3.0 EFI intake manifold modified for a 2.2 head

[RallyBob]

I just got this in the mail today, thanks to Hiro (Hiroshi) in France. It's an intake manifold for an Opel CIH 3.0 litre inline 6-cylinder engine. This engine shares the intake port locations with those of a 2.2/2.4 CIH head, which is to say, about 5/8" higher than those of a 1.9.

One major problem for those looking to run EFI on a 2.2 or 2.4 head is the lousy small-runner 2.2 intake manifold. It just chokes the airflow horribly, reducing the 2.2's intake port flow down to the levels of a 1.9 head with EFI (at that point why bother with the 2.2 head?). The 2.4 EFI manifold flows tons better, but it is so tall it does not fit under the hood of any US-spec Opels (it will in fact barely fit under the hood of a Kadett but the throttle body will almost hit the radiator!).

An alternative which our European friends have discovered is to use the 3.0 litre inline 6 intake manifold, and cut off two of the runners, then weld the throttle body flange back to the plenum to create a 4-cylinder intake manifold. This intake manifold will then fit under the hood of most Opels thanks to its' lower profile, and it has the larger runners so necessary to provide airflow to a 2.2 or 2.4 head.

So as time allows it, I will be modifying this intake manifold, flow testing it, and then fitting it to Samdog's roller-cam 2.5 litre engine in his 1975 Sportwagon, along with a programmable EFI system (probably Megasquirt). Fortunately, the 'leftover' fuel injectors and fuel rail from the Carlisle turbo Manta will fit this manifold and provide fueling above and beyond this engine's needs. It will also make this a reasonably priced swap....

Dyno results will be posted when completed.

Bob

[neuropel]

Bob,
I'm glad to see you're trying one of these. I keep an eye on euro ebay and they pop up from time to time. I often see in their ads that they will fit Opel mantas and asconas but I never found anything on how well they work.
Cool!
Todd K.

[Gary]

Gee, that looks awfully familiar. I'd better lock the Senator's hood if I bring it to Carlisle...

Todd, Did you try Graham at "Only Opels" in the UK? http://www.onlyopels.co.uk/

[tekenaar]

Originally Posted by RallyBob I just got this in the mail today, thanks to Hiro (Hiroshi) in France. It's an intake manifold for an Opel CIH 3.0 litre inline 6-cylinder engine. This engine shares the intake port locations with those of a 2.2/2.4 CIH head, which is to say, about 5/8" higher than those of a 1.9. One major problem for those looking to run EFI on a 2.2 or 2.4 head is the lousy small-runner 2.2 intake manifold. It just chokes the airflow horribly, reducing the 2.2's intake port flow down to the levels of a 1.9 head with EFI (at that point why bother with the 2.2 head?). The 2.4 EFI manifold flows tons better, but it is so tall it does not fit under the hood of any US-spec Opels (it will in fact barely fit under the hood of a Kadett but the throttle body will almost hit the radiator!). An alternative which our European friends have discovered is to use the 3.0 litre inline 6 intake manifold, and cut off two of the runners, then weld the throttle body flange back to the plenum to create a 4-cylinder intake manifold. This intake manifold will then fit under the hood of most Opels thanks to its' lower profile, and it has the larger runners so necessary to provide airflow to a 2.2 or 2.4 head. So as time allows it, I will be modifying this intake manifold, flow testing it, and then fitting it to Samdog's roller-cam 2.5 litre engine in his 1975 Sportwagon, along with a programmable EFI system (probably Megasquirt). Fortunately, the 'leftover' fuel injectors and fuel rail from the Carlisle turbo Manta will fit this manifold and provide fueling above and beyond this engine's needs. It will also make this a reasonably priced swap.... Dyno results will be posted when completed. Bob

Looks like cutting off the rear pair would be the easiest . . . comments?

[RallyBob]

Originally Posted by tekenaar Looks like cutting off the rear pair would be the easiest . . . comments?

Either way I have to cut and weld...and at first glance I believe the airflow would be jeopardized by using the forward runners instead of the rear runners. They are significantly more twisted and look to be a restriction. But throwing it on the flowbench will settle that dispute for me. We'll see!

Bob

[Hiro]

Originally Posted by RallyBob Either way I have to cut and weld...and at first glance I believe the airflow would be jeopardized by using the forward runners instead of the rear runners. They are significantly more twisted and look to be a restriction. But throwing it on the flowbench will settle that dispute for me. We'll see! Bob

Hi Bob,
I'm glad this 30E manifold made it so fast to the US!
You're absolutely right about the runners to select:
German Opelers also say that the rear runners are better,
But the manifold will be a little bit taller too,
So it may not fit under the GT's hood,
But it should be OK for the Ascona A.
I'm very curious about your flowbench tests!
Cheers from Paris,
Hiro.

[RallyBob]

As you can see the 3.0 manifold is quite a bit shorter than the 2.4 manifold, so it should fit under the hood nicely. And my homemade fuel rail will just fit this new manifold. This will be interesting!

[tekenaar]

Originally Posted by RallyBob As you can see the 3.0 manifold is quite a bit shorter than the 2.4 manifold, so it should fit under the hood nicely. And my homemade fuel rail will just fit this new manifold. This will be interesting!

