Intake Manifold Flow Test: Super Vic, LS1/6, TBSS, LSX90, LSXR, LSXRT, Dor LS2 etc
 

I want to share the following data with the LS1TECH community.

New summary thread...with Mamo LSXR tested it's definitely time for new summary!

Blackbird-s-intake-manifold-cylinder-head-testing-summary


​First a big thank you to Land Speed Cylinder Heads and Bret for doing the testing in a professional and timely manner.

For testing I provided the following:

The Players

LS1 manifold - (w/o EGR) - the 97 Corvette had this manifold and its where we started

TBSS manifold - regarded as the best of the factory cathedral intakes

Dorman LS2 92mm - Dorman revised the intake to fix the well known LS2 manifold flaws. Three Dorman test eventually including a ported one
​​​​​

102 FAST LSXST - regarded by many as the BEST plastic cathedral intake under 7,000 rpm

Regarding the LS6 cylinder head the vendor will not be named as the focus is on the intake manifolds. Flow benches differ and I do not think the well regarded vendor that ported the head should have any negative press due to my test. The head was not from Land Speed, TEA or Wegner etc.

The LS6 head has stock 243 valves, was advertised as 228 cc intake port and 64cc chambers. The testing was done on a calibrated Super Flo 1020 bench at 28 inches of pressure on a 4 inch bore. The intake side had a clay radius for testing the head with out an intake. The right most port was tested that would be placed at the #7 or #2 cylinder position. We tested with intake manifolds in the #7 position.

Published Flow Numbers for
Ported LS6 heads

Intake Exhaust
.100 no data
.200 157 117
.300 226 167
.400 267 204
.450 275 215
.500 283 224
.550 290 227
.600 302 234
.650 no data

Our results flowing head, 28 inches, 4 inch bore & clay radius on intake port. No pipe on exhaust.

Intake Exhaust
.100 64.4 44.3
.200 134.5 112
.300 198 162
.400 246.5 190
.450 267 197
.500 281 203
.550 295.8 211
.600 305 214
.650 285 218

This established the base line for flow. We speculated on which intakes would perform best. Typically, LS plastic intakes will reduce airflow by 65 to 45 cfm and sometimes more. Losing less than 30 cfm would be excellent. Typically, even a Kinlser set up on a race motor will lose 5 to 10 cfm.

Several surprises, the intake port was 255 cc and it stalled at .650 lift. We didn't invest the time to determine the exact lift for the stall. Long term I plan to run stock rockers and keep cam lift under .600, so didn't feel it was an issue. There were several easy improvements revised valve job and a few spots that could be tweaked in the intake runner. The exhaust side could use similar tweaks. I have a spare set of LS6 valves so we may have some fun tweaking these heads later on and retesting the head.

Next up flow data with the intake manifolds in place.

Flow Data for heads, LS1(w/o EGR), TBSS, Dorman LS2 & FAST 102 LSXRT

Lift_______head_____ LS1(w/o EGR)___TBSS_____Dorman LS2___FAST LSXRT
.100_______64.4_______62.4____________59.2_____61_ ____________64.3
.200______134.5______127____________127.2____127.8 __________134.4
.300______198________174____________179______182.6 __________191
.400______246.5______211____________218.1____225.8 __________235
.450______267________221____________230.2____237.8 __________248
.500______281________230.2__________240.1____247.6 __________260
.550______295.8______238.5__________250.1____248.5 __________270.2
.600______305________242.1__________256.6____252.9 __________278
.650______285________244.3__________261.8____254.6 __________282.3

Note the WARR 92mm TB was used on all intakes manifolds except the LS1manifold. The WARR 92mm TB provided a smooth transition to snout of the various manifolds. The TB blade was zip tied open.

Gonna have to try a different format lol. I can't make heads or tales of that list. To me it looks like the ls1 intake makes the most.

Wow the Dorman did well for $350, a light port and it should be a stout intake, who's gonna be the first to send theirs to Peak Speed and see what they can do with it?

I plan on sending my Dorman LS2 to Peak tomorrow and then retesting it.

Are you looking with your phone? If so try turning sixeway like a land scape and the numbers will line up properly.

Those numbers for the dorman are borderline shocking. Thanks for taking the time to test these and share the results.:usa:

Here's how it shows up on my phone sideways.

Careful! This dangerously close to actual tech!

Thanks a ton for sharing. I gots a new to me LS2 that might like that dorman!!

Thanks for posting the numbers. That is great info.

Would love to see what a normal FAST 102 does so I can finally say I made the right choice to make the LSXrT work with my combo. Contemplating having to ported too, especially if I upgrade to some big-dollar heads next winter.

Any chance you could flow test a BBK intake?

BLK SS, I will tweak the format later this evening for you.

Happy to share the info :)

Yes, I am up for getting other manifolds tested if someone is will to allow me to borrow them for testing. We can use the same cylinder head. I think Land Speed would do that, I would need to run it by Bret and friends before fully committing to testing. We might have to crowd source funding if there are a lot of different manifolds to test. I would have liked to include an LS6, LSX, LSXR, LS3 with cathedral adapters, ported Dorman LS2, and so on as well but I don't have any of those manifolds.

I Want to See, GM LS6 vs Dorman LS6 vs Fast 78.

I would like too see that too plus Fast 92 and Fast LSXR. If members can round up the intakes, I can get the testing done.

IownCalculus, thank you for doing that very nice chart with the test data.

Thank you for taking the lead on this test, as a lover of verifiable results this speaks to me lol

I would still really like to see back to back results on a dyno for a run of the mill mid size cam LS1 with the Dorman LS2 vs LS6 vs LS6 TPIS modded. These flow numbers are great but what are they actually worth? After all, most of the builds our there are Heads cam, or cam only LS1's.

Can you expand on the claim of Dorman addressing the flaws of the original LS2 intake?