Cross ram intakes

[Alex]

Does anybody have any working experience with crossram intakes? More specifically, how well (or poorly) they tend to work (as compared against runners that just go straight up) assuming the runner lengths and shape/etc... have been properly constructed?

[Troy]

Finally, a real engine on this forum

Actually, I looked at both cross-ram and straight stack for my LS2, and have gone for a modified straight stack system. I like the cross-ram and plenum idea - and especially good if you want to super or turbocharge at a later date - but mine is a GT40 and I wanna see some trumpets!

Those intake runners look longer than those offered by, say, Edelbrock (see pic), but will have a lower finished height. Nice packaging for the back of an SLC too. Nice job!

[Doc Kaler]

Alex,

Generally, Long intake runner lengths (ie., cross ram) will work better on your large displacement engine and give better torque at low end. Larger tube diameter works better with large displacement engines at higher rpms. But a diameter too large may cause reversion and loss of power. Short intake runner lengths work better for increasing torque at lower rpms in smaller displacement engines. The smallest diameter without losing HP is the best size.

[EGLITOM]

Originally Posted by EFNFAST

Does anybody have any working experience with crossram intakes? More specifically, how well (or poorly) they tend to work (as compared against runners that just go straight up) assuming the runner lengths and shape/etc... have been properly constructed?

Hi ALex

How do you want to fit a carb on such an intake ?

TOM

[TimB]

Originally Posted by EGLITOM

Hi ALex

How do you want to fit a carb on such an intake ?

TOM

Easy

[EGLITOM]

Tim

That´s why this car has such a big battery ( probably a permanent driven starter to help volumetric efficience in low rpm´s)

TOM

[Alex]

Originally Posted by EGLITOM

Hi ALex

How do you want to fit a carb on such an intake ?

TOM

I'm currently examining all alternatives and may be dragged kicking&screaming out of the dinosaur era =(

With a carb, the most realistic intake manifold height is around 6'', which is farrrrr from ideal. So it's kind of like, do I accept something that I'm familiar with and that the engine will never function to the best of its abilities, or do I surrender, learn something new, and have an engine where 1 part is not restricting the whole of it.

[Jim Rosenthal]

I can't imagine ever getting the linkage working right on an engine where the carbs are THREE FEET apart. Those looked crazy when they were made, and they still look crazy to me.

I think the fabricated intake is for EFI, isn't it? Or did I miss something? Looks like it has a big hole at the front for the air metering device.

[Doug Sainlar]

Originally Posted by jimbo

I think the fabricated intake is for EFI, isn't it? Or did I miss something? Looks like it has a big hole at the front for the air metering device.

Yep, with the runners running crosswise from the plenum to the intake port on the heads. Pretty cool if you ask me!!!

Cheers from Doug!

[Julian]

TWM (now Borla) make a cross ram EFI (no Ford version yet), but IMO it's not half as sexy as the Morrison product from Australia, now the Aussies really do make a beautiful cross ram EFI setup.

See more here; MorrisonOz/Ford Manifolds

One big benefit is the almost straight runners feeding direct into the head.

[Mike Huddart]

Originally Posted by Joules5

TWM (now Borla) make a cross ram EFI (no Ford version yet), but IMO it's not half as sexy as the Morrison product from Australia, now the Aussies really do make a beautiful cross ram EFI setup.


One big benefit is the almost straight runners feeding direct into the head.

The TWM crossover manifold IS for a Ford, 351. They also do a billet version for the LS series with cast versions, same as the 351, on the way for 302, Chevy etc.
Mike

[Julian]

Originally Posted by mike huddart

The TWM crossover manifold IS for a Ford, 351. They also do a billet version for the LS series with cast versions, same as the 351, on the way for 302, Chevy etc.
Mike

Oops another senior moment, thanks for the correction.

[Alan Watkins]

Originally Posted by EFNFAST

..... do I accept something that I'm familiar with and that the engine will never function to the best of its abilities, or do I surrender, learn something new, and have an engine where 1 part is not restricting the whole of it?

The answer is,



YES!

[Alex]

Originally Posted by awatkins

The answer is,

Attachment 52038

YES!