Bob,
Begs the question, how 3.0 height compares to 2.2 manifold! Got one to compare? Share pic?

[RallyBob]

Sorry Otto, I no longer have any 2.2 manifolds. I chopped up the ones I had for their head flanges, but threw out the rest of the manifolds. They didn't serve any purpose to me.

[Gary]

Gotta love eBay: http://www.opelgt.com/forums/showpos...1&postcount=57

3.0 converted to 2.0

[houserc]

Gary,

That looks like the same manifold I have on my 2.0 EFI and it was not converted.

Was the read powder coated or do you know?

Mine had been painted, but the paint was peeling in areas so I stripped it down. I'm looking to either powder coat or chrome it.

[Motor Mouth]

Have just got hold of my 3litre plenum and have compared it against a 2litre and 2.2litre plenum.

The height difference between the 2.0 and 2.2 is minimal, mainly due to the 2.0 having the lower inlet ports.

The 3.0 and 2.2 are quite different in height, but this difference depends on whether the measurements are based on using the front 4 pipes or the rear 4. I have some reservations that using the rear 4 will fit under a standard GT bonnet and with this in mind I'll be using the front 4 pipes.

Hopefully the total cost of the modification will be about $80 including buying the plenum, chopping and welding and then painting.

The other interesting note is the butterfly valve, it's huge on the 3litre and according to the guy who's helping me do the work this should have no problem getting air into my 2.4 motor.......after all the same butterfly is supplying the air flow to his 360bhp BMW 2002

Tekenaar have you fitted your yet and did you have to modify the bulkhead in any way for the rear pipe?

Gary, I have to agree with Houserc, that manifold looks identical to my current 2litre plenum, are you sure it's a modified 3litre one?....either it's looks nice.

[Gary]

Originally Posted by Motor Mouth Gary, I have to agree with Houserc, that manifold looks identical to my current 2litre plenum, are you sure it's a modified 3litre one?....either it's looks nice.

Yup, you guys are right. It is the 1.9/2.0 with the larger throttle body on it.

[GoinManta]

Funny you guys should mention this particular intake.. seems if I remember having one kicking around in my garage somewhere. Something about doing a Bitter engine swap from another Bitter..

If anyone is interested email me.. BTW whats it worth?

Charles

[oldopelguy]

Originally Posted by GoinManta Funny you guys should mention this particular intake.. seems if I remember having one kicking around in my garage somewhere. Something about doing a Bitter engine swap from another Bitter.. If anyone is interested email me.. BTW whats it worth? Charles

I thought it was coming with the motor, which I'm leaving in 6 hours or so and driving 1300 miles to come get sometime late Sat or early Sun.......

[GoinManta]

Not normally, when you get a motor you usually just get the block and head, and timing cover. That said, I am sure it won't be a problem. That is if I can find it.. It was sitting outside my brother-in-laws garage for almost a year, I think we finally put it somewhere (Storage shed behind his garage if memory serves). If I had know it was special and worth something I would have probably treated it with more respect...

Anyway. look forward to seeing you.. I think I know what I am doing Saturday.. probably something like trying to get stuff moved in my garage to get the stuff for you out.

Hopefully I don't have to drop the Manta to do it..

Charles

[Marcus]

Does anyone know if there is an equation or a min/max amount of air volume the plenum should have. Even better would be if any one can get alittle technical as to it's exact purpose.

Basically I'm assuming you can't just drill a couple of holes in a stock intake for the 1.9 for the injectors. then bolt a throttle body in place of the carb.

But then again, maybe you can???

[namba209]

Marcus, a plenum is nothing more than a reservoir for the intake stroke on an engine. A standard intake manifold needs the individual tubes to help direct the fuel vapor into the correct cylinder when that valve opens. The real neat thing about a plenum is, with fuel injection and a turbo charger, there's no fuel vapor to worry about getting into the nooks and crannies where the corners and other deformaties in the plenum would trap the fuel vapors. In a turbo application, the plenum would normally keep a pressure charge during steady state throttle operations, so that an increase in throttle could possibly decrease the turbo lag until the turbo catches up with the demands of the engine. As far as a min/max size, they can be up to 3" or larger in diameter and as long as the engine. The larger the plenum, the more air available for the cylinder to fill up when the intake valve opens. HTH.

[RallyBob]

Originally Posted by Marcus Does anyone know if there is an equation or a min/max amount of air volume the plenum should have. Even better would be if any one can get alittle technical as to it's exact purpose. Basically I'm assuming you can't just drill a couple of holes in a stock intake for the 1.9 for the injectors. then bolt a throttle body in place of the carb. But then again, maybe you can???

A general rule of thumb that seems to be well accepted by most engine builders is a plenum with 80% to 100% the displacement of the engine. In reality it's more complex than that, as it depends on the rpms run, the power band desired, the runner lengths, N/A or forced induction. In other words, dyno testing is the only way to truly find the optimum setup. But as a starting point, 80% to 100% works just fine.

RE using the carb's intake for EFI: There's no reason you couldn't do it the way you suggested from a function point of view. But from a performance point of view the stock intake is severely lacking in airflow.

Bob