WS6GMguy

currently don't know which intake to run went through some flow numbers for other intakes and came up with that the best intake would be the LS6 intake ported, I was curious who ports intakes? and are these Flow numbers I got for the LS6 intake ported correct, they seem way up there compared to other intakes like the FAST 102 etc. kind of doesn't make sense lol... also does anyone have flow charts for the 92mm ported?

.200------157
.300------226
.400------267
.500------283
.600------302

any information will help. if you have any questions about the car let me know.

G Atsma

There is an entire thread, still pending, that compares a variety of intakes. Do a search, and you will find it.
Search for- "intake manifold flow test", and it should come up

Johnny_M

Although the intake is the choke point especially on 4th gens. because hood clearance. A flowed intake is not going gain much on a stock engine. What are the engine specs. If it's not stock.

WS6GMguy

It's a full bolt on car as of right now,
TSP 225cc heads
Torqued V4 cam
BBK LT
it's a 5.3l iron block bored to 5.7l with forged internals

Johnny_M

https://ls1tech.com/forums/generatio...sxrt-more.html

99 Black Bird T/A

iTrader: (4)

Types and brands of Flow benches vary in the cfm they report. So bench to bench can be difficult to evaluate. There's a link posted to my intake flow releasing thread. It might be of interest.

Those numbers look like they might be flow numbers of a ported LS6 cylinder head. Note how similar those flow numbers are to the ported LS6 head listed in my test data below. Those numbers don't look like flow numbers for a LS6 intake with a cylinder head attached on a 4 inch bore at 28 inches to me. I think intake manifolds need to be evaluated for flow with a cylinder head attached. Flow numbers are only a starting point. Airflow in a running engine is far more complex than any steady state flow bench simulation. With all that said...

Here's one of the charts that Jensen did with the data I've collected testing. The same cylinder head intake port is used in the testing. I think it helps show how the various intakes compare in a basic sense.



99 Black Bird's test data as compiled d by Jensen.

From testing my conclusion on the LS6 intake is the TB opening is the main restriction. The LS6 90mm TPIS/LPE snout intake picks up a lot of Flow over a stock LS6 intake. The exact same LS6 intake was used for both tests, it's the one that was on my 99TA for 15 years.

In the above testing the LS6 90's runners are untouched. If this LS6 90 intake was port matched to my specific testing cylinder head and had the runners cleaned up by a porting expert like Tony Mamo or Brian Tooley or Julio at Carter, it would probably gain ~5-10 cfm. Note the unported LSXRT would still out flow the tricked out LS6 90 in all reasonable likelihood.

I have another LS6 90, that is ported and matched on my 91 RS with a small cam (229/229) 383 LS1 stroker. In our actual dyno testing for my car the ported LS6 90 made 2hp more than the LSXRT. The LS6 90 also had better curves. With big duration 230+ and high rpm etc I'm sure the LSXRT would shine and blow the trick LS6 away. However, on cable drive TB's with 2002 or older PCM's the big 102 LSXRT can be a nightmare to get tuned for good drive ability on a manual transmission car.

My rule of thumb for great drive ability and good performance on under 400 cubes, cable drive TB and 2002 or older PCM is 92mm TB and LS6 90mm intake or 90/92mm Fast LSX intake. If the TBSS will fit it is also a very good intake for the cost used. Others will disagree and insist a 102 TB & LSXR or LSXRT is always the better choice even on smaller cube motors, cable TB's with older PCM's. From my experiences I have a $1000 LSXRT collecting dust sitting on the shelf.