Carrera intake on 3.0SC

[turbo6bar]

Quick facts:
78SC Euro coupe
rebuilt 83 3.0 (roughly 13k miles on stock rebuild by reputable pro)
small port heads, 34mm
running big port Euro CIS system, 39mm

I want to install EFI and eventually a turbocharger/supercharger.

I bought a 3.2 intake manifold, but the only hitch is the port sizes.

The options I see:
1) open heads to 3.2 intake port (40mm?, 41mm?)
2) run a spacer block between heads and manifold to reduce from 40-42mm down to 34mm

My goal is a strong street engine. I like the Carrera intake because it's clean, and it is ready for EFI.

What would you do?
Jürgen

[jluetjen]

If you can, I'd measure the ID of the heads every 1/2 inch moving in from the manifold face and see how far in you'll need to remove material to match the Carrera intake manifold.

You'll then need to make a decision about if you want to open up the intake ports on the heads or just replace them with some Carrera heads. You could add a spacer block as you described, but the change in length of the intake runner length will quite likely change the "tuning" of the intake and make it peak stronger and lower in the rev range. I also suspect that the spacer will have to have a fairly significant angle to make the transition. This could pose all sorts of problems to the flow through the intake.

[Mothy]

I am interested to know if there would be an issue using a spacer block to reduce the Carrera manifold down to the small port. Is 40mm down to 34mm just too far?

My reason is that I have an entire Carrera intake system in a box - purchased for a future engine upgrade where I intend to port the heads, go 3.2SS, change the cams etc etc.

Is there a way that I can use the Carrera system now on my existing 83SC engine with the small port heads as an interim step - it's probably going to be well over a year before I do the engine upgrade?

Even if I could do it, would I gain anything other than just having the CIS to MFI conversion step sorted out ahead of the engine upgrade.

Tim

[bullethole]

the thing to watch for is how the injector spray pattern will get into the head. The carrera intake has the injectors at a different angle than the cis, and do not put the injector directly into the port on the head. if you don't clearance the head (put the carerra phenolic spacer on, and mark where the injector cut out is and with a dremmel or die grinder, carefuly shape the intake port to match) you're fuel will hit the intake port and not properly atomize into the chamber. I've done this on 2 large port motors, but i don't think on a small port motor you have sufficient material on the head to do this properly.

[flat6pilot]

3.2 Carrera manifold on an SC

[Mothy]

Thanks. I had read that post on your project some time ago and it's what got me thinking.
Basically, from the posts so far and that link, it looks like the small ports and potential for interference with the injector spray pattern are going to be the biggest challenge.
I'll give Clewett a ring and see if they make their adapting spacers for small ports.

Tim