The Classic Opel Forums - View Single Post

DennisGardiner · 08-23-2007

I will add to the previous post. The 75 EFI is pretty bullet proof, as long as you keep the computer dry. {Ask me I'll tell you a tale of a friends car.}

I have run 1975 EFI on two cars; a retrofitted 74 Manta and a Kadett. The Manta was bone stock, ran perfect, but slightly less power than the 32/36 I had.

On the Kadett, I had 9:1 pistons, stock cam and the 75 EFI exhaust manifold. Ran great. Good power!

But the 75 EFI was designed by Opel to run on the lean side. This gave to good fuel economy, but as already stated, the system is not adjustable. So a cam is out of the question.

The other draw back to the 1.9L 75 EFI is the complicated throttle set up, that hooks the cable housing to the valve cover with the cable attaching to the rear of the center run throttle rod.
(in comparison the 2.0L system is cleaner as the throttle cable attaches directly to the throttle plate and manifold.)

If you want a cam.... use the simpler 2.0L systems manifold, throttle plate, t-stat, injectors, but not the computer. You would want to use a Lap-Top program-able system, such as from Redline.

08-23-2007	#3 (permalink)
DennisGardiner Kalifornia Kid Join Date: Jun 2002 Location: Soulsbyville, CA Posts: 357	I will add to the previous post. The 75 EFI is pretty bullet proof, as long as you keep the computer dry. {Ask me I'll tell you a tale of a friends car.} I have run 1975 EFI on two cars; a retrofitted 74 Manta and a Kadett. The Manta was bone stock, ran perfect, but slightly less power than the 32/36 I had. On the Kadett, I had 9:1 pistons, stock cam and the 75 EFI exhaust manifold. Ran great. Good power! But the 75 EFI was designed by Opel to run on the lean side. This gave to good fuel economy, but as already stated, the system is not adjustable. So a cam is out of the question. The other draw back to the 1.9L 75 EFI is the complicated throttle set up, that hooks the cable housing to the valve cover with the cable attaching to the rear of the center run throttle rod. (in comparison the 2.0L system is cleaner as the throttle cable attaches directly to the throttle plate and manifold.) If you want a cam.... use the simpler 2.0L systems manifold, throttle plate, t-stat, injectors, but not the computer. You would want to use a Lap-Top program-able system, such as from Redline. __________________ Drifting: dorifuto sōkō, a motor sport where the driver intentionally oversteers, causing loss of traction in the rear wheels through turns, while preserving vehicle control.