Thread: AIRFLOW "X IC /Gibson/MC1"
08-05-2008, 05:08 PM #1
- Join Date
- Dec 2006
- Crest Hill, IL
AIRFLOW "X IC /Gibson/MC1"
TDR for GPRXP
More airflow work, this time I got my hands on some nice toys. Thanks to forum members BeachBum0286 and Mrbtd for supplying me with the following…
- X IC setup from a 08 RXP-X, including the OEM rubber pipes
- 08 Exhaust pipe and waterbox
- Gibson exhaust setup
- TDR Waterbox with Riva Blue pipe
- OEM Yamaha GPR Exhaust with Sound Suppression
For history on previous flow work, and reference as to the numbers, please click on this link…
*** The numbers below represent AIRFLOW ONLY...They DO NOT represent any numbers in regards to EXHAUST HEAT, WATER INJECTION, or BOTH.....ALSO, it represents ANY 4TEC motor (N/A, non-IC SC'd, SC'd) that is spinning at roughly 6000 RPM, and does reflect any other modifications such as external IC, air intake, SC upgrades, etc....Nor does it reflect airflow behavior above 6000 RPM, such as modded motors that spin at 8100-8600 RPM...BUT these numbers can predict what effect some mods will do at those air rates...
08 RXP/T-X IC w/OEM Rubber Hose
This unit is straight out of a 08 RXP-X, which is the same unit on an RXT-X. This unit is also the 2nd Generation IC that is offered by Riva through the online store…
The backpressure (BP) measured at the flow rate of .460 (6000rpm) show the X IC with a BP of 7.5 in/water by itself, and 9.8 in/water with the OEM rubber tubes installed. In the graph below, you can see how it rates up next to the previous generation (1G) Riva IC…Crunch the numbers, and the X unit is 87% more restrictive than the 1G unit, but only requires a 15% bump in motor speed to create the same flow rate…
Physically, the units are WAY different. The only thing they have in common is they are both aluminum, and are being used in PWC…THAT’S IT…Physical size shows about a measured 75% wider CORE, which leads to more surface area for cooling, thus a more restrictive path.
This would explain why general response is that the 2G unit is not as responsive as the 1G. But the size (CORE layout excluded) would suggest a more efficient unit for cooling.
Turbulent, is the best way to describe the output of this unit. Because of the internal makeup and baffle setup, despite being a straight through design, showed a lot of turbulence on the bench. Previous waterboxes were a smooth, consistent flow. The Gibson setup created a loud hissing sound, which means turbulence, which means backpressure.
The measured BP of the Gibson setup was 11.5 in/water. The trimmed Jpipe had to be used in this session, and the flow of that was 8.0 in/water (normal Jpipe untrimmed is 7.5”). When combined as a unit the BP is 15.0 in/water. Below is the comparison between a Gibson setup, GreenBox, and a typical shorty waterbox with standard thru-hull pipe…
*** The above info can be seen here...
This setup puts it right in the middle of a Shorty Waterbox and Greenbox for total combined package, only to be edged out if the other two are incorporating a FLARED tip on the Jpipe.
TDR Waterbox/Yamaha OEM Exhaust
These numbers are based on the items typically used for building a conversion GPRXP exhaust system. Included in the system is the same trimmed Jpipe from above, along with a TDR waterbox, a Riva Blue exhaust tube, and some other parts of an entire OEM Yamaha 2-stroke exhaust system (see pics)…
The TDR box is WIDE OPEN, its BP numbers are the lowest we have ever seen, only to be closely matched by the OEM waterbox from Yamaha. The TDR flowed an AMAZING 3.0 in/water, while the OEM box came close at 3.6 in/water.
From testing we know that a standard Jpipe will flow 7.5”, while a FLARED unit will flow as low as 4.5”. YET a trimmed pipe will flow 8.0”, just a little more than a stock unit, BUT it is needed to be like this because of the tightness of mounting. Well, when a Jpipe is combines with a waterbox the combination usually yields a larger number. Not in this case, where the addition of the TDR box actually acts like one FLARE, and total BP for the combo is 7.0 in/water. When combined with the Blue Riva pipe, and the OEM outlet, total system BP is 7.6 in/water…The OEM complete system just beats it out, combos/numbers below…
If anyone has any questions, feel free to PM me or post here...
***** Other airflow work is available in these threads...
Manifold w/ IC setups (Piranha, Riva, XS)
Piranha/Riva IC and XS IC
Rotax Racing IC
GreenBox and Shorty Waterbox
X Waterbox and Pipe
OEM Waterbox and Full Size Gutted
08-05-2008, 05:17 PM #2
08-05-2008, 05:45 PM #3
Wow, now thats pretty nice databaseof flow info. Great work Danny!
08-05-2008, 05:46 PM #4
Thanks for all the work and to those who let you use the items.
08-05-2008, 05:53 PM #5
08-05-2008, 06:40 PM #6
Amazing work Danny
so if the 08 straight pipe flowed 5.4" and the yamaha 2 stroke exhaust flowed 7.3" would it be accurate to say that the combo that I'm unning on my coversion is roughly the sum of those 2 for a total of 12.7"?
And thanks to those that provided the parts necessary for these tests.
08-05-2008, 07:05 PM #7
On the GPRXP....The tuning box is the large black box that had the white stuff on it right ? If so we call it a Sound Suppresion box.
It looks like even with the Sound Suppresion box the flow numbers are the same as the GH shorty set up ? From what I have read this is a good gain over the OEM set up.
Obviously there is a huge size difference with the Yamaha OEM box - Does the size have anything to do with sound or performance ?
08-05-2008, 07:30 PM #8
Wow great job Danny! Crazy info!!
Its a shame that TDR dont make a waterbox that works with a rear exhaust on a RXP/RXT/GXT, I think that would be the absolute killer setup
08-05-2008, 07:47 PM #9
excellent information Danny
08-05-2008, 08:16 PM #10
Great work Danny!! Got any ideas as to how to mod the X water box yet?
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