C6RAPTOR

Have you had a chance to test your heads with the new LSXr with High HP or Race runners?
What was the differences in the CNC heads between the two test done with the FAST intake in this old post?

I assume that the tests using the FAST intake was done with a stock LS3 head then a CNC ported head. I was confused because the statement above the flow curves show all the heads as CNC heads

Suns_PSD

I did a lot of research on the FAST before going a different route.

Several shops told me they lost hp, broke even, or made very little when adding the FAST. I mean like 4-5 shops said they dynoed them and this was the result. a couple of those shops 1/4 mile ran the FAST too, no gains.

The other side of the argument is there is a poster or two here on the forums that agreed they gained little on the dyno but they claim substantial 1/4 ET improvements. Also there is an old Super Chevy article that claims significant gains using the FAST.

What is proven is Rick Crawford or Gwatney Performance adding radius rods to the OEM manifold. Gwatney (GPI) did mine in 2 days for $250 and the difference is very notable although I have not dynoed the difference yet. But the car pulls much harder up top with this mod. It feels like a solid 20 rwhp on my car which I guess is possible since I have other mods that probably complimented this mod.

~ good luck

C6RAPTOR

I also did a lot of research on FAST intakes two years ago and ended up having BER port my LS3 intake and TB to end up with a 416 CI TPiS engine with 650 engine HP at 6500 RPM. At the time FAST did not have what is needed to justify spending $1500.00 on a FAST intake.
The RPM Motors Inc. flow curves illustrate why I need a FAST intake with High HP or Race runners? My heads can flow 380 SCFM at .700" lift. I have a .0071" lift cam. With the stock ported LS3 intake it would be lucky to get 355 SCFM flow. WCCH also did a flow test that shows that this is true.
My engine with a sheet metal intake that will not fit in my Corvette engine bay will make 743 HP @ 6900 RPM. The sheet metal intake flows 80 SCFM more air than the LS3 intake.
I feel that the LS3 intake is not capable of flowing as much air as a FAST 102 MM intake with High HP or Race runners installed on a NA engine with heads & cam capable of 380 SCFM.
I have also been told by a tuner in Rochester NY that the Rick Crawford radius rods installed into the OEM LS3 manifold work very well but the LS3 intake flow is limited by design.

Suns_PSD

I don't disagree with your assessment.

Most of us are not playing in your hp range however and we are trying to optimize 400-525 hp street-able setups.

Going for peak flow rates in a 7K motor is a fair bit different than shooting for solid gains from say 2.5K-6.7K.

I will say this, I have a small cam and I disliked the way my powerband really flattened out around 6100 rpm but I couldn't justify the expense of getting a slightly larger cam. Well the GPI modified OEM LS3 manifold really did wonders for my powerband. It zings and keeps pulling right up until about 6600-6700 which is where I'm now shifting. Very pleased!

C6RAPTOR

I agree. If you want to get the most out of your LS3 intake send it to BER for a porting job. The porting along with the radius rods will make for a nice set-up. I think 650 HP is the limit for air flow for the LS3 intake.

C6RAPTOR

For some reason FAST has left it up to the consumer to test their LSXR intake including the new one with the three runner lengths that have the addition of the High HP & Race length runners.
I have been researching this FAST LSXR for my LS3 for the last two years including hitting up on this thread hoping to see some dyno tests on a high HP LS3.
I finally contacted WCCH on the subject and the owner and I talked about the new shorter runner LSXR intakes and how they may be the answer to my intake manifold needs. WCCH supplied my 380 SCFM @.700" heads on my TPiS built 416 LS3.
WCCH had also performed flow tests on their heads bolted to a OEM intake showing similar results as the RPM Motors very informative tests. The results showed that the OEM intake restricts the flow of the high flow heads.
I finally decided that I would order the new FAST LSXR with the High HP runners from WCCH. WCCH will be port matched and deburred the runners.
I should have the new intake in a few weeks because WCCH will do the port matching & deburring next week in their shop.
I hope to then install the heads in my garage in NY and have the car dyno tuned locally ASAP.

ChrisUlrich

Anyone ever get before and after tests/runs/whatever going from a LS3 intake to a "high hp runner" aka "middle length" runners on the FAST 102?

C6RAPTOR

I have my FAST installed and just waiting for some new dry sump related hoses so that I can start the engine with the new intake and NW 102 TB. I plan on trailering the car to RTR Automotive in Palmyra NY to have it dyno tuned in a week or two.
I removed the brackets that are molded into the bottom of the runners after talking to FAST.

ChrisUlrich

What are your other mods?

You have any dyno or track info in your car as it was prior to the FAST and NW?

C6RAPTOR

You can read my replies on this post that gives some of my engine details. I have had the engine engine dyno tuned after it was built by TPiS and chassis dyno tuned 2 times . I track the car at HPDEs at tracks all over the east coast . My home track is Watkins Glen

Flash68

Did this ever get dyno’d with the High HP Fast?