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No, I had the Dorman in the box ready to ship to Peak Performance when we learned the cathedral GMPP LPE heads wouldn't work well for my 416 engine. I decided the $400 for porting the Dorman needed to go toward new ported LS3 heads.
I have been curious about an equal comparison between the GM LS6 and the Dorman LS6/FAST 92 hybrid.
Considering that the LS6 performs so well with a stock size snout, the Dorman should also be tested with a stock GM throttle body and see if it can actually flow better or is the advantage only due to having a 90mm snout and utilizing a 90mm throttle body?
If I had an LS6 intake available to use for testing, I could get that question answered. Depending on how the ERL 416 swap goes for my 99 TA over the next month, I might have my old LS6 intake to use for testing and ported stock TB.
The LS3 head & intake flow numbers are going to be delayed a few days. There was an issue with the test equipment.
Here's the part 2 data. It's LS3 related but makes a nice compare to the cathedral data I posted earlier. This is what replaced the ported GMPP/ LPE LS6 heads and Dorman LS2 intake for the ERL 416 build when the GMPP heads had too much compression.
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 be
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 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.
Yeah but still, how much for a FAST? Especially a 102 after all the BS you need with it. You can find LS3 intakes used for like $150 or even less sometimes.
If someone will send the adapter I will be happy to test the LS3 intake on cathedral heads and cover the flow bench testing. Hell if someone will send one before I complete the 416, I will test the LS3 Fast LSXR as well. I'm not going to buy the $175 adapter to do the tests however.
If some will send the adapter, I will promptly return it.
According to those numbers, stock LS3 heads flow roughly the same as stock 243 heads up to 550 lift. Seems the advantage of ported LS3 heads is from 550 up.
According to those numbers, stock LS3 heads flow roughly the same as stock 243 heads up to 550 lift. Seems the advantage of ported LS3 heads is from 550 up.
Yes. And at higher rpm. Ls3 responds surprisingly well to rocket upgrade
According to those numbers, stock LS3 heads flow roughly the same as stock 243 heads up to 550 lift. Seems the advantage of ported LS3 heads is from 550 up.
I've not test any stock unported LS6 or LS3 heads yet on this thread. To compare flow bench numbers from different benches taken a grain of salt often 10-25 cfm variances occur between different benches. A SF-600 vs SF-1020 can easily be 10-20 cfm for the same head.
07-22-2017, 06:04 AM
