Plenum & Injector Housing Porting

[jss06c6]

Slow and steady.. one side of the plenum complete.IMG_20180629_101921711.jpg

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[Top Toy]

You may want to consider eliminating the secondaries while you're in there.

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[jss06c6]

Originally Posted by Top Toy

You may want to consider eliminating the secondaries while you're in there.

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Thanks, I've thought of this, but my tune brings the secondaries in earlier and I like the way the car drives right now. Cruises nicely and screams when I ask her to.. that said, with the radical change in the primary ports and runners, who knows what #473 will feel like after a new tune..

I'd probably take the secondaries out after a cam upgrade for sure..

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[Ccmano]

Just took the secondaries out on mine. I’ll let you know what I think shortly. The car will be on the road for the first time later today.
H

[Paul Workman]

Originally Posted by Ccmano

Just took the secondaries out on mine. I’ll let you know what I think shortly. The car will be on the road for the first time later today.
H

I predict you're gonna like the instant throttle response. Subtle, yes. But! Unmistakable! (Did I mention less coking on the secondary valves??

I pulled mine initially b/c of repeated (old stuff) failures. But, later my porting cross sections went beyond 36mm on all ports, leaving the SPTs sorta hanging in the breeze w/ nothing to do. So...OUTATHERE! (And, never looked back. And, NEVER regretting it for a heartbeat...dating back to 2010!

[jss06c6]

Flow numbers on one primary and one secondary Port. Using SuperFlo 1020. This is comparison of one stock '90 injector housing vs. one ported '91 injector housing. Longitudinal center of the runners in the ported housing are 32.5 mm, smoothed. The ports are 36.3 mm and the primary injector boss is removed. I suspect a little more is available by opening center up to 36.3 mm, but don't expect much more than 3-4 cfm gain. Secondary showed almost no gain over unported.. again, centers can be opened a bit more..

Will be finishing up, bolting together and running full suite of flow tests on all runners.19219.jpg19221.jpg

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[jss06c6]

Port matching heads now. IH's and Plenum finished. Next step is to pull the valve covers and send everything out for powder coating.. [ATTACH]

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[Top Toy]

Nice job! You're going to really enjoy the end result!

[jss06c6]

Heads port matched. I'm flow testing the assembled plenum/injector housings as well. Next will be removal of cam covers and stripping throttle body down before sending everything out to powder coating. During the wait, I'll be completing the swap to R134, doing a brake job and cleaning the engine valley and front end.

Anyone know where I can get a new set of secondary vacuum actuator valves?

Steve[ATTACH][ATTACH]

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[HAWAIIZR-1]

Nice work and very impressive.You’re a pro!! If you do find new secondary vacuum actuator valves, make sure they are tested to hold and you can return/exchange if defective. When I found my NOS I had to return a few.


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