and therefore lower emissions and better economy.

I think that a better choice would be to adapt a newer EFI system, and not necessarily from an Opel. Sure, you need Opel EFI intake, but finding an engine with similar HP and power peaks and adapting it might be a better choice. Preferably something with a mass air flow sensor (hot wire) rather than air flow meter (flap type), as there is a certain percentage of adaptability with such a system. The original Opel system is analog and quite dated. It cannot vary it's parameters far from stock.

HTH,
Bob

[Redskinsjbs]

So I have kind of scratched the idea of fuel injection in favor of a new weber carb and pertronix ignition

[MICAH1]

Jay,
Before you purchase a new weber, lets have a close inspection of the 32/36 that came with the car. Do your homework first with a compression check of the engine and other related test to asses the reliability of your GT. I hope to drop by around 12:30-1:00 pm today.

[Redskinsjbs]

ok. Will do. See you then hopefully!

[davegt27]

So here is the altered question. Is it worth it to put fuel injection in my GT if you weigh in amount of time and money saved from the lowered amount of maitnance?

sounds like you talked your self out of it before you even started but let me say this

I say it is the second best mod (5 speed being #1) I ran a GT for years with the 75FI and found it to be the best setup for the street

I started with a 1.9 and a new 32/36 that I bought from OGTS and the car ran a constant 19.2 in the 1/4 mile

when I upgraded to FI the 1/4 mile time jumped to 18.8 then with further mods got it down to 18.5

the big reason I switched to the FI was I found out that the stock Carb intake manifold was a big restriction

its a nice upgrade for a Opel GT looks good also

now years later I realize I would have had even greater gains if I knew how to tune the thing.

back then I would borrow my Friend Marty's Hal meter (AFR meter) and it showed the 75FI was running rich most of the time, also the fuel pressure was like 42 psi

anyway the gas mileage was down a bit but that was because I did not tune the thing

if you do go carb I would recommend a new 32/36 you can save your self a lot of headaches

some times Opel people can be on the cheap side
they get FI and try to run 30 year old fuel injectors or they get a used 32/36 Weber that might be just as old

good luck
Davegt27

[Redskinsjbs]

OK, I got my gt started today and I am sticking with the Weber 32/36 manual choke forever. This is so exciting