Okay, yea, that definateley won't fit :p

[Earl J. Castillo]

Here is the Cross Ram (“Ram Box”) Intake for the Small Block 289-302 Ford circa 1968-1970 made/casted by BuddyBar marketed by AutoSport with “Shelby” cast markings.
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I have both 4V and 8V top lids meaning it will take either a single or dual 4 barrel (Holley) Carburetors. The 2-4’s called for twin 600 cfm and the single called for an 850 cfm. Of special interest the underside of the dual 4 was open to the plenum. The single 4V carb has directional walls under the lid.
<o:p></o:p>
I was going to use the single 4V set-up with a Modified 700cfm double-pumper (see pic) but decided to run 48 IDA Webers instead.
<o:p></o:p>
Cheers,
~Earl J

[Earl J. Castillo]

Here is the Linkage to the Dual 4 (8V) set-up:
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The driver side carburetor is by design to be mounted backwards. Being a “double pumper” The primary butterflies are oriented to the rear (over 7 & 8) feedingthe back half of the plenum. The passenger side carburetor is mounted in the standard orientation where its primaries are feeding the front half of the plenum.
<o:p></o:p>
Note the linkage in the photograph and the reliefs in the lid correspond to the Holley throttle arms.
The top rod pulls back (passenger carb) the lower rod pushes (driver side carb).
<o:p></o:p>
Cheers,
~Earl J

[Howard Jones]

Very interesting website. Lots of Chevy LS and other stuff but some 351W parts also. Very good prices however.


CHEVY CROSS RAM MANIFOLD WEBER INTAKE Moon Rat SBC 350 - Listing # 144343 Ahwooga - Buy Sell Parts for New and Used Cars Trucks Motorcycles

[dallas_]

Alex,
Wayne Presley at Very Cool Parts has a cross ram manifold for Chevy's.
Looks awesome. I think it's set up for FI though, so you might just have to surrender.

Scroll down to see the cross rams...

http://www.verycoolparts.com/Stack.htm

[Mike Huddart]

We have built a lot of "Cross Ram " induction engines over the years, all for what would now be considered Historic racers. That in itself should tell the story, they don't flow enough air to make "modern" horse power.
Leaving the "look" aside, if you consider the length of the runner as a restriction and the point at which the runners cross as a huge restriction then you are always going to be up against it. We have found because of the length of the runners and small cross section that cam choice becomes super critical.
Small blocks particularly don't have enough room to package everything without compromising the runners. We have built several Bizzarinnis with crossover 327s with both Campagnolo and Moon intakes with 45 and 50 DCOEs, they make great torque for a small engine and original style heads but they only had about 300 HP in their day so air flow didn't really come into it. Surtees built some stroked 327s with something like 55mm Webers and a most peculiar cross over manifold for his T70 but they wouldn't breath. Similarly Allan Smith built some trick looking cross over F5000 engines with DFV style slide throttles, they were " sort of " OK and did produce plenty of torque but as soon as head technology took off they became obsolete very quickly. We have tried them on mildish Brodix heads and they're hopless.
I think you would need a VERY good reason to consider a crossover because from a power point of view you will have to work hard.
Mike

PS. I actually had one of those 413 Cross Ram Chrysler engines in a stock car back in the 60's and apart from being a sales gimmick for the 300E were "tuned" to produce maximum torque at 2500 rpm !

[Andrew Robertson]

Originally Posted by mike huddart

We have built a lot of "Cross Ram " induction engines over the years, all for what would now be considered Historic racers. That in itself should tell the story, they don't flow enough air to make "modern" horse power.

I can add a mild street example to Mike's excellent summary above. I used the moon clone manifold pictured above with 4 x 47mm OER (DCOE clones) on a 383 with 9.5 c.r., and a 218/224 hyd roller with 110 lobe centre, and some 170cc edelbrock heads.

Once I had completed the massive effort of getting the intake to fit nicely, making nice air boxes, and tuning the thing to have acceptable driveability and performance without ruinous economy, it was a combination that was substantially inferior to the single 750DP Holley and dual plane Edelbrock perfprmer intake that was on the engine previously.

The 4v set-up was useful to about 5600, had pin-sharp throttle response, good bottom and midrange. The ram was dead by 5k, felt like it had less peak torque, but had more torque below 1500, could not deliver enough pump shot to ever be truly clean on snappy transients (I think a diaphram pump like a dellorto would have cured that), was fussy to maintain, and used about 50% more fuel around town. It didnt stay on the motor for long.

Cheers, Andrew