Thread: Dual Quad Sequential EFI

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Mike, that's probably how I'll start out and see how it does. The secondary linkage is pretty easy to remove.

I definitely feel that it needs progressive linkage between the TB's. One 500 cfm TB should be plenty for normal driving unless it causes some kind of strange distribution problem and I wouldn't think that would be an issue since all it's passing is air. I have to say though, that I'm still intrigued by the prospect of getting this thing working with all 8 barrels, but it's something that I can experiment with any time once I get the car on the road.

I've been giving the total flow some more thought, too. These TB's are similar to the one's that came on some SBC multi port injections. Unless Holley engineering is being driven solely by bigger is always better marketing, then there has to be a reason that they felt 1000 cfm was a good flow rate for a wide range of engine sizes. I don't think they even offer a 4 barrel TB in anything smaller than 1000 cfm and with the CNC construction they could have built them any size they wanted with just a few simple tweaks to the basic program.

I've come to the conclusion that TB size just doesn't matter as much with multi port injection as carb cfm does since there is no need to maintain good velocity through a carb venturi. The 1000 cfm throttle body has 9.6 square inches of throttle bore. A stock 78 MM LS1 has 7.4 and some stock parts are almost 90mm. A 102 mm TB is a common oversize aftermarket part and has 12.6. That works out to over 1300 cfm. A lot of those 102's are going on 5.3 (323 CI) LS engines and even some 4.8's (292 CI)! Based on that, I'm not going to worry too much about flow at this point.

The air cleaner will be in this week. The first big issue is getting it all to fit under the hood. Gonna be close.