99 Black Bird TA

I wanted to share the flow bench numbers for Reher-Morrison port LS3 cylinder head, LS3 intake + head, Rick Crawford Radius Rod LS3 intake & WS6STORE / VR ported LS3 Fast LSXR intake.

I wish I'd had more intakes available for testing

The head is placed on the flow bench and flow tested. Then the respective intake manifolds were bolted to the head and flow tested. I think the factory LS3 intake is pretty good but the WS6STORE / VR ported LS3 Fast LSXR intake.blows it away on the flow bench.

The testing took longer than expected but I think the data collected was worth the wait. The flow bench had a bearing failure with on one of the internal orifice plate if I understood correctly in the middle of the test. After the flow bench was repaired, calibrated and a "known cylinder head checked" to confirmed my testing started over from Ground Zero.

We found an interesting result and to ensure accuracy re-ran the entire series of tests to confirm the results.

All testing on SF-1020, at 28 inches with a 4.060 bore. The owner told me this SF-1020 typically reads 15-25 cfm less than the typical SF-600. Previously, many know cylinder heads that claim 300+ cfm of flow delivered ~280 cfm on this bench. Based on data collected in another set of tests this SF-1020 tends to flow very similar to another heart breaking flow bench one of my NASCAR friends used to test several sets of heads. In short, I think these flow numbers are as accurate and fairly measured as is possible for an enthusiast to acquire.

A few comments on the testing. I took a WARR 92mm TB and a pair of Nick Williams 102 TB's to also test with the intakes. The TB,'s had no effect on the flow numbers. The WARR 92mm TB bases on flow bench testing does not restrict the stock LS3 intake. Neither of the Nick Williams TB's had any effect on the WS6 / VENGEANCE Racing Ported LS3 LSXR intake. Engine dyno testing might show an effect but flow bench didn't.

No clay intake radius was used on the cylinder head. The intake port was tested bare. No pipe on exhaust.






The two gray column are RM cylinder head intake and exhaust flow in cfm

The blue column is LS3 intake & RM head, note the LS3 intake kills up to ~50 cfm of flow similar to what an LS6 intake does with cathedral heads.

The medium blue Rick Crawford Radius Rod LS3 intake over 30cfm better than the stock LS3 and close to the ported LSXR.

The green column is the WS6/VR ported LS3 Fast LSXR intake. It reduced flow by a small amount at high lift and helps enhance low lifters flow.

The pink column shows how the WS6/VR ported LS3 Fast LSXR intake.increased or decreased flow at various lifts compared to the bare RM head.

This was the very first time I had actually saw an intake manifold match with a cylinder head so well that it enhances flow any any lift.

I did notice the cylinder head intake port sounded crisp & clean when being flow tested. Some cylinder heads have a muddy turbulent sound when they are flow tested. A cylinder head with a dirty sounding port usually isn't a very good head.

Note dyno and track testing are the ultimate measure to make judgements by not flow bench numbers. I think flow bench testing when properly done can help us evaluate parts.

​

xBoostx

Thanks for sharing nice comparison tests and very use full for the tens of thousands ls3 and L76 users out there.

I have a reasonable suspicion the ls3 intakes are good I use a round tubing in front of the intake upper entry and I felt it rite away.

I had to do it sense I flat milled the heads quite a bit and didn't think I would be able to mill the Fast lsxr intake that much in order to line up the intake ports.

On first track day after heads and cam cai and headers using the ls3 factory ported intake and 90mm throttle body an A6 stock block and cubes car run consistent 10.5 with a 3400 stall (with out the radius rods)

I believe the car has 10.3 in it with the radius rods smaller tire 3800 stall and an MSD launge controller (no power adders) waiting on November to head back for track day two.


Frankly I like to try another intake but will likely not do better without cutting the hood, my car looks innocent and stock with oem intake and t/body and I kind of enjoy that.

Have any pictures of the Reher-Morrison intake you can share thanks again, Dave.

99 Black Bird TA

Here are a few pictures...setting up for flow testing and the Rick Crawford Radius Rod modified LS3 Intake. With my cell phone camera and an LED light these were the best pictures I could get of intake.

Given the smaller runner in the factory intake the velocity has to be better than the LSXR. I'm more impressive with the trick factory piece than the Fast LSXR with the long runners. For ~ 6,500ish rpm motor - the Rick Crawford looks like an excellent choice to me.

