My findings; Ported Weaind vs Ported LS6 intake
 

Although there have been charts & dyno comparisons made, thought I'd post the information found when I swapped a PORTED Weiand (aluminum) intake for a PORTED LS6. Both airflows were measured through AFR 205 heads, stock 346 ci, .556/.563, 216/220, 214 LSA, an 85mm TB & an 85mm screened MAF. Tests were done @ normal engine operating temperature @ WOT, 100 kPa MAP.

-Both intakes flowed similarly through 250-260 g/s (410-426 CFM) with a slight advantage going to the LS6, as confirmed by a slightly leaner A/F ratio.

-From 261-416 g/s, (428-682 CFM) the LS6 flowed consistantly around 8% greater than did the Weiand.

-From 417-425 g/s, (683-697 CFM) the LS6 flowed 4% greater than the Weiand.

-Above 425 g/s, (697 + CFM) they were close to even, as I'm sure that the valve train was maxed by then. Aiflow numbers top out @ 442 g/s (723 CFM).

Note: values (g/s & CFM) are the total amount of air entering the engine as, measured by the MAF, not to be confused w/ individual intake runner airflows normally associated w/ intake comparisons. Further, the inlet of the LS6 intake used would be similar to a TPIS oval (75x90mm), not stock & the Weiand an 85mm inlet.


The swap was made mainly to reduce front end weight & the "under the curve" airflow is a bonus. I am very please w/ the results & wonder how anyone w/ a stock valvetrain could ever need anything more than even a stock LS6 intake (am guestimating a stock valvetrain to flow somewhere in the neighborhood of 325-350 g/s, 553-574 CFM).

Wow. Thanks for that write-up!

Who did the port job of the LS6 intake? any pics of it?

I did. Sorry, don't have any pics.

who ported the weiand

Good test man, I hope everyone references this in the neverending LS6 vs. Weiand debate. Better flow, lighter weight, no heat soak. Win for the LS6.

I did them both. The Weiand was on my car for four years & is a very good performer. A non-ported LS6 will not out perform a ported Weiand. My post is a record of what was measured when each manifold was ported in a similar fashion & then applied to an engine that was set-up to take full advantage of airflow up to 6300 RPM.

It is my opinion, based on personal evaluation of the manifolds & measuring airflow while installed, that the LS6 tends to be more air speed based, where the Weiand seems to be more air volume based than the LS6. So, I would expect the Weiand to do better with forced induction or spray.

the reason i asked, my intake was ported at lingenfelfter by the actual tech who designed the intake. my intake picked up plenty of power of an ls6 but then again i opened my up to except a 85mm tb.

You'll get no argument from me. I am sure that you did. The interesting thing might be to see how yours stacks up against a ported LS6 (85mm). It is also a must that the heads, valve lift, cam specs, inlet size, & whether or not the test was done while on the spray. My test was noted as, "a ported 85mm inlet Weiand compared to a ported LS6. The Weiand was 85mm & the LS6 being similar to the 75x90 TPIS LS6 intake manifold." So, it's pretty much an apples to apples comparison when tested on my engine only, nothing more. It's also not to say that one is better than the other. It is to say that based on the test results, I would find it hard to find a better intake manifold for stock engines, than the LS6. This was also noted in my post. It's just another post to reference in the archives, as we all continue to learn & share our findings. As we all know, there are far too many good combinations that can be made & very few to completely dismiss.

great post i was not trying to argue

isn't the aluminum weiand better and safer for nitrous backfires as well?

got dyno's?