Rennsport fuel injection?

(Jeff Smith) #1

Has anyone tried this?

(Kirbert - author of the Book, former owner of an '83 XJ-S H.E.) #2

I think the answer is no, because the pic shown is an arrangement that wouldn’t actually fit a Jaguar V12. The intake manifold flanges on the Jaguar V12 are horizontal, so individual throttle bodies would either need little bends in them or they’d point straight up, forming two parallel rows of six. And the spacing between #3 and #4 on each bank is larger than the spacing of the others. What is shown is apparently a generic arrangement of 12 throttle bodies, and they’ll figure out the actual configuration if and when someone actually orders a set.

Pricey. And there’s a whole pile of stuff you’ll need to order separately, and I’m betting it’s pricey too. I certainly hope there are airboxes involved with proper air filters; running engines without air filters is a long-proven bad idea.

(ronbros) #3

quick pic of GRP44 car Daytona 24hr, , 12 tbs angled to meet the inlet ports, tapered inlet funnels,
slide valve types.002 .

said to make 750HP , 1987! thats chief tech Lanky Foushe.

(Kirbert - author of the Book, former owner of an '83 XJ-S H.E.) #4

I’ve never really cared for the slide valve idea. I like the Rennsport idea better, a shaftless butterfly; when it’s open there’s just the thin disc in the air path.

(ronbros) #5

Kirby , with slide valve there is nothing in the air path when wide open!

what you should note , is the nice flow angle of the flow matches the port perfect , done 40yrs ago!

(Kirbert - author of the Book, former owner of an '83 XJ-S H.E.) #6

I realize that. But if airflow is the issue, you can just make the air path a bit bigger to compensate for having a butterfly in there.

The angles of the runners are interesting. Unless the heads have been modified somehow, the mating flanges where the intakes mount are perfectly flat, there is no angle to them whatsoever. It’s been too long since I’ve looked at one, but I’m guessing what you’re saying is the passage itself proceeds at an angle down toward the intake valve, so these intakes have been designed to align with that. I’m not even sure what good that accomplishes, but considering how much effort was involved I guess they found a significant benefit on the dyno.

For any of us considering the Rennsport package, I would not expect that level of alignment. I’d expect 12 intakes pointing straight up, 4 groups of 3. I’d also expect that anyone spending this level of lettuce is going to want to port the heads, basically opening up the intake ports to match the openings in the bottom of the new intakes. And when done, you’re going to have intake runners that are actually shorter and larger diameter than the stock intake manifolds, which probably means you’ll have more top-end power but less low-end torque. It’ll look like a million bucks, though, and probably scream like a banshee.

(ronbros) #7

pretty much what you say is correct!!

but in reality who needs it ??

a stock set of manifolds lightly ported would more than suffice , maybe oversize TBs, mine are 1/4" oversize, if any improvement ,DAMIFINO!
like said for looks be GREAT at a car show, id love it and sling the BS to go with it! LOL.

by the way those are Pre HE heads i think port angles are different from HE, along with plug angles!

years back many people flow tested both type heads , and it always comes down to the valve location in the chamber, just does not lend itself well to hi flow area, my Pre heads do have oversize valves bought from GRP44 26yrs ago , and heads are ported and blended to match the valves after talking with 44 tech Lanky, he has passed now!
ron thanks