I have that sinking feeling the Fast LSXR is the wrong intake for my 416 LS3 build.

99 Black Bird TA

My Reher-Morrison ported LS3 heads

xBoostx

Thank you Wade for the nice pics those are the best pics I've seen from RC radius rod job very nice how he finish the floor flat which I do also.

I do have one on him though sense the rear cylinders run leaner due to getting more air in than the front cylinders I use an alum thin wall tubing to rout additional air into the front two cylinders via two 3/8 well placed holes per runner (facing the runner) on the front two cylinder on each side.

The pics I requested though are from Rehen-Morrisons intake manifold I tried to pull an image and didn't find one nor in his Webb site, it is my understanding you are using one of his intakes thanks again.

99 Black Bird TA

I would like to see your set up. It sounds very interesting.

I don't have a Reher-Morrison intake. Just the Reher-Morrison heads. The second column of flow numbers is from only the head being flowed. Darrin Morgan of Reher-Morrison and I discussed one his ported Fast intakes but Darrin felt I would need to turn 7000+ rpm to really benefit. My 416 is a daily driver type build.

This is the Fast LSXR intake I tested that was ported by Vengeance Racing. It's a nice piece. Maybe later if I go with a low lash solid roller cam and mid length runners it will really shine.

xBoostx

Hey man my bad I thought in the first bar reading Rehen-Morrison head - intake was actually a Rehen-Morrison Intake manifold but is his porting on your head.

Curious how the intake manifold itself reduces flow, interesting...

I have an additional trick for the intake I like to try and is simple I think it might bump the flow over that of the ported fast but will need help in doing the flow test work cause I don't have the flow bench.

I believe if I split a 1/2 inch round tubing as the one I'm using as a radius rod I can put IT flat against the floor rite under the radius "tubing" to further increase the air flow speed into the port, of course the test will need to be with and without it to know whether is a keeper or toss.

ckchan10

Thank you for posting, I thought your findings were very informative. Question: Is the Rick Crawford intake ported as well as rodded? I ask because I have the Gwatney Intake that is rodded (like Rick's), but does not have any port work. Thanks again.

jleews6

Thanks for all this info. My frinds Grand sport ran 11.0 just about every pass but never faster then an 11.0 and 123 was the norm and the best. Then he installed a Gwatney intake with the rods and no porting and the car ran a string of 10.80s @125.

99 Black Bird TA

Xboost, my 416 is going together the first of next week, or I would offer to get your intake set up flow bench tested. I sounds very interesting.

xBoostx

It's fine man let me know when ready.

madmatt9471

Nice information - much appreciated!

Thank you for putting it together and doing the testing

Thanks,Matt

Suns_PSD

Thanks so much for this! Great info.

I had decided on a ported OEM LS3 manifold sometime back for fitment reasons but also because my OEM manifold had been paint matched by the previous owner of my car and looked really nice.

Then I decided that radius rods were the only REAL improvement available for the OEM LS3 manifold and tried to get ahold of Rick Crawford but he was completely unavailable and also only did business through FB, which is, err unprofessional imo. When he responded he also had like a 6-8 week wait time. I do think he is really the best option if you can wait.

The other radius outfit was Gwatney Performance. They were less $ but were frank that they only did the radius rods and nothing else. They said they did this because all the other porting had not shown to really do anything in their experience.

Now my LS3 has headers, ported heads, small cam, tune, etc... and was running nicely at around 505 rwhp at that time. But the powerband notably flattened out at around 6100 rpm. It was noticeable.

Then I installed that Gwatney performance radius rod LS3 manifold and it was a lot different, particularly up top. The car pulled notably harder right thru my 6600 rpm redline. It honestly felt like another 20+ rwhp. Very notable difference.

Thanks again!

EBuckC6

Suns, what was your price for the intake manifold with Gwatney, if you dont mind? and the time it took you to get it? I am ready to pull the trigger on this mod and was looking for best case senarios.

Thanks
Eric

Suns_PSD

Cheap, I want to say $275 total and that even included shipping. They turned it around in 24 hours.

It showed up with grindings and stuff inside so be sure and clean it.

EBuckC6

Thanks buddy I appreciate it!!!

Mike Bour

@xBoostx , do you also modify owners LS3 intakes? I’d so, let me know as I might be interested.

jimbob8915

Any benefit to an LS7 manifold?

KW Baraka

LS7 intake only goes with LS7 heads.

So...the short answer is "No".

KW